Localisation of function Flashcards
Language Centres - Broca’s area
- Responsible for 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 had difficulty finding words and naming certain
objects. - Patients with Broca’s Aphasia have difficulty with prepositions and
conjunctions (e.g. ‘a’, ‘the’, ‘and’).
Language Centres - Wernicke’s Area
- Responsible for language comprehension.
- Identified by Wernicke in the 1880’s in the back of the 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.
Motor Cortex
- The motor area is located towards the back of the frontal lobe (in both hemispheres) and is responsible for voluntary movements by sending signals to the muscles in the body.
- Hitzig and Fritsch (1870) first discovered that different muscles are coordinated by different areas of the motor cortex by electrically
stimulating the motor area of dogs. - This resulted in muscular contractions in different areas of the bodydepending on where the probe was inserted.
- The regions of the motor area are arranged in a logical order, for example, the region that controls finger movement is located next to the region that controls the hand and arm and so on.
The Somatosensory Cortex
- The somatosensory cortex is located in the front of the parietal
lobe and receives incoming sensory information from the skin to
produce sensations related to pressure, pain, temperature, etc. - Different parts of the somatosensory area receive messages from
different locations of the body, and the amount of somatosensory
area devoted to a particular body part denotes it’s sensitivity. - Robertson (1995) found that this area of the brain is highly adaptable, with Braille readers having larger areas in the somatosensory area for their fingertips compared to sighted participants.
Visual Cortex
- At the back of the brain, in the occipital lobe is the visual area, which
receives and processes visual information. - Information from the right-hand side visual field is processed in the
left hemisphere, and information from the left-hand side visual field
is processed in the right hemisphere. - It contains different parts that process different types of information including colour, shape or movement.
Auditory Cortex
- The auditory area is located in the temporal lobe and is responsible
for analysing and processing acoustic information, (speech based
information). - Information from the left ear goes primarily to the right hemisphere
and information from the right ear goes primarily to the left
hemisphere. - The auditory area contains different parts, and the primary auditory
area is involved in processing simple features of sound, including
volume, tempo and pitch.
Evaluation of Localisation of Function - Equipotentiality
We need to TOP and TAIL:
Equipotentiality -
Research by Lashley (1950) showed that higher cognitive functions (e.g. learning and language) are not localised, but distributed in a more holistic way in the brain. He found that the process of learning a maze in rats required every part of the cortex, rather than being localised.
He showed the extent of damage to an area is more important than
the location of damage in terms of effects on behaviour.
Evaluation of Localisation of Function - Brain scan evidence
TOP:
Peterson et al (1988)used brain scans to show activity in Wernicke’s
area during a listening task, and in Broca’s area during a reading task,
suggesting these areas of the brain have different functions.
Also a study of LTM by Tulving (1994) revealed semantic and episodic
memories are located in different parts of the frontal cortex.
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