Publications

projections to the medial superior olive from the medial and lateral nuclei of the trapezoid body in rodents and bats.	in this study we present direct evidence of axonal projections from both the medial and lateral nuclei of the trapezoid body to the medial superior olive. projections were traced by intracellularly labeling cells and axons in a tissue slice preparation of two rodent species, mus musculus and meriones unguiculatus and two bat species, eptesicus fuscus and pteronotus parnellii. the main axon of most principal cells in the medial nucleus of the trapezoid body gives off one or more collateral branch ...	1992	1430335
calcium-binding protein-containing neuronal populations in mammalian visual cortex: a comparative study in whales, insectivores, bats, rodents, and primates.	this study is focused on comparative analysis of gamma-aminobutyric acid-positive (gabaergic) neuronal populations in primary visual cortex of totally aquatic toothed whales and select terrestrial mammals with different evolutionary histories and various ecological adaptations. the distribution of neuronal populations containing the calcium-binding proteins calbindin and parvalbumin, which are recognized markers for the gabaergic neurons in cerebral cortex, is compared in five species of toothed ...	1993	8324371
tonotopic and functional organization in the auditory cortex of the big brown bat, eptesicus fuscus.	1. in eptesicus the auditory cortex, as defined by electrical activity recorded from microelectrodes in response to tone bursts, fm sweeps, and combinations of fm sweeps, encompasses an average cortical surface area of 5.7 mm2. this area is large with respect to the total cortical surface area and reflects the importance of auditory processing to this species of bat. 2. the predominant pattern of organization in response to tone bursts observed in each cortex is tonotopic, with three discernible ...	1993	8294966
evidence for perception of fine echo delay and phase by the fm bat, eptesicus fuscus.	the big brown bat, eptesicus fuscus, can perceive small changes in the delay of fm sonar echoes and shifts in echo phase, which interact with delay. using spectral cues caused by interference, eptesicus also can perceive the individual delays of two overlapping fm echoes at small delay separations. these results have been criticized as due to spectral artifacts caused by overlap between stimulus echoes and extraneous sounds (pollak 1993). however, no amplitude or spectral variations larger than ...	1993	8331604
discrimination of two-wavefront echoes by the big brown bat, eptesicus fuscus: behavioral experiments and receiver simulations.	1. echolocating bats (eptesicus fuscus) were trained to discriminate between simulated targets consisting of one or two echo-wavefronts with internal time delays of up to 100 microseconds. spectral and temporal properties and total signal energy of the targets were evaluated and predictions for performances of bats derived from receiver models were compared with measured performances. 2. eptesicus fuscus was able to discriminate a one-wavefront target from two-wavefront targets with distinct int ...	1993	8510056
directional sensitivity of inferior collicular neurons of the big brown bat, eptesicus fuscus, to sounds delivered from selected horizontal and vertical angles.	under free field stimulation conditions, directional sensitivity of 336 inferior collicular (ic) neurons of 6 eptesicus fuscus was studied by recording the minimum threshold (mt) and number of impulses of each neuron to a best frequency (bf) sound delivered from selected horizontal and vertical angles. an auditory response center was determined for each neuron by delivering a bf sound from a specific point of the bat's frontal auditory space. at the response center, the neuron had maximal direct ...	1993	8275800
responses of superior collicular neurons of the big brown bat, eptesicus fuscus, to stationary and moving sounds.	responses of 59 superior collicular neurons (sc) of the big brown bat, eptesicus fuscus, to stationary and moving sounds were studied under free-field stimulation conditions. neurons responding to sound stimulation were recorded from all three layers of the sc; however, responses of neurons in the superficial and upper intermediate layers generally show poor signal to noise ratio. spatial sensitivity of each sc neuron was studied by determining variation of the number of impulses and minimum thr ...	1993	8020338
acoustic image representation of a point target in the bat eptesicus fuscus: evidence for sensitivity to echo phase in bat sonar.	echolocating bats, eptesicus fuscus, were trained in two distinct behavioral tasks to investigate the images they perceive of a sonar point target. in the first task, bats were trained in a two-alternative forced-choice procedure to detect electronically simulated target echoes at a range of approximately 57 cm. half of the trials in the detection task contained echoes from a stationary target (simulated by a fixed echo delay) and half contained echoes from a jittering target (simulated by an ec ...	1993	8473609
response properties of single units in the dorsal nucleus of the lateral lemniscus and paralemniscal zone of an echolocating bat.	1. connectional evidence suggests that the dorsal nucleus of the lateral lemniscus (dnll) and the paralemniscal zone (pl) function as centers for binaural analysis interposed between the superior olivary complex and the midbrain. in addition, the dnll is known to be a major source of inhibitory input to the midbrain. the aim of this study was to characterize the response properties of neurons in dnll and pl of the echolocating bat eptesicus fuscus, a species that utilizes high-frequency hearing ...	1993	8463819
neurons in the inferior colliculus, auditory cortex and pontine nuclei of the fm bat, eptesicus fucus respond to pulse repetition rate differently.	single-neuron responses to pulse repetition rate in the inferior colliculus, auditory cortex and pontine nuclei of the fm bat, eptesicus fuscus were studied under free-field stimulation conditions. the best frequency (bf) and minimum threshold (mt) of each neuron were first determined with a 4 ms pulse broadcast from a specific point (response center) of the bat's frontal auditory space at which the neuron had maximal spatial sensitivity. the neuron's intensity-rate function was then studied wit ...	1993	8348298
a computational model of echo processing and acoustic imaging in frequency-modulated echolocating bats: the spectrogram correlation and transformation receiver.	the spectrogram correlation and transformation (scat) model of the sonar receiver in the big brown bat (eptesicus fuscus) consists of a cochlear component for encoding the bat's frequency modulated (fm) sonar transmissions and multiple fm echoes in a spectrogram format, followed by two parallel pathways for processing temporal and spectral information in sonar echoes to reconstruct the absolute range and fine range structure of multiple targets from echo spectrograms. the outputs of computations ...	1993	8270744
a possible neuronal basis for representation of acoustic scenes in auditory cortex of the big brown bat.	behavioural studies and field observations demonstrate that echolocating bats simultaneously perceive range, direction and shape of multiple objects in the environment as acoustic images derived from echoes. cortical echo delay-tuned neurons contribute to the perception of object range, because focal inactivation of these neurons disrupts behavioural discrimination of range. we report here that response properties of delay-tuned neurons in the cortical tonotopic area of the bat, eptesicus, trans ...	1993	8350920
the brain-stem auditory-evoked response in the big brown bat (eptesicus fuscus) to clicks and frequency-modulated sweeps.	three experiments were performed to evaluate the effects of stimulus level on the brain-stem auditory-evoked response (baer) in the big brown bat (eptesicus fuscus), a species that uses frequency-modulated (fm) sonar sounds for echolocation. in experiment 1, the effects of click level on the baer were investigated. clicks were presented at levels of 30 to 90 db pspl in 10-db steps. each animal responded reliably to clicks at levels of 50 db pspl and above, showing a baer containing four peaks in ...	1994	7930082
synonymy of longibucca eptesica with longibucca lasiura (nematoda: rhabditoidea) and new host and geographic records.	the genus longibucca chitwood, 1933 (nematoda: rhabditoidea) is reviewed based on examination of museum and adult specimens collected from 4 species of bats (myotis lucifugus, myotis ciliolabrum, eptesicus fuscus, and lasionycteris noctivagans) in alberta, canada. two species are considered valid, namely longibucca vivipara chitwood, 1933, and longibucca lasiura mcintosh and chitwood, 1934. longibucca eptesica elsea, 1953 is considered a synonym of l. lasiura. new hosts of longibucca lasiura inc ...	1994	8195954
complex sound analysis in the fm bat eptesicus fuscus, correlated with structural parameters of frequency modulated signals.	big brown bats, eptesicus fuscus, were presented with artificial frequency modulated (fm) echoes that simulated an object becoming progressively closer to the bat. a stereotyped approach phase behavioral response of the bat to the virtual approaching target was used to determine the ability of the bat to analyze fm signals for target distance information. the degree to which the bats responded with approach phase behavior to a virtual approaching target was similar when they were presented with ...	1994	8006857
frequency tuning and response latencies at three levels in the brainstem of the echolocating bat, eptesicus fuscus.	to determine the level at which certain response characteristics originate, we compared monaural auditory responses of neurons in ventral cochlear nucleus, nuclei of lateral lemniscus and inferior colliculus. characteristics examined were sharpness of frequency tuning, latency variability for individual neurons and range of latencies across neurons. exceptionally broad tuning curves were found in the nuclei of the lateral lemniscus, while exceptionally narrow tuning curves were found in the infe ...	1994	8014918
neural tuning for sound duration: role of inhibitory mechanisms in the inferior colliculus.	duration is a biologically important feature of sound. some neurons in the inferior colliculus of the big brown bat, eptesicus fuscus, are tuned to sound duration, but it is unclear at what level the tuning originates or what neural mechanisms are responsible for it. the application of antagonists of the inhibitory neurotransmitters gamma-aminobutyric acid or glycine to neurons in the inferior colliculus eliminated duration tuning. whole-cell patch-clamp recordings of synaptic currents suggested ...	1994	8171341
responses of inferior collicular neurons of the fm bat, eptesicus fuscus, to pulse trains with varied pulse amplitudes.	under free field stimulation conditions, we studied the responses of inferior collicular neurons of the fm bat, eptesicus fuscus, to pulse trains with varied pulse amplitudes. each pulse train consisted of 7 pulses of 4 ms delivered at 24 ms interpulse-intervals (i.e. 42 pulses/s). for a control pulse train, all pulse amplitudes were equal to a neuron's best amplitude which, when delivered in single pulses, elicited maximal number of impulses from the neuron. the amplitudes of individual pulses ...	1994	7806473
pulse repetition rate increases the minimum threshold and latency of auditory neurons.	the effect of pulse repetition rate on auditory sensitivity of the big brown bat, eptesicus fuscus, was studied by determining the minimum threshold, response latency and recovery cycle of inferior collicular neurons at different repetition rates under free field stimulation conditions. in general, collicular neurons shortened the response latency and increased the number of impulses monotonically or non-monotonically with stimulus intensity. they recovered at least 50% when the interpulse inter ...	1994	7982089
fos-like immunoreactivity elicited by sound stimulation in the auditory neurons of the big brown bat eptesicus fuscus.	c-fos immunocytochemistry was used as a rapid and sensitive technique for identification of sound activated neurons in the cerebral cortex, the cerebellum and subcortical nuclei of the big brown bat, eptesicus fuscus. when bats were stimulated with sounds under the both-ears opened conditions, fos-like immunoreactive neurons were bilaterally and symmetrically distributed in all subcortical auditory nuclei, the auditory cortex, the superior colliculus, the pontine nuclei and the cerebellar deep n ...	1994	7895036
echo spl influences the ranging performance of the big brown bat, eptesicus fuscus.	four bats of the species eptesicus fuscus were trained in a two-alternative forced-choice procedure to discriminate between two phantom targets that differed in range. the rewarded stimulus was located at a distance of 52.7 cm, while the other unrewarded stimulus was further away. only one target was presented at a time. in the first experiment we measured the range discrimination performance at an echo spl of -28 db relative to the bat's sonar transmission. a 75% correct performance level was a ...	1994	7965921
observations on the pineal gland of the big brown bat, eptesicus fucus: possible correlation of melanin intensification with constant darkness.	our initial observation of the macroscopically pigmented pineal gland of the big brown bat, eptesicus fuscus, led to this study. information has been lacking on pigmentation in the pineal and its significance in mammals in general and bats in particular. this report begins to address this situation.	1994	7825733
sensorimotor model of bat echolocation and prey capture.	a model of the bat sensorimotor system is developed using acoustics, signal processing, and control theory to illustrate the fundamental issues in accomplishing prey capture with echolocation. this model indicates that successful nonpredictive tracking of an ideal prey can be accomplished with a very simple system. circular apertures approximate the mouth and ears for deriving acoustic beam patterns, using the big brown bat eptesicus fuscus as a model. fundamental and overtone frequency componen ...	1994	7963018
jamming bat echolocation: the dogbane tiger moth cycnia tenera times its clicks to the terminal attack calls of the big brown bat eptesicus fuscus.	certain tiger moths emit high-frequency clicks to an attacking bat, causing it to break off its pursuit. the sounds may either orient the bat by providing it with information that it uses to make an attack decision (aposematism) or they may disorient the bat by interrupting the normal flow of echo information required to complete a successful capture (startle, jamming). at what point during a bat's attack does an arctiid emit its clicks? if the sounds are aposematic, the moth should emit them ea ...	1994	7964403
the epidemiology of bat rabies in new york state, 1988-92.	in 1993 new york and texas each reported a human rabies case traced to a rare variant of rabies virus found in an uncommon species of bat. this study examined the epidemiology of bat rabies in new york state. demographic, species, and animal-contact information for bats submitted for rabies testing from 1988-92 was analysed. the prevalence of rabies in 6810 bats was 4.6%. nearly 90% of the 308 rabid bats identified to species were the common big brown bat (eptesicus fuscus), which comprised 62% ...	1994	7995360
capillary-fiber geometry in pectoralis muscles of one of the smallest bats.	we previously reported striking similarities in the structural capacity for o2 flux in the highly aerobic flight muscles of a hummingbird and bat despite their significant differences in capillary-fiber geometry and number, and fiber size. however, the bats of that study (eptesicus fuscus, bw 15-16 g) were about 5 times larger than the hummingbirds (selasphorus rufus; bw 3-4 g). in this study, we examined the flight muscle in a bat of approximately the same size as the hummingbird to determine w ...	1994	8191038
origin of ascending projections to the nuclei of the lateral lemniscus in the big brown bat, eptesicus fuscus.	the nuclei of the lateral lemniscus in the echolocating bat, eptesicus fuscus, are large and highly differentiated. in each nucleus, different characteristic response properties predominate. to determine whether the dissimilar response properties are due in part to differential ascending input, we examined the retrograde transport from small deposits of horseradish peroxidase (hrp) or hrp conjugated with wheat germ agglutinin (wga-hrp) in the nuclei of the lateral lemniscus. the intermediate nuc ...	1995	7545702
responses of pontine neurons of the big brown bat, eptesicus fuscus, to temporally patterned sound pulses.	under free field stimulation conditions, this study examined the responses of pontine neurons of eptesicus fucus to temporally patterned sound pulses by means of repetitive single pulses and pulse trains. among 93 pontine neurons isolated, 90 always discharged less than 5 impulses to sound pulses presented during this study and 3 discharged impulses throughout the whole duration of each presented pulse. responses to sound pulses at different repetition rates were examined in 65 neurons. the numb ...	1995	7559171
steering by echolocation: a paradigm of ecological acoustics.	1. flights of three big brown bats (eptesicus fuscus) landing on a hand and catching a suspended mealworm were video analysed. 2. results were consistent with the bats using the same basic control procedure in the quite different approach tasks--namely keeping tau (r) = kr and tau (a)/tau (r) = k alpha r. here r is the current distance to the destination; alpha is the angle between the current direction of the destination and the goal direction of final approach (beta min); tau (r) = r/r, tau (a ...	1995	7707270
the haemoproteid parasite, bioccala deanei, from a colombian bat, eptesicus fuscus (vespertilionidae).		1995	7741601
spatially dependent acoustic cues generated by the external ear of the big brown bat, eptesicus fuscus.	to measure the directionality of the external ear of the echolocating bat, eptesicus fuscus, the left or right eardrum of a dead bat was replaced by a microphone which recorded signals received from a sound source that was moved around the stationary head. the test signal was a 0.5-ms fm sweep from 100 khz to 10 khz (covering all frequencies in the bat's biosonar sounds). notches and peaks in transfer functions for 7 tested ears varied systematically with changes in elevation. for the most promi ...	1995	7560511
delay-tuned neurons in the midbrain of the big brown bat.	1. the auditory midbrain in eptesicus contains delay-tuned neurons that encode target range. most delay-tuned neurons respond poorly to tones or individual frequency-modulated (fm) sweeps and require combinations of fm sweeps. they are combination sensitive and delay tuned. the index of facilitation (if), a coefficient measuring combination sensitivity for individual delay-tuned neurons, ranged from 0.14 to 1.0, with an average of 0.64 +/- 0.24 (mean +/- sd). of the 33 facilitated responses from ...	1995	7608757
temporal integration in the echolocating bat, megaderma lyra.	temporal integration is a crucial feature of auditory temporal processing. we measured the psychophysical temporal integration of acoustic intensity in the echolocating bat megaderma lyra using a two-alternative forced-choice procedure. a measuring paradigm was chosen in which the absolute threshold for pairs of short tone pips was determined as a function of the temporal separation between the pips. the time constants determined with this paradigm are a crucial characteristic of the sonar syste ...	1996	8951448
integration time for short broad band clicks in echolocating fm-bats (eptesicus fuscus).	vespertilionid fm-bats (four eptesicus fuscus and one vespertilio murinus) were trained in an electronic phantom target simulator to detect synthetic echoes consisting of either one or two clicks. the threshold sound pressure for single clicks was around 47 db pespl for all five bats corresponding to a threshold energy of -95 db re 1 pa2*s. by varying the interclick interval, delta t, for double clicks it was shown that the threshold intensity was around -3 db relative to the threshold for singl ...	1996	8592305
the degradation of distance discrimination in big brown bats (eptesicus fuscus) caused by different interference signals.	the ability of two big brown bats (eptesicus fuscus) to discriminate the distance to an electronically synthesized "phantom" target by echolocation was tested in the presence of interfering signals presented slightly before the target echo. interfering signals were chosen to have differing degrees of similarity to the typical echolocation emission used by the bat in this task (which was the signal used to create the phantom target), and we predicted that the degree of disruption of ranging would ...	1996	8888581
responses of bat inferior collicular and auditory cortical neurons to pulsatile amplitude modulated sound pulses.	under free field stimulation conditions, this study examined the responses of inferior collicular and cortical neurons of the big brown bat, eptesicus fuscus, to pulsatile amplitude modulated sound pulses by means of temporally patterned pulse trains. when the pulse trains were delivered at different pulse repetition rates between 1 and 100 pps, inferior collicular neurons can follow pulse repetition at a higher rate than can auditory cortical neurons. 85% of 40 inferior collicular neurons studi ...	1996	8955563
representation of perceptual dimensions of insect prey during terminal pursuit by echolocating bats.	the echolocating big brown bat, eptesicus fuscus, broadcasts brief frequency-modulated (fm) ultrasonic sounds and perceives objects from echoes of these sounds returning to its ears. eptesicus is an insectivorous species that uses sonar to locate and track flying prey. although the bat normally hunts in open areas, it nevertheless is capable of chasing insects into cluttered environments such as vegetation, where it completes interceptions in much the same manner as in the open except that it ha ...	1996	8776847
corticofugal control of central auditory sensitivity in the big brown bat, eptesicus fuscus.	using bats as a model auditory system, we studied corticofugal control of auditory sensitivity of neurons in the inferior colliculus. we demonstrate for the first time that the corticocollicular pathway continuously regulates acoustic signal processing in the inferior colliculus by increasing the threshold, reducing the auditory spatial response area, and sharpening the frequency tuning curve of recorded inferior collicular neurons. regulation of auditory sensitivity of recorded inferior collicu ...	1996	8832656
effects of gonadal sex steroids on sexual behavior in the big brown bat, eptesicus fuscus, upon arousal from hibernation.	vespertilionid bats are thought to have a dissociated pattern of reproduction; mating occurs in autumn as well as during periodic arousals from hibernation when testes are regressed and ovaries are "in stasis." sex steroid levels in both sexes are basal at this time. this pattern would indicate that sex steroids per se may not be activating sexual behavior. gonadectomy of male and female big brown bats, eptesicus fuscus, months before the mating season, did not significantly affect the probabili ...	1996	8797024
distribution of gabaa, gabab, and glycine receptors in the central auditory system of the big brown bat, eptesicus fuscus.	quantitative autoradiographic techniques were used to compare the distribution of gabaa, gabab, and glycine receptors in the subcortical auditory pathway of the big brown bat, eptesicus fuscus. for gabaa receptors, the ligand used was 35s-t-butylbicyclophosphorothionate (tbps) for gabab receptors, 3h-gaba was used as a ligand in the presence of isoguvacine to block binding to gabaa sites; for glycine, the ligand used was 3h-strychnine. in the subcortical auditory nuclei there appears to be at le ...	1996	8723704
whole-cell patch-clamp recording reveals subthreshold sound-evoked postsynaptic currents in the inferior colliculus of awake bats.	the inferior colliculus receives excitatory and inhibitory input from parallel auditory pathways that differ in discharge patterns, latencies, and binaural properties. processing in the inferior colliculus may depend on the temporal sequence in which excitatory and inhibitory synaptic inputs are activated and on the resulting balance between excitation and inhibition. to explore this issue at the cellular level, we used the novel approach of whole-cell patch-clamp recording in the midbrain of aw ...	1996	8622130
temporally patterned pulse trains affect directional sensitivity of inferior collicular neurons of the big brown bat, eptesicus fuscus.	the directional sensitivity of inferior collicular neurons of the big brown bat, eptesicus fuscus, was studied under free field stimulation conditions with 3 temporally patterned trains of sound pulses which differed in pulse repetition rate and duration. the directional sensitivity curves of 92 neurons studied can be described as hemifield, directionally-selective, or non-directional according to the variation in the number of impulses with pulse train direction. when these neurons were stimula ...	1996	8785008
spatial tuning of neurons in the inferior colliculus of the big brown bat: effects of sound level, stimulus type and multiple sound sources.	we examined factors that affect spatial receptive fields of single units in the central nucleus of the inferior colliculus of eptesicus fuscus. pure tones, frequency- or amplitude-modulated sounds, or noise bursts were presented in the free-field, and responses were recorded extracellularly. for 58 neurons that were tested over a 30 db range of sound levels, 7 (12%) exhibited a change of less than 10 degrees in the center point and medical border of their receptive field. for 28 neurons that wer ...	1996	8965261
sound source elevation and external ear cues influence the discrimination of spectral notches by the big brown bat, eptesicus fuscus.	measurements of external ear transfer functions in the echolocating bat eptesicus fuscus have revealed a prominent spectral notch that decreases in center frequency (50 to 30-35 khz) as elevation decreases [wotton et al., j. acoust. soc. am. 98, 1423-1445 (1995)]. to examine the influence of this notch, four eptesicus were trained to discriminate between two sets of electronically generated artificial echoes. the negative (unrewarded) stimulus contained a test spectral notch at a specific freque ...	1996	8817902
the columnar region of the ventral nucleus of the lateral lemniscus in the big brown bat (eptesicus fuscus): synaptic arrangements and structural correlates of feedforward inhibitory function.	neurons of the columnar region of the ventral nucleus of the lateral lemniscus of eptesicus fuscus respond with high-precision constant-latency responses to sound onsets and possess remarkably broad tuning. to study the synaptic basis for this specialized monaural auditory processing and to elucidate the excitatory or inhibitory nature of the input and output circuitry, we have used classical transmission electron microscopy, and postembedding immunocytochemistry for gamma aminobutyric acid (gab ...	1997	9211825
prevalence of rabies in bats in michigan, 1981-1993.	to analyze the species distribution of animals submitted to the michigan department of public health (mdph) for rabies testing during 1993. to determine whether any of the 9 species of bats residing in michigan carries a disproportionate rabies burden, and to determine whether bats contributed the most cases of confirmed rabies during 1981 through 1992.	1997	9018352
human rabies--montana and washington, 1997.	on january 5 and january 18, 1997, respectively, a man in montana and a man in washington died of neurologic illnesses initially suspected to be creutzfeldt-jakob disease (cjd) but diagnosed as rabies encephalitis during subsequent histologic examination on autopsy. the cases were not linked epidemiologically, and no secondary cases occurred. postexposure prophylaxis (pep) was administered to 113 potential contacts. this report summarizes the clinical presentations of the cases and the epidemiol ...	1997	9272584
detection of jitter in intertarget spacing by the big brown bat eptesicus fuscus.	we trained bats to detect intertarget jitter, i.e., relative motion between two virtual (electronically synthesized) targets. both targets were themselves moving with respect to nearby objects (e.g., the microphone and speaker used to create the virtual targets) so that the only reliable cue available to the bats was variation in intertarget spacing. given a target at 80 cm and another at 95, 110 or 125 cm, the threshold for intertarget jitter (itj) of the two bats tested was < 10 microseconds, ...	1997	9309868
the combination of echolocation emission and ear reception enhances directional spectral cues of the big brown bat, eptesicus fuscus.	the acoustic information used by bats is produced by a combination of the properties of the sound emission and the reception at the eardrum. the potential localization cues used by bats can only be fully revealed when the magnitude spectra of the emission and the external ear are convolved to produce the echolocation combination magnitude spectra. the spatially dependent changes in the magnitude spectra of the echolocation combination of eptesicus fuscus are described. the emission and external ...	1997	9069638
cytoarchitecture and sound activated responses in the auditory cortex of the big brown bat, eptesicus fuscus.	under free field and closed-system stimulation conditions, we studied the frequency threshold curves, auditory spatial sensitivity and binaurality of neurons in the primary auditory cortex (ac) of the big brown bat, eptesicus fuscus. all 298 recorded ac neurons discharged phasically. they were recorded at depths less than 1,000 microns with response latencies of 7-25 ms, best frequencies (bfs) of 28-97 khz and minimum thresholds (mts) of 8-90 db spl. they received excitatory inputs from the cont ...	1997	9442846
responses of bat inferior collicular neurons to recorded echolocation pulse trains.	under free field stimulation conditions, we studied the responses of inferior collicular neurons of the big brown bat, eptesicus fuscus, to echolocation pulse trains which were recorded during the entire process of hunting. the entire series of recorded echolocation pulse trains was edited in different sequences according to echolocation pulses of different hunting phases. when stimulated with all edited sequences of echolocation pulse trains, the temporal characteristics and the relative positi ...	1997	9170550
binaural and frequency representation in the primary auditory cortex of the big brown bat, eptesicus fuscus.	this study examines the binaural and frequency representation in the primary auditory cortex (ac) of the big brown bat, eptesicus fuscus, by using an ear-phone stimulation system. all 306 cortical neurons studied were excited by contralateral sound stimulation but they were either excited, inhibited or not affected by ipsilateral sound stimulation. these cortical neurons were columnarly organized according to their binaural and frequency-tuning properties. the excitation-excitation columns which ...	1997	9449819
a backpropagation network model of the monaural localization information available in the bat echolocation system.	the information echolocating bats receive is a combination of the properties of the sound they emit and the sound they receive at the eardrum. convolving the emission and the external ear transfer functions produces the full spectral information contained in the echolocation combination. spatially dependent changes in the magnitude spectra of the emission, external ear transfer functions, and the echolocation combination of eptesicus fuscus could provide localization information to the bat. prin ...	1997	9165742
neural tuning to sound duration in the inferior colliculus of the big brown bat, eptesicus fuscus.	neural tuning to different sound durations may be a useful filter for identification of certain sounds, especially those that are biologically important. the auditory midbrains of mammals and amphibians contain neurons that appear to be tuned to sound duration. in amphibians, neurons are tuned to durations of sound that are biologically important. the purpose of this study was to characterize responses of neurons in the inferior colliculus (ic) of the big brown bat, eptesicus fuscus, to sounds o ...	1997	9163363
neural selectivity and tuning for sinusoidal frequency modulations in the inferior colliculus of the big brown bat, eptesicus fuscus.	most communication sounds and most echolocation sounds, including those used by the big brown bat (eptesicus fuscus), contain frequency-modulated (fm) components, including cyclical fm. because previous studies have shown that some neurons in the inferior colliculus (ic) of this bat respond to linear fm sweeps but not to pure tones or noise, we asked whether these or other neurons are specialized for conveying information about cyclical fm signals. in unanesthetized bats, we tested the response ...	1997	9084622
audiogram of the big brown bat (eptesicus fuscus).	the audiograms of three big brown bats (eptesicus fuscus) were determined using a conditioned avoidance procedure. the average audiogram ranged from 0.850 khz at 106 db to 120 khz at 83 db spl, with a best threshold of 7 db at 20 khz and a distinct decrease in sensitivity at 45 khz. the results confirm those of a previous study by dalland (1965a) that the big brown bat has good high-frequency hearing coupled with poor low-frequency hearing. comparative analysis suggests that the bat's good high- ...	1997	9083817
the echolocation calls of the spotted bat euderma maculatum are relatively inaudible to moths	previous studies of the spotted bat euderma maculatum have demonstrated that this bat emits echolocation calls that are lower in frequency, shorter in duration and fainter in intensity compared with those of most other insectivorous bats, acoustic characteristics which should render it less conspicuous to eared moths. we tested this prediction by monitoring electrophysiologically the ears of sympatric noctuoid (noctuid, arctiid and notodontid) moths in a site in western canada. auditory threshol ...	1997	9317482
organization of forelimb motoneuron pools in two bat species (eptesicus fuscus and myotis lucifugus).	the present investigation provides further evidence of the conservation of motor nuclei in amniotes. the position of six forelimb and shoulder motor pools were mapped in two species of bat, eptesicus fuscus and myotis lucifugus. the intraspinal locations of motor pools were revealed by labeling with the retrograde neuronal tracer wga-hrp injected into the bellies of six muscles: m. pectoralis, m. spinodeltoideus, mm. triceps brachii (long and lateral heads), m. infraspinatus, m. supraspinatus, a ...	1997	9311421
processing of sinusoidally frequency modulated signals in the nuclei of the lateral lemniscus of the big brown bat, eptesicus fuscus.	neurons in the nuclei of the lateral lemniscus (nll) of the big brown bat, eptesicus fuscus, show several distinctive patterns of response to unmodulated tones. previous work suggests that sustained responders are specialized to transmit information about sound level and duration while onset responders transmit precise timing information. the biosonar signals of e. fuscus consist of multiple, downward frequency modulated sweeps that change in slope and repetition rate as the bat approaches a tar ...	1998	9872144
frequency tuning, latencies, and responses to frequency-modulated sweeps in the inferior colliculus of the echolocating bat, eptesicus fuscus.	neurons in the inferior colliculus (ic) of the awake big brown bat, eptesicus fuscus, were examined for joint frequency and latency response properties which could register the timing of the bat's frequency-modulated (fm) biosonar echoes. best frequencies (bfs) range from 10 khz to 100 khz with 50% tuning widths mostly from 1 khz to 8 khz. neurons respond with one discharge per 2-ms tone burst or fm stimulus at a characteristic latency in the range of 3-45 ms, with latency variability (sd) of 50 ...	1998	9447715
gabaergic disinhibition affects responses of bat inferior collicular neurons to temporally patterned sound pulses.	using the big brown bat, eptesicus fuscus, as a model mammalian auditory system, we studied the effect of gabaergic disinhibition by bicuculline on the responses of inferior collicular (ic) neurons to temporally patterned trains of sound pulses delivered at different pulse repetition rates (prrs) under free-field stimulation conditions. all 66 neurons isolated from eight bats either discharged one to two impulses (phasic on responders, n = 41, 62%), three to eight impulses (phasic bursters, n = ...	1998	9582206
the effect of pulse repetition rate, pulse intensity, and bicuculline on the minimum threshold and latency of bat inferior collicular neurons.	this study examines the effect of pulse repetition rate (prr), pulse intensity, and bicuculline on the minimum threshold (mt) and latency of inferior collicular neurons of the big brown bat, eptesicus fuscus, under free-field stimulation conditions. it tests the hypothesis that changes in mt and latency of collicular neurons are co-dependent on prr. the number of impulses in inferior collicular neurons (n = 245) increased either monotonically (25%) or non-monotonically (75%) with pulse intensity ...	1998	9530836
ontogenetic influences on foraging and mass accumulation by big brown bats (eptesicus fuscus).	juvenile flying animals, including bats, often cease increasing, or even decrease in body mass after the onset of flight. the low body mass of juvenile bats may be a result of stresses associated with the initiation of flight, or may be an adaptation to reduce flight costs. to test these hypotheses, the body masses of adults and unknown aged juvenile big brown bats (eptesicus fuscus) were separately compared in august 1990 through to 1995. it was hypothesized that there should be little variatio ...	1998	26412372
echo-delay resolution in sonar images of the big brown bat, eptesicus fuscus.	echolocating big brown bats (eptesicus fuscus) broadcast ultrasonic frequency-modulated (fm) biosonar sounds (20-100 khz frequencies; 10-50 microseconds periods) and perceive target range from echo delay. knowing the acuity for delay resolution is essential to understand how bats process echoes because they perceive target shape and texture from the delay separation of multiple reflections. bats can separately perceive the delays of two concurrent electronically generated echoes arriving as litt ...	1998	9770540
a new genus and species of predaceous mite in the parasitic family macronyssidae (acari: mesostigmata).	coprolactistus whitakeri radovsky & krantz, a new genus and species of macronyssidae, is described in all stases. unlike other macronyssids, all of which are vertebrate parasites, c. whitakeri is predaceous, feeding on other mites in bat guano. its morphology confirms the family assignment, and it has the peculiar macronyssid life cycle in which a regressive, nonfeeding deutonymph follows a normal, feeding protonymph. the chelicerae are typically macronyssid despite the predatory diet. available ...	1998	9701940
experience-dependent corticofugal adjustment of midbrain frequency map in bat auditory system.	recent studies of corticofugal modulation of auditory information processing indicate that cortical neurons mediate both a highly focused positive feedback to subcortical neurons "matched" in tuning to a particular acoustic parameter and a widespread lateral inhibition to "unmatched" subcortical neurons. this cortical function for the adjustment and improvement of subcortical information processing is called egocentric selection. egocentric selection enhances the neural representation of frequen ...	1998	9770543
coexistence of fmrfamide-like and lhrh-like immunoreactivity in the terminal nerve and forebrain of the big brown bat, eptesicus fuscus.	the coexistence of molluscan cardioexcitatory neuropeptide (fmrfamide) and luteinizing hormone-releasing hormone (lhrh) was studied in the nervous system of the big brown bat, eptesicus fuscus, with immunocytochemistry. within mammals, this is the first report of the coexistence of these neuropeptides in the terminal nerve. in juvenile and adult bats, both neuropeptides are distributed identically throughout the terminal nerve (tn), and they coexist in many parts of the prosencephalon from the o ...	1998	9693160
echo spl, training experience, and experimental procedure influence the ranging performance in the big brown bat, eptesicus fuscus.	four eptesicus fuscus were trained in a range discrimination experiment to choose the closer of two phantom targets. echo attenuation was roving between trials returning echoes ranging from -10 db to -50 db spl (sound pressure level) relative to emission spl. discrimination thresholds were determined. after sufficient training, ranging performance was stable and about the same in the range between -20 db and -50 db with range difference thresholds around 300 microseconds. at -10 db, performance ...	1998	9693992
gabaergic and glycinergic inhibition sharpens tuning for frequency modulations in the inferior colliculus of the big brown bat.	discrimination of amplitude and frequency modulated sounds is an important task of auditory processing. experiments have shown that tuning of neurons to sinusoidally frequency- and amplitude-modulated (sfm and sam, respectively) sounds becomes successively narrower going from lower to higher auditory brain stem nuclei. in the inferior colliculus (ic), many neurons are sharply tuned to the modulation frequency of sfm sounds. the purpose of this study was to determine whether gabaergic or glyciner ...	1998	9658029
cryptosporidiosis in a bat (eptesicus fuscus).	cryptosporidial infection was diagnosed histologically in the small intestine of a big brown bat (eptesicus fuscus) from oregon. this is the first report of cryptosporidiosis in a bat.	1998	9645870
passive sound-localization ability of the big brown bat (eptesicus fuscus).	the passive sound-localization ability (i.e. minimum audible angle) of the big brown bat, eptesicus fuscus, was determined using a conditioned avoidance procedure in which the animals were trained to discriminate left sounds from right sounds. the mean threshold of three bats for a 100-ms broadband noise burst was 14 degrees, a value that is about average for mammals. a similar threshold of 15 degrees was obtained for one animal when it was retested with one of its own recorded echolocation call ...	1998	9641317
recovery cycles of neurons in the inferior colliculus, the pontine nuclei and the auditory cortex of the big brown bat, eptesicus fuscus.	this study examines the recovery cycles of neurons in the inferior colliculus (ic), the pontine nuclei (pn) and the auditory cortex (ac) of the big brown bat, eptesicus fuscus, using a pair of identical pulses at different interpulse intervals. although the recovery cycle varies among neurons, on average, ac neurons have the longest recovery cycle and pn neurons have the shortest one. the recovery cycle of ic neurons is slightly longer than pn neurons. neurons tend to have longer recovery cycles ...	1998	9629476
corticofugal regulation of auditory sensitivity in the bat inferior colliculus.	under free-field stimulation conditions, corticofugal regulation of auditory sensitivity of neurons in the central nucleus of the inferior colliculus of the big brown bat, eptesicus fuscus, was studied by blocking activities of auditory cortical neurons with lidocaine or by electrical stimulation in auditory cortical neuron recording sites. the corticocollicular pathway regulated the number of impulses, the auditory spatial response areas and the frequency-tuning curves of inferior colliculus ne ...	1998	9861704
arctiid moths and bat echolocation: broad-band clicks interfere with neural responses to auditory stimuli in the nuclei of the lateral lemniscus of the big brown bat.	clicks emitted by arctiid moths interfere with the ranging ability of echolocating bats. to identify possible neural correlates of this interference, we recorded responses of single units in the nuclei of the lateral lemniscus to combinations of a broad-band click and a test signal (pure tones or frequency-modulated sweeps). in 77% of 87 units tested, clicks interfered with neural responses to the test stimuli. the interference fell into two categories: latency ambiguity and suppression. units s ...	1998	9463919
corticofugal modulation of the midbrain frequency map in the bat auditory system.	the auditory system, like the visual and somatosensory systems, contains topographic maps in its central neural pathways. these maps can be modified by sensory deprivation, injury and experience in both young and adult animals. such plasticity has been explained by changes in the divergent and convergent projections of the ascending sensory system. another possibility, however, is that plasticity may be mediated by descending corticofugal connections. we have investigated the role of descending ...	1998	10195109
apneic oxygen uptake in the torpid pocket mouse perognathus parvus.	the apneas of many torpid mammals can persist longer than estimated o2 stores allow. this suggests that some o2 is acquired during these apneas by either cutaneous uptake or by a nonventilatory flux down an open airway (tracheal flux). previous experiments confirmed apneic o2 uptake in the bat eptesicus fuscus with the conclusion that the uptake most likely occurred by tracheal flux. however, the bat's large cutaneous wing area remained a potential source of cutaneous o2 uptake, leaving uncertai ...	1998	9798250
range resolution and the possible use of spectral information in the echolocating bat, eptesicus fuscus.	individuals of the echolocating bat eptesicus fuscus were trained to discriminate simulated two-wave-front targets with internal time delays of 0 to 100 microns between the wave fronts from a one-wave-front target. the ability of bats to discriminate between such targets can be referred to as range resolution. in eptesicus fuscus, this ability is limited to distinct internal time delays (12, 32-40, and 52-100 microns) between the two wave fronts of a double-wave-front target. analysis of the sim ...	1998	2212300
processing of sinusoidally amplitude modulated signals in the nuclei of the lateral lemniscus of the big brown bat, eptesicus fuscus.	changes in amplitude are a characteristic feature of most natural sounds, including the biosonar signals used by bats for echolocation. previous evidence suggests that the nuclei of the lateral lemniscus play an important role in processing timing information that is essential for target range determination in echolocation. neurons that respond to unmodulated tones with a sustained discharge are found in the dorsal nucleus (dnll), intermediate nucleus (inll) and multipolar cell division of the v ...	1998	9872145
six new eimeria species from vespertilionid bats of north america.	twenty species of bats (molossidae, vespertilionidae) were collected from california, new mexico, oregon, south carolina, utah, and baja california norte (mexico), and 29 of 404 (7%) animals, including antrozous pallidus, eptesicus fuscus, myotis auriculus, myotis californicus, myotis ciliolabrum, myotis evotis, myotis lucifugus, myotis thysanodes, myotis vivesi, myotis volans, myotis yumanensis, and nycticeius humeralis were infected with eimeria spp., which represent 6 new species. sporulated ...	1999	10386443
temporally patterned pulse trains affect duration tuning characteristics of bat inferior collicular neurons.	this study examines the effect of temporally patterned pulse trains on duration tuning characteristics of inferior collicular neurons of the big brown bat. eptesicus fuscus, under free-field stimulation conditions. using a 50% difference between maximal and minimal responses as a criterion, the duration tuning characteristics of inferior collicular neurons determined with pulse trains of different pulse durations are described as band-pass, long-pass, short-pass, and all-pass. each band-pass neu ...	1999	10573869
plasma leptin decreases during lactation in insectivorous bats.	we previously demonstrated high leptin levels during late pregnancy in little brown bats (myotis lucifugus). we now extend these observations to a second species, the big brown bat (eptesicus fuscus), and also report that leptin increases after the first trimester of pregnancy. leptin decreased to baseline 1 week following parturition, with a half-time decay of 2 days. during lactation, leptin was significantly correlated with body mass in e. fuscus, but not in m. lucifugus. no circadian pattern ...	1999	10093906
spectral cues and perception of the vertical position of targets by the big brown bat, eptesicus fuscus.	big brown bats (eptesicus fuscus) were trained to discriminate between vertical angles subtended by paired beads suspended from fishing line. bats were rewarded for choosing the smaller of the two angles presented. the difference between the angles was changed systematically using a transformed up-down procedure and the bats' ability to detect the difference was measured at different vertical locations. when the beads were centered at +20 degrees (above the horizon), at 0 degree (the horizon), a ...	2000	10687712
range discrimination by big brown bats (eptesicus fuscus) using altered model echoes: implications for signal processing.	the sonar emissions of two big brown bats (eptesicus fuscus) were modeled to create a "normal" echolocation signal for each bat which was then used as an artificial echo to synthesize a phantom target. the bat's task was to indicate which of two phantom targets (presented singly) was the "near" target and which the "far" target. threshold range discrimination at a nominal target distance of 80 cm was about 0.6 cm for both bats. the normal signal was then modified to change the relative energy in ...	2000	10641671
neural measurement of sound duration: control by excitatory-inhibitory interactions in the inferior colliculus.	in the inferior colliculus (ic) of the big brown bat, a subpopulation of cells ( approximately 35%) are tuned to a narrow range of sound durations. band-pass tuning for sound duration has not been seen at lower levels of the auditory pathway. previous work suggests that it arises at the ic through the interaction of sound-evoked, temporally offset, excitatory and inhibitory inputs. to test this hypothesis, we recorded from duration-tuned neurons in the ic and examined duration tuning before and ...	2000	10980020
vocal control of acoustic information for sonar discriminations by the echolocating bat, eptesicus fuscus.	this study aimed to determine whether bats using frequency modulated (fm) echolocation signals adapt the features of their vocalizations to the perceptual demands of a particular sonar task. quantitative measures were obtained from the vocal signals produced by echolocating bats (eptesicus fuscus) that were trained to perform in two distinct perceptual tasks, echo delay and doppler-shift discriminations. in both perceptual tasks, the bats learned to discriminate electronically manipulated playba ...	2000	10790052
interdependence of spatial and temporal coding in the auditory midbrain.	to date, most physiological studies that investigated binaural auditory processing have addressed the topic rather exclusively in the context of sound localization. however, there is strong psychophysical evidence that binaural processing serves more than only sound localization. this raises the question of how binaural processing of spatial cues interacts with cues important for feature detection. the temporal structure of a sound is one such feature important for sound recognition. as a first ...	2000	10758135
reorganization of the frequency map of the auditory cortex evoked by cortical electrical stimulation in the big brown bat.	in a search phase of echolocation, big brown bats, eptesicus fuscus, emit biosonar pulses at a rate of 10/s and listen to echoes. when a short acoustic stimulus was repetitively delivered at this rate, the reorganization of the frequency map of the primary auditory cortex took place at and around the neurons tuned to the frequency of the acoustic stimulus. such reorganization became larger when the acoustic stimulus was paired with electrical stimulation of the cortical neurons tuned to the freq ...	2000	10758097
neural responses to overlapping fm sounds in the inferior colliculus of echolocating bats.	the big brown bat, eptesicus fuscus, navigates and hunts prey with echolocation, a modality that uses the temporal and spectral differences between vocalizations and echoes from objects to build spatial images. closely spaced surfaces ("glints") return overlapping echoes if two echoes return within the integration time of the cochlea ( approximately 300-400 micros). the overlap results in spectral interference that provides information about target structure or texture. previous studies have sho ...	2000	10758096
experience-dependent plasticity in the auditory cortex and the inferior colliculus of bats: role of the corticofugal system.	in the big brown bat, eptesicus fuscus, the response properties of neurons and the cochleotopic (frequency) maps in the auditory cortex (ac) and inferior colliculus can be changed by auditory conditioning, weak focal electric stimulation of the ac, or repetitive delivery of weak, short tone bursts. the corticofugal system plays an important role in information processing and plasticity in the auditory system. our present findings are as follows. in the ac, best frequency (bf) shifts, i.e., reorg ...	2000	10884432
neural inhibition sharpens auditory spatial selectivity of bat inferior collicular neurons.	this study examines the role of neural inhibition in auditory spatial selectivity of inferior collicular neurons of the big brown bat, eptesicus fuscus, using a two-tone inhibition paradigm. two-tone inhibition decreases auditory spatial response areas but increases the slopes of directional sensitivity curves of inferior collicular neurons. inferior collicular neurons have either directionally-selective or hemifield directional sensitivity curves. a directionally-selective curve always has a pe ...	2000	10798726
direction-dependent corticofugal modulation of frequency-tuning curves of inferior collicular neurons in the big brown bat, eptesicus fuscus.	this study examined if corticofugal modulation of subcortical frequency-tuning curves varied with sound direction. both excitatory and inhibitory frequency tuning curves of inferior collicular neurons of the big brown bat, eptesicus fuscus were plotted before and during electrical stimulation in the auditory cortex at two sound directions (contra-40 degrees and ipsi-40 degrees). most collicular neurons had broader excitatory frequency-tuning curves at contra-40 degrees but had broader inhibitory ...	2000	11138792
brief and short-term corticofugal modulation of subcortical auditory responses in the big brown bat, eptesicus fuscus.	recent studies show that the auditory corticofugal system modulates and improves ongoing signal processing and reorganizes frequency map according to auditory experience in the central nucleus of bat inferior colliculus. however, whether all corticofugally affected collicular neurons are involved in both types of modulation has not been determined. in this study, we demonstrate that one group (51%) of collicular neurons participates only in corticofugal modulation of ongoing signal processing, w ...	2000	11110836
echolocation behavior of big brown bats, eptesicus fuscus, in the field and the laboratory.	echolocation signals were recorded from big brown bats, eptesicus fuscus, flying in the field and the laboratory. in open field areas the interpulse intervals (ipi) of search signals were either around 134 ms or twice that value, 270 ms. at long ipi's the signals were of long duration (14 to 18-20 ms), narrow bandwidth, and low frequency, sweeping down to a minimum frequency (fmin) of 22-25 khz. at short ipi's the signals were shorter (6-13 ms), of higher frequency, and broader bandwidth. in woo ...	2000	11108382
bicuculline application affects discharge patterns, rate-intensity functions, and frequency tuning characteristics of bat auditory cortical neurons.	this study examined the effect of bicuculline application on the auditory response properties in the auditory cortex of the big brown bat, eptesicus fuscus. all auditory cortical neurons studied discharged either 1-2 or 3-7 impulses to 4 ms sound stimuli. cortical neurons with high best frequencies tended to have high minimum thresholds. bicuculline application increased the number of impulses and shortened the response latencies of all cortical neurons as well as changing the discharge patterns ...	2000	11077201
corticofugal inhibition compresses all types of rate-intensity functions of inferior collicular neurons in the big brown bat.	recent studies have shown that the auditory corticofugal system modulates and improves signal processing in the frequency, time and spatial domains. in this study, we examine corticofugal modulation of rate-intensity functions of inferior collicular (ic) neurons of the big brown bat, eptesicus fuscus, by electrical stimulation in the primary auditory cortex (ac). cortical electrical stimulation compressed all types of rate-intensity functions so as to increase the slope but decrease the dynamic ...	2000	11033094
cyclodiene insecticide, dde, ddt, arsenic, and mercury contamination of big brown bats (eptesicus fuscus) foraging at a colorado superfund site.	rocky mountain arsenal (rma) national wildlife area, near denver, colorado, is a superfund site contaminated by past military and industrial uses, including pesticide manufacturing. from an ecosystem standpoint, the most critical contaminants at rma are certain cyclodiene insecticides and metabolites, p,p'-dde, p,p'-ddt, arsenic, and mercury. bats are important ecosystem components that can be impacted by persistent contaminants because of their position in the food chain and their potential lon ...	2001	11116346
temporally patterned sound pulse trains affect intensity and frequency sensitivity of inferior collicular neurons of the big brown bat, eptesicus fuscus.	this study examined the effect of temporally patterned pulse trains on intensity and frequency sensitivity of inferior collicular neurons of the big brown bat, eptesicus fuscus. intensity sensitivity of inferior collicular neurons was expressed by the dynamic range and slope of rate-intensity functions. inferior collicular neurons with non-monotonic rate-intensity functions have smaller dynamic ranges and larger slopes than neurons with monotonic or saturated rate-intensity functions. intensity ...	2001	11763959
gabaergic and glycinergic neural inhibition in excitatory frequency tuning of bat inferior collicular neurons.	this study examined the effect of gabaergic and glycinergic inhibition on excitatory frequency tuning curves (ftcs) of inferior collicular (ic) neurons of the big brown bat, eptesicus fuscus. the excitatory ftcs of 70 ic neurons were either v-shaped (57, 81%), closed (11, 16%), or double-peaked (2, 3%). by means of a two-tone stimulation paradigm, inhibitory ftcs were obtained at one frequency flank only (low-frequency flank: 11, 16%; high-frequency flank: 7, 10%), at both frequency flanks (36, ...	2001	11715077
medial superior olive of the big brown bat: neuronal responses to pure tones, amplitude modulations, and pulse trains.	the structure and function of the medial superior olive (mso) is highly variable among mammals. in species with large heads and low-frequency hearing, mso is adapted for processing interaural time differences. in some species with small heads and high-frequency hearing, the mso is greatly reduced in size; in others, including those echolocating bats that have been examined, the mso is large. moreover, the mso of bats appears to have undergone different functional specializations depending on the ...	2001	11698513
a computational sensorimotor model of bat echolocation.	a computational sensorimotor model of target capture behavior by the echolocating bat, eptesicus fuscus, was developed to understand the detection, localization, tracking, and interception of insect prey in a biological sonar system. this model incorporated acoustics, target localization processes, flight aerodynamics, and target capture planning to produce model trajectories replicating those observed in behavioral insect capture trials. estimates of target range were based on echo delay, azimu ...	2001	11519584