Biopsychology: L6-9

Question 1

Cerebrum

Answer 1

• Central hemisphere, in the forebrain
• Split into hemispheres
  Four lobes; Frontal (Thought and speech production), Temporal (Cognitive skills), Parietal (Sensory information) and occipital (Image processing)

Question 2

Diencephalon

Answer 2

• In the forebrain, just inside the cerebrum
• Responsible for sensory function, food intake and the body’s sleep cycle
  Sections:
• Thalamus
• Hypothalamus
• Epithalamus
• Subthalamus

Question 3

Cerebellum

Answer 3

• Hindbrain, bellow the cerebrum & attached to the brain stem
• Controls motor function, balance and ability to interpret sensory information

Question 4

Brain stem

Answer 4

• Midbrain and hindbrain
• Governs blood pressure, some reflexes, ‘fight or flight’, breathing and heartbeat
• Motor and sensory neuron travel through the brain stem, passing between the brain and spinal cord

Question 5

Somatosensory cortex

Answer 5

• Receives sensory information from receptors in the skin
• Located in the parietal lobe
• Faces and hand take up over half the space

Question 6

Motor cortex

Answer 6

• Generation of voluntary movement
• Within the frontal lobe
• Found on both sides of the brain

Question 7

Visual centre

Answer 7

• Found in the occipital lobe
• Responsible for sight
• Damage can lead to prosopagnosia

Question 8

Auditory centre

Answer 8

• Found in the temporal lobes in both hemispheres
• Responsible for hearing

Question 9

Broca’s area

Answer 9

• Found in the frontal lobe
• Important for speech production
• Damage can lead to Brocas aphasia

Question 10

Wernickes area

Answer 10

• Left temporal lobe
• Involved in understanding language
• Damage leads to Wernickes aphasia

Question 11

Strengths of localisation of function

Answer 11

Brain scan evidence - Peterson et al used brain scans to show how Wernickes area was active during listening tasks & Broca’s area was active during a reading task, suggesting that language is localised in these areas — Further increases validity due to scientific evidence

Neurosurgical evidence - Dougherty et al found that 44 OCD patients who had undergone brain surgery, after 32 weeks it was found that 1/3 of patients had recovered from the symptoms of OCD, while 14% had some recovery — Mental disorders are localised

Phineas Gage - Suffered brain damage where he lost his temporal lobe, suffered a complete change in personality — Case studies support localisation

Question 12

Weaknesses of localisation of function

Answer 12

Reductionist - Lashley found that higher cognitive functions (eg learning) are not localised. Lashley removed areas of the cortex (10-50%) in rats brains and found that no area was more important in terms of a rats ability to run the maze

Plasticity - When the brain is damaged or a function is lost, the brain reorganises itself to compensate for lost function — Suggests that the brain can compensate for damage to brain localisation

Individual differences - Harasty et al found gender differences in the size of the Broca’s and Wernickes areas, with women’s being proportionally larger. This may be due to women’s greater use of language — Suggests that localisation of function may not be generalised

Question 13

Brain lateralisation

Answer 13

The two halves of the brain are not exactly identical, the two hemispheres have functional specialisations eg the left side is dominant for language

The brain is contralateral - The left hemisphere deals with the right side of the body. Includes taste, sight and smell

Question 14

Narumoto et al & Clarke et al

Answer 14

Studies that support brain localisation - Narumoto found the right hemisphere is dominant for emotion, Clarke suggested the right hemisphere deals with spatial recognition

Question 15

Strengths of lateralisation

Answer 15

• Rogers et al: brain lateralisation is linked with an enhanced ability to preform two tasks simultaneously -> Lateralisation increases efficiency in cognitive tasks that demand simultaneous but difference use of both hemispheres
• Tonnessen et al: found a small but significant relationship between handedness and immune disorders suggesting a link between lateralisation and the development of the immune system -> Study left handedness (right brain dominance), as they tend to suffer higher rates of allergies

Question 16

Weaknesses of lateralisation

Answer 16

• Szaflarski et al: found that language became more lateralised to the left hemisphere, up until the age of 25 but decreased after that -> Suggests that lateralisation changes over time and is only relevant up to a certain age
• Brain plasticity: Lateralisation has shown that the other hemisphere can take over the job of both hemispheres, suggesting that brain plasticity can overcome potential limitations associated with lateralisation

Question 17

Split brain research

Answer 17

Studies lateralisation as it shows what is dominant in each hemisphere

• Patients with epilepsy have their corpus callosum cut, preventing communication between hemispheres, this allows studies to be conducted on which hemisphere is most dominant

Question 18

Sperry and Gazzaniga

Answer 18

Researchers would use the divided field procedure to send visual information to just one hemisphere at a time. There were 3 tasks;

• See: A picture was presented to the left or right & the pps had to describe what they saw
• Tactile: An object was placed in one hand & pps had to describe what they felt
• Drawing: Pps were presented with a picture on one side & draw what they saw

Question 19

Findings of Sperry and Gazzaniga

Answer 19

See: Picture on the RVF could be described verbally (Left hemisphere = language production). While they often could not describe what was present on the LVF

Tactile: Objects in the RH could described or identified (left hemisphere) however in the LH (right hemisphere) it could only be identified, not described

Drawing: Pictures presented to the RVF/LVF -> The LHs drawing was clearer than the RH (Right hemisphere is better at visual motor tasks), and dominant hand had no effect

Question 20

Turk et al

Answer 20

Conducted a study on JW (who had split brain surgery). The stimuli were morphed faces;
- One was JWs, the other a familiar researchers
They ranged from 100% one, to a mix of both -> used the divided field procedure

Right hemisphere is better at facial processing, but left hemisphere is important in self recognition

Question 21

Strengths of split brain research

Answer 21

• Research: For example, Sperry and Gazzanigas research can be used to show that hemispheric lateralisation exists -> Eg the right hemisphere is responsible for visual spatial programming and facial recognition

Question 22

Weaknesses of split brain research

Answer 22

• Very few patients -> only 10-15 have been subjected to extensive study (small sampling size)
• Extremely varied group -> ranges in age, gender and handedness (Unclear cause and effect)
• The operations were not always the same -> some only had part of the corpus callosum cut

These all lead to issues with generalisability

Question 23

Plasticity

Answer 23

The ability of the brain to adapt synapses, pathways, and structures in light of various experiences.

Question 24

Plasticity in the newborn brain

Answer 24

By the end of the first year, the brain has more neurons and more synapses than it will have when it becomes fully mature
- There are more new stimuli & more processing required

If a baby has a hemispherectomy & the hemisphere is removed soon after birth then the adult shows few, if any cognitive/behavioural impairments (Villablanca and Hovda)

Question 25

Plasticity as a result of life experiences

Answer 25

Boyke et al: found evidence of plasticity in a group of 60 year olds who were taught a new skill (juggling) had an increase of grey matter in the visual cortex -> when practice stopped, the changes were reversed

Question 26

Plasticity and meditation

Answer 26

Davidson et al: compared 8 practitioners of Tibetan meditation & 10 volunteers (control group) and asked both to meditate. They found monks had a much greater increase in gamma waves -> concluded that meditation may produce permanent changes

Question 27

Strengths of plasticity

Answer 27

• Animal studies: Kempermann et al found an increase in new neurons for rats in complex environments vs rats in ordinary cages. Also, the rats in complex environments had an increase i neurons in the hippocampus -> Evidentiary support for plasticity
• Human studies: Maguire et al studied London taxi drivers using MRI scanners to calculate the amount of grey matter in the brain compared to a set amount of pps. The front part of the hippocampus was larger & correlated how long they spent driving taxis -> Changes as a result of spatial experiences

Question 28

Weaknesses of plasticity

Answer 28

• Negative plasticity: Medina et al found evidence that the brains adaptations to prolonged drug use leads to poorer cognitive functioning in later life & increase in risk of dementia -> Plasticity is not always beneficial & and may have negative behavioural consequences
• Generalisation: Animal species are completely different from humans eg rats & kittens are mobile from birth so there brain development would be much faster than humans -> Should be cautious when applying animal results to humans
• Ethics: Studies carried on animals can be questionable eg in Blakemore and Mitchells study involved exposing kittens to only vertical stripes. As the kittens were denied a normal environment then ethically the study was not correct -> Cannot be applied to humans as they are not denied a normal environment

Question 29

Common types of brain trauma

Answer 29

• Physical trauma eg blows & missile wounds
• Cerebral haemorrhage eg stroke - when a blood vessel in the brain bursts, brain areas that are supplied begin to die & the pressure can cause damage
• Cerebral ischaemia eg stroke - When a blood vessel is blocked by a clot (Thrombosis) or the thickening of the blood vessel due to fatty deposits (arteriosclerosis) brain areas that are supplied begin to die
• Viral or bacterial infections eg meningitis - Destroys brain tissue

Question 30

What can brain injuries do?

Answer 30

Causes;
- Movement paralysis
- Aphasia
- Amnesia
- Perception difficulties

As blood supply is often lateralised, then so is the damage causing effects of trauma to be one sided

Question 31

Doidge 2007

Answer 31

The brain is able to retire and reorganise itself by forming new synaptic connections close to the area of damage secondary neural pathways that would not typically be used to carry out specific functions are activated/ unmasked to enable continued functioning

Question 32

Axonal sprouting

Answer 32

The growth of new nerve endings which connect with other unmanaged nerve cells to form new neuronal pathways

Question 33

Denervation supersensitivity

Answer 33

Axons that do a similar role become aroused to a higher level to compensate for the ones that have been lost. However this can cause over sensitivity to messages such as pain

Question 34

Recruitment of homologous areas

Answer 34

Opposite areas of the brain can be used to preform specific tasks eg if the Broca’s area was damaged then the equivalent right side may begin to carry out that function — after a period of time it may shift back to the left

Question 35

Neuronal unmasking

Answer 35

Wall (1977) first identified dormant synapses in the brain. This means synaptic connections exist but the functions are blocked. Increasing the rate of input to these synapses (happens when areas of the brain are damaged) can unmask them, opening connections to dormant areas of the brain creating a lateral spread of activation which allows for the development of new structures

Question 36

Danelli et al (2013)

Answer 36

EB had an operation at 2.5 years where a large tumour was removed from his left hemisphere. After EB lost all his linguistic abilities
- He underwent intensive rehab and by age 5 his language abilities had started to improve
- At age 8 he no longer had any difficulties

When tested against controls at 7, they found his right hemisphere had compensated for the loss of the left hemisphere — Supports the idea of recruitment of homologous areas

Question 37

Strengths of functional recovery

Answer 37

• Practical application: Contributed to the field of neurorehabilitation, although recovery can happen naturally, it tends to slow after a few weeks. Physical therapy can improve recovery to aid cognitive/motor deficits — Functional recovery is natural but aid increases quality of recovery
• Research: Schneider et al (2014) found that patients with the equivalent of a college education are 7x more likely to be disability free one year after a moderate to severe brain trauma compared to those who did not finish high school. Researchers concluded this was due to a cognitive reserve that factors in neural adaptation

Ratcliffe et al (2007) examined 325 patients with brain trauma to assess their level of response for cognitive skills to rehabilitation. It was found that women preform significantly better than men on tests of attention/working memory and language whereas men outperformed females in visual analytical tasks

Question 38

Weaknesses of functional recovery

Answer 38

• Age differences: Huttenocher et al concluded that beyond childhood, the only option for recovery is develop compensatory behavioural strategies to work around deficits. Despite indications for adult plasticity Elbert et al concluded that the capacity for neural reorganisation is greater in children.