Corticofugal Modulation of Time-Domain Processing of Biosonar Information in Bats

Yan, Jun; Suga, Nobuo

doi:10.1126/science.273.5278.1100

Cited by 182 publications

(133 citation statements)

References 28 publications

Supporting

Mentioning

127

Contrasting

Order By: Relevance

“…Echo-delay facilitation has been demonstrated previously in several species of bat and in several structures of the ascending auditory pathway, including dorsal nucleus of the lateral lemniscus (DNLL) (Covey, 1993), intertectal nucleus (ITN) (Feng et al, 1978;Dear and Suga, 1995), inferior colliculus (IC) (Mittmann and Wenstrup, 1994;Yan and Suga, 1996), medial geniculate body (MGB) (Olsen and Suga, 1991), and auditory cortex (AC) (Suga and O'Neill, 1979;Wong and Shannon, 1988;Dear et al, 1993a,b). Comparing the mean neural response latencies across structures studied in Eptesicus fuscus, the time to firing in the SC (2D: 8.5 Ϯ 3.4 msec; 3D: 9.7 Ϯ 2.3 msec) falls between the average latencies reported for DNLL (7.8 Ϯ 3.5 msec; Covey, 1993) and AC (non-delay-tuned: 13.8 Ϯ 5.7 msec; delay-tuned: 12.1 Ϯ 5.5 msec, Dear et al, 1993b), although the overlap with the brainstem nucleus is considerable.…”

Section: Neurophysiological and Anatomical Considerationsmentioning

confidence: 99%

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

Valentine

Moss

1997

J. Neurosci.

View full text Add to dashboard Cite

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...

show abstract

Section: Neurophysiological and Anatomical Considerationsmentioning

confidence: 99%

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

Valentine

Moss

1997

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…The shift of a BF, together with a frequency-tuning curve, is called a BF shift. Such corticofugal modulation, called egocentric selection (1), improves the input to the stimulated cortical neurons and the subcortical and cortical representations of the stimulus parameters to which the stimulated cortical neurons are tuned (2)(3)(4)(5)(6)(7)(8) There are two types of BF shifts: centripetal and centrifugal. Centripetal BF shifts are the shifts toward the BF of electrically stimulated cortical neurons, and centrifugal BF shifts are the shifts away from the stimulated cortical BF.…”

mentioning

confidence: 99%

Reorganization of the auditory cortex specialized for echo-delay processing in the mustached bat

Xiao¹,

Suga²

2004

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

Focal excess sensory stimulation evokes reorganization of a sensory system. It is usually an expansion of the neural representation of that stimulus resulting from the shifts of the tuning curves (receptive fields) of neurons toward those of the stimulated neurons. The auditory cortex of the mustached bat has an area that is highly specialized for the processing of target-distance information carried by echo delays. In this area, however, reorganization is due to shifts of the delay-tuning curves of neurons away from those of the stimulated cortical neurons. Elimination of inhibition in the target-distance processing area in the auditory cortex by a drug reverses the direction of the shifts in neural tuning curves. Therefore, such unique reorganization in the time domain is due to strong lateral inhibition in the highly specialized area of the auditory cortex.bicuculline ͉ centrifugal shift ͉ centripetal shift ͉ delay tuning ͉ plasticity E lectric stimulation of cortical auditory neurons evokes both facilitation and inhibition of the auditory responses of cortical and subcortical neurons. The amount of facilitation and inhibition varies with the frequency of a tone burst to which the neurons respond and with the relationship in frequency tuning between the stimulated and recorded neurons. When the best frequency (BF) of a recorded neuron matches that of a stimulated cortical neuron, the response of the matched neuron to its BF is often augmented, and the responses at frequencies lower and͞or higher than the BF are inhibited. When unmatched, the response of the unmatched neuron is inhibited at its BF and is facilitated at non-BFs. As a result, frequency tuning of the unmatched neuron is shifted. The shift of a BF, together with a frequency-tuning curve, is called a BF shift. Such corticofugal modulation, called egocentric selection (1), improves the input to the stimulated cortical neurons and the subcortical and cortical representations of the stimulus parameters to which the stimulated cortical neurons are tuned (2)(3)(4)(5)(6)(7)(8) There are two types of BF shifts: centripetal and centrifugal. Centripetal BF shifts are the shifts toward the BF of electrically stimulated cortical neurons, and centrifugal BF shifts are the shifts away from the stimulated cortical BF. These two types of BF shifts occur in a specific spatial pattern along the frequency axis in the auditory cortex (AC), medial geniculate body, and inferior colliculus. The spatial pattern is basically the same in the AC and the inferior colliculus of the big brown bat (3,5,6,9) and the mustached bat (1, 2, 10). In the ACs of the big brown bat (5, 6) and Mongolian gerbil (8), centripetal BF shifts occur in a large area surrounding the matched neurons, and small centrifugal BF shifts occur in the narrow zone surrounding this large centripetal area; i.e., center-surround reorganization occurs. Because centrifugal BF shifts are small, the major reorganization in these ACs is due to centripetal BF shifts. In the Doppler-shifted constant frequency (DSCF)...

show abstract

“…Here views diverge, ranging from estimate of less than a millisecond (König et al 1995;Softky 1995) to tens of milliseconds (Shadlen & Newsome 1994). Data on echo location and spatial location of sound sources show that neurons are capable of very precise conicidence detection (Yan & Suga 1996). Whether this is also true in the cortex remains to be seen, but recent evidence on action potentials backpropagating into dendrites (Stuart & Sakmann 1994) and other regenerative events in dendrites (Connors & Gutnick 1990) may lead to a drastic change in views on the timescale of dendritic integration.…”

Section: R33 What Are the Time-scales Of Synchronization?mentioning

confidence: 98%

Progress toward an understanding of cortical computation

Phillips¹,

Singer²

1997

Behav Brain Sci

View full text Add to dashboard Cite

The additional data, perspectives, questions, and criticisms contributed by the commentaries strengthen our view that local cortical processors coordinate their activity with the context in which it occurs using contextual fields and synchronized population codes. We therefore predict that whereas the specialization of function has been the keynote of this century the coordination of function will be the keynote of the next

show abstract

Corticofugal Modulation of Time-Domain Processing of Biosonar Information in Bats

Cited by 182 publications

References 28 publications

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

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

Reorganization of the auditory cortex specialized for echo-delay processing in the mustached bat

Progress toward an understanding of cortical computation

Contact Info

Product

Resources

About