Biopsychology : Localisation of Function Flashcards
What does localization of function mean?
Functions, such as movement, speed and memory and performed in distinct regions of the brain (localised)
Whats the holistic theory?
Belief that all parts of the brain are involved in the processing of thought and action at the same time
How does this contrast to a holistic view?
Modern day understanding sees the brain as being more localised for specific functions (not 100% how the brain works as its complicated and not fully understood)
How is the brain divided?
Two nearly symmetrical halves – the right and left hemisphere
What is lateralisation?
Some physical and psychological functions are controlled/ dominated by one hemisphere.
What is contralateral control?
Activity on the left-hand side of the body is controlled by the right hemisphere and vice versa
What is the outer layer of the brain called?
The cerebral cortex (grey matter). About 3mm thick. Separates humans from other animals as its more developed.
What are gyri?
The bumps on the brains surface
What are sulci?
The grooves on the brains surface
Why do we have gyri and sulci?
To increase the surface area of the brain, allowing the heart to control blood flow and metabolism
What are the 4 lobes of the brain called?
Frontal lobe, parietal lobe, temporal lobe, occipital lobe
4 lobes - Frontal
language, memory, attention, executive function
4 lobes - parietal
spatial orientation and perception of sensory info
4 lobes - temporal
Auditory info
4 lobes - occipital
Visual info
What is the role of the limbic system?
(Mammalian brain/ midbrain) is unique to mammals. According to MacLean (1990), it’s the centre of emotion and learning
What did Broca and Wernicke find?
(SEPARATE) Provided the first scientific evidence for the idea of localisation of function. They found that if a certain area becomes damaged through illness or injury, the function associated with that area will also be affected.
What is Broca’s aphasia, and how is it caused?
Damage to Broca’s area, a small area in the left posterior frontal lobe responsible for speech production. They can understand and comprehend language but their speech is slow, laborious and lacking fluency.
What is Wenicke’s aphasia, and how is it caused?
Wenicke (1873) found an area, Wernicke’s area in the left posterior temporal lobe responsible for language comprehension. Damage to this area causes no problems producing language but severe difficulties understanding it.
How is the case of Phineas Gage seen as evidence for the localisation of function?
He had a meter long metal rod go though his cheeks, behind his left eye and through his skull, taking part of the frontal cortex with it – associated with planning, reasoning and control. He had drastic personality changes as the part of his brain taken out was part of what makes up personality. This shows that different parts of the brain perform different tasks.
What does the motor context do?
Located in the frontal lobe, responsible for voluntary movements by sending signals to the muscles in the body
What does the Somatosensory area do?
Located in the parietal lobe and receives incoming sensory info from the skin to produce sensations related to pressure, pain, temperature, etc. Different parts of the somatosensory area receive messaged from different locations of the body.
What does the visual cortex do?
In the occipital lobe at the back of the brain, receives and processes visual info. The visual cortex contains different parts that process different types of info including colour, shape and movement.
What does the auditory cortex do?
Located in the temporal lobe and is responsible for analysing snd processing acoustic info. The auditory cortex contains different parts and the primal auditory cortex is involved processing simple features of sound including loudness, tempo and pitch.
What is Broca’s area?
Named after Paul Broca, located in the left frontal lobe responsible for speech production.
Whats Wernickes area?
Named after Carl Wernicke, located in the left temporal lobe, responsible for speech comprehension
Strengths of localisation…
• Evidence from brain scans → Tulving (1994) found that semantic and episodic memories are located in different parts of the prefrontal cortex, with the semantic memories in the left hemisphere and episode in the right. Furthermore, Petersen (1988), showed how Wernicke’s area was active during a listening task and Broca’s area during a reading task, supporting the theory that neurological functions are localised.
• Case studies from patients with brain damage → patient HM has his hippocampus removed to treat his epilepsy and after the surgery could not transfer episodic or semantic memories from his STM to LTM but could learn and get better at new procedural tasks (mirror drawing). This supports the theory of localisation as different parts of the brain are responsible for different tasks.
Limitations of localisation…
• Alternative theory → Lashley (1950) had an alternative theory - ‘Principle of Equipotentiality’ which suggests that basic motor and sensory functions are localised but higher mental functions are not. In a study, he removed 10-50% of the cortex of rats and found no area to be more important than others. He claimed that the intact areas of the brain could take over responsibility for specific cognitive functions.
• Individual differences → Harasty et al (1997) found that women have proportionally larger Broca’s and Wernicke’s area vs men, explaining women’s greater ease with language. This is a beta bias as the theory overlooks gender differences and doesn’t account for variations in brain regions’ size and activity between men and women, leading to inaccurate generalisations
