Biopsychology Flashcards
Parts of the brain
Motor cortex Somatosensory cortex Visual cortex Wernicke's area Auditory cortex Broca's area
Motor cortex
Controls voluntary movement.
Frontal lobe.
Somatosensory cortex
Detects senses.
Parietal lobe.
Visual cortex
Processes information from sight/eyes.
Receives information via the phrenic nerve.
Occipital lobe.
Auditory cortex
Processes information from hearing/ears.
Temporal lobe.
Broca’s area
Controls production of speech.
Frontal lobe.
Wernicke’s area
Responsible for understanding of language.
Temporal lobe.
What are the two brain hemispheres connected by
Corpus callosum
Left hemisphere handles…
Language functions.
Also logic, analysis and problem solving.
Right hemisphere handles…
Spatial comprehension, emotions and facial recognition.
What do the left and right hemispheres control?
Left controls: right body
Right controls: left body
Split brain surgery
Severs the corpus callosum in severe cases of epilepsy. This stops seizures spreading across the brain.
Effects of split brain surgery study
Sperry and Gazzaniga 1967
Sperry 1968
Method and results
Effects of split brain surgery
Method: 11 participants, androcentric. Control group (with corpus callosum).
Participants covered one eye and looked at fixed point on screen. Pictures projected on left or right of screen at high speed so no time for eye movement.
Result: picture shown on right, participants could say or write what it was no problem. If shown on left, participants could not say or write what it was, but could feel for the representative object in left hand if what had been shown to left visual (right hemisphere) but didn’t know why they selected that.
Sperry 1968
Conclusion and evaluation
Effects of split brain surgery
Conclusion: Shows different areas of the brain specialise in different functions.
Left hemisphere receives from right visual converts sight into spoken and written language.
Right hemisphere receives from left visual can produce non-verbal response.
Evaluation: got qualitative and quantitative data. Small sample - low pop validity. Epilepsy patients also on meds - affected brains? Can’t compare to non epilepsy. Low ecological validity as artificial experiment situation - hard to generalise to real-life.
Methods of studying the brain
fMRI
EEG
ERP
Post Mortem Examination
fMRI
Carries out task while in scanner, part of brain involved will be more active (more oxygen there from red blood cells) and is coloured on computer.
Used to diagnose medical problems as show damaged/diseased areas of brain.
+non-invasive
- expensive
- not good for those with claustrophobia
- poor temporal resolution (don’t show changes over time)
EEG
Shows overall electrical activity of the brain - picks up signal of many neurons.
Electrodes on scalp and activity recorded which produces a pattern of waves.
Used in sleep studies.
Help diagnose depression/schizophrenia/anorexia nervosa.
Use to diagnose.
+non-invasive
+ cheaper
+good temporal resolution
- poor spatial resolution (hard to work out specific area of brain waves originate).
ERP
Method of EEG but patient carries out activity to see how wave patterns change in response to a stimulus. Same task carried out to cancel ‘noise’ and focus on specific function.
Used in memory research- information processing in the brain.
Help diagnose those with psychiatric disorders by comparing waves to normal people.
Post mortem examination
Shows structural abnormalities that could explain condition.
+Provided evidence for localisation of function.
E.g. Paul Broca did PM on two people with speech problems due to brain damage and found they both had damage to same area (now called Broca area).
- person had to die so they won’t benefit from results.
Disadvantage of all methods of studying the brain
Don’t allow us to determine cause and effect.
What does fMRI stand for
Functional magnetic resonance imaging
What does EEG stand for
Electroencephalogram
What does ERP stand for
Event-related potential
Evidence for Broca’s area controlling language
Carried out post-mortem on patient Tan who had speech problems during his life.
Paul Broca was able to identify what became known as Broca’s area in the brain.
Brain plasticity
The brain is flexible and can change shape.
How does the brain change shape
Bridging: new connections are formed due to use and new stimulus.
Pruning: where connections are lost due to lack of use.
Studies for Brain plasticity and functional recovery?
Kuhn 2014
Davidson et al 2004
Kempermann 1998
Maguire 2000
Kuhn 2014
Participants play super mario bros for 30mins per day for 2 months. Compared to group not playing.
Increased grey matter of gamers -motor cortex, cerebellum (coord of movement) and hippocampus.
+ longitudinal (reduce individ. diff, shows cause and effect)
+ real world application (games are good)
- extraneous variables (not lab, other factors effect)
Davidson et al 2004
Tibetan monks compared to non meditation controls. Both groups meditate for short period - then fitted to electrical sensors to detect activity in brain.
Monks had more gamma activity (which helps coord neuron activity).
+ real life application
+ used a control group
- small sample group
- extraneous variables
- monks are hard to generalise as such a different lifestyle and have been meditating for a long time
Kempermann 1998
Found that rats who were raised in an enriched environment (more stimulation, more colours) had an increased amount of neurons compared to rats raised in lab cages.
Maguire 2000
Found that London taxi drivers had a larger posterior hippocampus than non-taxi drivers. This part is responsible for spatial navigation.
To provide more evidence for cause and effect he found that those who had been drivers for longer had a larger hippocampus.
Studies for functional recovery of the brain
Teuber 1975
Schneider 2014
Teuber 1975
Age
If you are older, you are less able to recover.
60% under 20s showed significant improvement.
20% over 26s.
Schneider 2014
More educated - better recovery.
Those who went to college (or equivalent) are seven times more likely to be disability free 1 yer after traumatic brain injury than those who didn’t finish school.
Localisation of function evaluation
Strengths:
- support from aphasia case studies
- support from brain scanning techniques
- support from phantom limb
Weaknesses:
- case studies specific and rare
- communication not localisation (pathway more damaged than areas)
-individual differences (no two people are the same)
Evaluation of lateralisation and split brain research
+ scientific cause and effect
+ supported by evolutionary theory (more efficient to have hemispheric lateralisation)
- small sample sizes, low pop and temporal val.
- participants epileptic, normal brains to compare?
- Gazzaniga and Turk both discovered some ability to speak in the right hemisphere as well.
- case studies: individual differences (some people have more lateralised brains) women have less.
- Reductionist explanation
Functional recovery after trauma
Neuronal Unmasking
Neuronal unmasking: activating dormant synapses after trauma to compensate for the damaged synapses.
1) Axon sprouting: axon is arm of nerve cell - helps connect to other neurons. Sprouting: new axons grow and connect to undamaged areas.
2) Recruitment of homologous areas in opposite hemisphere: functions taken care of by the dormant areas of the other hemisphere.
Study for neuronal unmasking
Wall 1977
Found brains contain a lot of dormant synapses which are not receiving input but can be still be called upon in need.
Example of someone who managed functional recovery after a trauma
Ben Underwood
Lost his eyes to cancer and regained sight through echolocation.
Functional recovery after trauma
Stem cells
Unspecialised cells with the potential to perform any function.
Implanted into the brain to deal with trauma recovery.
1) Direct implants: replace damaged cells
2) Rescue implants: release growth hormones to repair damaged cells.
3) Neural networks: link damaged to undamaged to create functional recovery.
Circadian Rhythms
Rhythms which work on a daily cycle.
Sleep-wake cycle.
Hormone production:
Melatonin: makes sleepy, increases before bedtime, dec as day progresses as inhibited by light
Cortisol: inc alertness, peaks at 6am ready to wake up, lowest around midnight ready for sleep.
Exogenous zeitgebers
External cues
Endogenous pacemakers
Internal cues
Study for Circadian Rhythms
Michel Siffre
Lived underground in cave for 6 months, Texas.
No external cues , internal body clock influenced behaviour.
No daylight, clocks or radio.
Concluded: natural circadian rhythm settled to just over 24 hours.
+ got into internal rhythm due to endogenous factors (25 hours).
- some dramatic variations -up to 48hours- so external cues needed to regulate cycle.
Evaluation of Siffre
Case study of 1 man:
+ rich in detail
- individual differences, androcentric
Used dim artificial light to get around:
+ dim light, less impact, ethical as less likely to get injured.
- external factor, cue? (Czeisler)
Cold dark cave 6 months:
+ longitudinal, see change
- unrealistic situation, hard to generalise.
Real world app:
+ Gov. dim public lighting at certain times
+ NASA space exploration
+ therapy for sleep deprivation
- flawed study, society shouldn’t change based on this study
Circadian Rhythms
Czeisler
1999:
- Found circadian rhythms of different people vary, from 13-65 hours. So can’t generalise, poor pop validity.
- Altered participants circadian rhythms down to 22hrs or up to 28hrs by using dim artificial lighting.
Circadian Rhythms evaluation
\+ scientific measures \+ research support, Hughes \+ real world app (chronotheraputics, timing of drug treatment) - use of artificial lighting (czeisler) - could be temperature not lighting
Ultradian Rhythms
A type of biological rhythm with a frequency of more than one cycle in 24 hours.
Sleeping is made up of cycles.
The Sleep Stages
1. Hallucinations 5-10mins, 4-5%, transition from awake to sleep 2. Brain wave spindles 20mins, 45-55%, HR slows, brain activity 3. Delta waves 4-6%, transition light to deep sleep 4. Delta Sleep 30mins, 12-15%, deep sleep
3+2 repeat
REM Sleep
20-25%, (dreams here) inc respiration and HR
Sleep Stages Order
1234 Only go through 1 once
32 REM BRAC (brain rest activity cycle)
234 Cycles last 90 mins and repeat
until awake.
32 REM
234
Infradian Rhythms
A type of biological rhythm with a frequency of less than one cycle in 24 hours.
E.g. Menstrual cycle
Seasonal affective disorder (SAD)
Feelings of sadness/depression during winter when there is less light.
Due to too much melatonin in the brain, a hormone inhibited by light (produced in abundance in dark).
Leads to sleepiness and feeling weary in the day.
Treatment is exposure to light.
Evaluation of Ultradian Rhythms
+ Russell (sweat lip study)
+ Penton-Voak (menstrual cycle and mate choice)
+ effectiveness of phototherapy
- arguments against Russell, cycles vary in length and match up by chance
Endogenous pacemaker
SCN (suprachiasmatic nucleus): main pacemaker in brain, hypothalamus, regulates circadian rhythm.
Has its own internal clock based on cellular processes.
SCN is endogenous but relies on external info to ensure synchronisation.
SCN
-cycle resets by use/absence of light
- type of light receptor in retina gauges brightness
With light: receptors send melanopsin to SCN
SCN communicates with pineal gland to inc melatonin in absence of light and inhibit production with light.
Exogenous zeitgebers
Light: regulates rhythms with melatonin and cortisol
Social cues: regulated by presence of others.
Evaluation of exogenous zeitgebers and endogenous pacemakers
Endogenous:
Morgans hamsters
DeCourseys chipmunks
Exogenous: Skene and Arendt Klein and Wegmann Burgess et al Vetter et al
Outline the structures and processes involved in synaptic transmission
Neurotransmitters in vesicles in pre-synaptic terminal release neurotransmitters into synaptic cleft when stimulated by action potentials/nerve impulses arriving at pre-synaptic terminal.
Neurotransmitters combine with post-synaptic receptors.
Post-synaptic effects whether its going to be either excitatory or inhibitory.
