Make a brief note on forebrain.
Forebrain consists of cerebrum, thalamus and hypothalamus. Cerebrum occurs as two cerebral hemispheres that are joined together by corpus callosum. Each cerebral hemisphere is divided by other grooves into four lobes – frontal, parietal, temporal and occipital. The convolutions and fissures greatly enlarge the surface area of the cortex. The outer surface of cerebrum (cortex) has grey matter and inner to the cortex is white matter. Thalamus lies just underthe cerebrum, i.e., cerebrum wraps around the thalamus. Thalamus is the major coordinating centre for sensory and motor signals. Hypothalamus lies at the base of the thalamus. . It has centres to control body temperature, hunger, thirst, etc. It contains several groups of neuro secretory cells which secrete hormones. Limbic system is constituted by the inner parts of cerebral hemispheres and a group of structures called amygdala and hippocampus. Along with the hypothalamus, limbic system is involved in the regulation of sexual behaviour, expression of emotions, motivation, etc.
