3. Hind brain or Rhombencephalon: It includes cerebellum, pons varolii and medulla oblongata.
4. Fore brain

Cerebrum: It is the largest and most advanced part of brain which comprises of two cerebral hemispheres on the dorsal surface. A longitudinal groove is present between both cerebral hemisphere known as median fissure. Both hemispheres are somewhat connected with curved thick nerve fibres called corpus callosum. The outer portion of cerebrum is called the cerebral cortex which is made upcontains numerous cell bodies and relatively few myelinated axons. This gives as overall grey appearance and hence called asgrey matter. The surface of cortex is highly folded. The upward folds are called as gyri consecutive with the downward grooves called sulci. Beneath the grey matter there are millions of myelinated axon tracts and contains relatively very few cell bodies which give an opaque white appearance. Hence they are collectively called as white matter. Each cerebral hemisphere is divided into four lobes: frontal or anterior, parietal or middle, temporal or lateral and occipital or posterior lobe. Central sulcus separates frontal lobes from parietal lobes. Lateral sulcus or sylvian sulcus separate temporal lobe from frontal lobe and parietal lobe. Occipital lobe is separated by parietal lobe by parieto-occipital sulcus (Shown in Figure 14.1).

Fig. 14.1: Dorsal surface of cerebral hemisphere

There are three main functional area of each cerebral hemisphere.

1. Sensory area: They receive impulse form receptors.
2. Association area: They interpret the input, store the input and initiate a response. This area is involved in memory, learning and reasoning.
3. Motor area: They transmit impulse to the effector organs.