Properties of echo delay-tuning receptive fields in the inferior colliculus of the mustached bat

2012 ◽  
Vol 286 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Silvio Macías ◽  
Emanuel C. Mora ◽  
Julio C. Hechavarría ◽  
Manfred Kössl
Keyword(s):  
Inferior Colliculus ◽  
Receptive Fields ◽  
Mustached Bat ◽  
Echo Delay ◽  
Delay Tuning

Comparison of properties of cortical echo delay-tuning in the short-tailed fruit bat and the mustached bat

2010 ◽  
Vol 197 (5) ◽  
pp. 605-613 ◽  
Author(s):  
Cornelia Hagemann ◽  
Marianne Vater ◽  
Manfred Kössl
Keyword(s):  
Fruit Bat ◽  
Mustached Bat ◽  
Echo Delay ◽  
Delay Tuning

Delay-Tuned Neurons in the Inferior Colliculus of the Mustached Bat: Implications for Analyses of Target Distance

1999 ◽  
Vol 82 (3) ◽  
pp. 1326-1338 ◽  
Author(s):  
Christine V. Portfors ◽  
Jeffrey J. Wenstrup
Keyword(s):  
Inferior Colliculus ◽  
Tuning Curve ◽  
Central Nucleus ◽  
Harmonic Frequency ◽  
High Frequency Signal ◽  
Response Properties ◽  
Mustached Bat ◽  
Medial Geniculate ◽  
Higher Harmonic ◽  
Delay Tuning

We examined response properties of delay-tuned neurons in the central nucleus of the inferior colliculus (ICC) of the mustached bat. In the mustached bat, delay-tuned neurons respond best to the combination of the first-harmonic, frequency-modulated (FM1) sweep in the emitted pulse and a higher harmonic frequency-modulated (FM2, FM3 or FM4) component in returning echoes and are referred to as FM-FM neurons. We also examined H1-CF2 neurons. H1-CF2 neurons responded to simultaneous presentation of the first harmonic (H1) in the emitted pulse and the second constant frequency (CF2) component in returning echoes. These neurons served as a comparison as they are thought to encode different features of sonar targets than FM-FM neurons. Only 7% of our neurons (14/198) displayed a single excitatory tuning curve. The rest of the neurons (184) displayed complex responses to sounds in two separate frequency bands. The majority (51%, 101) of neurons were facilitated by the combination of specific components in the mustached bat’s vocalizations. Twenty-five percent showed purely inhibitory interactions. The remaining neurons responded to two separate frequencies, without any facilitation or inhibition. FM-FM neurons (69) were facilitated by the FM1 component in the simulated pulse and a higher harmonic FM component in simulated echoes, provided the high-frequency signal was delayed the appropriate amount. The delay producing maximal facilitation (“best delay”) among FM-FM neurons ranged between 0 and 20 ms, corresponding to target distances ≤3.4 m. Sharpness of delay tuning varied among FM-FM neurons with 50% delay widths between 2 and 13 ms. On average, the facilitated responses of FM-FM neurons were 104% greater than the sum of the responses to the two signals alone. In comparing response properties of delay-tuned, FM-FM neurons in the ICC with those in the medial geniculate body (MGB) from other studies, we find that the range of best delays, sharpness of delay tuning and strength of facilitation are similar in the ICC and MGB. This suggests that by the level of the IC, the basic response properties of FM-FM neurons are established, and they do not undergo extensive transformations with ascending auditory processing.

scholarly journals Natural echolocation sequences evoke echo-delay selectivity in the auditory midbrain of the FM bat, Eptesicus fuscus

2018 ◽  
Vol 120 (3) ◽  
pp. 1323-1339 ◽  
Author(s):  
Silvio Macías ◽  
Jinhong Luo ◽  
Cynthia F. Moss
Keyword(s):  
Inferior Colliculus ◽  
Sweep Rate ◽  
Eptesicus Fuscus ◽  
Target Range ◽  
Temporal Patterning ◽  
Stimulus Context ◽  
Constant Frequency ◽  
New Findings ◽  
Echo Delay ◽  
Delay Tuning

Echolocating bats must process temporal streams of sonar sounds to represent objects along the range axis. Neuronal echo-delay tuning, the putative mechanism of sonar ranging, has been characterized in the inferior colliculus (IC) of the mustached bat, an insectivorous species that produces echolocation calls consisting of constant frequency and frequency modulated (FM) components, but not in species that use FM signals alone. This raises questions about the mechanisms that give rise to echo-delay tuning in insectivorous bats that use different signal designs. To investigate whether stimulus context may account for species differences in echo-delay selectivity, we characterized single-unit responses in the IC of awake passively listening FM bats, Eptesicus fuscus, to broadcasts of natural sonar call-echo sequences, which contained dynamic changes in signal duration, interval, spectrotemporal structure, and echo-delay. In E. fuscus, neural selectivity to call-echo delay emerges in a population of IC neurons when stimulated with call-echo pairs presented at intervals mimicking those in a natural sonar sequence. To determine whether echo-delay selectivity also depends on the spectrotemporal features of individual sounds within natural sonar sequences, we studied responses to computer-generated echolocation signals that controlled for call interval, duration, bandwidth, sweep rate, and echo-delay. A subpopulation of IC neurons responded selectively to the combination of the spectrotemporal structure of natural call-echo pairs and their temporal patterning within a dynamic sonar sequence. These new findings suggest that the FM bat’s fine control over biosonar signal parameters may modulate IC neuronal selectivity to the dimension of echo-delay. NEW & NOTEWORTHY Echolocating bats perform precise auditory temporal computations to estimate their distance to objects. Here, we report that response selectivity of neurons in the inferior colliculus of a frequency modulated bat to call-echo delay, or target range tuning, depends on the temporal patterning and spectrotemporal features of sound elements in a natural echolocation sequence. We suggest that echo responses to objects at different distances are gated by the bat’s active control over the spectrotemporal patterning of its sonar emissions.

Differences in response properties of neurons between two delay-tuned areas in the auditory cortex of the mustached bat

1993 ◽  
Vol 69 (5) ◽  
pp. 1700-1712 ◽  
Author(s):  
H. Edamatsu ◽  
N. Suga
Keyword(s):  
Auditory Cortex ◽  
Poor Response ◽  
Target Range ◽  
Terminal Phase ◽  
Sound Pulse ◽  
Response Properties ◽  
Tuning Curves ◽  
Mustached Bat ◽  
Echo Delay ◽  
Delay Tuning

1. The orientation sound (pulse) of the mustached bat, Pteronotus parnellii parnellii, consists of four harmonics (H1-4), each containing a long constant-frequency component (CF1-4) followed by a short frequency-modulated component (FM1-4). The auditory cortex of this species contains several "combination-sensitive" areas: FM-FM, dorsal fringe (DF), ventral fringe (VF), CF/CF, and H1-H2. The FM-FM, DF, and VF areas each consist of neurons tuned to particular delays of echo FMn (n = 2, 3, or 4) from pulse FM1, and have an echo-delay (target-range) axis. This delay axis is from 0.4 to approximately 18 ms in the FM-FM area, to approximately 9 ms in the DF area, and to approximately 5 ms in the VF area. Therefore we hypothesized that the VF area was more specialized for the processing of range information in the terminal phase of echolocation than was the FM-FM area. The aim of our present studies was to find differences in response properties between neurons with best delays shorter than 6 ms in the VF and FM-FM areas and thus to test our hypothesis. 2. In the terminal phase of target-directed flight, the rate of pulse emission becomes higher, pulse duration (in particular, CF duration) becomes shorter, echo delay becomes shorter, and echoes (both the CF and FM components) are less Doppler shifted. Therefore, a "temporal-pattern-simulating (TPS)" stimulus was designed to mimic the train of pulse-echo pairs that would be heard by the bat during the terminal phase, and responses of single neurons to the TPS stimulus and other types of stimuli were recorded from the VF and FM-FM areas of the auditory cortex of unanesthetized bats with a tungsten-wire microelectrode. 3. Best delays of the neurons studied range between 0.9 and 5.5 ms (2.64 +/- 0.72 ms, N = 181) for the VF area, and between 0.6 and 6.0 ms (3.64 +/- 1.14, N = 144) for the FM-FM area. More neurons in the VF area than those in the FM-FM area showed no response or a poor response to the TPS stimulus. Therefore VF neurons are less suited than neurons in the FM-FM area for processing target ranges in the terminal phase of target-directed flight. Facilitative delay-tuning curves were commonly sandwiched between inhibitory delay-tuning curves. The lack of response or poor response to the TPS stimulus can be explained by this inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)

Neurons in the inferior colliculus of the mustached bat are tuned both to echo-delay and sound duration

Neuroreport ◽  
2013 ◽  
Vol 24 (8) ◽  
pp. 404-409 ◽  
Author(s):  
Silvio Macías ◽  
Julio C. Hechavarría ◽  
Manfred Kössl ◽  
Emanuel C. Mora
Keyword(s):  
Inferior Colliculus ◽  
Mustached Bat ◽  
Sound Duration ◽  
Echo Delay

Auditory Motion Induces Directionally Dependent Receptive Field Shifts in Inferior Colliculus Neurons

1998 ◽  
Vol 79 (4) ◽  
pp. 2040-2062 ◽  
Author(s):  
Willard W. Wilson ◽  
William E. O'Neill
Keyword(s):  
Receptive Field ◽  
Inferior Colliculus ◽  
Apparent Motion ◽  
Target Location ◽  
Receptive Fields ◽  
Silent Interval ◽  
Auditory Motion ◽  
Motion Direction ◽  
Motion Sequence ◽  
And Shifts

Wilson, Willard W. and William E. O'Neill. Auditory motion induces directionally dependent receptive field shifts in inferior colliculus neurons. J. Neurophysiol. 79: 2040–2062, 1998. This research focused on the response of neurons in the inferior colliculus of the unanesthetized mustached bat, Pteronotus parnelli, to apparent auditory motion. We produced the apparent motion stimulus by broadcasting pure-tone bursts sequentially from an array of loudspeakers along horizontal, vertical, or oblique trajectories in the frontal hemifield. Motion direction had an effect on the response of 65% of the units sampled. In these cells, motion in opposite directions produced shifts in receptive field locations, differences in response magnitude, or a combination of the two effects. Receptive fields typically were shifted opposite the direction of motion (i.e., units showed a greater response to moving sounds entering the receptive field than exiting) and shifts were obtained to horizontal, vertical, and oblique motion orientations. Response latency also shifted as a function of motion direction, and stimulus locations eliciting greater spike counts also exhibited the shortest neural latency. Motion crossing the receptive field boundaries appeared to be both necessary and sufficient to produce receptive field shifts. Decreasing the silent interval between successive stimuli in the apparent motion sequence increased both the probability of obtaining a directional effect and the magnitude of receptive field shifts. We suggest that the observed directional effects might be explained by “spatial masking,” where the response of auditory neurons after stimulation from particularly effective locations in space would be diminished. The shift in auditory receptive fields would be expected to shift the perceived location of a moving sound and may explain shifts in localization of moving sources observed in psychophysical studies. Shifts in perceived target location caused by auditory motion might be exploited by auditory predators such as Pteronotus in a predictive tracking strategy to capture moving insect prey.

scholarly journals Amygdala and auditory cortex differentially modulate tonal receptive fields in the inferior colliculus

IBRO Reports ◽  
2019 ◽  
Vol 6 ◽  
pp. S162-S163
Author(s):  
Jeongyoon Lee ◽  
Jeff Lin ◽  
Adam Swiercz ◽  
Zhe Yu ◽  
Paul J. Marvar ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Receptive Fields

Azimuthal receptive fields are shaped by GABAergic inhibition in the inferior colliculus of the mustache bat

1994 ◽  
Vol 72 (3) ◽  
pp. 1080-1102 ◽  
Author(s):  
T. J. Park ◽  
G. D. Pollak
Keyword(s):  
Inferior Colliculus ◽  
Action Potentials ◽  
Receptive Fields ◽  
Sound Field ◽  
Glass Electrode ◽  
Gabaergic Inhibition ◽  
Gamma Aminobutyric Acid ◽  
Response Properties ◽  
Inferior Collicular ◽  
Stimulation Of

1. In this study we examine the effects of GABAergic inhibition on the response properties and the constructed azimuthal receptive fields of 54 excitatory/inhibitory (EI) neurons tuned to 60 kHz in the inferior colliculus of the mustache bat. The constructed azimuthal receptive fields predict the spike counts that would be evoked by different intensities of 60-kHz sounds presented from each of 13 azimuthal locations in the frontal sound field. 2. Action potentials were recorded with a micropipette attached to a multibarrel glass electrode. Bicuculline, an antagonist specific for gamma-aminobutyric acid-A (GABAA) receptors, was iontophoretically applied through the multibarrel electrode. Both monaural and binaural response properties were initially recorded at a variety of interaural intensity disparities (IIDs) and absolute intensities, and the same response properties were subsequently assessed while GABAergic inhibition was blocked by bicuculline. Azimuthal receptive fields both before and during the application of bicuculline were constructed from response properties obtained with earphones after correcting for the directional properties of the ear and the IIDs generated by 60-kHz sounds presented from a variety of azimuthal locations. 3. Bicuculline had virtually no effect on either the monaural or binaural properties of 19 cells (35%). The constructed azimuthal receptive fields of these cells were also unaffected by bicuculline. Presumably the properties of these cells were formed in a lower nucleus, most likely the contralateral lateral superior olive (LSO), and were imposed on the collicular cell via the crossed projection from the LSO to the inferior colliculus, which is known to be excitatory. 4. In more than half of the neurons (65%) GABAergic inhibition influenced one or more features of the cell's response properties and thus its azimuthal receptive field. Some response properties were formed in the colliculus through GABAergic inhibition, whereas others appear to have been shaped initially in a lower nucleus and then further modified by GABAergic inhibition in the inferior colliculus. Moreover, a number of features of GABAergic inhibition that acted on inferior collicular cells were evoked by stimulation of the contralateral (excitatory) ear, whereas other features were influenced by stimulation of the ipsilateral (inhibitory) ear. 5. In 20 cells (37%) blocking GABAergic inhibition reduced or abolished the inhibition evoked by the ipsilateral ear. The receptive fields of cells in which the ipsilaterally evoked inhibition was reduced by bicuculline expanded further into the ipsilateral sound field than they did before bicuculline.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Reorganization of receptive fields following hearing loss in inferior colliculus neurons

Neuroscience ◽  
2007 ◽  
Vol 147 (2) ◽  
pp. 532-545 ◽  
Author(s):  
K. Barsz ◽  
W.W. Wilson ◽  
J.P. Walton
Keyword(s):  
Hearing Loss ◽  
Inferior Colliculus ◽  
Receptive Fields
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