TOPIC 7 - BIOPSYCHOLOGY

what is localisation of function?

different parts of the brain are responsible for different things. Therefore, if brain damage occurs to just one area, only the functions linked to this area will be affected.

what theory does localisation of function contrast?

holistic - different areas of the brain work together.

What is the case of Phineas Gage?

1) pole through left cheek passing behind his eye and exiting his skull exiting the top of his head taking most of left frontal lobe
2) survived but the damage to brain had a mark on his personality - turned from calm to quick tempered and rude.

what does the case of Phineas gage suggest

the frontal lobe may be responsible for regulating mood.

what is in the brain?

frontal lobe (including Broca's area and the motor cortex)

parietal lobe (somatosensory cortex)

occipital lobe (visual cortex - inside)

temporal lobe (Wernicke's area, auditory cortex - inside)

what is the frontal lobe?

located at the front of the brain
associated with reasoning, motor skills, cognition, and expressive language

what is the parietal lobe?

located in the middle section of the brain
processing pressure, touch and pain.

what is the occipital lobe?

located at the back portion of the brain
interpreting visual stimuli and information

what two parts are only located in the left hemisphere in the brain?

Wernicke's area
Broca's area

what is broca's area?

discovered by paul broca who looked into the lesions in a patients brain who could only say the word 'tan'. Lesions found in left frontal lobe
showed area associated with language production.
underactivity leads to stuttering
broca's aphasia

what is broca's aphasia?

difficulty "finding words"
miss out words e.g. "the" etc that add sense
speak in short meaningful sentences
no difficulty comprehending language

what is wernicke's area?

same time as Broca, Carl Wernicke studied language deficits
found damage to an area located on temporal lobe
further study - area associated with speech comprehension .

what is Wernicke's aphasia?

aka fluent aphasia
struggles to understand language
produces long fluent sentences easily - sentences have little to no meaning.

what is the motor cortex?

- Responsible for voluntary motor movements
- Located in frontal lobe
- Both hemispheres have motor cortex, with each one controlling the muscles on the opposite side of the body

what is the somatosensory cortex?

area at the front of the parietal lobes that registers and processes body touch and movement sensations.
along the postcentral gyrus (area of cortex dedicates to processing sensory info rel to touch, pressure, pain, temp)
somatosensory cortex on each side of brain receives sensory info from opposite side of body

what is the visual cortex?

back of the brain in the occipital lobe.
contains dif area each processing different types of visual info e.g. colour, shape etc.

how does the visual cortex receive information?

visual processing begins in retina where light enters and strikes the photoreceptors (rods and cones)
2) nerve impulses from retina are transmitted to brain via optic nerve
3) some nerve impulses from retina travel to areas of brain involved in circadian rhythms, but majority terminate in the thalamus in brain, which acts as a relay station, passing this info to the visual cortex.

what is the auditory cortex?

- concerned with hearing
lies w/i temporal lobes on both sides of brain

how does the auditory cortex receive information in the brain?

1) auditory pathways begin in cochlea in the inner ear, where sound waves are converted to nerve impulses, that travel via auditory nerve to auditory cortex in brain.
2) on journey from cochlea to brain, 1st stop is brain stem. w/i this a decoding takes place (e.g. duration of a sound)
3) next stop is thalamus, acts as a relay station and carries out further processing of auditory stimulus
4) final stop is auditory cortex. sounds largely decoded by now but here it is recognised and result in appropriate response.

what are the strengths of localisation of function?

- support for the role of Broca's and Wernicke's area come from different patients with different types of aphasia. can be applied to rest of brain and that dif areas have dif specialist functions
- supporting scientific evidence from brain scans to support role of Broca's and Wernicke's area. Petersen et al (1988) brains scans demonstrate how wernicke area active during listening task, broca's active during reading task.
- there are applications of localisation theory in terms of treatments for OCD and depression. Dougherty et al (2002). reported 44 people w. OCD undergone cingulotomy (procedure involves lesioning of cingulate gyrus) at follow up after surgery at 32 weeks, 1/3 had met criteria for successful response to surgery, 14% for partial response. Shows symptoms and behaviours associated with serious mental disorders are localised.

what are the limitations of localisation of function?

- considering language localised by Broca's may be simplistic following research from Dronkers et al (2007) - re-examined preserved brains of two Broca's patients to identify extent of lesions using MRI. revealed other areas also contributed to patients reduced speech abilities. Suggest lang and cognition are more complex than thought and involve networks of brain regions.
- Lashley's equipotentiality theory challenges localisation - simple functions are localised yet more complex functions e.g. learning involve whole cortex working together

what is lateralisation?

two halves of the brain are functionally different and certain processes or behaviours a re controlled by one hemisphere rather than the other
- R hemisphere processes info from L side of body e.g. visual information from left VF
- L hemisphere processes info from R side of body e.g. visual information from right VF

what is contra lateral functioning?

the cross over from the hemisphere of the brain and the side of the body

Who are split-brain patients?

had a commissurotomy - where the corpus callous is severed so that the two hemispheres are separated and don't communicate with each other
this was done to control frequent and severe epileptic fits

What is the Sperry 1968 study?

studied split brain patients and compared them to patients with no hemisphere separation
PROCEDURE:
- a word/picture is projected into the left or right visual field which is then dealt with by the opposite hemisphere of the brain and the information isn't shared between the two hemispheres

what was the findings (sperry study) on describing what they see?

when a picture of an object was shown to a patients RVF, they could easily describe what was seen

when a picture of an object was shown to the LVF they could not describe it (often say nothing was there)

what was the findings (sperry study) on recognition by touch?

- if patients shown an object in their LVF and asked to select this object from a selection with their LH, they would be able to select the object because it was seen by R hemisphere and the LH is also controlled by the right hemisphere.
couldn't verbalise what they were selecting
- LH able to select an object most closely associated with the object presented to the LVF

what was the findings (sperry study) on recognition by touch if two different objects were placed in each hand and then hidden in a pile?

each hand searches for it sown object but if the LH picks up the object which the RH is looking for, the object is rejected but the other hand continues to search

what was the findings (sperry study) on drawing?

drawings are consistently better when drawn by LH (controlled by R hemisphere)
this was despite patients being actually RH
suggests that the R hemisphere and therefore LH was superiority at drawing ability.

what was the findings on facial recognition? Fem \= L, Male \= R

if they had to name they would say man as man side processed by L hemisphere which deals with language
if they were asked to pick photo of what they have seen, select a woman as the woman side is processed by the R hemisphere

what was the findings on composite words?

composite words: two words presented simultaneously one on either side of the visual field (e.g. key to the LVF and ring to the RVF)
the person would say ring as that is processed by the L hemisphere and they would be able to pick up the key with LH as that was processed by R Hemisphere

what are the strengths of hemispheric lateralisation?

- Quasi experiment: controlled conditions - standardised procedures (good internal validity) and external validity - replicable
- assume that the main reason for lateralisation is that it creates more processing capacity. Roger et al (2004) found that in chickens, brain lateralisation was more associated with the ability to perform 2 tasks at once. Shows how lateralisation can be helpful when performing cognitive tasks.

what are the limitations of hemispheric lateralisaiton?

- quasi experiment: lack of ecological validity - in real life, the patients can adjust visual position, so information goes to both hemispheres. Quasi - looking fir feature of individuals they already have. Pps variables we cannot control e.g. split brain patients have epilepsy.
- sample size issues. Lack of split-brain patients these days due to better epilepsy treatments - ability to futher reaserch in lateralisation hampered.
- sperry's study used 11 pps. Andrew 2001 said many studies had 1-3 pps. Means past research \= generalisation issues. Cannot remedy unless unethically create split brain patients.
- cannot be sure that Rogers findings extrapolate to humans - do some same cog processes that chickens do, but we cant be sure when managing processing the same way. Issue with applying findings to human population - research into animals or unusual humans.

what did szaflasrski et al 2006 find?

lang became more lateralised to L hemi with inc age in children and adolescents, but after 25, lateralisation dec with each decade - suggests lateralisation changes with normal ageing. Lat func found in younger pps switch to bilateral func in healthy elders. - possibly due to extra processing of resources. implies lat only feature of young adults.

what did gazzaniga 1988 find?

early discoveries from split brain research disconfirmed e.g. SB research suggested that R hemi unable to handle with language, but case studies \= not the case. J.W studied by Turk et al developed talking out of R hemi, resulting that he can speak about info presented to L or R brain. Suggests lang not exclusively limited to L hemi. Supports brain plasticity as shows brain can recover functions

what is the organisation of the human nervous system?

Human NS breaks into central NS and the peripheral NS.
CNS breaks into brain and spinal chord
PNS breaks into autonomic NS and somatic NS
ANS breaks into sympathetic NS and parasympathetic NS

what is the brain in the NS?

part of the CNS
- deals with conscious awareness
-highly developed in humans

what is the spinal chord in the NS?

part of the CNS
- extension of the brain
- passes messages to and from the brain
- connects nerves to the peripheral NS
- responsible for reflex actions (e.g. pulling hand off something hot)

what is the ANS?

part of the peripheral NS
- deals with automatic functions e.g. breathing, HR, digestion, sexual arousal, stress response
- controls internal organs and glands
- acts largely unconsciously

what is the SNS?

part of the PNS
- deals with voluntary muscle control e.g. realising time to leave and moving response
- controls skeletal muscles and movement
- acts consciously

what is the Parasympathetic branch?

part of the ANS
- called 'rest and digest'
- calms body
- promotes routine activities

what is the sympathetic branch?

part of the ANS
- prepares body for action
- triggers stress response

what is involved in the parasympathetic branch?

- stimulaties saliva flow
- slow heartbeat
- constricts bronchi
- stimulates peristalsis and secretion
- stimulates release of bile
- contracts bladder

what is involved in the sympathetic branch?

- dilates pupils
- inhibits flow of saliva
- accelerates heartbeat
- dilates bronchi
- inhibits peristalsis and secretion
- conversion of glycogen to glucose
- secretion of adrenaline and noradrenaline
- inhibits bladder contraction

what is the sensory neuron?

- has cell body on top, flow of impulse from receptor at top to dendrite at bottom

takes information from the senses and send to CNS for further processing

what is the relay neuron?

flow of impulse \= R to L. dendrites on the end of the star shape. nucleus in the middle.

Connect sensory neurons to to other neurones.
located in the spinal chord and acts as a go b/w, communicates w/ all neurons to decide response

what is the motor neuron?

cell body with dendrites on the L, flow of impulse L to R. dendrites at the end

opposite flow of direction as information from CNS and transmitted to muscles.
Control movement.

What are neurons?

cells that transmit electrical signals

structure of a neuron?

dendrite at the top
cell body (soma) in the middle
nucleus in the cell body
myelin sheath
nodes of ranvier
axon
receptors (axon terminal - synapse)

function of the parts of a neurone?

dendrite - where impulses received from other cells at synapses are transmitted to the cell body
cell body (soma) - maintain cell and keep neuron functioning efficiently
nucleus - provides genetic information and directs protein synthesis (proteins are vital for parts of neuron to function)
myelin sheath - fatty layer that insulates to prevent interference of impulses. the protection speeds up elec transmission
node of ranvier - electrical signals can sum up b/w these and speed up transmission
axon - carries signals away from the cell body to receptors to transmit electrical signals to other neurons.
receptors - releases neurotransmitters across the synapse

what are the reasons why the action potential travels one way?

1) the diffusion of neurotransmitter across the concentration gradient (pre to post)
2) vesicles only in pre-synaptic neuron
3) receptors only on post-synaptic neuron

what is the study for meditation changing the structure of the brain?

- lazar et al (2005)
MRI scans
experienced meditators have thicker cortex (the outer part of the brain) than non-meditators - especially in areas associated with sensory processing and attention

What is plasticity?

the brain's ability to change because of environment and lifestyle choices.
thoughts the brain is changeable in the same way as plastic.

what is negative plasticity?

when the brain in changing for the worse in response to something that we shouldn't be doing.

what is the research supporting negative plasticity?

medina et al (2007) - prolonged marijuana use resulted in poorer cognitive functioning and increased dementia risk.
ramachandran and hirstein 1998 - phantom limb syndrome in 60-80% of amputees - thought to be due to the somatosensory cortex reorganising itself

what is the Maguire et al study for plasticity?

(2006) researchers compared MRI scans of London bus drivers to cab drivers. bus \= set routes, cab \= awareness of larger area
FOUND: cab drivers had more grey matter on hippocampus
TELLS US: inc grey matter of cab drivers (comp to bus drivers) supports idea that env changes shape of brain structure and function.

what is the rosenzweig study for plasticity?

Rosenzweig et al (1972)
rats placed in enriched or deprived env for b/w 30-60 days. Eriched \= objects to explore and mazes. (10-12 rats here)
Rats then euthanised and brains dissected.
FOUND: rats in enriched \= greater activity in neurones of cerebral cortex. involved in learning and memory
TELLS US: shows env has direct effect on brain

what is the kuhn study for plasticity?

Kuhn et al (2014)
control comp to experimental group who played super mario 64 for 30 minutes a day for 8 weeks
FOUND: exp group \= inc grey matter volume in R hippocampus and other areas linked to spatial navigation
TELLS US: dems that brain change in response to the environment.

what are two strengths of plasticity?

- seen throughout the ages: Bezzola et al (2012) found pps aged 40-60 undergone golf training showed reduced motor cortex activity, suggesting more efficient neural representations
- practical application: use understanding of plasticity for neurorehabilitation e.g. stroke victims may have movement therapy or electrial brain stimulation

what is synaptic transmission?

the process of neurons communicating with each other

what is the process of ST?

elec impulse (action potential) sent down axon to the end of the neuron (presynaptic terminal)
al the pst, nts are released from synaptic vesicles
these nts travel across synapse
bind to receptor sites on post synpatic cell
once receptors activated, procude excitatory or inhibitory effects on post-synaptic cell

what is summation?

the sum of the overall inhibitory and excitary influences

what are excitatory effects?

the post synaptic neuron has a +ve charge making more likely to fire (send msg to next neuron). e.g. adrenaline causes excitatory response

what are inhibitory effects?

the post synaptic neuron has a -ve charge meaning it is less likely to fire e.g. serotonin causes inhibition

what would an excitatory nt do?

e.g. noradrenaline
binds to post-synaptic receptors it will cause an electirc charge in the cell membrane which results in an excitatory post synaptic potential (EPSP) making post synaptic cell more likely to fire.

what would an inhibitory nt do?

same as excitatory BUT

IF inhibitory nt binds to post synapatic receptors it will results in an inhibitory post-synaptic potential (IPSP) making post-synaptic cell less likely to fire.

what is neurogenesis in brain recovery?

- new neurons developing from neural stem cells (we know it happens in hippocampus and olfactory bulbs)

what is neuronal masking in brain recovery?

dormant neurons grown new branches to create new synapses

what are three key points about neurogenesis?

neurons important for learning and memory
inc neurogenesis - learning new things, running etc, eating (especially blueberries, dark chocolate), also way and when eat/drink
dec neurogenesis: stress, sleep deprivation, alcohol, saturated fat diet

what is axonal sprouting in brain recovery?

axons of surviving neurons grown new branches to create new synapses

what is recruitment of homologous areas on the opposite hemisphere in brain recovery?

similar areas on the opposite side of the brain perform similar tasks

what is evidence for recruitment of homologous areas?

animal studies
hubel and wiesel (1963) involved sewing one eye of kitten shut and analysing brain's response
found are of visual cortex associated with the eye shut was not idle and continued to process info from open eye
shows specialisations not fixed and can change.

STRENGTHS of functional recovery

- understanding has a +ve impact on development of new treatments. induced mvmt therapy encouraged massed practice with an arm whose movement is affected by brain damage while other restrained. understanding of axonal growth and rewiring pathways to do this. Improve people's lives.

supported by research from animal studies - Tajiri et al (2013) injected rats w/ stem cells into damaged brain areas. 3 months later, evidence that stem cells had developed into useable cells. but limited in generalisation to humans.

LIMITATIONS of functional recovery

differs in age - hukkelhoven et al (2003) looked at 2664 patients with brain injury. found older people are less likely to recover from their personal injuries.

what is fMRI?

functional magnetic resonance imaging

works: uses magnets to detect changes in blood oxygenationa dn flow that occur as a result of neural activity in the brain. more active areas consume more O2 so more blood travels to that area (haemodynamic response). produces 3D images

shows both structure and function

high spatial resolution (detail down to mm), poor temporal resolution (5s time lag)

EVALUATION for fMRIs

adv:
- look at different angles of the brain
virtually risk free no use of radiation, non-invasive as no injections
high spatial resolution
PETERSON ET AL using fMRIs to locate areas of Broca's and Wernicke's doing speech vs comprehension tasks

dis:
- stay still for 45 mins
- constricting tube, not applicable to all
- sensory issues for young people
- expensive and require much upkeep
- need to stay perfectly still
- cannot identify action of individual neurons
- poor temporal resolution

what are EEGs?

electroencephalogram

works: measures electrical activity using electrodes attached to skull, brainwave patterns produced to show overall activity of neurons, can look for arrhythmic patterns to indicate sleep disorders, tumours, epilepsy etc

shows function

high temporal resolution (down to ms)

EVALUATION of EEGs

adv: virtually risk free, no use of radiation, non invasive
instantaneous results
useful for diagnosis of epilepsy and our understanding of sleep
high temporal resolution

dis:
- cannot pinpoint source of brain waves
- lots of background noise

what are ERPs?

event related potentials


works: EEG taken, pps asked to do specific thing, corresponding brain activity is picked out of EEG using statistical averaging techniques
sensory/exogenous ERPs represent the later response (one brain has processed this task)

shows function

same high temporal resolution as EEGs

EVALUATION of ERPs

adv:
- more specific that EEGs
- high temporal resolution

dis:
- lack of standardisation in the ERP methods between researchers - difficult to confirm findings
difficult to eliminate all background data

what are post mortems?

NOT SCANNING tech

works: individual brain dissected after death, areas of brain looked at for abnormality
CASE OF CHARLES WHITMAN - Texas tower sniper, asked for a post mortem before he died, found tumour pressing against amygdala which stimulated this area to feel violent impulses

shows structure of the brain

good spatial resolution, poor temporal resolution (wait for person to pass first)

EVALUATION of post mortems

adv:
- vital for early brain research e.g. broca and wernicke

dis:
- issues with causation - any damage noted can be unrelated to behaviour of interest
-patients not consent before their death
- HM couldn't give legal consent due to his issues forming LT memory - consent by proxy.

What is the endocrine system?

made of of a number of glands (that secrete hormones)
controls the internal environment of the body to ensure correct hormone levels
system helps regulate the activity of cells ad organs in the body.

how does the endocrine system differ from CNS?

slower system, more longer-lasting effects, wider-spread effects

what is the hypothalamus?

location: part of brain attached to posterior pituitary gland hormone: releasing hormones

function: synchronises the information from the brain and secretion

what is the pituitary gland?

location: base of brain and size of a pea. divided into anterior and posterior sections

hormone: secretes endorphins - reduce sensitivity to pain

function: controls many other endocrine system glands. Helps to control body and tissue growth

what is the pineal gland

location: brain

hormone: melatonin

function: regulates our internal clocks and any rhythmic sensitivities
plays large role in sleep and wake cycles.

what is the thyroid?

location: wraps around the trachea at the base of the neck

hormone: thyroxine

function: regulates the metabolic rate of almost all the cells in the body. glands need iodine to create thyroxine, that is why salt is now iodised

what is the thymus?

location: below the thyroid between the right and left lung

hormone: thymosin

function: stimulates T-cell (type of WBC) production in children. gland shrinks with age as we are exposed to more germs that use up antibody stores

what is the parathyroid?

location: four small gland embedded in thyroid gland

hormone: parathyroid hormone

function: regulates amount of calcium in the blood and its absorption by bones

what is the adrenal gland

function: located at the top of the kidneys

hormone: medulla secretes adrenaline and noradrenaline. cortex - aldosterone and cortisol

function: noradrenaline regulates fight or flight response at time of extreme stress.
aldosterone - regulates reabsorption of nutrients from kidneys
cortisol - controls rate of metabolism of carbs, fats and proteins

what are the ovaries?

location: females

hormone: oestrogen and progesterone

function: regulates female menstrual cycle.

what are the testicles?

location: males

hormone: testosterone

function: controls the development of male characteristics such as sex organ funct, sperm development and puberty characteristics (deep voice, facial hair etc)

what is the sympathomedullary pathway?

1) higher brain centre notices stress. sends message to the
2) hypothalamus which activates ANS (sympathetic branch). Causes
3) adrenal medulla secretes adrenaline and non adrenaline

what happens in the fight or flight response?

- saliva flow decreases: not needed in the situation, diverting energy to muscles instead
- skin, blood vessels constrict, chills and sweating: to cool/warm up body
- increased heart beat
-stomach: output of digestive enzymes decrease to divert energy
- eyes dilate: more light to see better
- lungs: quick deep breathing so more O2 in blood for o respiration
- bowel: food mvts slow down to divert energy to muscles
- blood vessels: inc in blood pressure as maj vessels dilate to get more O2 and glucose around body faster.

where did the fight or flight response come from?

evolutionary trait, used to be used to have a burst of energy to deal with stressful situation e.g predators. This is because stressors in evolutionary past could have been ought or run away from

EVALUATION of fight or light response

- modern life: response may be maladaptive. evolved as a survival mechanism. therefore responses from f/f may be triggered by stresses today you may not need to flee from.Repeated inc blood pressure - heart disease. Cortisol can help body fighting infection/healing tissue, too much supresses immune response.

- Gary (1988) argues first phase of reaction isn't to fight or flee. Suggests first is to avoid confrontation - free response of stop, look and listen, hyper vigilance. Useful when unclear to f/f. humans freezing - look for info to make best response.

-gender differences in response to stress. Taylor et al (2000), fems characterised by tend and befriend - may be due to evolution of primary carer of children . studies using rats - response that inhibits flight. Oxytocin inc relaxation, dec stress of f/f response. BUT dawans et al (2012) found acute stress lead to cooperation and friendly behaviour - suggests classic view of f/f not the only way humans react to stress.

what are biological rhythms?

changes in bodily activity that happen at set times
can be influenced by external changes (zeitgebers) to env e.g. light

What are circadian rhythms?

biological rhythm operates along 24-hour cycle. Regulates bodily processes e.g. sleep/wake cycle and core body temperature

what is ascoff and wever 1976?

group of pp spend 4 weeks in WWII bunker deprived of natural light
all but one pp displayed circadian rhythms b/w 24 and 25 hours
suggest natural sleep/wake cycle may be longer than 24 hours but that is entrained by zeitgebers associated with our 24-hour day e.g. typical mealtimes