Functional topography of cat primary auditory cortex: representation of tone intensity

Schreiner, Christoph E.; Mendelson, J. R.; Sutter, Mitchell L.

doi:10.1007/bf00230388

Cited by 135 publications

(85 citation statements)

References 43 publications

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“…Although this is a possibility, multiple considerations argue against N1 enhancement as an explanation for the current set of results. First, results of animal studies indicate that at the suprathreshold intensities used in the current study, the firing rates of neurons change very little in response to intensity level if they have monotonic rate intensity functions, and can even decrease for those cells that have nonmonotonic intensity functions (e.g., Schreiner et al, 1992). Moreover, in humans, at the intensity and frequency levels used in the current study, only a minimal difference in N1 amplitude has been reported (Biermann and Heil, 2000;Schröger, 1994).…”

Section: Discussionmentioning

confidence: 79%

Neurophysiological evidence for context-dependent encoding of sensory input in human auditory cortex

Sussman

Steinschneider

2006

Brain Research

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Attention biases the way in which sound information is stored in auditory memory. Little is known, however, about the contribution of stimulus-driven processes in forming and storing coherent sound events. An electrophysiological index of cortical auditory change detection (mismatch negativity [MMN]) was used to assess whether sensory memory representations could be biased toward one organization over another (one or two auditory streams) without attentional control. Results revealed that sound representations held in sensory memory biased the organization of subsequent auditory input. The results demonstrate that context-dependent sound representations modulate stimulusdependent neural encoding at early stages of auditory cortical processing.

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Section: Discussionmentioning

confidence: 79%

Neurophysiological evidence for context-dependent encoding of sensory input in human auditory cortex

Sussman

Steinschneider

2006

Brain Research

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“…At each site, the spontaneous firing rate collected during the 100 ms before stimulus onset was subtracted from the stimulus onset response (mean duration of the onset response Ϯ SD, 21.44 Ϯ 10.68 ms). Each RLF was normalized to its maximum firing rate, and the following measures (defined below) were derived according to the method outlined by Schreiner et al (1992): (1) minimum response threshold; (2) transition point; (3) best level; (4) slope of the RLF between the minimum response threshold and the transition point; and (5) monotonicity. If the spike rate remained at zero for two consecutive sound levels, all sound levels less than or equal to the greater of the two levels were considered subthreshold.…”

Section: Methodsmentioning

confidence: 99%

Perceptual Learning Directs Auditory Cortical Map Reorganization through Top-Down Influences

Polley¹,

Steinberg²,

Merzenich³

2006

J. Neurosci.

505

418

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The primary sensory cortex is positioned at a confluence of bottom-up dedicated sensory inputs and top-down inputs related to higherorder sensory features, attentional state, and behavioral reinforcement. We tested whether topographic map plasticity in the adult primary auditory cortex and a secondary auditory area, the suprarhinal auditory field, was controlled by the statistics of bottom-up sensory inputs or by top-down task-dependent influences. Rats were trained to attend to independent parameters, either frequency or intensity, within an identical set of auditory stimuli, allowing us to vary task demands while holding the bottom-up sensory inputs constant. We observed a clear double-dissociation in map plasticity in both cortical fields. Rats trained to attend to frequency cues exhibited an expanded representation of the target frequency range within the tonotopic map but no change in sound intensity encoding compared with controls. Rats trained to attend to intensity cues expressed an increased proportion of nonmonotonic intensity response profiles preferentially tuned to the target intensity range but no change in tonotopic map organization relative to controls. The degree of topographic map plasticity within the task-relevant stimulus dimension was correlated with the degree of perceptual learning for rats in both tasks. These data suggest that enduring receptive field plasticity in the adult auditory cortex may be shaped by task-specific top-down inputs that interact with bottom-up sensory inputs and reinforcement-based neuromodulator release. Top-down inputs might confer the selectivity necessary to modify a single feature representation without affecting other spatially organized feature representations embedded within the same neural circuitry.

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“…The first tonotopic auditory neocortical map was demonstrated by Woolsey and Walzl (1942) in the form of a cochleotopic organization in the primary auditory cortex (AI) of the cat. Other functional maps in AI include binaural interaction bands (Imig and Adrian, 1977;Middlebrooks et al, 1980), threshold/intensity (Tunturi, 1950;Schreiner et al, 1992), and sharpness of tuning (Schreiner and Mendelson, 1990). Interestingly, these maps are patchy or discontinuous in their distribution relative to the frequency map Brugge and Imig, 1978;Middlebrooks et al, 1980;Reale and Imig, 1980;Redies et al, 1989;Schreiner, 1991Schreiner, , 1992Schreiner et al, 1992Schreiner et al, , 2000Mendelson et al, 1993Mendelson et al, , 1997Fitzpatrick et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Functional Subregions in Primary Auditory Cortex Defined by Thalamocortical Terminal Arbors: An Electrophysiological and Anterograde Labeling Study

et al. 2003

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Several functional maps have been described in primary auditory cortex, including those related to frequency, tuning, latency, binaurality, and intensity. Many of these maps are arranged in a discontinuous or patchy manner. Similarly, thalamocortical projections arising from the ventral division of the medial geniculate body to the primary auditory cortex are also patchy. We used anterograde labeling and electrophysiological methods to examine the relationship between thalamocortical patches and auditory cortical maps. Biotinylated dextran-amine was deposited into physiologically characterized sites in the ventral division of the medial geniculate body of New Zealand white rabbits. Approximately 7 d later, the animal was again anesthetized and the ipsilateral auditory cortex was mapped with tungsten microelectrodes. Multi-unit physiological data were obtained for the following characteristics: best frequency (BF), binaurality, response type, latency, sharpness of tuning, and threshold. Immunocytochemical methods were used to reveal the injection site in the ventral division of the medial geniculate body as well as the anterogradely labeled thalamocortical afferents in the auditory cortex. In 86% of the cases (12 of 14), entry into a thalamocortical patch was associated with a marked change in physiological responses. A consistent BF and binaural class were usually observed within a patch. The patches appear to innervate distinct functional regions coding frequency and binaurality. A model is presented showing how patchy thalamocortical projections participate in the formation of tonotopic and binaural maps in primary auditory cortex.

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Functional topography of cat primary auditory cortex: representation of tone intensity

Cited by 135 publications

References 43 publications

Neurophysiological evidence for context-dependent encoding of sensory input in human auditory cortex

Neurophysiological evidence for context-dependent encoding of sensory input in human auditory cortex

Perceptual Learning Directs Auditory Cortical Map Reorganization through Top-Down Influences

Functional Subregions in Primary Auditory Cortex Defined by Thalamocortical Terminal Arbors: An Electrophysiological and Anterograde Labeling Study

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