FM signals produce a robust paradoxical latency shift that is important for coding of target range in the bat inferior colliculus

2002 ◽  
Vol 112 (5) ◽  
pp. 2288-2288
Author(s):  
Albert S. Feng ◽  
Alexander Galazyuk
Keyword(s):  
Inferior Colliculus ◽  
Target Range ◽  
Fm Signals ◽  
Latency Shift

Neural Selectivity and Tuning for Sinusoidal Frequency Modulations in the Inferior Colliculus of the Big Brown Bat, Eptesicus fuscus

1997 ◽  
Vol 77 (3) ◽  
pp. 1595-1605 ◽  
Author(s):  
John H. Casseday ◽  
Ellen Covey ◽  
Benedikt Grothe
Keyword(s):  
Inferior Colliculus ◽  
High Frequency ◽  
Limited Range ◽  
Eptesicus Fuscus ◽  
Fm Signals ◽  
Big Brown Bat ◽  
Pure Tones ◽  
Sinusoidal Frequency Modulations ◽  
Frequency Modulations ◽  
Neural Selectivity

Casseday, John H., Ellen Covey, and Benedikt Grothe. Neural selectivity and tuning for sinusoidal frequency modulations in the inferior colliculus of the big brown bat, Eptesicus fuscus. J. Neurophysiol. 77: 1595–1605, 1997. 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 of 116 neurons in the IC to pure tones, noise with various bandwidths, single linear FM sweeps, sinusoidally amplitude-modulated signals, and sinusoidally frequency-modulated (SFM) signals. With the use of these stimuli, 20 neurons (17%) responded only to SFM, and 10 (9%) responded best to SFM but also responded to one other test stimulus. We refer to the total 26% of neurons that responded best to SFM as SFM-selective neurons. Fifty-nine neurons (51%) responded about equally well to SFM and other stimuli, and 27 (23%) did not respond to SFM but did respond to other stimuli. Most SFM-selective neurons responded to a limited range of modulation rates and a limited range of modulation depths. The range of modulationrates over which individual neurons responded was 5–170 Hz( n = 20). Thus SFM-selective neurons respond to low modulation rates. The depths of modulations to which the neurons responded ranged from ±0.4 to ±19 kHz ( n = 15). Half of the SFM-selective neurons did not respond to the first cycle of SFM. This finding suggests that the mechanism for selective response to SFM involves neural delays and coincidence detectors in which the response to one part of the SFM cycle coincides in time either with the response to a later part of the SFM cycle or with the response to the first part of the next cycle. The SFM-selective neurons in the IC responded to a lower and more limited range of SFM rates than do neurons in the nuclei of the lateral lemniscus of this bat. Because the FM components of biological sounds usually have low rates of modulation, we suggest that the tuning of these neurons is related to biologically important sound parameters. The tuning could be used to detect FM in echolocation signals, modulations in high-frequency sounds that are generated by wing beats of some beetles, or social communication sounds of Eptesicus.

scholarly journals Tuning for rate and duration of frequency-modulated sweeps in the mammalian inferior colliculus

2018 ◽  
Vol 120 (3) ◽  
pp. 985-997 ◽  
Author(s):  
James A. Morrison ◽  
Roberto Valdizón-Rodríguez ◽  
Daniel Goldreich ◽  
Paul A. Faure
Keyword(s):  
Inferior Colliculus ◽  
Bayesian Model ◽  
Model Comparison ◽  
Tuning Curve ◽  
Extracellular Recording ◽  
Sweep Rate ◽  
Center Frequency ◽  
Bayesian Model Comparison ◽  
Fm Signals ◽  
Big Brown Bat

Responses of auditory duration-tuned neurons (DTNs) are selective for stimulus duration. We used single-unit extracellular recording to investigate how the inferior colliculus (IC) encodes frequency-modulated (FM) sweeps in the big brown bat. It was unclear whether the responses of so-called “FM DTNs” encode signal duration, like classic pure-tone DTNs, or the FM sweep rate. Most FM cells had spiking responses selective for downward FM sweeps. We presented cells with linear FM sweeps whose center frequency (CEF) was set to the best excitatory frequency and whose bandwidth (BW) maximized the spike count. With these baseline parameters, we stimulated cells with linear FM sweeps randomly varied in duration to measure the range of excitatory FM durations and/or sweep rates. To separate FM rate and FM duration tuning, we doubled (and halved) the BW of the baseline FM stimulus while keeping the CEF constant and then recollected each cell’s FM duration tuning curve. If the cell was tuned to FM duration, then the best duration (or range of excitatory durations) should remain constant despite changes in signal BW; however, if the cell was tuned to the FM rate, then the best duration should covary with the same FM rate at each BW. A Bayesian model comparison revealed that the majority of neurons were tuned to the FM sweep rate, although a few cells showed tuning for FM duration. We conclude that the dominant parameter for temporal tuning of FM neurons in the IC is FM sweep rate and not FM duration. NEW & NOTEWORTHY Reports of inferior colliculus neurons with response selectivity to the duration of frequency-modulated (FM) stimuli exist, yet it remains unclear whether such cells are tuned to the FM duration or the FM sweep rate. To disambiguate these hypotheses, we presented neurons with variable-duration FM signals that were systematically manipulated in bandwidth. A Bayesian model comparison revealed that most temporally selective midbrain cells were tuned to the FM sweep rate and not the FM duration.

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.

A single-unit analysis of inferior colliculus in unanesthetized bats: response patterns and spike-count functions generated by constant-frequency and frequency-modulated sounds

1978 ◽  
Vol 41 (3) ◽  
pp. 677-691 ◽  
Author(s):  
G. K. Pollak ◽  
D. S. Marsh ◽  
R. Bodenhamer ◽  
A. Souther
Keyword(s):  
Inferior Colliculus ◽  
Single Unit ◽  
Response Pattern ◽  
Spike Count ◽  
Silent Interval ◽  
Response Patterns ◽  
Constant Frequency ◽  
Threshold Functions ◽  
Fm Signals ◽  
Wide Range

1. Single-unit activity evoked by constant-frequency (CF) and frequency-modulated (FM) sounds was recorded from the inferior colliculus of unanesthetized Mexican free-tailed bats. The FM bursts were designed to mimic the natural orientation cries emitted by this species. 2. The feature of greatest concern in this study is the response patterns evoked by acoustic signals. Four major types of response patterns are recognized: a) the phasic on patterns where up to 4 spikes were evoked with a total firing duration occurring within a period of about 5 ms, b) the on-off patterns characterized by a phasic on-response followed by a silent interval with a brief burst of impulses occurring to the off-set of the signal, c) the phasic burst patterns where the unit typically fired 3-7 spikes over a 5-10 ms (or longer) duration with the same response pattern being evoked by a wide range of signal durations, d) the tonic or sustained patterns characterized by a sustained firing whose duration faithfully followed the signal duration. 3. Constant frequency and FM signals were not equally effective for eliciting the various response patterns. While all of the major response categories and most of the subtypes were evoked with CF stimulation, FM signals, which mimicked the natural echolocation cries, evoked predominantly phasic on-responses and a much smaller number of phasic bursters. Tonic and on-off patterns were never observed with FM signals. 4. Many units exhibited a particular response pattern with CF signals which differed from the pattern evoked by FM signals. This finding demonstrated that utilizing CF signals to investigate encoding features relevant for echolocation is an inappropriate approach and can result in misleading conclusions. 5. In many electrode penetrations most units, and in some cases all units, had the same response pattern. This was observed for phasic constant-latency responders (pELRs), phasic erratic-latency responders (pELRs), phasic burst, and tonic units, and provides evidence that units having a particular response pattern are organized in vertical arrays within the volliculus. 6. Several of the response patterns were strongly correlated with a particular spike-count function. The pCLRs almost always had a steeply rising monotonic function, phasic bursters were always nonmonotonic but never upper threshold, while the tonic units typically had monotonic functions. The pELRs were heterogeneous with regard to spike counts having monotonic, nonmonotonic, and upper-threshold functions. Upper-threshold functions were observed only in pELRs.

FM signals produce robust paradoxical latency shifts in the bat’s inferior colliculus

2006 ◽  
Vol 193 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Xinming Wang ◽  
Alexander V. Galazyuk ◽  
Albert S. Feng
Keyword(s):  
Inferior Colliculus ◽  
Fm Signals

Sound-evoked oscillation and paradoxical latency shift in the inferior colliculus neurons of the big fruit-eating bat, Artibeus jamaicensis

2011 ◽  
Vol 197 (12) ◽  
pp. 1159-1172 ◽  
Author(s):  
Julio C. Hechavarría ◽  
Ariadna T. Cobo ◽  
Yohami Fernández ◽  
Silvio Macías ◽  
Manfred Kössl ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Artibeus Jamaicensis ◽  
Latency Shift

Serotonin Effects on Frequency Tuning of Inferior Colliculus Neurons

2001 ◽  
Vol 85 (2) ◽  
pp. 828-842 ◽  
Author(s):  
Laura M. Hurley ◽  
George D. Pollak
Keyword(s):  
Inferior Colliculus ◽  
Frequency Tuning ◽  
Gain Control ◽  
Central Nucleus ◽  
Complex Signals ◽  
Constant Intensity ◽  
Fm Signals ◽  
Spectral Components ◽  
Induced Changes ◽  
Response Area

We investigated the modulatory effects of serotonin on the tuning of 114 neurons in the central nucleus of the inferior colliculus (ICc) of Mexican free-tailed bats and how serotonin-induced changes in tuning influenced responses to complex signals. We obtained a “response area” for each neuron, defined as the frequency range that evoked discharges and the spike counts evoked by those frequencies at a constant intensity. We then iontophoretically applied serotonin and compared response areas obtained before and during the application of serotonin. In 58 cells, we also assessed how serotonin-induced changes in response areas correlated with changes in the responses to brief frequency-modulated (FM) sweeps whose structure simulated natural echolocation calls. Serotonin profoundly changed tone-evoked spike counts in 60% of the neurons (68/114). In most neurons, serotonin exerted a gain control, facilitating or depressing the responses to all frequencies in their response areas. In many cells, serotonergic effects on tones were reflected in the responses to FM signals. The most interesting effects were in those cells in which serotonin selectively changed the responsiveness to only some frequencies in the neuron's response area and had little or no effect on other frequencies. This caused predictable changes in responses to the more complex FM sweeps whose spectral components passed through the neurons' response areas. Our results suggest that serotonin, whose release varies with behavioral state, functionally reconfigures the circuitry of the IC and may modulate the perception of acoustic signals under different behavioral states.

Author response for "Distribution and co‐expression of adrenergic receptor‐encoding mRNA in the mouse inferior colliculus"

2020 ◽  
Author(s):  
Charles A. Williams ◽  
Kimberly E. Miller ◽  
Nisa P. Williams ◽  
Christine V. Portfors ◽  
David J. Perkel
Keyword(s):  
Inferior Colliculus ◽  
Adrenergic Receptor ◽  
Author Response
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