An investigation of sensory deficits underlying the aphasia-like behavior of macaques with auditory cortex lesions

Harrington, Ian A.; Heffner, Rickye S.; Heffner, Henry E.

doi:10.1097/00001756-200105080-00032

Cited by 47 publications

(45 citation statements)

References 17 publications

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“…Postoperatively, frequency difference thresholds increased in the range of 7-25 Hz from preoperative thresholds (Weber fractions increased between 1.4 and 4.9%), and the size of the increase correlated with the size of the lesion. Harrington et al (2001) reported that two Japanese macaques with near-complete bilateral lesions of superior temporal cortex had pure tone frequency difference thresholds that were over twice those of two monkeys without lesions (center frequency near 625 Hz). The average Weber fraction associated with discrimination scores less than 0.80 [hit rate Ϫ (hit rate ϫ false alarm rate)] was 5.8% compared with 2.4% in monkeys without superior temporal lesions.…”

Section: Functional Effects Of Auditory Cortex Lesions In Primatesmentioning

confidence: 99%

Functional Role of Auditory Cortex in Frequency Processing and Pitch Perception

Tramo

Shah

Braida

2002

Journal of Neurophysiology

112

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. 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. I N T R O D U C T I O NMany neurons in mammalian auditory cortex respond selectively to pure tone frequencies over a narrow range of the audible spectrum, and several anatomical subdivisions of auditory cortex are organized topographically with respect to frequency selectivity (for reviews, see Aitkin et al. 1984;Brugge and Reale 1985;Clarey et al. 1992;de Ribaupierre 1997;Kaas et al. 1999;Phillips et al. 1991;Schreiner 1992). On theoretical grounds, it would seem reasonable to propose that neuronal frequency selectivity at the physiological level contributes to frequency discrimination at the perceptual level. However, the functional effects of auditory cortex lesions in animals and humans have been interpreted as evidence against this hypothesis. In their authoritative review of a large number of lesion studies in the Handbook of Sensory Physiology, Neff et al. (1975) concluded, "Frequency discrimination may be learned or relearned after bilateral lesions involving all or nearly all of primary auditory cortex in animals such as the cat and monkey and in human patient...

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Section: Functional Effects Of Auditory Cortex Lesions In Primatesmentioning

confidence: 99%

Functional Role of Auditory Cortex in Frequency Processing and Pitch Perception

Tramo

Shah

Braida

2002

Journal of Neurophysiology

112

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“…Physiological studies have shown that ACx neurons respond to spectrotemporally complex stimuli such as frequency-modulated (FM) stimuli, at times better than they respond to pure tones Phillips et al, 1985;Rauschecker and Tian, 2000;Tian and Rauschecker, 2004;WhitWeld and Evans, 1965). Conversely, lesions of ACx in animals diminish their ability to discriminate FM stimuli (Harrington et al, 2001;Kelly and WhitWeld, 1971;Ohl et al, 1999;Wetzel et al, 1998). ACx lesions in humans indicate a role in speech perception, or perhaps more precisely, in the perception of temporal or spectrotemporal transitions in speech (Phillips, 1998;Phillips and Farmer, 1990).…”

Section: Introductionmentioning

confidence: 99%

Spectral integration in auditory cortex: Mechanisms and modulation

et al. 2005

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“…Auditory cortex is involved in the perception of temporal distinctions (Merzenich et al 1993). Humans, non-human primates, and rodents exhibit temporal processing deficits after auditory cortex lesions (Clark et al 2000a,b;Fitch et al 1994;Harrington et al 2001;Herman et al 1997;Mummery et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Environmental Enrichment Increases Paired-Pulse Depression in Rat Auditory Cortex

Percaccio

Pruette²,

Pandya

et al. 2005

Journal of Neurophysiology

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Earlier studies have shown that cortical processing of temporal information can be altered by long-term experience with modulated sounds. In a previous study, we observed that environmental enrichment dramatically increased the response of cortical neurons to single tone and noise burst stimuli in both awake and anesthetized rats. Here, we evaluate how enrichment influences temporal information processing in the auditory cortex. We recorded responses to repeated tones and noise bursts in awake rats using epidural evoked potentials and in anesthetized rats using microelectrodes. Enrichment increased the response of cortical neurons to stimuli presented at slow rates and decreased the response to stimuli presented at fast rates relative to controls. Our observation that enrichment substantially increased response strength and forward masking is consistent with earlier reports that long-term potentiation of cortical synapses is associated with increased paired-pulse depression. Enrichment also increased response synchronization at slow rates and decreased synchronization at fast rates. Paired-pulse depression increased within days of environmental enrichment and was restored to normal levels after return to standard housing conditions. These results are relevant to several clinical disorders characterized by abnormal gating of sensory information, including autism, schizophrenia, and dyslexia.

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An investigation of sensory deficits underlying the aphasia-like behavior of macaques with auditory cortex lesions

Cited by 47 publications

References 17 publications

Functional Role of Auditory Cortex in Frequency Processing and Pitch Perception

Functional Role of Auditory Cortex in Frequency Processing and Pitch Perception

Spectral integration in auditory cortex: Mechanisms and modulation

Environmental Enrichment Increases Paired-Pulse Depression in Rat Auditory Cortex

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