A01 Localisation Of Function In The Brain

• Wernicke and Broca


  In the 19th century, they discovered that specific areas of the brain are associated with particular physical and psychological functions.
• Before invesitgations of Localisation

  A holistic theory was supported where all parts of the brain are involved in processing thoughts/actions.
• Localisation of functions


  Wernicke and Broca argued however that the brain has different parts that perform different tasks and are responsible for different parts of the body- cortical specialisation
• Hemispheres of the brain

  The brain is divided into two symmetrical halves called left&right hemispheres. Some of our physical and psychologcial functions are controlled/dominated by a particular hemisphere (lateralisation).
• General rule for the brain

  The left hemisphere controls the right-hand side of the body and the left hemisphere controls the left-hand side of the body.
• Cerebral cortex


  The outer layer of the brain which is 3mm thick and separates humans from animals because the human cortex is much more developed. It also appears grey.
• Lobes


  The cerebral cortex is sub-divided into four lobes which are named after the bones beneath they lie.
• Frontal lobe


  This lobe is at the front of the brain. Responsible for personalty and the motor area is at the back of the frontal lobe controlling voluntary movemement in the opposite side of the body. Damage to this lobe may lead to loss of control over fine movement.
• Parietal lobe


  At the front of both parietal lobes is the somatosensory area (which is separated from the motor area by a valley called the central sulcus) and it collects sensory information.
• Somatosensory area


  The amount of somatosensory area devote to a particular body bpart denotes its sensitivity. Receptors for the face and hands occupy half of the somatosensory area.
• Occipital lobe


  The visual area. Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex. Thus, damage to the left hemisphere, can lead to part blindness to the right visual field.
• Temporal lobe


  The auditory area which analyses speech-based information. Damage to this lobe can profuce partial hearing loss and the more extensive damage, the more extensive loss.
• The language area of the brain


  Language is restricted to the left side of the brain
• Broca's area


  Broca identified this area in the left frontal lobe which is responsible for speech productions. Damage to this area can lead to Broca's aphasia, characterised by speech that is slow and lacking in fluency.
• Wernicke's area


  Wernicke identified this area in the left temporal lobe which is responsible for language comprehension. Damage to this area can lead to Wernicke's aphasia where the person often produces nonsense words (neologisms) as paer of content in their speech.