Lecture 08

Brain 5

1. Brain
1. Divisions
1. Hindbrain
2. Midbrain
3. Forebrain (aka Cerebrum)
2. Brain Development
1. Ontology
2. Phylogenesis
2. Brain Stem
1. Structures
2. Function
3. Forebrain
1. Subcortical Structures
2. Limbic System

Overview

The brain consists of a variety of structures that are organized into divisions and functional systems. The broadest division involves the hindbrain, midbrain, and forebrain. Each of these divisions, in turn, consists of specific neurological structures.

The three divisions emerge early in fetal development, differentiated four weeks after conception. Later development in humans brings further differentiation. There is also reason to believe these structures evolved at different times. The hindbrain and midbrain areas are well-developed in fish and reptiles, while the forebrain is well-developed only in birds and mammals. Primates have a particularly large and well-developed forebrain.

The hindbrain and midbrain regulate instinctive behaviors and govern processes relevant to survival. Animals whose forebrains have been surgically severed from the other two areas of the brain can perform many behaviors that normal animals perform, as long as they are externally stimulated. The limbic system, which we identified as having six subcortical structures, governs learned and motivated behavior.

Specifics

1. Visually identify the hindbrain, midbrain, and forebrain.
2. Describe the specific structures that comprise the hindbrain, midbrain, and brain stem.
3. Know the location and importance of the reticular formation.
4. Describe the structures that comprise the limbic system and, for each one, specify how they influence learned and motivated behavior.