Tonotopical organization and pure tone response characteristics of single units in the auditory cortex of the Greater Horseshoe Bat

1984 ◽  
Vol 155 (6) ◽  
pp. 821-834 ◽  
Author(s):  
Joachim Ostwald
Keyword(s):  
Auditory Cortex ◽  
Pure Tone ◽  
Single Units ◽  
Response Characteristics ◽  
Horseshoe Bat

scholarly journals Functional Role of Auditory Cortex in Frequency Processing and Pitch Perception

2002 ◽  
Vol 87 (1) ◽  
pp. 122-139 ◽  
Author(s):  
Mark Jude Tramo ◽  
Gaurav D. Shah ◽  
Louis D. Braida
Keyword(s):  
Auditory Cortex ◽  
Pure Tone ◽  
Current Knowledge ◽  
Frequency Discrimination ◽  
Frequency Selectivity ◽  
Frequency Resolution ◽  
Frequency Change ◽  
Fine Grained ◽  
Difference Thresholds ◽  
Frequency Processing

Microelectrode studies in nonhuman primates and other mammals have demonstrated that many neurons in auditory cortex are excited by pure tone stimulation only when the tone's frequency lies within a narrow range of the audible spectrum. However, the effects of auditory cortex lesions in animals and humans have been interpreted as evidence against the notion that neuronal frequency selectivity is functionally relevant to frequency discrimination. Here we report psychophysical and anatomical evidence in favor of the hypothesis that fine-grained frequency resolution at the perceptual level relies on neuronal frequency selectivity in auditory cortex. An adaptive procedure was used to measure difference thresholds for pure tone frequency discrimination in five humans with focal brain lesions and eight normal controls. Only the patient with bilateral lesions of primary auditory cortex and surrounding areas showed markedly elevated frequency difference thresholds: Weber fractions for frequency direction discrimination (“higher”—“lower” pitch judgments) were about eightfold higher than Weber fractions measured in patients with unilateral lesions of auditory cortex, auditory midbrain, or dorsolateral frontal cortex; Weber fractions for frequency change discrimination (“same”—“different” pitch judgments) were about seven times higher. In contrast, pure-tone detection thresholds, difference thresholds for pure tone duration discrimination centered at 500 ms, difference thresholds for vibrotactile intensity discrimination, and judgments of visual line orientation were within normal limits or only mildly impaired following bilateral auditory cortex lesions. In light of current knowledge about the physiology and anatomy of primate auditory cortex and a review of previous lesion studies, we interpret the present results as evidence that fine-grained frequency processing at the perceptual level relies on the integrity of finely tuned neurons in auditory cortex.

Potentials evoked by sound in the auditory cortex of the cat

1961 ◽  
Vol 200 (6) ◽  
pp. 1219-1225 ◽  
Author(s):  
Robert J. Gumnit ◽  
Robert G. Grossman
Keyword(s):  
Auditory Cortex ◽  
White Noise ◽  
Pure Tone ◽  
Evoked Response ◽  
Moderate Intensity ◽  
Positive Potential ◽  
Positive Wave ◽  
Natural Sleep ◽  
Negative Shift ◽  
Long Duration

The electrical responses of the auditory cortex of awake, loosely restrained cats were examined with chronically implanted calomel electrodes and d-c recording systems. Stimulation with a single click evoked a complex triphasic response in which a large surface positive potential (duration, 250 msec) followed the classic diphasic response. This second positive wave was absent in natural sleep and under light barbiturate anesthesia. A similar late positive wave of long duration, evoked by a flash of light, was found in the visual cortex. A rapid series of clicks evoked a surface negative shift which was maintained for the duration of the stimulus. A tone or white noise presented for several seconds evoked a negative shift of the same general form. A pure tone of moderate intensity presented simultaneously with a click greatly enhanced the click-evoked response. White noise of moderate intensity presented simultaneously with a click diminished the size of the click-evoked response.

Neural response characteristics in auditory cortex of the awake ferret

2002 ◽  
Vol 112 (5) ◽  
pp. 2287-2287
Author(s):  
Didier A. Depireux ◽  
Bing‐Zhong Chen ◽  
Peter Marvit ◽  
Yaan Li
Keyword(s):  
Auditory Cortex ◽  
Neural Response ◽  
Response Characteristics
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