What are the three main types of white matter fibres in the cerebrum?

The cerebral white matter consists of three fibre types based on their connections: Association fibres connect areas within the same hemisphere, commissural fibres connect identical areas across the two hemispheres, and projection fibres connect the cerebral cortex with subcortical structures, brainstem, and spinal cord.

What is the function of the internal capsule?

The internal capsule is a compact band of projection fibres that transmits ascending and descending signals between the cerebral cortex and subcortical areas. It is crucial for motor and sensory pathways, and its damage can lead to significant neurological deficits like hemiplegia.

What happens if there is a hemorrhage in the internal capsule?

A hemorrhage in the internal capsule, often due to rupture of Charcot’s artery in hypertension, typically affects the posterior limb. This can cause contralateral hemiplegia (paralysis on the opposite side of the body) and sensory loss.

What are the major commissural fibres in the brain?

The major commissural fibres include the corpus callosum (largest, connecting multiple lobes), anterior commissure (connects anterior temporal and olfactory areas), posterior commissure (involved in visual reflexes), hippocampal commissure (connects crura of the fornix), and habenular commissure (connects habenular nuclei).

How are projection fibres organized in the cerebrum?

Projection fibres are organized into two main types: corticofugal fibres (efferent, from cortex) and corticopetal fibres (afferent, to cortex). In the neocortex, they form structures like the corona radiata and internal capsule, while in the allocortex, they include the fimbria and fornix.

What are the parts of the internal capsule and their functions?

The internal capsule is divided into parts with specific functions: Anterior limb contains corticopontine fibres and anterior thalamic radiation, genu contains corticonuclear fibres and superior thalamic radiation, posterior limb contains corticospinal and corticorubral fibres and superior thalamic radiation, retrolentiform part contains optic radiation, and sublentiform part contains auditory radiation.

What arteries supply the internal capsule?

The internal capsule is supplied by different arteries based on its parts: Anterior limb by medial striate branches (from ACA) and lateral striate branches (from MCA), genu by recurrent artery of Heubner and internal carotid branches, and posterior limb by lateral striate branches (from MCA) and anterior choroidal artery.

Cerebral White Matter – Association, Commissural, Projection

❓ Frequently Asked Questions