biopsych Flashcards
1
Q
the nervous system
A
2 main functions:
- to collect, process + respond to info in the environment
- to coordinate the working of different organs + cells in the body
made up of:
- central nervous system
- peripheral nervous system
2
Q
central nervous system
A
made up of the brain + spinal cord:
- the brain = centre of all conscious awareness
- the spinal cord = an extension of the brain + responsible for reflex actions
3
Q
peripheral nervous system
A
made up of neurones that connect the CNS to the rest of the body
further divided into:
- somatic nervous system: controls conscious activities (eg running)
- autonomic nervous system: controls vital functions in body (eg breathing, heart rate, digestion etc)
4
Q
the endocrine system
A
- works alongside the NS to control vital functions in the body through the action of hormones
- acts more slowly but has v widespread + powerful effects
- instructs glands to release hormones directly into the bloodstream to be carried to target organs
5
Q
glands
A
- organs in the body that produce hormones
- pituitary gland (aka master gland) = major endocrine gland located in the brain which controls the release of hormones from all other endocrine glands in the body
6
Q
hormones
A
- secreted into the bloodstream + affect any cell in the body that has a receptor for that particular hormone
7
Q
fight or flight
A
endocrine system + autonomic nervous system work together during stressful events
- when a stressor is perceived, the hypothalamus triggers activity in the sympathetic NS
- stress hormone adrenaline is released from the adrenal medulla into the bloodstream
- adrenaline triggers physiological changes in target organs + causes: increased heart rate, pupil dilation, decreased production of saliva (fight or flight)
- once the threat has passed, the parasympathetic NS returns the body back to its resting state (rest + digest)
8
Q
structure of a neurone
A
- cell body (soma): includes a nucleus which contains the genetic material of the cell
- dendrites: branch-like structures that protrude from the cell body - carry nerve impulses from neighbouring neurons towards the cell body
- axons: carries electrical impulse away from the cell body down the length of the neuron
- myelin sheath: fatty layer that covers the axon + speeds up electric transmission of impulse
- nodes of Ranvier: gaps in the myelin sheath from/to which impulses jump
- terminal buttons: at the end of the axon - communicate w the next neuron in the chain across the synapse
9
Q
firing of a neurone
electric transmission
A
when neurone is at rest:
- inside of cell is more negatively charged compared to the inside
when neurone is stimulated:
- inside of cell becomes positively charged for a split second, causing an AP to occur
- this creates an electrical impulse that travels down the axon toward the end of the neurone
10
Q
types of neurones
A
sensory
- carry messages from the PNS to CNS
- long dendrites and short axons
relay
- connect sensory neurons to motor neurons
- short dendrites and short axons
motor
- connect CNS to effectors e.g. muscles + glands
- short dendrites and long axons
11
Q
synaptic transmission
A
- when the electrical impulse reaches the end of the preSN, it triggers the release of NTs from the synaptic vesicles
- once NT diffuses across synaptic cleft, it’s taken up by the postsynaptic receptor sites (aka dendrites) of the next neurone
- chemical message is converted back into an electrical impulse + process of transmission begins again
12
Q
excitation
A
- when a NT increases the positive charge inside the postsynaptic neurone (depolarisation)
- making it more likely to fire an AP
- eg adrenaline
13
Q
inhibition
A
- when a NT increases the negative charge inside the postSN (hyperpolarisation)
- making it less likely to fire an AP
- eg serotonin
14
Q
summation
A
- accumulation of NTs in the synapse where both excitatory + inhibitory influences are summed
- net effect of NTs on postSN decides whether an AP is fired or not
- is only fired if depolarisation reaches the threshold
15
Q
brain localisation
A
scientists first supported the holistic theory (that all parts of the brain were involved in processing of thought + action
- was replaced by the localisation theory
- Broca & Wernicke discovered specific areas of the brain that are associated w specific functions
- if an area of the brain is damaged, the function associated w that area is also affected
16
Q
lobes
A
- cortex of both hemispheres is subdivided into 4 lobes:
- frontal, parietal, occipital and temporal
- each lobe is associated with different functions
- language, unlike other areas, is restricted to the left hemisphere
17
Q
motor area
A
- found at the back of the frontal lobe
- controls voluntary movement in the opposite side of the body
- damage may result in loss of control over fine motor movements
18
Q
somatosensory area
A
- found at front of parietal lobe
- processes sensory information from the skin (touch, heat, pressure etc)
19
Q
visual area
A
- found at the back of the occipital lobe
- each eye sends info from right visual field to left visual cortex + vice versa
- damage to left hemisphere can produce blindness in the right visual field of both eyes
20
Q
auditory area
A
- found in the temporal lobe
- analyses speech-based info
- damage may produce partial hearing loss
21
Q
Broca’s area
A
- found in left frontal lobe
- responsible for speech production
- damage results in Broca’s aphasia - characterised by slow, laborious speech, lacking in fluency
22
Q
Wernicke’s area
A
- found in the left temporal lobe
- responsible for language comprehension
- damage results in Wernicke’s aphasia - produce neologisms (nonsense words) as part of their speech
23
Q
brain localisation
ao3
A
✔ brain scan evidence
- Peterson used brain scans to demonstrate how Wernicke’s area was active during a listening task + Broca’s area was active during a reading task, showing that these areas of the brain have different functions
- Tulving revealed that semantic + episodic memories reside in different parts of the prefrontal cortex
✔ Phineas Gage case study
- damage to left frontal lobe caused a change in his personality
- calm + reserved –> quick-tempered + rude
- suggests frontal lobe is responsible for regulating mood
- HOWEVER, case studies cannot be generalised
✘ neural plasticity
- suggests that the rest of the brain is able to reorganise itself to recover lost function, following damage
- this poses as a challenge to the localisation theory as it suggests that localisation is not as rigid/permanent as made out to be
- although this doesn’t happen everytime, there are several documented case studies of stroke victims recovering seemingly lost abilities
✘ Lashley’s rats provide counter-evidence
- Lashley removed between 10-50% of the cortex in rats learning a maze
- found that no one area was more important than any other in the rats’ ability to learn the maze
- shows that learning requires every part of the cortex, not just some areas
- suggests learning is too complex to be localised + requires involvement of the whole brain
- HOWEVER, can’t generalise rats to humans
24
Q
hemispheric lateralisation
A
- brain is divided into 2 halves: left + right hemispheres
- generally, left side of body is controlled by right hemisphere + vice versa
lateralisation: idea that 2 halves of the brain are functionally different
- certain mental processes are mainly controlled by a particular hemisphere
- eg language is controlled by the left hemisphere
- suggests language is subject to hemispheric lateralisation
- questions whether other neural processes may be organised this way
- investigated in series of experiments conducted by Sperry via split brain research
25
split brain research
* series of studies (began in 60s)
* involving epileptic pxs who had undergone cerebral commissurotomy (surgical lesioning of the corpus callosum) to control epileptic seizures
* where info processed by 1 hemisphere can’t be relayed onto the other
* allowed Sperry to investigate the extent to which brain function is lateralised
26
split brain research
PROCEDURE
* image/word projected to px’s RVF (processed by LH)
* and same or different image/word projected to px’s LVF (processed by RH)
* in the ‘normal’ brain, the corpus callosum would immediately share info between both hemispheres
* however, in a split brain, info cannot be conveyed between hemispheres
27
split brain research
DESCRIBING WHAT YOU SEE
* when object shown to RVF, they could easily describe what was seen
* but when same object shown to LVF, they reported that nothing was there
**why?**
* language is processed in LH
* so px's inability to describe objects in LVF is due to the lack of language centres in the RH
* info couldn't be relayed to LF via corpus callosum
28
split brain research
RECOGNITION BY TOUCH
* when objects shown to LVF
* pxs couldn't name them but could select a matching object using left hand
**why?**
* LH is needed to verbally identify the objects
* but could understand what the object was using the RH
29
split brain research
COMPOSITE WORDS
* when 2 words presented simultaneously, 1 to either VF
* eg, key on the left + ring on right
* px would select key with their left hand
* and they would say the word ‘ring’
**why?**
* LVF goes to RH which controls left hand
* RVF goes to LH which controls language
30
split brain research
MATCHING FACES
* when composite picture made of 2 halves of a face presented
* the LH dominated verbal description
* RH for selecting matching picture
**why?**
- RH = dominant in recognising faces
- LH
31
split brain research
AO3
✔ **theoretical basis for discussion**
- Sperry's work triggered a theoretical + philosophical debate regarding the** nature of consciousness** + the **degree of communication** between the 2 hemispheres in everday functioning
- Pucetti suggested the hemispheres are so functionally different, they represent a form of duality in the brain, implying we are 2 minds
- others argued the hemispheres are highly integrated + work together
✔ **strengths of methodology**
- use of highly specialised + standardised procedures
- to present visual info to 1 hemispheric field at a time
- ppts asked to stared at fixation point w 1 eye + image flashed for 0.1s
- so ppts had no time to move their eye across the image + spread info to both sides of the visual field
- this allowed Sperry to vary aspects of the basic procedure + ensure only 1 hemisphere received info at a time
✔ **clearly demonstrates lateralised brain function**
- Sperry's work has produced an impressive body of research findings
- has been **pivotal in establishing difference in function** of the 2 hemispheres
- and also **opposing the holistic theory** of brain function
- concludes that LH is analytical + verbal (analyser) whilst the RH is adept at spatial tasks + music (synthesiser)
- **HOWEVER,** **recent research suggests that this distinction may be oversimplified**
- many behaviours associated w 1 hemisphere can also be carried out by the other when situations require
- suggests that Sperry may have overstated differences between the 2 hemispheres
✘ **issues w generalisation**
- split-brain patients constitute such an unusual sample of people
- there were only 11 individuals who took part in all variations of the procedure + they all were epileptic patients w a history of seizures
- this may have caused unique changes to the brain that may have influenced findings
- limits the extent to which finding can be generalised to the wider population
- lowers validity
32
brain plasticity
***brain's tendency to change + adapt as a result of experience + new learning***
* during infancy, brain experiences rapid growth in no of synaptic connections
* **synaptic pruning:** as we age, rarely used connections are deleted + frequently used ones are strengthened
* originally thought that synaptic pruning was restricted within childhood + adult brain would remain fixed in terms of function + structure
* however, more recent studies suggest that at any time in life, existing neural connections can change or new ones can be formed
33
brain plasticity research
Maguire
* studied brains of London taxi drivers
* found **significantly more volume of grey matter** in **posterior hippocampus** than in matched control group
* this part of the brain is **associated w development of spatial + navigational skills**
* they require these skills because as part of their training, taxi drivers have to take the **Knowledge test**, which assesses their recall of city streets
* found a **positive correlation** between an **increase in grey matter volume** + the **amount of time they had been a taxi driver**
34
brain plasticity research
Draganski
* imaged brains of **medical students** 3 months **before + after their final exams**
* **learning-induced changes** seen in **posterior hippocampus** + **parietal cortex** as a result of the exams
35
brain plasticity research
Michell
* found a **larger parietal cortex** in brains of people who were **bilingual** compared to matched monolingual controls
36
functional recovery
* form of plasticity, following damage through trauma
* brain's ability to redistribute functions usually performed by a damaged area to other unaffected areas
* can happen quickly after trauma - spontaneous recovery - and then slow down after several weeks/months
* may need rehabilitative therapy at this point to further their recovery
**what happens in the brain during recovery?**
* brain is able to rewire + recover by forming new synaptic connections
* and secondary neural pathways that aren't typically used are activated, enabling functioning to continue
**this process is supported by a no. of structural changes in the brain:**
* **axonal sprouting** - growth of new nerve endings which connect w other undamaged nerve cells to form new neural pathways
* **reformation of blood vessels**
* **recruitment of similar areas** - on opposite side of brain to perform specific tasks
37
brain plasticity
ao3
✔ **practical application**
- understanding processes involved in plasticity has contributed to the field of **neurorehabilitation**
- techniques including movement therapy + electrical stimulation of the brain are used to counter deficits to cognitive functioning following a stroke
✔ **research support in animal studies**
- when 1 eye of a kitten was sewn shut
- analysis of brain's cortical response found area of visual cortex, associated w the shut eye, was not idle but continued to process info from open eye
- shows how loss of function leads to compensatory activity in the brain
- provides evidence for neural plasticity
- **HOWEVER,** can't generalise cats to humans
✘ **negative plasticity**
- brain's ability to rewire itself can have **maladaptive behavioural consequences**
- eg prolonged drug use has been shown to result in poorer cognitive functioning + increased risk of dementia
- and a lot of amputees experience phantom limb syndrome which is often painful + unpleasant
38
investigating the brain
fMRI
- works by detecting changes in blood oxygenation + flow that occur as a result of neural activity in specific parts of brain
- when brain area is more active, it consumes more oxygen
- so to meet this increased demand, blood flow is directed to active area - **haemodynamic response**
- produces 3D images (activation maps) showing which parts of the brain are involved in particular mental process
- **has important implications for understanding of localisation of function**
39
fMRI
ao3
✔ **doesn’t’ rely on radiation**
✔ **risk-free, non-invasive + straightforward**
✔ produces images w a **high spatial resolution**
- details by the mm
✘ **expensive** compared to other neuroimaging techniques
✘ **poor temporal resolution**
- 5 second time lag between initial firing of neuronal activity and the image on the screen
✘ person **has to be perfectly still** to capture clear image
✘ **can only measure blood flow**
- can’t hone in on activity of individual neurones so difficult to tell what Kind of brain activity is being represented
40
investigating the brain
EEGs
- record of electrical impulses produced by brain’s activity
- measures electrical activity within brain via **electrodes** that are fixed to a person’s scalp using a skull cap
- scan recording represents brainwave patterns generated from the action of millions of neurons
- providing overall account of brain activity
- often used by clinicians as a **diagnostic tool** as unusual arrhythmic patterns of activity may indicate neurological abnormalities e.g. epilepsy, tumours, sleep disorders
41
EEGs
ao3
✔ extremely **high temporal resolution**
- accurately detects brain activity at a resolution of a single millisecond
✔ contributed to understanding of sleep stages
✘ generalised nature of info received
- EEG signal not useful for pinpointing exact source of neural activity - **poor spatial resolution**
- doesn't allow researchers to distinguish between activities originating in different but adjaecent locations
42
investigating the brain
ERPs
* event-related potentials
* EEG data contain all the neural responses associated w/ specific sensory, cognitive + motor events
* these responses are isolated using a statistical averaging technique
* ERPs are what is left when all extraneous brain activity from an EEG recording is filtered out
* leaving only those responses that relate to the presentation of a specific stimulus or performance of a certain task
* research has revealed many different forms of ERP + their link to cognitive processes
43
ERPs
ao3
44
investigating the brain
post-mortem examinations
* analysis of a person’s brain following their death
* usually those w a rare disorder + have experienced unusual deficits in mental processes or behaviour during their lifetime
* areas of damage in the brain are examined after death as a means to establish the likely cause
* may involve comparison w a neurotypical brain to see extent of difference
45
post-mortem examinations
ao3
46
biological rhythms
- all living organisms are subject to bio rhythms
- these are changes in body processes or behaviour in response to cyclical changes within the environment
all rhythms governed by 2 things:
* **endogenous pacemakers:** body’s internal biological clock
* **exogenous zeitgebers:** external changes in environment
47
bio rhythms
CIRCADIAN
* last around 24 hours
* eg sleep wake cycle
48
circadian rhythms
SLEEP-WAKE CYCLE
* feel drowsy when it’s night
* alert during day
* demonstrates effect of daylight - exogenous zeitgeber
49
sleep-wake cycle
SIFFRE
* spent extended periods underground to study the effects on his own bio rhythms
* deprived of exposure to natural light + sound
* spent 2 months underground before resurfacing
* a decade later, he spent 6 months underground
* in each case, his rhythm settled to one that was around 25 hours
* he did have a regular sleep-wake cycle
50
sleep-wake cycle
ASCHOFF & WEVER
* got a group of ppts to spend 4 weeks in a WWII bunker
* deprived of natural light
* all but 1 ppt displayed a circadian rhythm between 24-25 hours
both studies suggest that the 'natural' sleep-wake cycle may be slightly longer than 24 hours but is entrained by EZs associated w our 24 hour day
(eg no of daylight hours, typical meal times)
51
sleep-wake cycle
FOLKARD
* got a group of people to spend 3 weeks in a dark cave, going to bed and waking up at certain times
* over course of study, researchers gradually sped up the clock, without the ppts knowing
* so 24 hour day eventually only lasted 22 hours
* only 1 ppt was able to comfortably adjust to this new regime
* **suggests the existence of a strong free-running circadian rhythm that can’t be easily overridden by changes in the environment**
52
circadian rhythms
AO3
✔ practical application
-
✘ use of case studies + small samples
-
✘ poor control in studies
-
53
bio rhythms
INFRADIAN
* last longer than 24 hours
* eg menstrual cycle, SAD
54
infradian rhythms
MENSTRUAL CYCLE
* lasts about 28 days
* rising levels of oestrogen cause the ovary to develop + release an egg (ovulation)
* then, progesterone helps womb lining to thicken, preparing body for pregnancy
* if pregnancy doesn't occur, egg is absorbed into body + womb lining comes away + leaves the body (menstrual flow)
55
menstrual cycle
STERN & MCCLINTOCK
* studied group of women w irregular periods
* phermones were taken from some at different stages of their cycle via a cotton pad under their armpits
* these pads were cleaned w alcohol + later rubbed on upper lips of other ppts
* 68% of women experienced changes to their cycle that brought them closer to the cycle of their 'odour donor'
56
infradian rhythms
SAD
* circannual cycle
* depressive disorder w a seasonal pattern
* symptoms triggered during winter months when no. of daylight hours becomes shorter
* during the night, the pineal gland secretes melatonin until dawn when there is an increase in light
* during winter, lack of light in morning means secretion goes on for longer
* has a knock-on effect on production of serotonin in the brain
* low levels of serotonin associated w low mood
57
infradian rhythms
AO3
✔
✔✘
✘
58
bio rhythms
ULTRADIAN
* last less than 24 hours
* eg stages of sleep
59
ultradian rhythms
STAGES OF SLEEP
* psychologists identified 5 distinct stages of sleep
* each stage characterised by diff level of brainwave activity
* monitored using EEG
**stage 1 + 2:**
* light sleep, person is easily woken
* beginning → brainwave patterns start to become slower and more rhythmic (alpha waves)
* becoming even slower as sleep becomes deeper (theta waves)
**stage 3 + 4:**
* delta waves → slower + have greater amplitude
* deep sleep or slow wave sleep
* difficult to rouse someone
**Stage 5 REM:**
* body = paralysed yet brain activity speeds up, resembling awake brain
* REM activity correlates w/ dreams
60
ultradian rhythms
AO3
61
endogenous pacemakers
62
exogenous zeitgebers
63
