Mid brain

The mid brain forms connection between the hind and the fore brain. The crisscrossing nerve fibers form the reticular activating system ( RAS ). Nerve fibers originating in hind brain extend into hypothalamus and thalamus. The ascending RAS is connected to the higher centers of the brain and hence these fibers regulate the state of alertness whereas the descending fibers are largely involved in mediating voluntary movement. One of its prominent role is sensory gating— the process of filtering the incoming impulses to the brain. The roof of the mid brain plays an important role in visual and auditory processing. It controls head and neck movements and is also one of the locations in the brain where pain is registered.