Essay bio-psych Flashcards
(20 cards)
Describe plasticity
ability of brain to change and adapt due to environment and learning
- occurs at any age + synaptic pruning (reg used connections strengthened/ unused deleted)
-plasticity shown through: homogenous areas (taking over lost function+using opposite hemisphere eg JW
Functional recovery
spontaneous recovery- more likely to recover soon after damage
Structural changes allow
1. Axonal sprouting- growth of new nerve endings
2. Blood vessel reformation- reconnect blood supply to areas of damage
3. Secondary neural pathways- new nerve connections that reconnect brain areas using diff routes
Factors affecting functional recovery
Age- at any age but less likely after 40
Marques de la plata- recovery after rehabilitation - less recovery in over 40s, declined 5yrs after recovery
Juggling- 60+, more grey matter in visual cortex after learning- when not practised
Gender- females more lateralised so recover more likely/ more plasticity
325 patients- neurorehabilitation and follow up after 1yr - found women better at working memory, attention
men better at visual analytical skills
Evaluate plasticity and functional recovery
+MRI scans on London taxi drivers, more grey matters in posterior hippocampus (navigation)- experience
+rats in complex vs simple cages- increased neurons formed in hippocampus
+spontaneous recovery slows down- movement therapy required to maintain improvements
-recovery more complex- adults require more training than children- indies have more ability than others
-neg consequences- 60-80% amputees develop phantom limb syndrome, pain from somatosensory cortex
explain localisation of function
- specific functions localised in specific areas of brain
-frontal lobe- decision making
includes brocas area- speech production- aphasia- slow speech
motor cortex- fine motor movements- drawing
-Parietal- interpreting sensory info- somatosensory cortex- touch and feeling pain
-Occipital lobe- vision and visual perspective - blindness
-Temporal lobe- auditory info - hearing loss
Wernicke’s area- understanding language- muddled sentences
language in left hemisphere
Evaluate localisation of function
+ brain damaged patients- Broca’s aphasia, Wernicke’s aphasia
+ brain scan research- Wernicke’s area active in listening tsk, Brocas- reading, Tulving- episodic and semantic mems diff sides of prefrontal cortex
- Lashley removed 10-50% cortex in rats learning a maze, no area more important
+ brain areas communicate is more important than which control- CS- lost ability to read and damaged visual cortex
-lashley- brainm damaged- rest can repair itself, strobe victim recover
Explain Lateralisation of function
Hemispheric lateralisation= 2 hemispheres ae functionally different eg left=lang, right= emotion
Sperry aim- explain functions of 2 hemispheres and corpus callosum
11 split brain patients, control of blindfolded over one eye, quasi, controlled DV= ability to complete tasks
Controls- 1/10th sec saw image using tachtiscope
1) Describe what they can see- image flashed to 1VF and asked to describe it eg LVF can’t say it as right hem no lang centres
2) Recognition by touch- imagine shown to 1VF, ppts select object from behind screen so LVF- select with left hand (LVF, right hem, contralateral control)
3) Composite words- image to each vf at same time and say what they see in RVF and draw or select saw in LVF with left hand
Results- lang= left hem, contra laterally controlled, object recognition in right hem, corpus callosum allows 2 hemispheres to communicate
Evaluate lateralisation of function
control, standardised, eye blindfolded and 1/10th sec, high int v
flawed, unusual/limited sample, patients epilepsy with diff treatments for diff periods of time, doubtful conclusions
oversimplifies distinctions, verbal and non verbal labels useful, most scientists say more complicated, lacks credibility
case studies say lang not only be in left, JW developed speech out of right hem, refutes Sperry, left hem not solely lanh
lateralisation may change over time, research found lang more to left as children turn to adults, decreased after 25 each decade, more complex
Explain circadian rhythms as a biological rhythm
occurs once every 24 hours
melatonin and growth hormone peak at midnight
cortisol=lowest at midnight
Suprachiasmatic Neuron- main endogenous pacemaker (internal biological clock) in hypothalamus- causes pineal gland to release melatonin=sleepy
Exogenous zietgebers (external time givers) influence circadian rhythms eg light
Exogenous and endogenous factors act as social cues eg mealtimes are same time of day as exercise and work schedules
Evaluate circadian rhythms
+ SCN key in sleep-wake cycle, study where removed in hamsters= rhythms disappear, re-established by transplanting SCN cells from foetal hamsters, cause and effect
ANIMALS PHYSIOLOGICALLY DIFFERENT
+human evidence supports factors, Siffre lived in underground cave for 6 months- no cues from sun, settled into free-running rhythm of 25 hours, endogenous important despite no exogenous
-ignores conscious control, ppts sleep and wake at certain time shown on clock, sped to 22hrs and couldn’t keep up so reverted back, endogenous driving force
+exogenous control, light on back of knees shifts rhythms, natural light plays similar role in entraining biological clocks to be in synchrony with outside world
+prac apps, employers, organise shift patterns, helps night shift workers adapt, benefits economy
Explain Infradian Rhythms
biological and psychological activity occurring less than once every 24 hours
Menstrual cycle- every 28 days
controlled endogenously. by pituitary gland= ovulation
Seasonal Affective Disorder
exogenous zietgebers- light for SAD disorder
Pheromones released in sweat influences menstrual cycles nearby
Explain Ultradian Rhythms
occurs more than once every 24 hours
Stages of sleep= 90 minute cycles, brainwave activity measured using EEGS
Stages 1 and 2- light sleep, easily woken, alpha waves, waves slow to theta waves
Stages 3 and 4- deep sleep, delta waves, slow wave sleep- hard to arouse someone
Stage 5- REM sleep- correlated with dreaming
body paralysed and brain activity speeds up
Endogenously controlled-similar trend in all humans
Evaluate infradian and ultradian rhythms
Sweat samples of groups of women- applied pads to upper lip of second group, groups separated and synchronised with each donor, pheromone as exogenous zietgeber
HOWEVER- takes long time to entrain, no. of months so endogenously controlled
Prac apps, light therapy resets SCN to improve mood
Sleep-wake cycle endogenously controlled support, REM every 92 mins, waking up ppts= vivid dreams, timings have further research
Support for external factors eg alcohol, drugs, sleep, alcohol= deep sleep but fragmented cycle, reduces time spent in REM, stages changed by external and influence endogenous
Explain fMRIs as a way of studying the brain
detecting changes in blood oxygenation and flow
Haemodynamic response- blood flow to areas that are active due to consuming more oxygen
3D images called activation maps- helps to understand localisation of function
shows 1sec after, 1-2mm into brain, 5 sec time lag between image and activity
Evaluate fMRIs as a way of studying the brain
detect deeper regions, shows haemodynamic response, understand how brain produces behavioural responses
specific brain activity that can pinpoint specific responses- via a magnetic field, Tulving- ep and sem in frontal lobe, pro in cerebellum on activation map
HOWEVER
ignores communication between areas- where it is occurring not how communicating, may be more complex
expensive to buy and maintain- only done in hospital and research environments, require specialists so not used readily and often subjective
low temporal resolution- 5 sec delay- conclusion not 100% accurate
Explain EEGs as a way of studying the brain
measures electrical activity via electrodes using a skull cap
scan represents brainwave patterns generated by millions of neurons
activity measured immediately under electrode
real time- within millisecond of brain activity
Explain ERPs as a way of studying the brain
ERPS= types of brainwaves relate to specific function
Collects data of all neural responses associated with sensory, cognitive and motor events
Using statistical averaging technique- extraneous activity filtered out from original EEG recording
This leaves only ERPS
Waveform peaks and dips show when a specific cognitive process happens in response to stimulus presented e.g. language, attention
Within a millisecond of brain activity
Evaluate EEGs and ERPs as ways of studying the brain
cheaper methods so widely available, used to develop knowledge about brain, EEGs- communication between neurons, ERPs- teasing out what is associated with tasks, helps those with neurological conditions
high temporal resolution- info provided during scan
poor spatial resolution- only accurate for activity measured close to electrodes, finer detail missed and not deeper regions
ERP criticism- lack of standardisation between studies, accuracy differs depending on researcher, issues with reliability
Explain Post-Mortem Examinations as a way of studying the brain
analysis of person’s brain post-death
likely to be of those with a rare disorder/ unusual deficits in mental processes
Purpose- establish likely cause of affliction
Involves comparison with a neurotypical brain
Evaluate post-mortem examinations as a way of studying the brain
Provided early foundation for understanding of key processes- Broca and Wernicke relied on for lang centres, improved medical knowledge
no discomfort for individual, eg slicing brain up to see where damage is and associating with issues in life, person is dead
no brain activity is measured, done when brain not functioning, value limited to structural issues
can only make assumptions when comparing with functionig before death, less valid conclusions
some brains affected by reason for death, can’t isolate causes of illness in life, limits usefulness when comparing to similar alive
