P2: Biopsychology Flashcards
Describe localisation in the brain
Specifically
-Localisation theory
-Hemispheres of the brain
-Localisation theory: Different areas of brain responsible for different behaviours/process/activity.
Replaced Holistic theory
-Lateralisation: some physical/psychological functions controlled by particular hemisphere.e.g.Right controls left
-Cerebral cortex: Covers inner part of brain.3mm Thick.
What separates us from animals ∵ humans=developed
Describe localisation in the brain
Specifically
Each different area/centre
-Motor: Controls voluntary motion(Back frontal lobes)
-Somatosensory: Process sensory info from skin(Front Parietal lobes)
-Visual: Eye send info to opposite cortex(Back Occipital lobe)
-Auditory: Analyses speech-based info(Temporal lobe)
-Broca Damaged= slow speech. Difficult finding words n naming certain objects(Left frontal lobe)
-Wernioke Damaged= problem understanding language. can produce nonsense words(neologisms)
(Back temporal lobe)
Evaluate Localisation in the brain
- BrainScans: LTM study= semantic/episodic memories located in different parts of fontal cortex= many objective methods to measure brain activity ∴ proof of localisation
+ Case study(Phones Gage): Brain damage via expulsion on railroad= damaged frontal lobe. Personality shift= Calm->Rude∴ temperament change suggests frontal lobe responsible for regulating mood - Neural plasticity(Cortical remapping): Damaged brain reorganises self= recover function. Law of equipotentiality= other areas chip in to function that area. Doesn’t always happened, but several noted cases.
Describe Brain plasticity
-Plasticity: Brains tendency to adapt/change after new experience/learning
-Synaptic pruning: rarely used connections deleted, frequently used ones strengthened
Brain experiences rapid growth in infancy. Peaking 15,000 at age 2-3yrs
STUDY INTO PLASTICITY
Taxi drivers= more grey matter in posterior hippocampus vs control. Associated= spatial/navigational skills.
-The Knowledge test(Taxi Drivers): Assess recall of city streets/routes in LDN ∴ alters brain.
Describe Functional recovery after trauma(Neural plasticity)
Healthy areas of brain reorganising self n forms new synaptic connections close to damage= take over functions. Occurs quickly after trauma then slows down. Rehab helps
-Secondary neural pathways activated/unmasked= continued function.
STRUCTUAL CHANGES INCLUDE:
-Axonal sprouting: new nerve cells connect with other undamaged cells=form new neural pathways
-Reformation of blood vessels
-Recruitment of homologous: similar areas of brain preform specific tasks
Evaluate Plasticity n functional recovery of the brain
+ Practical application: Contribution= neurorehabilitation. Techniques.e.g.movement therapy, electrical stimulation=counter defects after stroke ∴ brain can fix itself to a point
- Negative Plasticity:60-80%amputees get phantom limb syndrome= sensation of missing limb ∵ somatosensory reorganisation ∴ not always beneficial
- Relation. Age n plasticity: Functional plasticity drops with age. kids mind= reorganisation constant ∵ learning
HOWEVER: 40yrs of gold training= changes in neural plasticity(40-60yr ppl) of motor skills∴ continues through lifespan
Describe split-brain research into hemispheric lateralisation
-Hemispheric lateralisation: 2 halves of brain function differently. Behaviour controlled by 1 hemisphere
Split Brain Studies:AIM: Display 2 hemispheric-spheres specialised for certain functions.
Participants had operation(Commissurotomy). Cuts corpus callosum= controls epileptic seizures
PROCEDURE:
Image/word showed to RVF n another to LVF
DESCRIPTION OF SIGHT:
RVF: describes what’s seen easily
LVF: nothing there ∴ RH lacks language
RECOGNITION BY TOUCH:(matching obj)
LVF: With Left hand. Couldn’t name but could select matching/associated obj ∴ Verbal identification ≠ without LH but with RH can identify/match objs.
COMPOSITE WORDS: 2 words showed on either side.
LVF->RH linked to left hand. RVF->LH linked to right hand.
MATCHING FACES:
LH dominated verbal description
RH dominated selection of matching pictures
Evaluate Split-brain research into hemispheric lateralisation
- Generalisation: Split-brain patients= unusual sample of ppl. Only 11ppl took part, also had history of seizers ∴ possible change in brain ∴ limits validity
+ Demonstration power: LH=analytical/verbal. RH=Spatial/music, contributes to emotional language - Differences overstated: Modern neuroscientists argue distinctions ≠clear-cut. Many behaviours associated with 1. Can be preformed by other hemisphere when required(Flexibility) ∴ theory oversimplified
Describe ways of studying the brain
4techniques
-FUNCTIONAL MAGNETIC RESONANCE IMAGING
(fMRI): Detects changes in blood oxygenation/blood flow.
-Haemodynamic response: Brain activity=oxygen/blood flow directed.
Produces 3D image= shows active parts of brain ∴involved in mental process
ELECTROENCEPHALOGRAM(EGG): Measures electrical activity within brain via skull cap.
-Scans brainwave patterns from millions of neurons. -Uses= diagnostic tool. Unusual arhythmic patterns= possibles.e.g.epilepsy, tumours….
EVENT-RELATED POTENTIAL(ERP): Statistical technique.
Filters all extraneous brain activity from EEG recording. Displays only responses related to representation of specific stimulus/performance of specific task
POST-MORTEM EXAMINATION: Brain analysis after death. Aim: to locate areas of deficits/disorder suffered during life. Comparisons with neurotypical brain= assess extent of difference
Evaluate ways of studying the brain
fMRI
+ Non-intrusive: No reliance on radiation ∴ safe. Produces high quality images
- Expensive: (in comparison to other techniques). Clear image only if patient stays still.Poor temporal validity. 5s delay between image n activity ∴ not real-time
EEG
+ Practical assistance: Helps understanding of sleep stages. high temporal resolution= 1millisecond
- Isolation/location of neurons: hard to pinpoint/know exact source ∵signal generalised from thousands of neurons
ERP
+ Specific: more specific than raw EEG data. Good temporal validity vs fMRI
-Lack standardisation: in methodology. Background noise/ extraneous data must be completely eliminated. Not always achievable
POST-MORTEMS
+ Foundation for brain standings: e.g. Broca/Wernicke. Improves medical knowledge
-Ethics: Ethics, no informed consent. Observed damage ≠ to defects maybe due to trauma/decay
Describe Circadian rhythms
Biological rhythms governed by endogenous pacemakers n exogenous Zeitgebers
Endogenous pacemakers: internal biological clocks
Exogenous Zeitgebers:external changes in environment
-Ultradian rhythms: Occurs many days a day
-Infradian rhythms: Longer than a day to complete
-Circannual rhythms: Much longer than a day
Endogenous pacemakers= stronger influence vs
exogenous Zeitgebers ∵ STUDIED”
-12ppl living in dark cave for 3 weeks.
Sleep at 11:45pm, wake 7:45am. Researchers sped up clock sneaky ∴24hr day=22hr day.
FOUND:
Only 1 person adjusted comfortable ∴ strong free-running circadian rhythm cannot be easily overridden by external changes
Describe cave studies preformed investigating Circadian rhythms by Siffre and Aschoff
SIFFRE’S CAVE STUDY:
Siffre spent long period in dark cave= study effect of free-running bio rhythms.
6Months=Texas cave. 2Months=Southern Alps
FOUND:
Each case free-running circadian rhythm settled just above 24hrs(25hrs). He did have a regular sleep/wake cycle
ASCHOFF:
4weeks in WW2 bunker
FOUND:
1ppl=29hrs, rest=24-25hrs ∴ natural sleep/wake= longer than 24hrs but entrained by exogenous Zeitgebers
Evaluate biological rhythms: Circadian Rhythms
+ Practical application: Lapse of concentration from around 6am. Link between shift work/poor health. Shift wrokers= 3x likely develop heart disease. ∴ economic impact.How to best manage productivity
- Case study/sample size: Studies involve 1ppl or small group ∴ cannot generalise. Siffre noted internal clock ticked slower at 60yrs vs youthful ∴ age is another factor
- Individual differences:Sleep/wake cycle varies from 13-65hrs. some ppl early birds vs night owls ∴ hard to generalise
Describe biological rhythms: Infradian rhythms
1)E.g. Menstrual cycle: About 28days. Less than 1 cycle in 24hrs
EXOGENOUS ZEITGEBERS SYNCHRONISE CYCLES?
29 women with irregular periods studied= samples of pheromones(Swear) taken at different stages of cycle
FOUND:
68% experienced changes to cycle ∴ bringing closer to odour donor
2)E.g. Seasonal affective disorder(SAD)
Depressive disorder with seasonal pattern.
Symptoms triggers during winter ∵less daylight
Suspected cause by Melatonin hormone
NIGHT: Pineal gland secretes melatonin until dawn
WINTER: Lack of light in morning= longer secretion ∴
Effect on production of serotonin (low=depressed)
Describe biological rhythms: Ultradian rhythms
E.g. Stages of sleep. Sleep pattern occurs in 90minutes periods. 5 Stages. Characterised by different lv of brain wave activity(monitored via EEG)
-Stage 1-2: Light sleep
Alpha waves. Slow/rhythmic
Slowing further(Beta waves) as sleep gets deeper
-Stage 3-4: Deep sleep
Delta waves, slow/greater amplitude
-Stage 5: REM(Rapid eye movement)
Fast,jerky eye activity
Body paralysed yet brain activity speeds up
(Correlated with experience of dreaming)
