The grey matter s mainly composed of neuronal cell bodies and unmyelinated axons. The grey matter serves to process information in the brain. Structures within the grey matter process signals generated in the sensory organs or other areas of the grey matter. This tissue directs sensory (motor) stimuli to nerve cells in the central nervous system where synapses induce a response to the stimuli. These signals reach the grey matter through myelinated axons that make up the bulk of the white matter in the cerebrum, cerebellum and spine