The capacity of adult barrel cortex to show experience-dependent plasticity after early restricted neonatal sensory deprivation was analyzed in barrel field cortex neurons. Selective sensory deprivation was induced by trimming two whiskers from postnatal day 0 (P0) to P21, namely, the principal D2 whisker plus one adjacent surround whisker (D3). At maturity (P90), responses of supragranular (la...

Early in development, cortical networks generate particular patterns of activity that participate in cortical development. The dominant pattern of electrical activity in the neonatal rat neocortex in vivo is a spatially confined spindle-burst. Here, we studied network mechanisms of generation of spindle-bursts in the barrel cortex of neonatal rats using a superfused cortex preparation in vivo. ...

Internal brain states affect sensory perception, cognition, and learning. Many neocortical areas exhibit changes in the pattern and synchrony of neuronal activity during quiet versus active behaviors. Active behaviors are typically associated with desynchronized cortical dynamics. Increased thalamic firing contributes importantly to desynchronize mouse barrel cortex during active whisker sensin...

The whisker representations in the somatosensory barrel cortex of mice are modulated by sensory inputs associated with animal motor behavior which shows circadian rhythmicity. In a C57/BL mouse strain kept under a light/dark (LD 12:12) regime, we observed daily structural changes in the barrel cortex, correlated with the locomotor activity level. Stereological analysis of serial electron micros...

Background & Aims: Thyroid hormones are of great importance in the development of the central nervous system. Congenital hypothyroidism may affect the reorganization of specific and non-specific thalamocortical afferents to whisker–related sensory (wS1) corticol region in rats. Methods: Congenital hypothyroidism was induced by adding propylthiouracil (PTU) (25 ppm) to the rats...

Thalamocortical (TC) connectivity is reorganized by thalamic inputs during postnatal development; however, the dynamic characteristics of TC reorganization and the underlying mechanisms remain unexplored. We addressed this question using dendritic refinement of layer 4 (L4) stellate neurons in mouse barrel cortex (barrel cells) as a model; dendritic refinement of L4 neurons is a critical compon...

The phospholipase C-beta1 (PLC-beta1) signalling pathway, activated via metabotropic glutamate receptors (mGluRs), is implicated in activity-dependent development of the cerebral cortex, as both PLC-beta1 and mGluR5 knockout mice exhibit disrupted barrel formation in somatosensory cortex. To characterize the effects of this signalling system on development of synaptic circuitry in barrel cortex...

The somatosensory barrel cortex in rodents contains a topographic map of the facial whiskers where each cortical barrel is tuned to a corresponding whisker. However, exactly when this correspondence is established during development and how precise the functional topography of the whisker protomap is at birth, before the anatomical formation of barrels, are questions that remain unresolved. Her...

Introduction Plasticity after unilateral forepaw/hindpaw denervation has been shown to lead to detection of ipsilateral cortical fMRI responses to stimulation of the good paw in rats [1]. This ipsilateral activation is proposed to involve interhemispheric callosal connections and is relevant to some human studies that show similar plasticity after peripheral or central nervous system damage and...

Whereas it is widely accepted that the adult cortex is capable of a remarkable degree of functional plasticity, demonstrations of accompanying structural changes have been limited. We examined the basal dendritic field morphology of dye-filled neurons in layers III and IV of the mature barrel cortex after vibrissal-deafferentation in adult rats. Eight weeks later, the tendency for these neurons...