Thalamocortical Radiations
Nonspecific Nuclei. The first group includes the midline (median) and intralaminar nuclei and the medial portion of the ventral anterior nucleus. These nuclei receive ascending input from the mesencephalic reticular…
Forebrain Regions Associated with Hypothalamus
Behavioral changes produced by cortical ablations, such as prefrontal lobotomy, are well known. Other such changes, varying from mania and hyperphagia to apathy, aphagia, and somnolence, result from lesions to…
Hippocampus
The hippocampus is a part of the marginal cortex of the parahippocampal gyrus that has been invaginated, or rolled, into the floor of the inferior horn of the lateral ventricle…
Rhinencephalon and Limbic System
The limbic forebrain refers to the areas that are functionally and anatomically connected structures that relate to emotion, motivation, and self-preservation. The limbic system is thought to be a major…
Corpus Callosum
Agenesis of the corpus callosum (ACC) is a congenital birth defect characterized by an absence of a corpus callosum. This condition can occur in isolation (with little to no impact…
Corticocortical and Subcorticocortical Projection Circuits
Corticocortical Circuits. Local short association fibers, or U fibers, connect adjacent cortical gyri and lie beneath the sixth cortical layer. Neighborhood association fibers traverse longer distances than U fibers, but…
Major Cortical Association Bundles
Lesions to cortical association bundles can provide clinical relevance to fiber pathway tracts and cortical origins and destinations. For instance, a patient who develops acute damage to the uncinate fasciculus…
Cerebral Cortex: Function and Association Pathways
Association Pathways. When one cortical area is activated by a stimulus, other areas also respond. This is due to the rapid activity along a large number of precisely organized, reciprocally…
