Single neuron, evoked potential and metabolic techniques show that attention influences visual processing in extrastriate cortex. We provide anatomical, electrophysiological and behavioral evidence that prefrontal cortex regulates neuronal activity in extrastriate cortex during visual discrimination. Event-related potentials (ERPs) were recorded during a visual detection task in patients with damage in dorsolateral prefrontal cortex. Prefrontal damage reduced neuronal activity in extrastriate cortex of the lesioned hemisphere. These electrophysiological abnormalities, beginning 125 ms after stimulation and lasting for another 500 ms, were accompanied by behavioral deficits in detection ability in the contralesional hemifield. The results provide evidence for intrahemispheric prefrontal modulation of visual processing.

In order to clarify the roles played by the primary motor cortex and the supplementary motor area in the execution of complex sequential and simple repetitive finger movements, regional cerebral blood flow (rCBF) was measured with PET using 15O-labelled water in five normal subjects. The PET data of each individual subject co-registered to his own MRI, was analysed. Compared with the resting condition, the mean rCBF was markedly increased in the contralateral sensorimotor cortex (M1-S1) and moderately increased in the contralateral cingulate gyrus and putamen in both the simple and complex motor tasks. During the complex motor task, in addition to the above, the mean rCBF was markedly increased in the supplementary motor area and the contralateral premotor area, and moderately increased in the ipsilateral M1-S1 and cerebellum. In the supplementary motor area, there was a moderate rCBF increase also during the simple task. However, comparison of the mean rCBF increase against the resting condition between the two tasks revealed a greater increase during the complex task than in the other only in the supplementary motor area and the ipsilateral M1-S1. Thus, in agreement with our previous electrophysiological findings, not only the supplementary motor area but also the M1-S1 seems to play an important role in the execution of complex sequential finger movements.

The temporal and spatial characteristics of the cortical processes responsible for absolute pitch (AP) and relative pitch (RP) were investigated by multi-channel event-related potentials (ERPs). Compared to listening, pitch-naming of tones in non-possessors of AP elicited three ERP components (P3b, parietal positive slow wave, frontal negative slow wave) over parietal and frontal scalp between 300 and 900 ms in latency, representing the cortical processes for RP. Possessors of AP elicited a unique left posterior-temporal negativity ('AP negativity') at 150 ms in both listening and pitch-naming conditions, representing the cortical processes for AP that were triggered by pitch input irrespective of the task the subjects were asked to perform. Congruency of auditory Stroop stimuli modulated the amplitudes of parietal positive slow wave (non-possessors of AP) and 'AP negativity' (possessors of AP), confirming that these components reflect the verbal labeling or pitch-to-pitch-name associative transformation that is central to pitch-naming. These results are consistent with the hypothesis that AP is subserved by neuronal processes in the left auditory association cortex that occur earlier and more automatically than the processes for RP, which involve broader areas of the cortex over longer periods of time.

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The consonance of individual chords presented out of musical context, or the noncontextual consonance of chords, is usually defined as the absence of roughness, which is a sensation perceived when slightly mistuned frequencies are not clearly resolved in the cochlea. The present work uses evoked potentials to demonstrate that the absence of roughness is not sufficient to explain the entirety of noncontextual consonance perception. Presented with a random sequence of various pure-tone intervals (0-13 semitones), listeners' cerebral cortical activities distinguished these stimuli according to their noncontextual consonance in a manner consistent with standard musical practice, even when the intervals exceeded the critical bandwidth (approximately three semitones). The roughness-based model of noncontextual consonance could not account for this result because these wide intervals had indistinguishably low levels of roughness. Further, this effect was evident only in musicians, indicating plasticity in the underlying neural mechanisms. The results are consistent with the hypothesis that, although the absence of roughness may represent an important aspect of noncontextual consonance, properties of intervals other than those related to roughness also contribute to this perception, underpinned by neural activity in the central auditory system that can be plastically modified by experience.

Our study identified specific cognitive impairments in DM1. Specific cognitive functions and psychological factors may be potential contributors to QoL. Muscle Nerve 57: 742-748, 2018.

Cortical processes underlying perception of musical consonance were investigated by long-latency auditory evoked potentials (EPs). Subjects listened to a random sequence of dyadic pure tones paired at various pitch intervals (1, 4, 6, 7, or 9 semitones). Amplitudes of P2 and N2 components of auditory EPs were significantly modulated by pitch interval of the dyads, being most negative for 1 semitone (minor second) and least negative or most positive for 7 semitones (perfect fifth). The results indicate that neural processing of consonance depend not only on peripheral mechanisms in the inner ear but also on higher associative processing of pitch relationships in the cerebral cortex.

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