Biopsychology - The brain Flashcards
What is the purpose of SSRI’s?
- SSRI’s work to stop the reuptake of serotonin back into the presynaptic neurone
- This causes there to be more serotonin in the synapse thus increasing serotonin levels
What is localisation of function in the brain?
- Functions such as movement, speech and memory are performed in distinct regions of the brain (localised)
- The opposite view is that the brain acts holistically to perform functions
Where are each functionally specialised brain areas found in the brain?
Motor cortex: Both sides
Somatosensory cortex: Both sides
Visual: Both sides
Auditory cortex: Both sides
Broca’s area: Left hemisphere only (hemispheric lateralisation)
Wernicke’s area: Left hemisphere only (hemispheric lateralisation)
What is hemispheric lateralisation?
-The theory that each hemisphere of the brain is specialised to perform different functions
(The language centres are in the left hemisphere, whereas visuospatial tasks are best performed by the right hemisphere)
What does contralateral mean?
- The theory that each hemisphere of the brain controls the opposite (contralateral) side of the body
- This is including both motor and sensory pathways and vision of the contralateral visual field
- This also means that the right side of the brain receives the information from the left visual field from both eyes (and the opposite for the other side)
What is the cortex?
The thin outside layer of the brain (the grey matter)
What is the white matter?
Myelinated axons
What are the 4 lobes in the brain?
The frontal lobe
The parietal lobe
The temporal lobe
The occipital lobe/visual cortex
What is the function of the visual cortex? (Occipital lobe)
- The occipital lobe is the brains visual processing centre, each hemispheres occipital lobe receives information from the contralateral visual field
- Damage to this part of the brain can lead to partial or complete loss of vision (Cortical blindness)
- Damage to one cortex can lead to loss of vision in the opposite visual field
What is the function of the motor cortex?
-The motor cortex is at the back of the frontal lobe
-The motor cortex and the somatosensory cortex is divided by a fold called the central sulcus and both parts of the brain are contralateral
-The motor cortex is responsible for voluntary motor
movements (contralateral)
-Damage to one side of the motor cortex can lead to loss of muscle function or after severe trauma, paralysis on the opposite side of the body due to the contralaterality
What is the function of the auditory cortex?
- Located at the top of the temporal lobe on both sides of the brain
- It receives and processes sound information from the ears
- Damage to the auditory cortex can lead to cortical deafness (Patient is unable to hear but there is no damage done to the ear)
What is the function of the Broca’s area?
- Located in the left frontal lobe (left hemisphere only)
- Responsible for speech production
- Discovered after case study and post mortem of Tan Whon
- Damage to Broca’s area causes Broca’s aphasia which is difficulty producing fluent speech, speech is slow, effortful and has missing words leading to poor grammar
What is the function of the Wernicke’s area?
-Located in the top of the temporal lobe (left hemisphere only)
-Responsible for speech comprehension
-Discovered after case studies of individuals who could produce fluent sounding speech that made
little sense
-Damage to Wernicke’s area causes Wernicke’s aphasia which is having difficulty understanding speech or written language, speech sounds fluent but lacks meaning/nonsense words are used
What is global aphasia?
- When there is damage to both, Broca’s and Wernicke’s area
- This causes an inability to produce or understand speech
What is a strength of studies on localisation of function?
- Case study research demonstrates a loss of certain functions if damage is caused to certain areas of the brain
- For example: Broca and Wernicke’s case studies and Clive Wearing suggest that functions are localised in these areas
What is a weakness of studies on localisation of function?
-Use of case studies is unscientific, especially in brain research with damage often covering multiple regions
-This was seen in modern MRI scans that were made of Tans brain which showed damage far beyond just Broca’s area
-This suggests damage to other areas could be
responsible for Tans speech problems
What is a strength of studies on localisation of function?
- Modern brain scanning techniques like FMRI support older research on language centres (Broca’s and Wernicke’s area)
- They show activation, in the regions associated, when healthy participants perform language tasks
What is a weakness of studies on localisation of function?
-Some areas of the brain appear to be more localised than others
-Motor and somatosensory functions are highly localised, however systems like language is more
distributed
-This suggests the correct approach in arguing for the localised or holistic nature is different depending on
the area and function
-Also due to the high connectivity of the brain no, one area is truly independent
What did Lashley’s experiment on rats conclude about localisation of the brain?
- Lashley found that the rats ability to remember the route of the maze was decreased depending on how much of the brain was removed rather than which part
- This cause Lashley to conclude that higher cognitive processes such as learning and memory are not localised but distributed across the whole brain
What is brain plasticity?
- When the brain adapts in both its function and structure as a result of a change in the environment
- These changes could be due to damage or to meet the cognitive demands of learning new skills
- This can occur due to: Learning a new skill, as a result of developmental changes, in response to direct trauma to an area of the brain or in response to indirect effects of damage such as brain swelling or bleeding (from a stroke)
- This can cause neuronal cells to die so the brain structure must change to compensate for the areas that are permanently damaged
What is functional recovery?
When the functions that were performed by areas of the brain that are lost due to neuronal cell death are performed by undamaged parts of the brain (Functional reorganisation)
How does plasticity actually occur?
- Synaptic pruning occurs, this is when synapses that are frequently used become stronger over time
- However unused synaptic connections are also lost
- This makes the brain a more efficient communication system over time