(p2) Biopsychology Flashcards
(94 cards)
1
Q
What is the nervous system?
A
A specialised network of cells in the human body and is our primary internal communication system. It is based on electrical and chemical systems.
2
Q
2 main functions of the nervous system
A
- To collect, process and respond to info in the environment.
- To co-ordinate the working of different organs and cells in the body.
3
Q
The nervous system is divided into what 2 subsystems?
A
Central nervous system (CNS) and peripheral nervous system (PNS)
4
Q
What is the Central nervous system made up of
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Made up of the brain and spinal cord
5
Q
Describe the brain
A
Centre of all conscious awareness. The brain’s outer layer (cerebral cortex) is 3mm thick and covers the brain like an orange peel. The brain is highly developed in humans and is what distingushes us from animals. The brain is divided into 2 hemispheres.
6
Q
Describe the spinal cord
A
An extension of the brain. It passes messages to and from the brain and connects nerves to the PNS. It is also responsible for reflex actions.
7
Q
Describe function of PNS
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Transmits messages, via millions of neurons, to and from the CNS.
8
Q
The PNS is subdivded into…
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- Autonomic Nervous System (ANS)
- Somatic Nervous System (SNS)
9
Q
Describe the autonomic nervous system
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Governs vital functions in the body such as breathing and heart rate
10
Q
Autonomic is split up into…
A
- Sympathetic
- Parasympathetic
11
Q
Sympathetic
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Flight or fight, prepares body for activity, increases: heart rate and breathing rate, pupils dilate and decreases: digestion and salivation
12
Q
Parasympathetic
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Rest and digest, returns functions back to normal (homeostasis), decreases: heart rate and breathing, pupils contract, increases: digestion and salivation
13
Q
Describe the somatic nervous system
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Governs muscle movement and recieves info from sensory receptors
14
Q
What is the endocrine system
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Works alongside the nervous system to control vital functions in body. It acts more slowly than the NS but has very widespread powerful effects.
15
Q
Hormones
A
Various glands produce hormones. Hormones are secreted into the bloodstream and affect any cell that has a receptor for that particular hormone. Most affect cells in more than 1 body organ, leading to many diverse and powerful responses.
16
Q
Pituitary gland
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Located in the brain.
‘Master gland’
Controls release of hormones from all other endocrine glands
17
Q
Endocrine and ANS working together: fight of flight
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- When a stressor is perceived the first thing that happens, is that a part of the brain called the hypothalamus activates the pituitary gland and this triggers activity in the sympathetic branch of ANS.
- ANS changes from its normal resting state (parasympatheic) to the physiologically aroused sympathetic state.
18
Q
Adrenaline
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Released from the adrenal medulla into bloodstream. It triggers physiological changes changes in the body which creates the physiological arousal necessary for the flight or fight response.
19
Q
Parasympathetic action
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- Once the threat has passed the parasympathetic nervous system returns the body to resting state.
- It works in opposition to the sympathetic nervous system- its actions are antagonistic to the sympathetic NS
- It acts as a break and reduces the activities of the body
- ‘rest and digest’ response.
20
Q
Structure of a neuron
A
- Cell body includes a nucleus which contains the genetic material of cell.
- Branchlike structures called dendrites protrude from cell body- these carry nerve impulses from neighbouring neurons towards cell body
- The axon carries the impulses away from the cell body down the length of the neuron.
- Axon covered in fatty layer- myelin sheath that protects it and speed up electrical transmission of impulse.
- Myelin sheath segmented by gaps- nodes of Ranvier- forcing impulse ‘jump’ across gaps.
- At end of axon are terminal buttons that communicate w next neuron in chain across a synapse.
21
Q
Relay neuron
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Connect sensory to motor. Short dendrites, short axons.
22
Q
Sensory neuron
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Carry messages from PNS to CNS. Have long dendrites and short axons
23
Q
Motor neuron
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Connect the CNS to efforts (eg: muscles). Short dendrites, long axon.
24
Q
Location of neuron
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- Cell bodies of motor may be in CNS but they have long axons which may form part of PNS.
- Sensory neurons located outside CNS, in PNS in clusters (ganglia).
- Relay neurons make up 97% of all neurons and most are found within brain and visual system.
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Electrical transmission (firing of a neuron)
- When a neuron is in a resting state: inside of cell is - charged compared to the outside
- When a neuron is activated by a stimulus, the inside of the cell becomes + charged for a second (causing an action potential)
- This creates an electrical impulse that travels down the axon towards the end of the neuron.
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Chemical transmission
- neurons communicate within groups (neural networks)
- each neuron is separated by synapse
- signals are transmitted chemically across synapse
- when electrical impulse reaches end of neuron (presynaptic terminal) it triggers the release of neurotransmitter from tiny sacs (synaptic vesicles).
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Excitatory and inhibitory
- eg: serotonin causes inhibition in the recieving neuron, resulting in neuron becoming more - charged and less likely to fire.
- eg: adrenaline causes excitation of postsynaptic neuron by increasing its + charge and making it more likely to fire.
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Summation
- decides whether a postsynaptic neuron fires
- inhibitory: less likely to fire
- excitatory: more likely
= so, action potentional is only triggered if the sum of the excitatory & inhibitory signals at any one time reaches the threshold
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What is localisation of function?
- Different parts of the brain perform diff tasks and are involved with diff parts of the body.
- If a certain area of brain is injured, the function of the area will also be affected.
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Hemispheres of the brain
- cerebrum: divided into 2 havles (right & left hemisphere)
- left-hand side of body: controlled by right hemisphere
- right-hand side of body: controlled by left hemisphere.
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What is lateralisation?
Some of our physical and psychological functions are controlled or dominated by a particular hemisphere.
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What is the cerberal cortex subdivded into?
1. frontal lobe
2. parietal lobe
3. occippital lobe
4. temporal lobe
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Motor area (where is it located, function, damage?)
- at the back of frontal lobe
- controls voluntary movement in opposite side of body
- damage: loss of control over fine movements
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Somatosensory area (where is it located, how is it seperated from motor area, function?)
- at the front of both parietal lobes
- seperated from the motor area by a 'valley' called central sulcus.
- where sensory info from skin is presented
- the amount of somatosensory area devoted to a particular body part denotes its sensitivity.
35
Visual area (where is it located, function, damage?)
- in occipital lobe at back of brain
- each eye sends info from right visual field to left visual cortex, and from left visual field to right visual cortex.
- means damage to left hemisphere, for example, can produce blindness in part of the right visual field of both eyes.
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Auditory area (where is it located, function, damage?)
- in temporal lobes
- analyses speech-based info
- damage: partial hearing loss.
- damage to Wernicke's area may affect ability to comprehend lang
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Broca's area (where is it located, function, damage?)
- small area in left frontal lobe
- responsible for speech production
- damage: can cause Broca's aphasia (speech that is slow and lacks fluency)
- Broca's most famous patient 'Tan' bc that was the only word he could say
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Wernicke's area (where is it located, function, damage?)
- in left temporal lobe
- responsible for language understanding
- damage: Wernicke's aphasia- often produce nonsense words
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Draw and label the brain
-
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Strengths (localisation) : evd from brain scans
Evidence from brain scans:
- Peterson et al used brain scans to demonstrate how Wernicke's area was active in listening tasks, Broca's active in reading task
- Also, review of LT memory studies (Buckner & Peterson): semantic & episodic memories reside in diff parts of prefrontal cortex.
- Therefore objective measures for measuring brain actvity have given scientifc evd that brain fucntions r localised
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Counterpoint:
- Lashley removed areas of cortex in rats that were learning a maze route
- no area was proven to be more important in their ability to learn the route.
- the learning process seemed to need every part of the cortex rather than a partcular area.
- Suggests that higher cognitive processes are not localised, but distributed in a more holisitic way
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Limitation (language localisation questioned)
- lang may not be limited to wernicke and broca's area
- Dick and Tremblay found only 2% of modern reasearchers think lang is completerly controlled by those 2 areas.
- advances in brain imaging techniques (eg: fMRI) mean neural processes can be studied with more clarity.
- so-called language streams have been idenitifed across the cortex.
- Suggests lang may be oragnised more holistically in brain
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What is brain plasticity?
- at any time in life, existing neural connections can change, or new neural connections can be formed, as a result of learning and experience
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What is synaptic pruning?
- rarely used connections are deleted and frequently used ones are strengthened.
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Research into brain plasticity (Maguire: taxi drivers)
- studied brain of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group.
- This part of the brain is associated w development of spatial and navigational skills.
- the knowledge that was assessed was their recall of the city streets & routes
- this learning alters structure of taxi driver's brains
- the longer they had been in the job, the more pronounced was the structural diff (+ correlation)
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Research into brain plasticity (Draganski: med students)
- imaged brains of medical students 3 months before and after their final exams.
- learning-induced changes were seen to have occured in the posterior hippocampus and the parietal cortex
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Research into brain plasticity (Mechelli: bilingual)
- found larger parietal cortex in the brains of people who were bilingual compared to matched monolingual controls.
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Strengths of plasticity: practical application
Practical application:
- contributed to neurohabilitation
- after bran injury, spontaneous recovery tends to slow down after a number of weeks so form so forms of physical therapy may be required to maintain improvements (eg: movement therapy)
- this shows that although the brain has the capacity to fix itself to a point, the process requires further intervention to be completely successful.
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Limitation: negative brain plasticity
- the brains ability to rewire itself may have maladaptive behavioural consequences
- (Medina): prolonged drug use, shown to result in poorer cognitive functioning as well + risk of dementia later in life
- also 60-80% of amputees develop phantom limb syndrome
- these sensations are usually unpleasant, painful, due to cortical reorganisation in the stomatosensory cortex
50
Limitation: age and plasticity
- functional plasticity tends to reduce w age.
- brain has greater propensity for reorganisation in childhood as its constantly adapting to new experiences & learning
51
What is functional recovery?
- a form of plasticity
- following damage through trauma, the brain's ability to redistribute or transfer functions usually performed by a damaged area to other damaged area
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What is spontaneous recovery?
- functional recovery can occur quickly after trauma (spontaneous recovery) and then slow down after several weeks.
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What happens in the brain during recovery?
The brain is able to rewire by forming new synaptic connections close to the area of damage
- secondary neural pathways that wouldnt typically be used to carry out certain functions are activated.
- Axonal sprouting: the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
- Reformation of blood cells.
- Recruitment of similar areas to the opposite side of the brain to perform specific tasks.
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Strength: support from animal studies
- Hubel and Weisel
- sew one eye of kitten shut
- found visual cortex area was not idle continued to process info from open eye
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Split brain research: (Sperry)
- Sperry (1968) studied 11 patients who had a corpus callosotomy
- projected info into each visual field, controlling which information each visual field accessed
-in a series of tests, participants would be asked to either say what they saw, draw it or pick out from hidden objects
- found that info presented to the left hemisphere could be spoken, but not if it had been delivered to the right hemisphere
- but, the info presented to the right hemisphere could be drawn or picked out from objects with the left hand
- supports lateralisation and shows the hemispheres working independently
- supports localisation of function as it shows the language centres are on the left side of the brain
- ppts had each of their hemispheres presented with faces, the right hemisphere was more capable of recognising them
- suggests the right hemisphere is responsible for face recognition
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Strengths
- split-brain research had a huge impact on the psychological understanding of the brain and individuals' identities
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Weaknesses
- small sample
- Results could have been due to individual participant variables as they had their brain cut and drug therapy, meaning the results may not be able to be generalised to the wider population
- The tasks the participants had to do, lacked mundane realism, which results in low external validity
58
What does Functional magnetic resonance imaging (fMRI) do?
- detecting blood flow (oxygenated haemoglobin blood which reacts to the magnets) in the brain
- uses large magnets to detect oxygenised blood and show deoxygenised blood
- brain areas that are more active, need more blood flow, this is oxygenised blood
inactive or less active parts of the brain will show deoxygenated blood
- active areas can then be compared with areas that are lower in activity and can be shown on the fMRI image
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Strengths of fMRI
- Good spatial resolution of 1mm. Precisely identifying active brain regions and patterns of activation over time
- It produces a moving picture, which allows for comparison over time
- non-evasive and safe technique for patients
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Weaknesses of fMRI
- expensive and hard to build
- patient needs to remain very still throughout and is not allowed to move
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EEG (Electroencephalogram)
- electrodes are placed on the scalp and they record activity in the brain
- electrodes are fitted to a cap and the cap is placed on the participant with conductive gel
- electrodes measure the activity of the cells directly below them, so the more electrodes the more detailed information and full picture of the brain it can give
- activity is displayed in brain waves.
- amplitude shows the brain intensity and the frequency shows the speed of activation
- giving a picture of the brain activity underneath the electrodes
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Strengths of EEG
- cheaper alternative to studying the brain than brain imaging techniques
- useful to test reliability on self reporting techniques: avoid social-desirability bias
- historically important in understanding the brain and studying it, especially related to sleep and medical diagnosis
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Weaknesses of EEG
- only reasonably accurate, which means finer details are missed
- Expertise is needed to interpret the outcome from the equipment
- not able to detect activity deep in the brain
-
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ERP (Event-related Potential)
- ERP uses the same apparatus and technique as EEG
- record when there is activity in reaction to a stimulus
- this stimulus is presented many times
- provides data using statistical averaging
- the waveform's peaks and dips show exactly when cognitive processes happen in the brain in relation to when the stimulus is presented
65
Strengths of ERPs
- cheaper alternative to studying the brain than brain imaging techniques
- useful to test reliability on self reporting techniques: avoid social-desirability bias
- historically important in understanding the brain and studying it, especially related to sleep and medical diagnosis
- allow researchers to isolate and study how individual cognitive process take place in the brain
66
Weaknesses of ERPs
- only reasonably accurate, which means finer details are missed
- Expertise is needed to interpret the outcome from the equipment
- not able to detect activity deep in the brain
- Some cognitive process can not be studied using ERP as they are unable to be presented multiple times
67
Post Mortem Dissection
- when a persons body, including their brain, is examined after they die
- during the examination, brains are precisely cut
- researchers will examine and dissect brains of individuals who had suffered from trauma or mental illness and compare the brain with someone who had a neurotypical brain
- allows researchers to identify key function of specific parts of the brain
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Strengths of Post Mortem Dissection
- fundamental in the development of understanding brains and how they function, including understanding localisation of function
- The individual is not alive and so cannot experience any discomfort
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Weaknesses Post Mortem Dissection
- No brain activity can be measured as the research is conducted on a dead person
- Brains could have been affected by the cause of death, effecting the results
- difficult to compare the brain after death with the functioning prior to death, any relationship found would be correlational and not causal
70
What is a biological rhythm?
- a change in the body processes or behaviour in response to cyclical changes within the environment.
- influenced by internal body clock (endogenous pacemakers) and external changes to environment (exogenous zeitgebers)
71
What is a circadian rhythm?
- 24 hr cycle
- regulates a number of body processes such as sleep/wake cycle & changes in core body temp
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Sleep wake cycle, (role of SCN, melatonin and exogenous zietgebers)
- sleep-wake cycle is an example of a circadian rhythm
- exogenous zeitgebers are environmental events, like the changing of light, which reset the body clock
- suprachiasmatic nuclei (SCN) in the hypothalamus detects the level of light present and then uses this information to coordinate the activity of the entire circadian system
- melatonin plays a role in ‘triggering’ sleep by responding to a decrease in the levels of light
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Supporting research: Siffre cave
- spent two months in a cave deprived of light and sound
- his circadian rhythm remained between 24-25 hours
-
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Supporting research: Folkard STM recall
- implemented a 22-hour sleep-wake cycle
- found that ppts experienced problems with recall in their short-term memory
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Strengths
- application to shift work
- application to drug treatment: reearch into circadian rhythms shows theres peak times to take medication where they're more likely to be effective
-
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Weaknesses of the supporting studies
- Case studies such as Siffre (1973) cannot be generalised beyond the single participant
- Folkard's research lacks ecological validity due to its lab setting
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What is an infradian rhythm?
- frequency of less than one cycle in 24 hrs
- takes longer than a day to complete
- eg: mensturation & SAD
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The menstural cycle
A typical menstrual cycle takes around 28 days to complete and is the result of a change in hormone levels including oestrogen
79
Research (McClintock: menstural cycles)
- 29 women w irregular periods
- samples of pheremones gathered from 9 of the women at diff stages of their cycle, via cotton pad placed on armpit
- pads treated w alchol and frozen, then rubbed on upper lip of other ppt
- on day 1: pads from 1st day of cycle and so on...
- found 68% of women experienced changes to their cycle which bought them closer to cycle of their 'odour donor'
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Strength of synchronised menstrual cycle
Evolutionary psychologists claim that the synchronised menstrual cycle provides an evolutionary advantage for groups of women, as the synchronisation of pregnancies means that childcare can be shared among multiple mothers who have children at the same time.
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Counterpoint: validity of evolutionary perspective
- Schank argued that if too many women were cycling together, it would produce competition for highest quality men, lowering fitness of any potential offspring. So, avoidance of synchrony would appear to be a better evoluntionary stratergy.
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Metholodigcal limitations in sychnroisation
- many factors can change womens cycle (eg: stress, diet) that might act as confounding variables
- also McClintock used small sample of women and relies on self report of their cycle
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Seasonal affective disorder (SAD)
- SAD is usually experienced during the darker months of winter when more melatonin is secreted which may result in higher levels of depression
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What is ultradian rhythm?
- freuqncy of more than one cycle in 24 hrs
- eg: stages of sleep
- occurs multiple times in a day
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Stages of sleep cycle
- Stages 1 & 2 are ‘light sleep’ stages, brainwave patterns become slower and more rhythmic, starting with alpha waves progress to theta waves.
- Stages 3 & 4 are ‘deep sleep’ or slow wave sleep stages, where it is difficult to wake someone up. This stage is associated with slower delta waves.
- Stage 5 :REM (or dream) sleep, body is paralysed, brain activity resembles that of an awake person.
86
Endogenous pacemakers (SCN)
- Suprachiamatic nucelus
- tiny bundle of nerve cells
- located in hypothalamus
- one of the primary endougenous pacemakers
- influential in maintaining circadian rhythms
- nerve fibres connected to eye area cross in an area called optic chiasm
- it recieves info about light directly from it
- continues even when eyes closed, enabling biological clock to adjust to changing patterns of daylight whilst we sleep
87
SCN limitation (obscure other body clocks)
- may obscure other body clocks
- research reveals theres numerous circadian rhythms in many organs and cells
- peipheral oscillators in organs infleunced by actions of scn but also act independtly.
- Damiola showed how changing feeding patterns in mice could alter the circadian rhythms up to 12 hrs, while leaving scn unaffected
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SCN limitation (interactionsit system)
- endogeoun
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Animal studies (SCN): DeCoursey, chipmunks
- DeCoursey: destroyed SCN connections in brain of 30 chipmunks and observed them for 80d
- their sleep/wake cycle disappeared and by the end of the study, a signficant proportion of them had been killed by predators
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Animal studies (SCN): Ralph, hamsters
- bred 'mutant' hamsters with 20 hr sleep/wake cycle
- when SCN cells from foetal tissue from mutant hamsters were transplanted into normal hamsters, the cycle defaulted to 20hrs
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Pineal gland & melatonin
- scn passes info on day length and light that it recieves to the pineal gland
- during night, pineal gland increases production of melatonin (a chemical that induces sleep and is inhibited during periods of wakefulness)
- melatonin has also been suggested as a casual factor in SAD.
92
Exogenous zeitgebers (Light)
- can reset the body's main endougeous pacemakers (SCN)
- plays a role in the maintaince of sleep/wake cycle
- light has a direct influence on key processes in body that control functions such as hormone secrfetion and blood circulation
93
Campbell & Murphy (light and knees)
- demonstared light may be detected in skin receptor sites even when the same info isnt being recieved by eyes
- 15 ppts woken at various times with a light pad was shone on back of knees.
- produced deviation in ppt's usual sleep/wake cycle of up to 3 hrs in some.
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Exogenous pacemakers (social cues)
- babies are rarely on same sleep/wake cycle as the same family
- at about 6 weeks, the cicrdaian rhythms begin and bhy about 16 weeks babie's rhythms have been entrained by the schedules imposed by parents.
- research on jet lags suggests that adapting to local times for eating and sleeping is an effetive way of entraining circadian rhythms and beating jet lag.
