Multiple time axes for representation of echo delays in the auditory cortex of the mustached bat

Suga, Nobuo; Horikawa, Junsei

doi:10.1152/jn.1986.55.4.776

Cited by 85 publications

(72 citation statements)

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“…For all age groups, CP was 2-6 dB more sensitive than PP (days 0-7: 64 ± 15 dB SPL; days 20-28: 54 ± 12 dB SPL; adult: 44 ± 9 dB SPL). The data for anaesthetized adult PP are comparable to published data on awake bats 3,6,7,16,17 . The threshold decrease of neurons that were grouped into short, medium and long CD units (Fig.…”

Section: Postnatal Maturation Of Characteristics Of Time Sensitive Nesupporting

confidence: 81%

Auditory cortex of newborn bats is prewired for echolocation

et al. 2012

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neuronal computation of object distance from echo delay is an essential task that echolocating bats must master for spatial orientation and the capture of prey. In the dorsal auditory cortex of bats, neurons specifically respond to combinations of short frequency-modulated components of emitted call and delayed echo. These delay-tuned neurons are thought to serve in target range calculation. It is unknown whether neuronal correlates of active space perception are established by experience-dependent plasticity or by innate mechanisms. Here we demonstrate that in the first postnatal week, before onset of echolocation and flight, dorsal auditory cortex already contains functional circuits that calculate distance from the temporal separation of a simulated pulse and echo. This innate cortical implementation of a purely computational processing mechanism for sonar ranging should enhance survival of juvenile bats when they first engage in active echolocation behaviour and flight.

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Section: Postnatal Maturation Of Characteristics Of Time Sensitive Nesupporting

confidence: 81%

Auditory cortex of newborn bats is prewired for echolocation

et al. 2012

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“…In contrast to the sharply delay-tuned responses observed in the MGB (Olsen and Suga, 1991) and AC of the mustache bat (Suga and Horikawa, 1986), delay-facilitated neurons in SC and other structures of Eptesicus (DNLL: Covey, 1993;ITN: Dear and Suga, 1995;AC: Dear et al, 1993a) are broadly tuned along the range axis. In the mustache bat, thalamic and cortical delay-sensitive neurons respond predominantly to delay values corresponding to close target ranges, typically between 14 and 140 cm, although BDs for ranges up to 400 cm also were reported (Suga and Horikawa, 1986).…”

Section: Neurophysiological and Anatomical Considerationsmentioning

confidence: 79%

“…The SC of the bat lies on the dorsal surface of the brain as shown in Figure 1. A surgical procedure was carried out both to expose the SC for extracellular recording and to mount a small pedestal that served to immobilize the bat's head during these experiments (see Suga et al, 1983;Suga and Horikawa, 1986). Under anesthesia (ketamine/xylazine, i.m., standard dosage of 52.4 mg/kg body weight), the muscle and skin covering the dorsal cranium were retracted and the restraint post was fastened with cyanoacrylate (Locktite 411) onto the bone surface anterior to the SC.…”

Section: Methodsmentioning

confidence: 99%

“…The sounds were broadcast as single-sound stimuli or as pulse-echo pairs in which the two sounds were separated by a time delay. In each of these experiments, the pulse (P), which stands for the bat's echolocation cry, is not self-produced but is played to the restrained bat (O'Neill and Suga, 1982;Suga and Horikawa, 1986;Wong and Shannon, 1988;Covey, 1993;Dear et al, 1993a,b;Dear and Suga, 1995). The simulated echo (E) is a second, weaker sound, presented with a time delay from the onset of P.…”

Section: Methodsmentioning

confidence: 99%

“…In the mustache bat, thalamic and cortical delay-sensitive neurons respond predominantly to delay values corresponding to close target ranges, typically between 14 and 140 cm, although BDs for ranges up to 400 cm also were reported (Suga and Horikawa, 1986). The distribution of BDs in the AC of FM bats, Eptesicus and Myotis, also covers close target ranges (Wong and Shannon, 1988;Dear et al, 1993b).…”

Section: Neurophysiological and Anatomical Considerationsmentioning

confidence: 99%

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Spatially Selective Auditory Responses in the Superior Colliculus of the Echolocating Bat

Valentine

Moss

1997

J. Neurosci.

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When a bat approaches a target, it continuously modifies its echolocation sounds and relies on incoming echo information to shape the characteristics of its subsequent sonar cries. In addition, acoustic information about the azimuth and elevation of a sonar target elicits orienting movements of the head and pinnae toward the sound source. This requires a common sensorimotor interface, where echo information is used to guide motor behaviors.Using single-unit neurophysiological methods and free-field auditory stimulation, we present data on biologically relevant specializations in the superior colliculus (SC) of the bat for orientation by sonar. In the bat's SC, two classes of spatially tuned neurons are distinguished by their sensitivity to echoes. One population shows facilitated, delay-tuned responses to pairs of sounds, simulating sonar emissions and echoes. Delay tuning, related to encoding target range, may play a role in guiding motor responses in echolocation, because the bat adjusts its emissions with changes in target distance. The delay-facilitated response depends on the direction of stimulation and on the temporal relationship between the simulated emission and echo in the sound pair, suggesting that this class of neurons represents the location of a target in three dimensions. A second population encodes the target in two dimensions, azimuth and elevation, and does not show a facilitated response to echoes delivered from any locus. Encoding of azimuth and elevation may be important for directing head aim, and this class may function in transforming auditory spatial information into signals used to guide acoustic orientation. Key words: superior colliculus; echolocation; bats; acoustic orientation; spatial perception; sensorimotor integrationThe midbrain superior colliculus (SC; optic tectum) of vertebrates is thought to play a role in spatial perception and in the translation of multisensory signals into commands for the control of quick (saccadic) orienting responses. In individual species, the organization of the SC reflects the importance of a particular sensory modality to an animal's goal-directed behavioral responses. By analogy with the role of the SC in the saccadic eye-movement system of primates (Sparks, 1986), in gaze-control orientation behavior in cat and barn owl (Knudsen, 1982;Middlebrooks and Knudsen, 1984;Du Lac and Knudsen, 1990;Munoz et al., 1991), and in prey-catching behavior in pit viper and frog (Hartline et al., 1978;Grobstein, 1988), the SC of the echolocating bat may play a role in integrating sensory and motor signals that drive this animal's acoustic orientation by sonar.The bat guides its flight and forages in darkness by emitting ultrasonic vocal signals and listening to the echoes returning to its ears from objects in space (Griffin, 1958;Moss and Schnitzler, 1995). Binaural differences in arrival time, intensity, and spectrum of echoes encode the location of an object in azimuth and elevation (Lawrence and Simmons, 1982;Simmons et al., 1983;Pollak, 1988). The third dim...

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Distribution of response types across entire hemispheres of the mustached bat's auditory cortex

1998

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The responses of neurons in the mustached bat's auditory cortex are specialized to extract particular information from biosonar signals. For this study, we mapped response properties across entire hemispheres in several animals. These experiments enabled us to construct a standard map that aided in determining the connections among the areas, as described subsequently. The mapping also yielded quantitative data regarding the relative sizes of areas and the proportion of cortex devoted to different response types. We identified six response types that were distributed in 11 areas. Eight areas, comprising two‐thirds of the auditory cortex, contained neurons sensitive to particular components in biosonar signals. Most were facilitated by combinations of frequency modulated and constant frequency biosonar signal components (FMs and CFs, respectively). There were three major types of combination‐sensitive neurons: FM‐FM, CF/CF, and FM‐CF. Each type of combination sensitivity occurred in multiple areas. The largest proportion were FM‐FM neurons (approximately 30% of all neurons in auditory cortex), followed by FM1‐CF2 (approximately 23%) and CF/CF (approximately 11%). In the other three areas comprising approximately one‐third of the auditory cortex, most neurons responded well to frequencies not contained in biosonar signals. J. Comp. Neurol. 391:353–365, 1998. © 1998 Wiley‐Liss, Inc.

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Multiple time axes for representation of echo delays in the auditory cortex of the mustached bat

Cited by 85 publications

References 0 publications

Auditory cortex of newborn bats is prewired for echolocation

Auditory cortex of newborn bats is prewired for echolocation

Spatially Selective Auditory Responses in the Superior Colliculus of the Echolocating Bat

Distribution of response types across entire hemispheres of the mustached bat's auditory cortex

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