Biopsychology Flashcards
Nervous system
PNS-Neurones
-ANS-autonomic functions
-SNS-muscle movement
Fight or flight (endocrine and nervous)
- hypothalamus detects threat
- ANS activated (parasympathetic to sympathetic state)
- Adrenaline realised
- Triggers physiological arousal
Structure of a neurone
-Soma (cell body)-nucleus, dendrites (carry impulses to the cell body)
-Axon and myelin sheath+nodes of ranvier (gaps)
-terminal bottons
-Negative at rest, activation causes it to be positive and creates action potential
Localisation of function
Lateralisation of function-some functions are controlled by a specific HEMISPHERE
ex) right side is controlled by left
Broca’s aphasia-slow and lacking speech
Wernicke’s aphasia-difficulty in understanding and comprehension so use nonsense words (neologisms)
Localisation-evaluation
Strengths:
-Brain scan evidence such as Tulving’s that showed blood flow in different brain parts
-Neurological evidence as removing parts of brain can change behaviour, lobotomy (frontal lobe) can control aggression
-case study evidence such as Phineas Gage
Weaknesses:
-Lashley’s study showed that higher cognitive functions are holistic , removed areas of cortex in rats (10-50%) and showed that no areas were more important than others in escaping the maze
-Lashley showed that when an area is damaged, other areas reorganises itself to recover the lost function (plasticity and law of equipotentiality)
Brain plasticity
-Brain experiences rapid growth in synaptic connection during infancy
-Adults delete rarely used connections and strengthens frequently used ones (synaptic pruning)
-Brain can change function and structure throughout life
Research into plasticity
-Maguire et al-taxi drivers had more grey matter in the posterior hippocampus (part linked to spatial and navigational skills), the longer they had the job, the more pronounced the structural difference
-Draganski-images of med students brain before and after final exams, learning induced changes seen in postural hippocampus and parietal cortex
-Mechelli-more parietal cortex in bilingual brains
Recovery after trauma
Functional recovery-healthy brain areas take over damaged brain after traumas such as stroke
Spontaneous recovery occur quickly after trauma, then shows down so rehabilitative therapy needed
New synaptic connections formed near area of damage, secondary neuronal pathway are activated to enable functiooning
-axonal sprouting (growth of new nerve endings)
-reformation of blood vessels
-recruitment of homologous areas on opposite side of brain
Plasticity-evaluation
Strengths:
-practical application on neurorehabilitation as methods could include movement therapy to counter motor/cognitive functions
-Animal studies support, sewing one eye of a kitten shut and analysing brain response showed that visual cortex linked to the shut eye was not idle
-Education background influence how well the brain recovers, 2/5 that had DFR (full recovery) had 16 years of education, only 10% had 12 years of education
Weaknesses:
-negative plasticity occurs such as prolonged drug use which results in poor cognitive functions. Phantom limb syndrome is experience of sensations of missing limbs
-Plasticity reduces with age however still continues, Golders had more efficient neural representations after training
Hemispheric lateralisation
Split brain studies:
Sperry studied people who had undergone commissurotomy (tissues connecting the hemispheres (corpus callosum) were cut down to control seizures)
-Image projected to right visual field, same/diff one on left visual field-info couldn’t be conveyed from one hemisphere to other
-Describing-when pic shown on right visual field, could describe what was seen. left-couldn’t describe/reported to see nothing as language is processed in the left hemisphere
-Recognition by touch-selected matching objects using left hand (right hemisphere) , couldn’t verbally identify the object but could understand and select the object
-Composite words-2 simultaneous words on each side of the brain (ex. key on left and right on right) would make the patient select a key and say the word ring
-matching faces-right hemisphere is dominant in recognising faces (pic presented on left hemisphere was ignored), left hemisphere dominates verbal description, right dominates selecting the matching pic
Lateralisation-evaluation
Strengths:
-Sperry’s research supported lateralised brain functions, left hemisphere analysis and right hemisphere synthesises
-Sperry’s method was standardised and specialised (image flashed quickly so can’t use both eyes)
-Provided theoretical basis about the degree of communication between hemispheres
Weaknesses:
-Unlimited sample (only 11 and had seizures) so can’t generalise
-Differences in function is overstated, actual distinction is less clear
Brain investigation techniques
fMRI (functional magnetic resonance imaging)-detects haemodynamic response and produce 3 dimensional images
EEG (electroencephalogram)-measures brain electrical activity using electrodes fixed to an individual’s scalp, records brainwave patterns, show unusual arrhythmic patterns that indicate abnormalities
ERPs (event related potentials)-isolating specific brain activities so that event related potentials (brainwaves triggered by specific events)
Post mortem examinations-Examining areas go damage after death, comparison with normal brain to see the difference
Brain investigation techniques-evaluation
FMRI:
Strengths-no radiation, high spatial resolution, localisation
Weaknesses-expensive, has to stay still, poor temporal resolution (5 sec time delay), don’t show activity
Electroencephalogram
Strengths-high temporal resolution, gave info about sleep stages
Weaknesses-can’t show specific source of neural activity, can’t distinguish different but adjacent locations
Event related potentials
Strengths-Specific, high temporal resolution
Weaknesses-lack of standardisation (can’t confirm findings), EVs
Post mortems
Strengths-provided important foundation for early brain for further studies (Broca and Wernicke used this0
Weaknesses-Causation is unclear, unethical (no informed consent)
Circadian rhythms
Endogenous pacemakers: internal clocks
Exogenous Zeitgebers: external changes on environment
-sleep wake cycle involves both
Circadian rhythms: last for around 24 hours
Siffre’s study
-spent time underground (light deprived), free running biological rhythms settled to 25 hours (still slept and got up regularly)
Aschoff and Wever’s study
participants spent time in bunker (light deprived), cycle extended to 29 hours
Folkard’s study
light deprived, bed at 11:45 and up at 7:45, speeded up the clock so 24h became 33h-only 1 adjusted (external influence isn’t strong)
Circadian rhythms-evaluation
Strengths:
-Application to shift work, night workers had reduced concentration at 6 in the morning-can manage worker productivity better
-Application to drug treatments, drugs are more effective at specific drugs
Weaknesses:
-Use of case studies and small samples
-lacked control (deprived of natural light but still had artificial light)
-Individual differences (sleep wake cycle vary)
