Association Tracts : axons that conduct nerve impulses between gyri in the same hemisphere.
Commissural Tracts : contain axons that conduct nerve impulses from the gyri in one hemisphere to the corresponding gyri in the other hemisphere. The Corpus Callosum is an example of a commissural tract which contains ~ 300 million fibres and is the largest fibre bundle in the brain. Projection Tracts : contain axons that conduct nerve impulses between the cerebrum and other parts of the CNS including the thalamus, brain stem, and spinal cord. The cerebrum functions in sensory and motor for skeletal movements, emotions, behaviour, perception, intelligence and learning.
Functional Organization of the Cerebral Cortex
Specific types of sensory, motor, and integrative signals are processed in certain regions of the cortex. 1. Sensory Areas: Sensory information arrives mainly in the posterior half of both cerebral hemispheres behind the central sulci. Primary sensory areas receive sensory information from lower regions of the brain. The following are some of the important sensory areas. 1A) Primary Somatosensory Area: This area receives nerve impulses for touch, pressure, vibration, itch, tickle, temperature, pain, proprioception and is involved in the perception of these somatic sensations. A map of the entire body is present in the primary somatosensory area with each point within the area receives impulses from a specific part of the body. This area also allows you to know exactly where the sensations originate.
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