In primary sensory cortices, neuronal circuits change throughout life as a function of learning. During associative learning a neutral sensory stimulus acquires the emotional valence of an aversive event or a reward after repetitive contingent pairing. One important consequence is the enlargement of the representational area of the conditioned stimulus in the cortical map of its sensory modality.
View Article and Find Full Text PDFSmall interfering RNAs (siRNA) are double-stranded RNAs of 9-29 nucleotides designed to reduce the expression of homologous genes by a process known as RNA interference (RNAi). Most studies using siRNA in neurons have been performed in mammalian cell cultures. Only few reports have reported the effects of in vivo infusion of siRNA into the brain.
View Article and Find Full Text PDFContiguous skin surfaces that tend to be synchronously stimulated are represented in neighbouring sectors of primary somatosensory maps. Moreover, neuronal receptive fields (RFs) are reshaped through ongoing competitive/cooperative interactions that segregate/desegregate inputs converging onto cortical neuronal targets. The present study was designed to evaluate the influence of spatio-temporal constraints on somatotopic map organization.
View Article and Find Full Text PDFThis study is an attempt to gain insight into the malleability of representational maps in the primary somatosensory cortex in relation to the expression of proteins involved in inhibitory and excitatory neurotransmitter systems that contribute to maintain these maps in a dynamic state. Malleability of somatosensory maps is characterized by changes in the sizes of neuron receptive fields (RFs) affecting the representational grain and in the locations and submodalities of these RFs modifying the map extent. The concomitance of these alterations remains so far hypothetical.
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