Localisation of function Flashcards
The human brain can be viewed as 3 concentric layers which are…
The central core, limbic system, cerebrum
The central core
Contains the hypothalamus and controls basic function (hunger, thirst, breathing.) Maintains homeostasis.
The limbic system
Emotional regulation, contains the hippocampus for memory consolidation.
The cerebrum
Regulates higher intellectual processes.
Outermost layer is the cerebral cortex.
Our sensory systems send messages to and from the cerebral cortex
made up of left and right hemispheres connected to the corpus callosum.
Each hemisphere in the cerebrum is split into 4 lobes
Frontal, parietal, temporal and occipical lobes.
Frontal lobe
Awareness of what we are doing within our environment (conscious impulse inhibition) Finishes developing at 25
Temporal lobes
Auditory ability and memory acquisition
Occipital lobes
Vision
Parietal lobes
Sensation and perception
Limbic system
Emotional regulation and memory consolidation
Cerebellum
Automated movement and balance.
Somatosensory cortex
located in the anterior part of the parietal lobe. Responds to sensory info. e.g heat/cold. Responds to our sense of body movement.
Motor cortex
Located at the posterior of the frontal lobe. Responsible for controlling voluntary movements (left hand side controlled by right hemisphere and visa versa.)
Auditory cortex
located in the temporal lobe: responsible for analysis of speech based information
Hemispheres
Lateralisation- idea each hemispshere is responsible for different function.
Left is for language (broca’s area- language production, Wernike’s area- language comprehension)
Case study evidence
Phineas gage was working in a tunnel and an iron rod went through his frontal lobe. Personality changed to rude and blasphemous. Suggests different parts of the brain affect different things.
Cannot be generalised as is a case study.
Scanning studies
Peterson (1988) used a PET scan to demonstrate how Wernicke’s area was active in a listening task and Broca’s area was during a reading task. Suggests differnet functions
Psychosurgical evidence
Lobotomy- removal of brain tissue
Leucotomy- Cutting the connections to a particular part of the brain.
Neurosurgery is used for OCD patients by severing the cingulate gyrus which suggests serious mental disorders and localised.
Not all functions are localised
1950 Karl lashley rats,
Suggested that basic motor and sensory functions were localised but higher mental functions were not.
Lashly removed increasing amounts of the rats cortical regions and observed the eggects on their ability o learn .
Effects were due to about removed not location. We cannot generalise between species.
Plasticity and functional recovery
The fact that humans can regain some cognitive abilities following damage to specific regions (plasticity) is evidence against the idea of cortocal specialisation e.g Jodie Millar and Gabby Giffords.
