Thalamic Relationships of the Medial Cortex in the Rat (Part 1 of 2)

TLDR

Comparisons with previous work indicate that thalamocortical projections are not always reciprocated by corresponding corticothalamic projections. Thalamic projections to the medial cortex (cingulate cortex and presubiculum) were studied by the use of anterograde degeneration methods. Lesion studies show that different thalamic nuclei project to overlapping cortical fields with distinct laminar patterns: AM, MD, and VM target infraradiate areas of the anterior cingulate cortex, AD and AV target the retrosplenial granular area of the posterior cingulate cortex, and the presubiculum receives inputs from AM, AD, and AV.

Abstract

Thalamic projections to the medial cortex (cingulate cortex and presubiculum) were studied by the use of anterograde degeneration methods. Observations made in rats with various lesions of the anterior (AM, AD, AV), mediodorsal (MD), and ventromedial (VM) nuclei provide evidence that different thalamic nuclei may project to the same cortical field, in which, each projection has an individual pattern of laminar distribution. The AM, MD, and VM nuclei project to the infraradiate areas of the anterior cingulate cortex, whereas both the AD and AV nuclei project to the retrosplenial granular area of the posterior cingulate cortex. The presubiculum receives thalamic afferents from AM, AD, and AV. Comparisons with previous work indicate that the thalamocortical projections are not always reciprocated by corresponding corticothalamic projections.