We have examined relative levels of metabolic and electrical activity across layer IV in the primary somatic sensory cortex (S1) of the rat in relation to regions of differential postnatal cortical growth. Each of several indices used--mitochondrial enzyme histochemistry, microvessel density, Na+/K+ pump activity, action potential frequency, and deoxyglucose uptake--indicate regional variations...

The morphology and distribution of neurons and terminals that are immunoreactive to glutamic acid decarboxylase (GAD) were investigated in barrel cortex of the rat and mouse. The morphology of the GAD-immunoreactive neurons located in layer IV of the barrel field resembles that of the large, smooth stellate neurons described previously in Golgi studies. Most of the somas of GAD-positive neurons...

N-methyl-d-aspartate receptor (NMDAR)-mediated activity is required for whisker-related neural patterning in the rodent brain. Deletion of the essential NMDAR subunit NR1 gene in excitatory cortical neurons prevents whisker-specific barrel formation and impairs thalamocortical afferent patterning. We used electrophysiological and voltage-sensitive dye imaging methods to assess synaptic and sens...

Perceptual decisions involve distributed cortical activity. Does information flow sequentially from one cortical area to another, or do networks of interconnected areas contribute at the same time? Here we delineate when and how activity in specific areas drives a whisker-based decision in mice. A short-term memory component temporally separated tactile "sensation" and "action" (licking). Using...

Sensory deprivation during a critical period reduces spine motility and disrupts receptive field structure of layer 2/3 neurons in rat barrel cortex. To determine the locus of plasticity, we used laser scanning photostimulation, allowing us to rapidly map intracortical synaptic connectivity in brain slices. Layer 2/3 neurons differed in their spatial distributions of presynaptic partners: neuro...

Rats were raised with altered tactile experience from P0 by removing all but one vibrissa (D1) from one side of the face (D1-spared animals). This procedure (univibrissa rearing) has previously been shown to cause neurons in cortical barrels surrounding D1 to develop greater than normal responses to D1 vibrissa stimulation and smaller than normal responses to principal vibrissa stimulation (Fox...

Cortical blood flow can be modulated by local activity across a range of species; from barrel-specific blood flow in the rodent somatosensory cortex to the human cortex, where BOLD-fMRI reveals numerous functional borders. However, it appears that the distribution of blood capillaries largely ignores these functional boundaries. Here we report that, by contrast, astrocytes, a major player in bl...

There is growing evidence that serotonin (5-hydroxtryptamine, 5-HT) has major influences on brain development in mammals. Genetic and pharmacological disruption of 5-HT signaling during early postnatal development in rodents causes neuroanatomical cortical abnormalities, including malformations in the somatosensory cortex. Possible functional consequences of this developmental perturbation by 5...