Biopsychology Flashcards
Divisions of Nervous System
CNS - brain and spinal cord
PNS - somatic and autonomic
Autonomic - sympathetic and parasympathetic
Brain
Centre of all conscious awareness
Cerebral cortex is highly developed and distinguishes is from animals
Hemispheres
Spinal cord
Relays info between brain and body
Also contains circuit of nerve cells the enable us to perform reflex actions
Somatic
Sensory and motor info to and from CNS
Controls skeletal muscle movement
Autonomic
Carries motor info to and from CNS
Controls internal organs and glands
E.g. breathing and heart rate
Sympathetic
Responses that help us deal with emergencies
Preparing body for rapid action
Released energy stores, pupil dilation
Slows down bodily processes such as digestion and urination
Parasympathetic
Returning to body at rest state after emergency has passed
Slows down heart and breathing rate
Bodily processes inhibited by sympathetic are returned to normal
Neurones
Cells that carry info throughout body via chemical and electrical signals
Structure of neurones
Dendrites at one end - receive signals from other neurones
Connected to cell body
Axon - impulse carried to axon terminal
Covered in myelin sheath which protects and speeds up transmission
Sensory neurones
Carries from sensory receptors in PNS to brain (or spinal cord when reflex)
Relay
Carries from one part of CNS to another
Allows communication between sensory and motor
Shorter dendrites and axon
Motor
Carries from CNS to effectors
When stimulated, NTs to receptors on muscle which triggers response
Synaptic transmission
Impulse reaches end of presynaptic neurone
Triggers release of NTs from synaptic vesicles
Diffuse across synapse
Bind to receptors on dendrites at postsynaptic neurone
Chemical message converted to electrical impulse
Reuptake
Some NTs travel back to presynaptic neurone to be stored again
Neurotransmitters
Chemical messengers that diffuse across synapse and bind to receptors to convert chemical message to electrical impulse
Inhibition
E.g. GABA
Inhibits postsynaptic neurone
Negatively charged
Off switches
Decrease likelihood of neurone firing
Excitation
E.g. adrenaline
Excites postsynaptic neurone
Positively charged
On switches
Increase likelihood of neurone firing
Summation
Receives both excitatory and inhibitory NTs
Adding up effect for net effect
Either more inhibitory or excitatory
Endocrine system
Chemical system of communication that instructs glands to release hormones directly into bloodstream
Regulates bodily functions
Glands
Organs in body that produce and secrete hormones
Pitituary
Master gland
Regulates many bodily functions
Hypothalamus
Pineal
Biological rhythms e.g. sleep cycle
Melatonin
Adrenal
Fight or flight
Adrenaline
Testes
Testosterone
Male sex hormone
Ovaries
Oestrogen and progesterone
Involved in menstrual cycle
Hormones
Chemical that circulates bloodstream and influences target organs in order to regulate bodily activity
Fight or flight
Aliens ———————— acute stressor
Triggers
Have ————————— hypothalamus
Directs
Somehow ———————- sympathetic branch
Send NTs
Always ——————————adrenal medulla
Releases
Adored —————————- adrenaline
Triggers
Foam —————————-fight or flight
Results in
Parties —————————-physiological response
Localisation of function
Specific functions have specific locations in brain
Motor cortex
Voluntary movement
Back of frontal lobe
Contralateral
Damage causes loss of control over fine movements
Somatosensory cortex
Detects sensory info from skin
Front of parietal lobe
Contralateral
Damages causes feeling non existent sensations or not feeling existent sensations
Visual cortex
Processes visual info from retina transmitted via optic nerve
Occipital lobe
Contralateral
Damage causes blindness
Auditory cortex
Processes auditory info processed by cochlea transmitted via auditory nerve
Temporal lobe
More extensive damage causes more extensive loss of hearing
Broca’s area
Speech production
Left frontal lobe
Inability to produce speech - Broca’s aphasia
Wernicke’s area
Understanding language
Left temporal lobe
Inability to produce coherent speech - Wernicke’s
Localisation of function - strengths
+brain scans
Patterson - brocas is active during reading task and wernickes is active during listening
Tulving
+Brocas aphasia - Tan
Wernickes aphasia
Localisation of function - weaknesses
-more complex than suggests
Communication between areas is more important than specific areas
Patients lost ability to read when damage between wernickes and visual
-animal studies that contradict
Lashley - removed 10-50% of rat cortex
Learning a maze no area was more important than another
Learning is too complex to be localised
-brain plasticity
Lashley - brain damaged - particular areas are lost or compromised - reorganises to compensate - stroke victims
More adaptive and holistic than suggested
Hemispheric lateralisation
Two halves are functionally different e.g. language centres
Split brain
Sperry
Patients with severe epilepsy who had undergone surgery
Cutting of corpus collosum
Asked to focus on dot in centre whilst words or images are projected to either visual field followed by task
Describe what you see
Right visual field - can easily describe due to language centre in left
Left visual field - can’t describe due to no language centres in right
In normal brain, info must be related across hemispheres
Recognition by touch
Left visual field - select matching object with left hand
- can’t verbally identify
Composite words
LVF - ‘face’ - write word with left hand
RVF - ‘key’ - can say it
Hemispheric Lateralisation - strengths
+well controlled
Blindfold
1/10th of a second
Hemispheric lateralisation - weaknesses
-flawed - unusual sample
All received drug therapy for different length of time
Control group didn’t have epilepsy- poorly matched
-language may not be restricted to left
Gazzaniga - JW developed ability to speak out of either
-complicated by age
Changes throughout life
Szflarski - more left as a child and less lateralised later
-differences are overstated
No clear cut distinction
Much messier as both sides in constant communication
Brain plasticity
Ability to change and adapt as a result of experience and new learning
During infancy - 15000 synaptic connections
Synaptic pruning - over time, rarely used are deleted and frequently used are strengthened
Changes can occur at any stage of life
Boyke - 60 years olds taught to juggle
Grey matter in visual increase and then decrease when stop practising
Functional recovery
When areas are damaged, unaffected areas adapt and compensate - neural plasticity - spontaneous recovery
Secondary neural pathways are activated or unmasked
-axonal sprouting - new nerve endings grow to connect to undamaged nerve cells and form new pathways
-reformation of blood vessels
-recruitment of similar areas on opposite side of brain
Brain plasticity - strengths
+animal study
Rats in complex environment increased number of new neurones compared to lab cages
Larger hippocampus for navigation
+human study
MRI - London taxi drivers have a larger hippocampus
Longer they’ve been a taxi driver, larger hippocampus
+practical application
Neurorehabilitation
Movement therapy and electrical stimulation
Stroke patients
Brain plasticity - weaknesses
-more complex
Certain individuals are more able
Adults require more intensive training than children
College education 7x more likely to be disability free one year after damage than someone who didn’t finished high school
-negative consequences
60-80% of amputees suffer from phantom limb diseases
Unpleasant and painful
Due to cortical reorganisation in somatosensory cortex caused by loss of limb
fMRI
Functional magnetic resonance imaging
Detects change in blood oxygenation and flow that occur as a result of neural activity
When a brain area is more active, it consumes more oxygen and to meet this increased demand, blood flow is directed to active area - haemodynamic response
Produces 3D activation maps
fMRI strengths
+records specific brain activity which can pinpoint specific responses and the exact source
E.g. it shows detail to the mm
Improve understanding of LoF
+detects activity in deeper regions
E.g. hypothalamus
Insight into areas of the brain that other techniques can’t detect
fMRI weaknesses
-low temporal resolution
5 second time lag
Cannot provide real time recording
-ignored networked nature of brain
Ignores communication between areas
Provides little insight into how brain areas work together to function
EEGs
Electroencephalogram
Measure electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap
Recording represents brainwave patterns that are generated from the action of millions of neurons
Often used by clinicians as diagnostic tool
EEGs strengths
+high temporal resolution
+takes account of networked nature
EEGs weaknesses
-records general brain activity - cannot pinpoint specific responses
-can’t detect deeper regions
ERPs
Event related potentials
EEG is an overly general measure - but the data contains all the neural responses associated with specific sensory, cognitive and motor events
These specific responses can be isolated using stat averaging technique
Extraneous brain activity is filtered out leaving only ERPs
Types of brainwaves that relate to specific function
ERP strengths
+records specific responses to specific stimulus
Stat tests used to filter out extraneous activity
Helps improve our understanding of specific brain functioning
+high temporal resolution
ERP weaknesses
-cannot detect deeper regions
-lack of standardisation between researchers over the way that the data is statistically analysed
Disagreement on how best to filter out extraneous
Post-mortem exam
Analysis of a persons brain following death
Individuals whose brains are subject to this are likely to be those with rare disorder and have experienced unusual deficits in mental processes and behaviour
Establishing likely cause and comparison with neurotypical brain
Post-mortem strengths
+deeper regions of brain
+provided vital foundation for our early understanding of brain
Broca and Wernicke both relied on this technique decades before neuroimaging
Other techniques used can build on this early work
Post-mortem weaknesses
-retrospective
Already dead
Cannot follow up on anything that arises from exam
Limits usefulness
-raises ethical issues
Not able to provide consent
Other techniques are more ethical
Biological rhythms
Cycles in biological or psychological activity that occur over a certain amount of time
Endogenous pacemakers
Internal biological clocks
Free running rhythm
SCN
Suprachiasmatic nucleus
Main endogenous
Tiny cluster of neurons located in hypothalamus
Maintains bodily rhythms
Can receive info about light levels and respond to external cues
Keeps rhythm in synchrony with environment
Exogenous zeitgebers
External time givers
Any external cues
Influence or entrain our biological rhythms
Light, social cues, alarms
Circadian rhythms
Every 24 hours
Sleep-wake cycle
Endo- SCN - pineal gland - melatonin
Exo- light - influences SCN
Circadian strengths
+ hamsters - remove SCN - rhythms disappear
reestablished when SCN from foetal implanted
+siffre - underground cave - no exo
Free running - 25 hours
- however not generalisable
+aschoff and Wever - WWII bunkers
+practical app - shift workers
Circadian weaknesses
- Folkard - conscious control
22 hour clock - couldn’t keep up
Infradian rhythms
Less than 24 hours
Menstrual - endo - SCN -pituitary gland
Exo - pheromones
SAD - light
Infradian strengths
+ armpits
+ practical app - light therapy
Infradian weakness
- Nomothetic - individual differences
Ultradian rhythms
More than 24 hours
Sleep stages
92 mins
Stages 1 + 2 - light sleep - alpha and theta waves
Stages 3 + 4 - SWS - slow wave sleep - delta waves
Stage 5 - REM - rapid eye movement - dreams
All humans have display similar trend so endo
Ultradian strengths
+Dement and Kleitman
REM is every 92 mins - likely to have vivid dreams when woken during rem
+ alcohol and drugs - aid sleep acceleration but more fragmented sleep
Reduce time spent in rem
Influenced by exogenous zeitgebers
