Localisation of function

• the motor cortex is responsible for the generation of voluntary motor movements; it's located in the frontal lobe of the brain, along a bumpy region known as the precentral gyrus. both hemispheres of the rain have a motor cortex, with the motor cortex on one side of the brain controlling the muscles on the opposite side of the body
• the function of the motor cortex is planning, controlling voluntary movements. damage to it may cause a loss of control over fine motor movements
• the somatosensory cortex detects sensory events arising from different regions of the body. it's located in the parietal lobe of the brain, along a region known as the postcentral gyrus. the postcentral gyrus is the area of the cortex dedicated to the processing of sensory information related to touch. using sensory information from the skin, the somatosensory cortex produces sensations of touch, pressure, pain and temperature, which it then localises to specific body regions
• the function of the somatosensory cortex is to process sensory information and damage to it may result in a reduction in the ability to perceive certain sensations or temperature in certain ways
• the primary visual centre in the brain is located in the visual cortex, in the occipital lobe of the brain. however, visual processing actual begins in the retina, at the back of the eye, where light enters and strikes the photoreceptors
• the function of the visual centres is to receive information directly from eyes and then the optic nerve takes information from the retina to the brain. damage to it may result in blindsight, some loss of vison and, in extreme cases, total blindness
• the visual cortex spans both hemispheres, with the right hemisphere receiving its input from the left-hand side of the visual field, while the visual cortex in the left hemisphere receives its input from the right-hand side of the visual field
• the auditory centre in the brain is concerned with hearing. most of this area lies within the temporal lobes of both sides of the brain, where we find the auditory cortex. the auditory pathways begin in the cochlea in the inner ear, where sound waves are converted to nerve impulses, which travels via the auditory nerve to the auditory cortex in the brain. on the journey from cochlea to the brain, the first stop is the brain stem
• the function of the auditory centres is to process auditory information, like sounds we hear and imagine. it also analyses information like pitch and volume. damage to it can lead to issues with hearing or complete deafness
• Broca's area is named after Paul Broca, the French neurosurgeon who treated a patient who he referred to as 'tan' because that was the only syllable this particular patient could express. Tan had an unusual disorder. although he had been able to understand spoken language, he was unable to speak, nor express his thoughts in writing
• Broca's area is located in the posterior part of only the left frontal lobe, near to the motor region which controls the mouth and vocal cords. it is involved in speech production
• the function of Broca's area is the production of speech as well as organising string of sounds necessary to express thoughts. the area also monitors speech to correct errors and adjust the flow of speech. damage to the area can cause slow speech and lacking in fluency, in some cases no more than four words can be spoken and limited reading and writing skills
• shortly after Broca had discovered a 'speech production' area in the brain, Carl Wernicke, a German neurologist, discovered another area of the brain that was involved in understanding language. this area, named Wernicke's area, was in the posterior portion of the left temporal lobe
• Wernicke proposed that language involves separate motor and sensory regions located in different cortical regions. the motor region, located in Broca's area, is close to the area that controls the mouth, tongue and vocal cords
• the function of Wernicke's area is understanding language, comprehending written and spoken language. damage can cause specific language impairments, however, patients could still produce fluent speech but doesn't always make sense