Biopsych Flashcards
What is the CNS made up of?
Brain
Spine: responsible for reflex action
What is the PNS made up of?
Somatic nervous system: governs muscle movement and receives info from sensory receptors
Autonomic Nervous system: governs vital bodily functions e.g. breathing and sympathetic/ parasympathetic response
what is the endocrine system role/ made up of?
works alongside nervous system
works through chemicals and glands
Thyroid: thyroxine; motabolism/growth
Pituitary: governs all other glands
Adrenal: adrenaline; fight or flight
What are the 3 types of Neuron and their structure?
Sensory: long dendrites, short axon
Relay: short dendrite, short axon
Motor: short dendrites, long axon
What is the structure of a neuron?
Dendrites receive and impulse from neigbouring cells and pull it towards the cell body. The axon covered by the Meylin sheith with nodes of Ranvier the impulse has to jump across, carries the message to the terminal button
What is action potentual?
A neurons resting state is negative. When it is acticated by a stimulus is becomes positive for a split second causing an action potential to occur creating the electrical impulse that is carried down the axon
how does Synaptic transmission occur?
Synaptic vesicals fuse to the wall of the presynaptic terminal and release neurotransmitters into the synaptic cleft. The neurotransmitters diffuse accross the gap to be picked up by the post synaptic receptor sites. some Neurotransmitters will be reuptaked back into the presynaptic terminal, some will be destroyed by enzymes
What is summation?
whether a neuron fires is determined by if the sum of the influences effected on it is net positive
what is Excitation and Inhibition?
Some neurotransmitters, like adrenaline, are excitory making the neuron more positive, some, like seritonin, are inhibitory, making the neuron more negative
what is localiseation of function?
The theory that different areas of the brain are resposible for spesific behaviours, processes or activities
what are the localised funtions of the brain?
Motor area: Frontal lobe. Damage causes loss of control over fine motor movements
Somatosensory: parietal lobe. damage causes loss of feeling
Visual: occipital lobe. damage causes partial blindness
Auditory: temporal lobe. damage can cause partial hearing loss
Broca’s area: left frontal lobe. Damage causes Broca’s aphasia charactorised by slow, laboureous, influid speach
Wernickes area: left temporal lobe. Damage causes Wernicke’s aphasia characterised by production of neolisms (nonsense words) in speach
Evaluate localisation of function
+ neurosurgery support
> Dougherty et al had 44 patents with OCD get a cingulotomy (isolating an area of the brain). 33% were successful meaning OCD is implicated with spesifically that area of the brain
+ brain scans
Peterson et al demonstrated wernicke’s area was active during spesific tasks
CA: Lashley took out 10%-50% of a rats brain then had them find their way out of a maze and it made no difernce
- Language may not be limited to Brocc and Wernicke’s areas.
> advances in brian imiging technique has found language processes in different areas of the brain
What is hemispheric lateralisation?
The4 idea that the two halves of the brain are funtionally different.
some functions (Broca’s area) can only be found on one side of the brain while others (vision) can be found on both
Evaluate hemispheric lateralisation
+ even in connected brains the two sides work differently
> in a PET scan, when participents looked at a whole image, the right hemisphere dominated while if they looked at smaller details, the left halve dominated
- Nielson et al analysed 1000 brain scans of people aged 7-29 an found no evidence of a dominant side
what is Sperry’s split brain research?
Procedure
11 split brain participants were studdied using a set up where an image could be projected into one FV and a different image in the other.
Findings
When an image was shown to the RVF they could describe what they saw
When an image was shown to the LVF they could not describe what they saw but could point to a related image and have an emotional reaction despite reporting having seen nothing
Evaluate Sperry’s split brain research
+ research support
Gazzaniga et al showed split brain participants perform better in certain tasks e.g. identifying an odd object out
- not generalisable
epilepsy is a confounding variable
What is brain placticity?
The brains tendency to change and adapt as a result of experiece through synaptic pruning
What research is into placiticity
Maguire et al studied london taxi drivers brains and found a higher volume of grey matter in their posterior hippocampus than a control group showing their brains had been changed due to experience
Similar findings by Draganski et al who studied medical students brains 3 months before and after exams
evaluate placticity
- it may have negetive behavioural consequences
> makes long term drug use, dementia and phantom limb syndrome more likley
+ life long
Bessola at al found after 40 hrs of golf training participants age 40-60, their motor cortex activity was reduced suggesting more efficient pathways
What is functional recovery after trauma?
A form of placiticity allowing the brain to recover after trauma by passing functions off to other areas
Axonal sprouting: growth of new nerve endings connecting to other nerve cells to form new neural pathways
Denervation supersensitivity: axons that do a similar job do so at a higher level to compensate. can lead to over sensitivity
Recruitment of homologou areas on the opposite side of the brain: spesific tasks can stil be proformed just controlled by a different area until the damaged area is repaired
evaluate functional recovery after trauma
+ real world application
> understanding placitity helps new therapies develop
- cognitive reserve
> research suggests there is a greater chance of disability free recovery for those in education for more than 16 years.
What are the ways of studing the brain?
fMRI: detects change in the flow of oxygen showing where the brain is more active
EEG: measure electrical activity in the brain with electrodes attatched to a skull cap
ERG: uses statistic averaging to filter out unrelated data from EEGs for more spesific data
Post mortem: Examining damaged areas of a brain after death compared to a neurotypical brain
Evaluate the ways of studing the brain
fMRI
+ does not rely on radiation
+ high res pictures
- expensive
- poor temporal resolution
EEG
+ use in longitudinal studies
+high temporal resolution
- very general data
ERG
same as EEG
+ more spesific data
- lack of standadisation
- removing ‘background noise’ is not always possible
Post mortem
+ foundation of early understanding of the brain
- confounding variables
- lack of consent
What are biological rhythms?
exert influence on how body systems behave
governed by internal biological clock (endogenous pacemakers) and changes in the environment (exogenous zeitgebers)
what is the Circadian Rhythm?
Rhythms that last 24 hours including Sleep wake cycle and core body temp
what is the sleep wake cycle governed by?
Exogenous zeitgebers: daylight, eating
Endogenous pacemakers: SCN that detects light
What research has been done around the circadian rhythm?
Siffes cave study:
- spent several extended periods in a cave with no natural light but adequate food and drink.
- His ‘free running’ biological rhythem settled to around a 25 hour cycle
Ashoff and Wever:
- had participants spend 4 weeks in an underground bunker
- all but one had a circadian rhythm of 24-25 hrs
Folkard et al
- Studied 12 people who lived in a cave for 3 weeks with clocks they gradually increased the speed on. 24 hrs became 22 and only 1 participant managed to comfortably adapat (zietgebers cannot override circadian rhythm)
Evaluate circadian rhythms
+ real world application
> provides an understanding for how shift work can be damaging as the circadian rhythm is disrupted
> shift workers are more likly to develop heart problems that people who work in more regular patterns
CA: studies investigating effect on shift workers are correlations. there may be extrenous variables
+ real world application in medical treatment
> helps find when different medications will be most effectivly administered
>Bonten et al supports this
- not generalisable
> peoples circadian rhythems are different and studies use only a small number of participants
what are Infradian Rhythms?
A thype of biological rhythm with a frequency of less than one cycle of 24hrs e.g. mentruating
What are Ultradian Rhythms?
Bio rhythm with a freaquency of more than one every 24hrs
what governs the menstruation cycle?
exogenous zietgebers like other womens cycles can effect it:
McClintock and stern had 29 women with irregular periods wipe samples of pheromones gatherd from women at various stages of their period on their upper lip.
68% of women had periods closer to their ‘odour donor’
What causes SAD?
hypothises: lack of melitonin with the decresed light having a knock on effect with seritonin
SAD can be classed as a circadian Rhythm as it may be due to a disruption of the sleep wake cycle
What are the stages of sleep?
An ultradian rhythm
Stage 1 and 2:
- alpha waves (with occational sleep spindles in stage 2)
Stage 3 and 4:
- deep sleep / slow wave sleep (SWS)
- delta waves
Stage 5 (REM sleep)
- body is paralysed but brain activity resembles being awake
- theta waves
- When dreams are most often experienced (though it can happen in deep sleep)
Evaluate research into the menstrual cycle
+ Evolutionary basis
> it may have been advantageous for women to mentrate and become pregnant at the same time so babies without mothers can still access food
- Methodological limitations
> confounding variables like change in diet, excersize, stress etc
+ real world application (SAD)
> light therapy
Evaluate Ultradian rhythms
+ improved understanding of age related changes in sleep
> can lead to better application of relaxation and medication for improved sleep
- individual differences
> there are significant differences in different peoples undradian Rhythms (tucker et al) so not generalisable
+ lab studies are well controlled
- lab studies have low external validity
What are endoginous pacemakers?
internal body clocks that regulate our biological rhythms like SCN
what are exogenous zietgebers’?
external factors that effect/ entrain biological rhythms
What research has been done into Endogenous pacemakers and the sleep/wake cycle?
DeCoursey et al destroyed the SCN of chipmunks and found their sleep wake cycle had disappeared by the end of the study
Ralph et al bred mutant hamsters with a 20 hr sleep cycle and when there SCN was transplanted into normal hamsters, their sleep cycle became 20hrs
The SCN is implicated in the production of melitonin (linking it with SAD)
Evaluate Research into Endogenous pacemakers effect on sleep wake cycle
- SCN may obscure other body clocks
> research has found numerous circadian rhythms in organs and cells in the body - Cannot be studied completely in isolation
> lowers research validity - unethical
ANIMALS DIED :(
what research has been done into exogenous Zeitgebers?
light
Cambell and Murphy demonstrated light may be picked up by skin receptors even when eyes don’t by shining light on the back of participants knees and waking them up
social cues
jet lag
babies
evaluate exogenous Zeitgebers
-do not have the same effect in all enviroments
> people in the arctic circle have the same year round sleep patterns despite 6 months of darkness
- case studies
Miles et al: a young man was blind from birth and had an abnormal sleep cycle despite social cues it could not be ajusted
