Discuss the representation of tactile information in the mammalian cerebral cortex?

Answer 1

The DCML- Dorsal column mediated leminiscal - system is one of the central pathways of the somatosensory system. This system is involved in mediating fine and discriminating touch. A-beta fibrers such as the Meisnerr's corpuscles, Merkel disks, Ruffinni corpuscles and Pacinian corpuscles are involved in this pathway. They are called Tactile fibres. Axons from tactile afferents ascends spinal cord and synapse on the 2nd order of the Dorsal column nuclei of the medulla. Axons of the 2nd order neurons cross to other side of brainstem and ascend to the VP (ventral posterior) complex of thalamic nuclei. The 3rd order of the thalamic nuclei project onto the primary somatosensory cortex of the mammalian brain where the information is processed. The cerebral cortex consists of 2 types of neurons- the pyramidal neurons which is excitatory; and stellate neurons which are excitatory and inhibitory. The 3rd neuron has its cell body still in the VP of the thalamic nuclei and ends in the parietal lobe- the postcentral gyrus.