Biopsychology L5 - 8 Flashcards
What happens what a person is faced w/ a threat and once this this threat has subsidised?
1) Amygdala is activated
2) Amygdala sends distress signal to hypothalamus
3) Hypothalamus communicates w/ rest of brain thru sympathetic nervous system
4) SNS sends signal to adrenal medulla, which releases adrenaline
5) Parasympathetic nervous system dampens stress response
What does the amygdala do?
Associates sensory signals with emotions associated with fight or flight
What physiological changes are caused because of adrenaline and why does this happen?
- Increased heart rate –> increases blood flow to organs
- Increased breathing rate –> increase oxygen intake
- Pupil dilation –> increase light entry to enhance vision
- Sweat production –> regulate body temperature
- Reduction of non-essential functions –> increase energy for essential functions
Evaluation of flight and fight response:
+ Makes sense from evolutionary standpoint
- Does not consider other responses - what about freeze?
- Gender differences
- Maladaptive response in modern-day life
In what way does the flight and fight response make sense from an evolutionary standpoint?
- Threats in past would have been more significant hence flight and flight response makes sense
- Makes sense as a survival instinct
What study shows our reaction is not limited to flight or fight response?
- Gray (1988)
- Suggests first response is to avoid confrontation altogether (freeze response)
- During this response, animals and humans are hyper-vigilant as they are deciding best course of action
How does flight and fight response have gender differences (+evaluation)?
- Typically male response to danger
- Recent research suggests females adopt ‘tend and befriend response’ in dangerous situations
- Taylor et al (2000) are more likely to form alliances and protect their offspring in rather than flight or fight
- Counterintuitive for women, as running may put offspring in danger as it is seen as a weakness
Evaluation: - Von Dawans (2012) found both men and females showed tend and befriend during 9/11 attacks
- Recognising gender similarities are positive as researchers avoid beta bias
How is flight or fight a maladaptive response in modern day life?
- Modern day life rarely requires such an intense biological response of life-threatening situations
- Negative consequences on health as stressors of modern day life can repeatedly activate fight or flight
What 3 main sections is the brain divided into?
- Forebrain
- Midbrain
- Hindbrain
What are the 4 regions of the brain and what part of the brain is each in?
- Cerebrum (forebrain)
- Diancephalon (forebrain)
- Brain stem (midbrain + hindbrain)
- Cerebellum (hindbrain)
What are each of the lobes in the cerebrum responsible for?
- Frontal: Thought and speech production
- Occipital: Image processing
- Temporal: Cognitive skills
- Parietal: Sensory information
3 Features of diancephalon:
- Located in cerebrum
- Responsible for sensory function, food intake, body’s sleep cycle
- Divided into thalamus, hypothalamus + epithalamus
Feature of cerebellum:
Controls motor function, balance + interpreting information from senses
Localisation of function:
Specific functions have specific locations in brain
What did Franz Gall propose, what was this theory called and what was the opposing view of this?
- Person’s personality was reflected in bumps on skulls that in turn reflected functions of brain lying underneath the bump
- Phrenology
- Opposing view: Large parts of the brain are involved in all behaviours
What did Paul Broca discover and in what year?
1865 –> Speech production was localised to an area in frontal lobe (Broca’s area), after conducting case studies of brain-damaged patients
By the end of the 19th century, what had researchers discovered?
- Small lesions could have highly specific effects on movement and perception shown by cats, dogs + monkeys
- Showed brain is organised in highly systematic way
What are the 6 key areas of the cerebrum?
- Somatosensory cortex
- Motor cortex
- Visual centre
- Auditory centre
- Broca’s area
- Wernicke’s area
3 Features of somatosensory cortex:
- Received sensory input from skin receptors
- Located in parietal lobe
- Greater the somatosensory area dedicated to body part, greater its sensitivity
3 Features of motor cortex:
- Responsible for generation of voluntary movements
- Located in back of frontal lobe
- Both hemispheres have this
2 Features of visual centre:
- Primary visual centre: located in occipital lobe
- Secondary visual centre convert sensation into perception
Where is the auditory centre located?
Temporal lobes
Specifically what case studies did Broca do to understand the brain and what conclusion did he make?
- Treated Tan in 1880s who could understand spoken language, but couldn’t speak or put thoughts down in writing
- 8 other similar patients who had lesions in left frontal hemisphere
- Patients with damage in right hemisphere did not have these issues
- Conclusion: Language centre is in frontal lobe of left hemisphere
Give one study evaluating Broca’s area’s localisation to just one function:
Federonko et al (2012) discovered 2 regions of this area –> one for language, the other for cognitive tasks
What did Karl Wernicke discover and when?
- Discovered another area in temporal lobe was responsible for language, which explains why Tan was able to understand language but not speak it
- Language involves separate motor and sensory regions
Features of motor and sensory region:
Motor region: Located in Broca’s area, close to area controlling mouth, tongue and vocal cords (speech)
Sensory region: Located in Wernicke’s area, close to regions response for auditory and visual input
What other feature is there between Broca’s area and Wernicke’s area?
Neural loop known as accurate fasciculus
Strengths and weaknesses of localisation of function (+4, -3):
+ Brain scanning evidence
+ Neurosurgical evidence
+ Case studies
+ Support from aphasia studies
- Reductionist
- Plasticity
- Individual differences in brain localisation
What brain scanning evidence is there of localisation and how does this make the theory more valid?
- Peterson et al (1988) used brain scans to show how Wernicke’s area was active during a listening task and Broca’s area was active during reading task
- Suggests language is localised to those two areas
- Brain scanning evidence means it is more objective
What neurosurgical evidence is there of localisation?
- Dougherty et al (2002) reported on 44 OCD patients who had undergone brain surgery lesioninb an area of brain seen responsible for OCD
- After 32 weeks of surgery, 1/3 had recovered from OCD symptoms whilst 14% had some recovery
What case study evidence is there of localisation?
- Landmark study on Phineas Gage
- Suffered brain damage w/ pole that forced frontal lobe out of his brain
- Complete change of personality
- Shows frontal lobe is responsible for regulating mood
How do aphasia studies support localisation?
- People who suffer damage to Broca’s area suffer expressive aphasia
- People who suffer damage to Wernicke’s area suffer receptive aphasia
What study shows localisation to be a reductionist method?
- Karl Lashley (1950) found higher cognitive functions aren’t localised to specific brain areas
- Removed areas of cortex (between 10 and 50%) in rat’s brains finding no area was important for rat’s ability to run the maze
How does plasticity argue against localisation?
When brain is damaged, rest of brain appears to reorganise itself to compensate for loss of function
What studies discovered individual differences in brain localisation?
- Bavelier et al (1997) found large variability in individual patterns of activation across individuals in right and left temporal lobes
- Harasty et al (1997) found gender differences in size of Broca’s and Wernicke’s area –> women have proportionately larger ones, as they tend to use language more
Brain lateralisation:
Idea that two halves of brain are not exactly alike
What functional specialisations does each hemisphere have?
- Left hemisphere is dominant for language
- right hemisphere for visual-motor tasks
What does it mean if the brain is contralateral?
Left hemisphere deals with right side of body and vice versa
What others senses are contralateral?
- Taste
- Smell
What does it mean if a part of the brain is lateralised?
Function is dealt with by one hemisphere
What is another reason for lateralisation?
Two hemispheres aren’t symmetrical so foundations cannot be the same
Give research evidence to show different functions of different hemispheres:
- Damage to left hemisphere leads to language deficits (not the case for damage to right hemisphere)
- Narumoto et al (2001) found right hemisphere to be dominant for recognising emotion –> study showed if photo of face is split w/ one half smiling and the other neutral, left hand side is the one recognised by pp
- Clarke et al (1993) –> Case study of woman w/ damaged right hemisphere would get lost even in familiar situations unless she had verbal instructions
How do the two hemispheres communicate with each other?
Corpus callosum acts as communicator between them
How did researchers investigate the different abilities of the hemispheres (split-brain research)?
- Commissurotomy procedure: Surgeons cut bundle of nerve fibres forming corpus callosum to stop electrical impulses of epileptic activity crossing over
- Communication is cut
Evaluation of lateralisation (+2, -2):
+ Better understanding of multi-tasking
+ Offers explanation for why left-handed people (right hemispheric dominance) tend suffer issues w/ immune system
- Lateralisation changes w/ age
- Does not explain brain plasticity
What research evidence shows association between lateralisation and multi-tasking?
Rogers et al (2004) found domestic chicken were able to perform 2 tasks simultaneously –> finding food and being vigilant
What research evidence suggests a link between lateralisation and the development of immune system?
Tennessean et al (1993) founds small but significant relationship
What research evidence shows that lateralisation is variable and changes with age?
Szaflarski et al (2006) found language became more lateralised to left hemisphere up to age of 25 but decreased after this
Why doesn’t lateralisation explain brain plasticity and what research evidence shows this?
- Conflicting evidence showing how one damaged hemisphere does not mean individual has abnormal brain
- Shows the other hemisphere takes over and does the job of both
- EB by Danielli et al (2013)
Who were the first researchers to study split-brain patients (hemispheric lateralisation) and what was the aim?
- Sperry and Gazzaniga (1967)
- Examine extent to which 2 hemispheres are specialised for certain functions
Procedure of Sperry and Gazzaniga’s research:
- Used ‘divided field procedure’
- 3 different experiments: describe what you see, tactile test & drawing task
Divided field procedure:
Image/word projected to patient’s left visual field (processed by right hemisphere) or right visual field (processed by left hemisphere)
What do each of the 3 tests include?
1) Describe what you see: Image shown to left/right visual field to be described by
2) Tactile test: Object placed in left/right hand and either had to describe what they felt or select similar object from series of alternate objects
3) Drawing task: Imagine shown to left/right visual field, where pp drew what they saw
Findings of Sperry and Gazzaniga’s research:
1) Describe what you see –> right visual field: described verbally showing left hemisphere is superior in language production, left visual field: couldn’t describe it and often reported nothing was there
2) Tactile test –> right hand: described verbally what they felt/identified correct object from series, left hand: couldn’t describe it but could select from series of objects
3) Drawing task –> right field: never as clear as left hand showing right hemisphere superiority for visual motor tasks, left field: left hand Dre better pics (even when pp was right-handed)
Conclusion of Sperry and Gazaniga’s research:
- Left hemisphere: Dominant in terms of speech and motor language
- Right hemisphere: Dominant in terms of visual motor tasks
Give a more recent study carried out in 2000s on split brain patients:
Turk et al (2002)
Aim of Turk et al (2002):
Whether patients own face was processed in different way to someone else’s familiar face
Procedure of Turk et al (2002):
- 48 yr old man (JW) who had commissurotomy for epilepsy 23 yrs ago
- Stimuli of 2 morphed faces: 0% JW (100% familiar), 50% JW (50% own/familiar), 100% own JW
- Use of divided field procedure
- In one set of trials: JD asked to press button if image presented was himself
- In another set: JD asked to press button if image presented was familiar other person
Results of Turk et al (2002) and conclusions
- Right hemisphere has clear bias towards identifying morphed faces as familiar other –> better at face-processing
- Left hemisphere has clear bias towards identifying morphed faces as himself –> better at self-recognition
Strengths and weaknesses of split brain research (+1, -5)
+ Research support for hemispheric lateralisation (Sperry, Turk)
- Has not shown brain to be organised into different areas w/ specific sections responsible for specific tasks
- Small sample size of 10 to 15
- Extremely varied grp of ppl eg different ages, gender –> too many confounding variables
- Operations not always comparable as not all connection pathways were cut git everyone
- Lacks temporal validity as this procedure is not done now due to modern brain scans that can observe these effects w/out brain surgery
