Summation of Excitation and Inhibition
The principle of summation relates to the fact that a neuron typically has a large number of synaptic terminals (boutons) ending upon it; alone, each bouton is capable of producing…
Types of Neurons in Cerebral Cortex
Interneurons. Interneurons have axons that do not leave the cortex and may be of several kinds. The most common are stellate (star-shaped), or granule, cells, which have symmetrically branching dendritic…
Chemical Synaptic Transmission
Synaptic transmitter substances are concentrated in synaptic vesicles within the bouton. Although the exact mechanism of its release is unknown, it appears that the transmitter substance is released in packets,…
Neuronal Structure and Synapses
The highly branched dendritic tree has a much greater surface area than the remainder of the neuron and is the receptive part of the cell. Incoming synaptic terminals make contact…
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…
