Distribution of combination-sensitive neurons in the ventral fringe area of the auditory cortex of the mustached bat

Edamatsu, Hideo; Kawasaki, Masashi; Suga, Nobuo

doi:10.1152/jn.1989.61.1.202

Cited by 34 publications

(19 citation statements)

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“…Part of this labeling was associated with a mark placed in the FM-FM area, at a location with an FM 1 -FM 2 response and a best delay of 5.1 ms (section 5). There was no label associated with a mark placed at a location with a best delay of 12.0 ms (section 8), consistent with the view that the VF area contains only neurons with relatively short best delays (Edamatsu and Suga, 1993;Edamatsu et al, 1989). A large patch of moderate label in the dorsal cortex (sections 7-11, arrow 2) was associated with a mark placed in the DF area (section 9) and included the core of the DF area (sections 8-11, arrow 2).…”

Section: Connections Of Areas Containing Fm-fm Neurons: Fm-fm Df Ansupporting

confidence: 72%

“…However, there is some evidence in favor of a direction of information flow. First, the latencies in the DF and VF areas are slightly longer than in the FM-FM area (Suga and Horikawa, 1986;Edamatsu et al, 1989), corresponding with the expected direction. Second, the DF and VF areas have moderate or strong connections with the perirhinal and retrosplenial cortex that are weak or absent from the FM-FM area.…”

Section: Technical Issuesmentioning

confidence: 74%

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Connections among functional areas in the mustached bat auditory cortex

1998

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Connections among functional areas in the mustached bat's auditory cortex were examined by placing anatomical tracers in physiologically defined locations. We identified at least two and probably three channels connecting the various areas. One channel is formed by interconnections among areas containing neurons sensitive to frequency-modulated components (FMs) of the pulse and echo. These neurons are tuned to echo delay, a cue for target range, and thus define a ranging channel. An additional one or two channels are formed by interconnections among areas that contain neurons sensitive to the constant frequency components (CFs) of echoes. These neurons are of two main types: either sensitive to CFs of both pulse and echo (CF/CF neurons) or sensitive to a pulse FM and echo CF (FM-CF neurons). There was only a weak connection between the largest area of each type, suggesting they lie in different channels. Connections among areas in the ranging channel and echo CF-sensitive channel(s) were weak. Thus, the interconnections among functional areas in the mustached bat's auditory cortex define parallel channels for processing different types of biosonar information. Most corticocortical connections were patchy, in a manner suggestive of a columnar organization. The average width of the patches was approximately 360 microm. Based on the sizes of the functional areas, we estimate the auditory cortex contains a total of approximately 150 columns. Individual areas contain from as many as approximately 20 to as few as 1-4 columns. Each area had abundant projections outside of the auditory cortex. Connections within the cortex included the frontal, anterior cingulate, retrosplenial and perirhinal cortices, and the claustrum. Subcortical targets included the amygdyla, auditory thalamus, pons, pretectum, superior and inferior colliculi, and central gray. Projections within the cortex were of modest strength compared with several of the subcortical projections. Thus, the auditory areas themselves are the primary source of cortically processed biosonar information to the rest of the brain.

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Section: Connections Of Areas Containing Fm-fm Neurons: Fm-fm Df Ansupporting

confidence: 72%

Section: Technical Issuesmentioning

confidence: 74%

Connections among functional areas in the mustached bat auditory cortex

1998

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“…1 A). The BD axis (i.e., target-range axis) goes up to Ϸ18 ms (310 cm) in the FM-FM area (25), Ϸ8 ms (140 cm) in the DF area (45), and Ϸ4 ms (70 cm) in the VF area (46). All of these areas consist of three types of FM-FM neurons: FM 1 -FM 2 , FM 1 -FM 3 , and FM 1 -FM 4 , and are mutually connected (47).…”

Section: Discussion Corticofugal Modulation and Shifts In Tuning Curvmentioning

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.

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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)...

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“…Suga and his colleagues (Edamatsu et al 1989;O'Neill and Suga 1982;Tsuzuki and Suga 1988) have conducted such experiments on awake bats and found that neuronal responses to particular aspects of FM stimuli, a crucial component of the bat's biosonar system, are topographically organized in the auditory cortex. To date, only two studies have been conducted on common mammals lacking acoustic specialization: a pioneering study on awake cats (Whitfield and Evans 1965) and a recent study on awake owl monkeys (Atencio et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Neuronal Responses to Frequency-Modulated Tones in the Primary Auditory Cortex of Awake Cats

Qin¹,

Wang²,

Sato³

2008

Journal of Neurophysiology

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Qin L, Wang J, Sato Y. Heterogeneous neuronal responses to frequency-modulated tones in the primary auditory cortex of awake cats. J Neurophysiol 100: 1622-1634, 2008. First published July 16, 2008 doi:10.1152/jn.90364.2008. Previous studies in anesthetized animals reported that the primary auditory cortex (A1) showed homogenous phasic responses to FM tones, namely a transient response to a particular instantaneous frequency when FM sweeps traversed a neuron's tone-evoked receptive field (TRF). Here, in awake cats, we report that A1 cells exhibit heterogeneous FM responses, consisting of three patterns. The first is continuous firing when a slow FM sweep traverses the receptive field of a cell with a sustained tonal response. The duration and amplitude of FM response decrease with increasing sweep speed. The second pattern is transient firing corresponding to the cell's phasic tonal response. This response could be evoked only by a fast FM sweep through the cell's TRF, suggesting a preference for fast FM. The third pattern was associated with the OFF response to pure tones and was composed of several discrete response peaks during slow FM stimulus. These peaks were not predictable from the cell's tonal response but reliably reflected the time when FM swept across specific frequencies. Our A1 samples often exhibited a complex response pattern, combining two or three of the basic patterns above, resulting in a heterogeneous response population. The diversity of FM responses suggests that A1 use multiple mechanisms to fully represent the whole range of FM parameters, including frequency extent, sweep speed, and direction. I N T R O D U C T I O NFM is an important feature of communication sounds, including both human speech and animal vocalizations; and the neuronal mechanisms that underlie the processing of FM signals have therefore received considerable attention. Many electrophysiological studies have been conducted on the auditory cortex of numerous species (bats: Suga 1965; rats: Mendelson and Ricketts 2001;Zhang et al. 2003; ferrets: Kowalski et al. 1995;Nelken and Versnel 2000;Shamma et al. 1993; cats: Heil and Irvine 1998; Heil et al. 1992b,c;Mendelson and Grasse 1992;Phillips et al. 1985; Rauschecker 1994, 1998; and monkeys: Godey et al. 2005;Tian and Rauschecker 2004). These studies in anesthetized animals generally reported that the auditory cortical neurons responded to FM sweeps in a phasic discharge pattern; that is, neuronal discharges were elicited only when the instantaneous frequency of FM sweep reached a particular trigger frequency corresponding to either the upper or lower boundary of the neuron's tonal receptive field (TRF). All neuronal discharges were restricted to considerably shorter time intervals compared with those required for FM sweeps to traverse the TRF. Such a phasic discharge pattern conforms to the general observation that most auditory cortical neurons in anesthetized animals respond only transiently at stimulus onset (deCharms and Merzenich 1996;DeWeese et al. 2003;Eggermont...

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Distribution of combination-sensitive neurons in the ventral fringe area of the auditory cortex of the mustached bat

Cited by 34 publications

References 0 publications

Connections among functional areas in the mustached bat auditory cortex

Connections among functional areas in the mustached bat auditory cortex

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

Heterogeneous Neuronal Responses to Frequency-Modulated Tones in the Primary Auditory Cortex of Awake Cats

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