Recordings from single units in kitten primary visual cortex show that a reversible blockade of the discharge activities of cortical neurons and geniculocortical afferent terminals by intracortical infusion of the sodium channel blocker tetrodotoxin (TTX) completely prevented the ocular dominance shift that would normally be seen after monocular deprivation. The blockade of cortical plasticity, like the blockade of discharge activity, was reversible, and plasticity was restored following recovery from the effects of TTX. These results extend previous work suggesting involvement of electrical activity at the level of the cortex in the phenomenon of cortical plasticity by demonstrating an absolute requirement for discharge activities in the primary visual cortex.
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http://dx.doi.org/10.1007/BF00243841 | DOI Listing |
PLoS Biol
January 2025
Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.
Goal-directed behavior requires the effective suppression of distractions to focus on the task at hand. Although experimental evidence suggests that brain areas in the prefrontal and parietal lobe contribute to the selection of task-relevant and the suppression of task-irrelevant stimuli, how conspicuous distractors are encoded and effectively ignored remains poorly understood. We recorded neuronal responses from 2 regions in the prefrontal and parietal cortex of macaques, the frontal eye fields (FEFs) and the lateral intraparietal (LIP) area, during a visual search task, in the presence and absence of a salient distractor.
View Article and Find Full Text PDFJ Neurophysiol
January 2025
Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, Korea.
Previous studies have shown that high-gamma (HG) activity in the primary visual cortex (V1) has distinct higher (broadband) and lower (narrowband) components with different functions and origins. However, it is unclear whether a similar segregation exists in the primary somatosensory cortex (S1), and the origins and roles of HG activity in S1 remain unknown. Here, we investigate the functional roles and origins of HG activity in S1 during tactile stimulation in humans and a rat model.
View Article and Find Full Text PDFHow the prefrontal hemispheres coordinate to adapt to spatial working memory (WM) demands remains an open question. Recently, two models have been proposed: A specialized model, where each hemisphere governs contralateral behavior, and a redundant model, where both hemispheres equally guide behavior in the full visual space. To explore these alternatives, we analyzed simultaneous bilateral prefrontal cortex recordings from three macaque monkeys performing a visuo-spatial WM task.
View Article and Find Full Text PDFUnderstanding the balance between plastic and persistent traits in the dyslexic brain is critical for developing effective interventions. This longitudinal intervention study examines the Visual Word Form Area (VWFA) in dyslexic and typical readers, exploring how this key component of the brain's reading circuitry changes with learning. We found that dyslexic readers show significant differences in VWFA presence, size, and tuning properties compared to typical readers.
View Article and Find Full Text PDFReading, face recognition, and navigation are supported by visuospatial computations in category-selective regions across ventral, lateral, and dorsal visual streams. However, the nature of visuospatial computations across streams and their development in adolescence remain unknown. Using fMRI and population receptive field (pRF) modeling in adolescents and adults, we estimate pRFs in high-level visual cortex and determine their development.
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