Distributions of alpha7 nicotinic acetylcholine receptor (nAChR) mRNA and [125]alpha-bungarotoxin (alpha-BTX) binding sites in the developing rat somatosensory cortex were characterized in relation to acetylcholinesterase (AChE) histochemical staining of thalamocortical terminals to investigate the role of this receptor in cortical development. Using quantitative in situ hybridization and recep...

Early events in the formation of the thalamocortical tract remain poorly understood. Recent work has suggested that thalamocortical axons follow a path pioneered by transient thalamic afferents originating from the medial part of the ventral telencephalon. We studied the development of these transient afferents and the thalamocortical tract in mutant mice lacking transcription factors normally ...

The organization of the whisker representation within the neocortex of the rat is dependent on an intact periphery during development. To further investigate how alterations in this cortical map arise we examined the organization of thalamocortical afferents to the whisker representation in adult animals in which the infraorbital branch of the trigeminal nerve was cut on the day of birth. The d...

Quantitative data on thalamocortical synapses in adult mouse barrels have been obtained largely by using lesion-nduced degeneration to label thalamic afferents. By the time degenerating axons can be identified with the electron microscope, they have broken up into many separate pieces, making it impossible to assess the distribution of synapses along unbroken lengths of afferent. Here, this def...

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...

Soma location, dendrite morphology, and synaptic innervation may represent key determinants of functional responses of individual neurons, such as sensory-evoked spiking. Here, we reconstruct the 3D circuits formed by thalamocortical afferents from the lemniscal pathway and excitatory neurons of an anatomically defined cortical column in rat vibrissal cortex. We objectively classify 9 cortical ...

To investigate the role of 5-HT in the development of the somatosensory cortex, this amine was depleted in newborn (P-0) rats with a single subcutaneous injection of the toxin 5,7-dihydroxytryptamine (5,7-DHT) and thalamocortical organization was assayed by application of the carbocyanine dye Di-I to the thalamocortical radiations or ventrobasal thalamus, or by staining cortical sections for AC...

The forms of the spiny dendrites in layer IV receiving degenerating thalamocortical axon terminals have been examined in serial thin sections. Reconstructions of segments of these dendrites show that the axon terminals synapse with both the dendritic spines and the dendritic shafts. No main shafts of apical dendrites of pyramidal neurons were found to synapse with the thalamic afferents, which ...

The neurochemical identities of afferents to the midline thalamus were investigated in chloral hydrate-anesthetized adult Sprague-Dawley rats. The retrograde tracers, FluoroGold or cholera toxin B subunit, were centered on the paraventricular thalamic nucleus (n.Pvt), a periventricular member of the diffuse thalamocortical projection system that is reciprocally linked with visceral areas of cer...