localisation of function Flashcards
What does localisation of function refer to?
The theory that different areas of the brain are responsible for different behaviours, processes, or activities.
What was the holistic theory in relation to brain function?
The idea that the whole brain was involved in processing thought and action.
Who were the scientists that contributed to the shift from holistic theory to localisation of function?
Broca and Wernicke.
In what decade did the belief in localisation of function gain support?
The 1880s.
How many lobes is the brain split into?
Four lobes.
What are the names of the brain lobes?
- Frontal Lobe
- Parietal Lobe
- Occipital Lobe
- Temporal Lobe
Fill in the blank: The Frontal Lobe, Parietal Lobe, Occipital Lobe, and _______ are the four lobes of the brain.
[Temporal Lobe]
True or False: The localisation of function theory suggests that all parts of the brain are equally involved in all functions.
False
What lobe is the motor area in?
frontal
What is the function of the motor area?
-Controls voluntary movement in opposite sides of the body
What hemisphere is the motor area in?
Both
What are the consequences of damage to the motor area?
Loss of control over fine motor movements
What lobe is the somatosensory area in?
Parietal Lobe
What is the function of the somatosensory area?
Where sensory information from the skin is processed
What hemisphere is the somatosensory area in?
Both
What are the consequences of damage to the somatosensory area?
Numbness/ pins and needles, won’t feel hot or cold in the area.
What lobe is the visual area in?
Occipital
What is the function of the visual area?
Each eye sends info from the Right Visual Field to the left cortex and from the Left Visual Field to the right cortex
What hemisphere is the visual area in?
Both
What are the consequences of damage to the visual area?
Damage to left hemisphere can cause damage to the RVF and damage to the right hemisphere can cause damage to the LVF
What lobe is the auditory area in?
temporal
What is the function of the auditory area?
-Analyses and processes acoustic information
What hemisphere is the auditory area in?
Both
What are the consequences of damage to the auditory area?
Partial hearing loss, the more extensive the damage the more extensive the loss.
What lobe is Broca’s area in?
frontal
What is the function of Broca’s area?
-Speech production
What hemisphere is Broca’s area in?
Left
What are the consequences of damage to Broca’s area?
-Broca’s Aphasia
-speech is slow and laborious and lacking in fluency
What lobe is Wernicke’s area in?
temporal
What is the function of Wernicke’s area?
-Language Understanding
What hemisphere is Wernicke’s area in?
Left
What are the consequences of damage to Wernicke’s area?
-Wernicke’s Aphasia
-often produce nonsense words (neologisms) as part of speech
What are the strengths of localisation of function?
-research support from brain scans
-research support from aphasia studies
What are the limitations of localisation of function?
-contrasting evidence from plasticity studies
-contrasting evidence from animal studies
Explain the strength of localisation of function that there is research support from brain scans?
-Petersen (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
-Tulving’s (1944) research revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
-These studies confirm localized areas for every-day behavior- the temporal lobe containing Wernicke’s area for listening, and the frontal lobe containing Broca’s area for reading.
-This is a strength because findings have high validity- brain scans are objective and provide sound scientific, empirical evidence.
Explain the strength of localisation of function that there is research support from aphasia studies?
-Broca’s (1861) case study of ‘Tan’ (so-called because that was the only word he could say) demonstrated Broca’s aphasia.
-A post mortem revealed that ‘Tan’ had a lesion in his left frontal hemisphere, the area now known as ‘Broca’s area’.
-Similarly, Wernicke reported case studies of Wernicke’s aphasia where post mortems revealed damage to the left temporal lobe, the area now known as ‘Wernicke’s Area’.
-This supports the idea of localisation of function, as damage to specific areas impaired only specific functions- damage to Wernicke’s area only caused Wernicke’s Aphasia, and did not impair language as a whole.
-However advances in brain imaging techniques mean that neural processes in the language function are distributed holistically in the brain than was first thought.
Explain the limitation of localisation of function that there is conflicting evidence from plasticity studies?
-Evidence suggests that functions may not be entirely localised- a theory is called ‘neuroplasticity’.
-Danelli et al (2013) examined patient EB who had his left hemisphere removed at age 2 ½ as treatment for a large benign tumour.
-At that time, all of his linguistic abilities disappeared too.
-After intensive rehabilitation, language abilities started to improve around the age of 5 and by age 17 EB’s language performance was comparable with healthy adult controls.
-This suggests that the brain is more holistic than we think, as the right hemisphere has taken over the language functions (which is called ‘recruitment of homologous areas’).
Explain the limitation of localisation of function that there is contrasting evidence from animal studies?
-For example, Lashley removed areas of the cortex (between 10-50%) in rats that were learning the route through a maze.
-No area was proven to be more important than any other area in terms of the rats ability to learn the route.
-The process of learning seemed to require every part of the cortex rather than being confined to a particular area.
-This suggests that higher cognitive processes such as learning are not localised but distributed in the brain in a more holistic way.
