AQA Psychology for A Level Year 2: Rev Guide

@ookx hs @ookx hs Melvin had a stroke (a burst blood vessel caused damage to part of his brain). He has problems walking because his right arm and leg are partly paralysed. He experiences numbness down his right side and also has trouble speaking, although he can understand what people are saying to him. Use your knowledge of localisation of brain function to explain Melvin’s experience and symptoms. Chapter 2: Biopsychology Localisation of function in the brain Spec spotlight Localisation of function in the brain Holistic theory replaced by localisation theory in recent years. Scientists in the early 19th century supported the holistic theory that all parts of the brain were involved in processing thought and action. But specific areas of the brain were later linked with specific physical and psychological functions (localisation theory). If an area of the brain is damaged through illness or injury, the function associated with that area is also affected. Brain is divided into two hemispheres and lateralised . Brain is divided into two halves – left and right hemispheres. Lateralisation: some physical and psychological functions are controlled by a particular hemisphere. Generally, the left side of the body is controlled by the right hemisphere; the right side of the body by the left hemisphere. Outer layer of brain is called the cerebral cortex . The cerebral cortex is like a ‘tea cosy’ covering the inner parts of the brain. It is about 3 mm thick and is what separates us from lower animals as it is highly developed. The cortex appears grey due to the location of cell bodies – hence the phrase ‘grey matter’. Cortex of both hemispheres is divided into four lobes (frontal, parietal, occipital and temporal). Motor area : at the back of the frontal lobe (both hemispheres). Controls voluntary movement. Damage may result in loss of control over fine motor movements. Somatosensory area : at the front of the parietal lobes. Processes sensory information from the skin (touch, heat, pressure, etc.). The amount of somatosensory area devoted to a particular body part denotes its sensitivity. Visual area : in the occipital lobe at the back of the brain. 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. So damage to the left hemisphere, for example, can produce blindness in the right visual field of both eyes. Auditory area : in the temporal lobe. Analyses speech-based information. Damage may produce partial hearing loss – the more extensive the damage, the more serious the loss. Broca’s area: Speech production. Identified by Broca in the 1880s, in the left frontal lobe. Damage to this area causes Broca’s aphasia which is characterised by speech that is slow, laborious and lacking in fluency. Broca’s patients may have difficulty finding words and naming certain objects. Patients with Broca’s aphasia have difficulty with prepositions and conjunctions (e.g. ‘a’, ‘the’, ‘and’). Wernicke’s area: Language comprehension. Identified by Wernicke in the 1880s, in the front temporal lobe. Patients produce language but have problems understanding it, so they produce fluent but meaningless speech. Patients with Wernicke’s aphasia will often produce nonsense words (neologisms) as part of the content of their speech. Localisation of function in the brain: motor, somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas. You will improve your marks if you use specialist terms wherever possible. Revision booster The person who came up with the name ‘brain’ for the brain must have used their brain to come up with it. So what that means, if you think about it, is that the brain named itself. Spooky. AO1 Description 30