Biopsychology - Brain Flashcards
1
Q
What are the three main sections of the brain?
A
- forebrain
- midbrain
- hindbrain
2
Q
What are the four main regions of the brain?
A
- cerebrum (cerebral hemispheres) = forebrain
- diencephalon = forebrain
- cerebellum = hindbrain
- brainstem = mid/hindbrain
3
Q
What is the cerebrum?
A
- largest section of the brain
- split into two hemispheres (left/right)
- they communicate via the corpus collusum
- four lobes:
- frontal =
- occipital
- temporal
- parietal
4
Q
What is the diencephalon?
A
5
Q
What is the cerebellum?
A
6
Q
What is the brain stem?
A
7
Q
What is localisation of function?
A
- the idea that specific functions (language, memory) have specific locations in the brain
8
Q
What are the motor and somatosensory areas of the brain?
A
- somatosensory cortex:
- receives sensory input from receptors in the skin
- located in parietal lobe
- face and hands take up over half the somatosensory area
- motor cortex:
- generates voluntary movements
- located in the back of frontal lobe
- both hemispheres control the muscles on the opposite side of the body
9
Q
What are the visual and auditory centres of the brain?
A
- visual centre:
- located in occipital lobe
- requires additional processing in neighbouring areas (perception)
- where sensation is converted into perception
- auditory centre:
- most of it is located in the temporal lobes of both the left and right hemispheres
- begins in the inner ear where sound waves are converted to nerve impulses
- this then travels via the auditory nerve to the auditory cortex
10
Q
What are the language centres of the brain?
A
- Broca’s area: (motor region)
- patient named Tan was able to understand a spoken language but could not speak it or put his thoughts into words
- found that the language centre is in the frontal lobe of the left hemisphere
- Wernicke’s area: (sensory region)
- found in the left temporal lobe
- involved in understanding language
11
Q
What are the strengths of localisation of function?
A
- brain scan evidence of localisation
- neurosurgical evidence
- case study evidence:
- Phineas Gage forced temporal lobe out of his brain
- aphasia study support
12
Q
What are the weaknesses of localisation of function?
A
- challenges to localisation = reductionist:
- plasticity argues against this theory
- individual differences:
- difference in patterns of activation across individuals
13
Q
What is brain lateralisation?
A
- idea that the two halves of the human brain are not exactly alike
- each hemisphere has functional specialisations
- left = language
- right = visual-motor tasks
- corpus callosum allows for the communication between the two hemispheres
14
Q
What is the right hemisphere dominant in?
A
- emotion
- spatial relationships
15
Q
What is the left hemisphere dominant in?
A
- language
16
Q
What are the strengths of lateralisation?
A
- helps to understand how specific functions are located on specific sides of the brain (multitasking)
- enhances brain efficiency
- can study left handedness and why they may be prone to allergies/illness
- link between immune system and lateralisation
17
Q
What are the weaknesses of lateralisation?
A
- changes with age, so this theory is not set in stone
- language became more lateralised to the left hemisphere up to the age of 25
- does not explain brain plasticity
- studies show that having one damaged hemisphere is not abnormal
- other hemisphere can take over the functions of the damaged hemisphere
18
Q
What is split-brain research?
A
- used to study brain lateralisation
- cutting of the corpus callosum is called commissurotomized
- communication between the hemispheres is stopped
19
Q
What is Sperry and Gazzaniga’s (1967) research?
A
- examined the extent to which two hemispheres are specialised for certain functions
- image/word projected in left or right visual field
- describe what you see
- tactile (touch)
- drawing task
20
Q
What did Sperry and Gazzaniga find?
A
- describe what you see:
- picture in right VF patient could verbally describe what they saw
- in left VF they could not describe the picture
- tactile test:
- right hand = could verbally describe object
- left hand = could not describe it, but could select similar objects
- drawing task:
- when pic presented to RVF, right hand could not draw as clear as the left hand
- LVF = left hand would consistently draw clearer images
- ** shows the superiority of the right hemisphere **
- ** left hemisphere is dominant in speech and language **
21
Q
What is Turk et al’s (2002) study?
A
- 48-year-old JW had commissurotomy for epilepsy
- stimuli
- morphed faces
- JW’s own and one of the researchers
- 0% JW’s face to 100% JW
- divided the field procedure to present stimulus to one or other hemisphere
- JW asked to press button if image was of his face/familiar other person
- results = right hemisphere showed clear bias identifying morphed faces as familiar
- left hemisphere showed bias towards identifying morphed faces as himself
- ** right is better at face processing and left is better at self-recognition **
22
Q
What are the strengths of split brain research?
A
- proves that there is hemispheric lateralisation
- both hemispheres have different functions
- research support for lateralisation through SBR
- shows that the connectivity between the different areas is important
- cutting of corpus callosum caused patients to struggle with verbally naming an object placed in the left hand
23
Q
What are the weaknesses of split brain research?
A
- has not shown that brain is organised into different areas with specific tasks
- SBR research had a small sample size
- some of the sample did not fully cut communications between the hemispheres
- they were an extremely varied group in terms of age, when epilepsy was developed and age of testing
- this makes the results less likely to be generalised to a wider population
- SBR is rarely carried out these days due to modern technology, so it lacks temporal validity
24
Q
What is brain plasticity?
A
- ability of the brain to change and adapt synapses, pathways, and structures in light of various experiences or after damage caused by trauma
25
What is Villablanca and Hovda’s (2000) study?
- plasticity in newborn brain:
- by the end of the first year, brain has more synapses and neurons than it will have when fully matured
- developing brain is exposed to a vast range of experiences, environment and stimuli
- *hemispherectomy* research where baby has one severely damaged hemisphere
- when it is removed soon after birth, the adult shows very few behavioural or cognitive impairments
26
What is Boyke et al’s (2008) study?
- plasticity as a result of new life experience:
- new experiences = nerve pathways developed
- 60 year olds taught new skill (juggling)
- found an increase in *grey matter* in the visual cortex
- ** when practise stopped, changes were reversed **
27
What is Davidson’s (2004) study?
- plasticity and meditation:
- meditation can change the inner workings of the brain
- 8 Tibetan meditation monks and 10 volunteers were asked to meditate for short periods
- electrodes picked up greater *gamma waves* (coordinate neuron activity) in monks
28
What are the strengths of plasticity?
- research support from animal studies
- Kempermann (1998) found increased no. of new neurons in rats in complex houses than in cages
- associated with new memories and ability to navigate from different locations
- Blakemore and Mitchell (1973) found that characteristics of visual neurons were changed by exposure to diff. environments
- kittens in black vertical striped environment did not respond to horizontal black stripes
- ** may be difficult to generalise to humans as this as conducted on cats (raised in only one env.) **
- research support from human studies:
- Maguire (2000) studied London taxi drivers and found that the front part of their *hippocampus* was larger than the control ppts
- positively correlates to how long they had been driving for
- age differences:
- Bezzola (2012) found how 40 hours of golf training produced changes in neural rep. of movement in ppts aged 40-60
- motor cortex activity increased compared to before training
- shows how people of all ages are able to improve their brain capacity
29
What are the weaknesses of plasticity?
- negative plasticity:
- Medina (2007) found that brain's adaptation to prolonged drug use leads to poor cognitive functioning
- generalisation issues:
- studies carried out on animals are hard to generalise to the human population
- e.g. kittens/rats are mobile at birth so their brain development is faster than humans
- ethical issues:
- e.g. cats in Blakemore and Mitchell's study were brought up in an ethically questionable environment
30
What is functional recovery after brain trauma?
- transfer of functions from a damaged area of the brain to other undamaged areas in the brain
31
What are common types of brain trauma?
- physical
- cerebral haemorrhage (stroke, blood vessel in brain bursts)
- cerebral ischaemia (stroke, blood vessel in brain blocked)
- viral/bacterial infections
32
How does the brain naturally recover?
- brain is able to rewire and reorganise itself by forming new *synaptic* connections
- *axonal sprouting*:
- growth of new nerve endings which connect with other undamaged nerve cells
- *denervation supersensitivity*:
- axons that perform similar role become aroused to higher level to compensate for lost ones
- *recruitment of homologous areas*:
- similar areas in opposite side of brain can take on the role of the damaged region
- *neuronal unmasking* (Wall 1977):
- increasing rate of input to blocked (dormant) synapses can open them which allows for more connections to regions of the brain
33
What is Danelli’s (2013) study?
- researchers used case study to support claims (Italian boy EB who lost linguistic abilities after brain tumour removal in left hem.)
- right handed so language ability was in left hem.
- joined rehabilitation programme which helped to improve his linguistic abilities until he no longer struggled
- after testing at 17, they found that his right hem. had compensated for the loss of the left hem.
- recruitment of homologous areas
34
What are the strengths and weaknesses of functional recovery after trauma?
- practical application:
- contributed to the field of *neuro-rehabilitation*
- doctors provide therapy and electrical therapy to the brain
- age differences:
- studies have shown that it is possible to improve abilities in adults with intensive retraining
- ** however, capacity for neural reorganisation is greater in children than adults **
- educational attainment and functional recovery:
- Schneider (2014) found that patients with college education are 7 times more likely to recover and be disability free after a year
- suggests that young gen. should carry on with edu. to help recover
- gender differences:
- women recover better as their function is not as lateralised as men
- Ratcliffe (2007) found that women perform better on tests of attention/language while men performed better in visual analytical skills
35
What are the ways of studying the brain?
- CT scans
- PET scans (glucose injected and accumulates in areas with greater activity)
- fMRI
- EEG
- ERP
- post-mortem examinations
36
What is fMRI?
- indirectly measures blood flow through conc. of O2 in the bloodstream
- signal used in fMRI is BOLD
- ppt may be asked to alternate between diff. periods of doing tasks to identify active parts of the brain
37
What are the strengths/weaknesses of fMRIs?
- strengths:
- non-invasive technique (allows more patients to undertake fMRI scans)
- good spatial resolution - smallest feature a scanner can detect (allows psychologists to distinguish between diff. brain regions)
- weaknesses:
- causation - fMRI scans do not provide a direct measure of neural activity (not clear whether brain region is associated with a particular function)
- poor temporal resolution (1-4 seconds, low accuracy)
- can only provide info on brain region and not individual neurons
38
What is EEG?
- provides an overall view of brain electrical activity
- small electrodes (24/32) are used on the skull and pick up elec. activity of millions of neurons
- amplitude = size/intensity
- frequency = speed/rapidity
- two states of EEG:
- synchronised pattern: recognisable waveform is identified
- desynchronised = no recognisable waveform
- can be used to detect various types of brain disorder/disease
39
What are the strengths/weaknesses of EEGs?
- strengths:
- provides recordings of the brain's activity in real time (temporal resolution)
- provides invaluable diagnosis of conditions like epilepsy (contributed to our understanding of stages involved in sleep - ultradian rhythms)
- weaknesses:
- can only detect activity in superficial regions of the brain and not deeper regions - e.g. hypothalamus
- not useful for pinpointing exact source of neural activity (poor spatial resolution)
40
What is ERP?
- very small voltage changes in the brain which are triggered by specific events/stimuli
- psychologist looks for specific electrical responses to the stimulus shown
- this is done multiple times with the same stimuli to separate the electrical activity and overall activity
- event-related potential then emerges
41
What are the strengths/weaknesses of ERPs?
- strengths:
- short latency - can reflect early stages of cog. processing (interval between stimulus presentation and beginning of ERP)
- can measure processing of stimuli even in absence of behavioural response
- weaknesses:
- poor spatial resolution (not possible to localise ERPs components to specific areas of the cortex)
- lack of standardisation in methodology so findings from studies are hard to generalise (extraneous variables must be minimised)
42
What are post-mortem examinations?
- when a person dies, researchers compare their brain to look for abnormalities
- e.g. Broca examined brain of man with displayed speech problems
- Wernicke discovered region where language is processed
- allows for a more detailed examination of anatomical and neurochemical aspects of the brain
43
What are the strengths/weaknesses of post-mortem examinations?
- strengths:
- enables researchers to examine deeper regions of the brain such as the hypothalamus and hippocampus
- Harrison (2000) claimed that post-mortem studies have played huge role in understanding of mental illnesses
- weaknesses:
- too many individual differences (length of time between death and post-mortem, drug treatment, age)
- ethical issues in terms of consent (especially as this is carried out on patients with severe psychological deficits)
- retrospective as person is already dead so follow ups cannot be made
