biopsych Flashcards
1
Q
What is the nervous system?
A
a specialised network of cells in the human body, our primary internal communication system
based on electrical signals
2
Q
what are the 2 main functions of the NS?
A
- to collect, process and respond to info in the environment
- to co-ordinate the working of different organs in the cells and body
3
Q
what are the subsystems that the NS is subdivided into?
A
CNS (central nervous
system)
PNS (peripheral nervous system)
4
Q
what makes up the CNS?
A
brain and spinal chord
5
Q
what is the role of the brain in the CNS?
A
the centre of all conscious awareness
cerebral cortex = 3mm thick (outer layer)
divided into 2 hemispheres
6
Q
what is the role of the spinal chord in the CNS?
A
extension of the brain
passes messages to and from the brain and connects nerves to th PNS
responsible for reflex actions
7
Q
what is the role of the PNS?
A
transmits messages via millions of neurones to and from the CNS
8
Q
what is the PNS subdivided into?
A
autonomic NS
somatic NS
9
Q
what is the function of the autonomic NS?
A
governs vital functions in the body (breathing, heart rate, digestion, stress responses)
10
Q
what is the function of the somatic NS?
A
governs muscle movement and receives info from sensory receptors
11
Q
what is the role of the endocrine system?
A
controls vital functions in the body, acts more slowly than NS (has powerful widespread effects)
12
Q
what are the main endocrine glands in the human body and what hormones do they secrete?
A
hypothalamus
pituitary gland
thyroid -> thyroxine
adrenal -> adrenaline
ovaries -> oestrogen
testes -> testosterone
13
Q
what is the role of the pituitary gland?
A
‘master gland’ = controls the release of hormones from the other endocrine glands in the body
14
Q
what is the role of the thyroid gland?
A
produces hormone thyroxine which increases heart rate by affecting cells in the heart
increases metabolic rates
15
Q
how does the endocrine system and the autonomic NS work together during the flight or fight response?
A
- stressor is perceived
- hypothalamus stimulates the pituitary gland
- this stimulates the adrenal gland to release hormone adrenaline from adrenal medulla
- triggers activity in the sympathetic branch of the ANS
- ANS changes from resting state of parasympathetic to sympathetic state
16
Q
what are features of the sympathetic state?
A
increased heart and breathing rate
dilated pupils
inhibits digestion
inhibits saliva production
contracts rectum
17
Q
what are features of the para sympathetic state?
A
decreased heart and breathing rate
constricted pupils
stimulates digestion
stimulates saliva production
relaxes rectum
18
Q
what are the 3 types of neurones?
A
sensory
relay
motor
19
Q
what are the features of a neurone?
A
cell body
dendrites
axon
myelin sheath
nodes of ranvier
terminal buttons
20
Q
what is the role of the cell body?
A
includes nucleus and contains the genetic material of the cell
21
Q
what is the role of the dendrites?
A
branch like structures that carry nerve impulses from neighbouring neurones to the cell body
22
Q
what is the role of the axon?
A
carries impulses away from the cell body
23
Q
what is the role of the myelin sheath?
A
fatty layer that covers the axon and protects it, speeding up electrical transmission
24
Q
what is the role of the nodes of ranvier?
A
gaps in the myelin sheath that speed up electrical transmission by forcing it to jump across the gaps
25
what is the role of the terminal buttons?
at the end of the axon that communicates with the next neuron in the chain across the synapse
26
where are the motor neurones located?
cell body in CNS but long axon in PNS
27
where are the sensory neurones located?
in PNS in ganglia (clusters)
28
where are the relay neurones located?
found within brain and visual system
29
how is a neurone fired?
- when activated by a stimulus, inside of cell (negative resting state) becomes positively charged for split second causing ACTION POTENTIAL
- creates electrical impulse that travels from axon towards end of neurone
30
how are signals WITHIN neurones transmitted?
electrically
31
how are signals BETWEEN neurones transmitted?
chemically
32
what are the features of a synapse?
presynaptic terminal
synaptic vesicle
synapse
neurotransmitters
postsynaptic receptor sites
33
what is the process of synaptic transmission?
1. when electrical impulse reaches presynaptic terminal, triggers the release of neurotransmitters from synaptic vesicles
2. neurotransmitters diffuse across the synapse and is taken up by postsynaptic receptor site on dendrons of next neurone
3. chemical message converted back into electric impulse and process begins again in this neurone
34
how can the direction of travel for an impulse only be one way?
neurotransmitters are released from the presynaptic neurone terminal and received by the postsynaptic neurone
35
how can a neurone have an inhibitory effect on a neighbouring neurone?
makes the neurone more negatively charged so it’s less likely to fire
e.g serotonin
36
how can a neurone have an excitation effect on a neighbouring neurone?
increasing its positive charge and making it more likely to fire
37
what is summation?
action potential of the post synaptic neurone is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold
38
what was the holistic theory of the brain?
all parts of the brain were involved in the processing of thought and action
39
what is the localisation of function discovered by broca and wernicke?
different parts of the brain perform different tasks and are involved with different parts of the body
if a certain area of the brain becomes damaged, the function associated with it is also affected
40
what is the main part of the brain?
the cerebrum
41
how is the cerebrum divided?
left and right hemisphere
42
what is lateralisation?
some of our physical and psychological functions are dominated/controlled by a particular hemisphere
43
how is the brain contralateral?
LHS of the body is controlled by the R hemisphere, RHS of the body is controlled by the L hemisphere
44
what are the 4 lobes of the brain?
frontal
parietal
temporal
occipital
45
where is the motor cortex?
frontal lobe
46
what is the role of the motor cortex?
controls voluntary movement on the opposite side of the body
damage = loss of control over fine movements
47
where is the somatosensory cortex?
parietal lobe
48
what is the role of the somatosensory cortex?
processes sensory information from the skin
(touch, heat, pressure)
49
where is the auditory cortex?
temporal lobe
50
what is the role of the auditory cortex?
analyses speech-based information
damage = produce partial hearing loss (more extensive the greater the loss)
51
where is the visual cortex?
occipital lobe
52
what is the role of the visual cortex?
each eye sends info from the R visual field to the L visual cortex and vice versa
damage = blindness in part of the right visual field of both eyes
53
where is the Broca's area (1880s) and what is it responsible for?
left frontal lobe
speech production
54
damage to the broca's area causes what?
what are its characteristics?
broca's aphasia
speech = slow, laborious and lacking in fluency
55
where is wernicke's area and what is it responsible for?
left temporal lobe
speech comprehension
56
damage to the wernicke's area causes?
wernicke's aphasia:
severe difficulty understanding language, speech produced = fluent but meaningless
produce nonsense words (neologisms) as part of their speech
57
eval: how is it a strength that there is supporting evidence from neurosurgery?
DAMAGE TO AREAS OF THE BRAIN HAVE BEEN LINKED TO MENTAL DISORDERS
dougherty et al. (2002) reported on 44 ppl w OCD that had undergone cingulotomy (isolating cingulate gyrus in brain)
follow up after 32 weeks: 30% met criteria for successful response to surgery, 14% 4 partial response
success of procedures suggests behaviours associated w mental disorders may be LOCALISED
58
how is it a strength that there is supporting evidence from brain scans?
SUPPORTS IDEA THAT MANY EVERYDAY BRAIN FUNCTIONS ARE LOCALISED
petersen et al. (1988) used brain scans to demonstrate wernicke's area was active during LISTENING TASK and broca's area was active during a READING TASK
tulving et al. (1944) long term study: semantic + episodic memories reside in diff parts of prefrontal cortex
objective methods for measuring brain activity have provided sound scientific evidence that MANY BRAIN FUNCTIONS LOCALISED
59
what is the counterpoint to the strength of supporting evidence from brain scans?
lashley (1950): removed areas of the cortex (10-50%) in rats that were learning the route though a maze
no area was proven to be more important than any other area -> process of learning seemed to require every part of the cortex rather than being confined to a particular area
SUGGESTS THAT HIGHER COGNITIVE PROCESSES (e.g learning) ARE NOT LOCALISED BUT DISTRIBUTED IN A MORE HOLISTIC WAY IN THE BRAIN
60
how is it a limitation that language may not be localised just to broca's and wernicke's areas?
dick and tremblay (2016) found 2% of modern researchers think that language in the brain = completely controlled Broca's + wernicke's areas
by advances in brain imaging techniques e.g fMRI means brain can be studied in more clarity -> seems language function is distributed far more holistically in the brain
language streams have been identified across the cortex
SUGGESTS LANGUAGE MAY BE ORGANISED MORE HOLISTICALLY (contradicts localisation theory)
61
what does brain plasticity mean?
describes the brain’s tendency to change and adapt as a result of experience and new learning
generally involves the growth of new connections
62
During infancy what happens to the brain and the number of synaptic connections?
brain experiences a rapid growth in the number of synaptic connections (gopnik et al. 1999)
63
what is synaptic pruning?
as we age, rarely used connections are deleted and frequently used connections are strengthened
this enables life long plasticity
64
what was the research into plasticity done by maguire et al 2000 on the brains of London taxi drivers?
what was found the longer the taxi drivers had been in the job?
as part of training taxi drivers had to recall city streets and routes for “The knowledge” test
found significantly more volume of grey matter in the posterior hippocampus than in a matched control group
b) the more pronounced was the structural difference (positive correlation)
65
what is the posterior hippocampus associated with?
the development of spatial and navigational skills on humans and other animals
66
what is functional recovery?
a form of plasticity following damage through trauma -> brains ability to redistribute/transfer functions usually performed by a damaged area to other undamaged areas
67
what happens after brain trauma in terms of functional recovery?
after physical injury, healthy brain areas may take over the function of those areas that are damaged
process can occur quickly (spontaneous recovery) and then slow down after several weeks
68
what happens in the brain during recovery?
brain is able to rewire and reorganise itself by forming new synaptic connections close to areas of damage
second neural pathways that would not typically be used to carry out certain functions are activated to enable functioning to continue
69
what is axonal sprouting? (supports brain during recovery)
the growth of new nerve endings which connects with other undamaged nerve cells to form new neuronal pathways
70
what is denervation super sensitivity? (supports brain during recovery)
occurs when axons that do a similar job becomes aroused to a higher level to compensate for the ones that are lost
(can have the consequence of over sensitivity to messages such as pain)
71
what is denervation super sensitivity? (supports brain during recovery)
occurs when axons that do a similar job becomes aroused to a higher level to compensate for the ones that are lost
(can have the consequence of over sensitivity to messages such as pain)
72
what is recruitment of homologous areas on the opposite side of the brain? (supports brain during recovery)
specific tasks can still be performed
e.g if Broca’s area was damaged on the left side of brain, the right sided equivalent would carry out its functions
after a period of time, functionality may then shift back to the left side
73
what was the similar finding found by draganski et al. 2006 (66 FLASHCARD)
images brains of medical students 3 months before and after final exam:
learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of learning
74
how is it a limitation of plasticity that it may have negative behavioural consequences?
Evidence has shown that the brains adaptation to poorer drug use leads to poorer cognitive functioning in later life
+ increased risk of dementia (medina et al 2007)
60-80% amputees develop phantom limb syndrome (continued experience of sensations in missing limbs) due to cortical reorganisation in the somatosensory cortex
SUGGESTS BRAIN’S ABILITY TO ADAPT TO DAMAGE IS NOT ALWAYS BENEFICIAL
75
how is it a strength of plasticity that it does not always decline sharply with age?
P reduces w age but Bezzola et al. 2012 demonstrated how 40hrs of golf training produced changes in the neural representations of movement in participants aged 40-60
researchers observed increased motor cortex activity in the novice golfers compared to control group
SHOWS NEURAL PLASTICITY CAN CONTINUE THROUGHOUT THE LIFESPAN
76
how is it a strength or functional recovery that there is real world application?
understanding processes involved in plasticity has contributed to field of neurorehabilitation: understanding axonal growth encourages new therapies to be tried
e.g constraint induced movement therapy used w stroke patients where they repeatedly practice w affected part of body
SHOWS THAT RESEARCH INTO FUNCTIONAL RECOVERY IS USEFUL AS IT HELPS MEDICAL PROFESSIONALS KNOW WHEN INTERVENTIONS NEED TO BE MADE
77
how is it a limitation of functional recovery that the level of education may influence recovery rates?
schneider et al. 2014 revealed more time ppl w a brain injury had spent in education = greater their chance of a disability free recovery
40% w DFR had more than 16 years education compared to 10% who has less than 12 years education
IMPLIES PPL W BRAIN DAMAGE WHO HAS INSUFFICIENT DFR ARE LESS LIKELY TO ACHIEVE A FULL RECOVERY
78
what is hemispheric lateralisation?
idea that 2 hemispheres of the brain are functionally different
certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other
79
how is the LH the analyser and the RH the synthesiser?
language is later used to LH and RH can only produce rudimentary words and phrases but contributes emotional context to what is being said
80
How is vision contra lateral and ipsilateral?
LVF of both eyes connected to RH
RVF of both eyes connected to LH
enables visual areas to compare perspective of each eye and aids depth perception
81
What is a “split-brain” operation?
severed the connections between the RH and LH (corpus callosum)
to reduce epilepsy
82
what does split brain research study?
how the hemispheres function when they can’t communicate with each other
83
what was the procedure proposed by sperry 1968 for his split brain research?
11 ppl who has split brain operation studied using tachistoscope: image projected to ppts RVF (processed by LH) and the same or different image could be projected to LVF (processed by RH)
info cannot be conveyed from that hemisphere to another unlike neurotypical brains give a complete picture of the visual world
84
what were sperry’s findings (1968)
if visual material presented to RVF (processed by LH): able to describe it in speech and draw it w R hand (LH responsible for language)
if visual material presented to LVF (processed by RH) ppt says they saw nothing as RH not responsible for language but able to draw with L hand (controlled by RH)
85
what is the conclusion of sperry’s split brain research?
show how certain functions are lateralised in the brain and support the view that LH is verbal and RH is silent but emotional (2 independent streams of consciousness)
86
how is it a strength that there is lateralisation in the connected brain?
Fink et al (1996) used PET scans to identify which brain areas were active during visual processing task
ppts w connected brains asked to attend to global elements of an image (forest) regions of RH were much more active
when asked to focus on details (individual trees) specific areas of LH dominated
SUGGESTS THAT HEMISPHERIC LATERALISATION IS A FEATURE OF CONNECTED BRAIN AS WELL AS SPLIT BRAIN
87
how is it a limitation that the idea of the LH as an analyser and the RH we a synthesiser may be wrong?
research suggests people do not have a dominant side of the brain which creates a different personality:
nielsen er al (2013) analyses brain scans from 1000+ ppl (7-29): found people used certain hemispheres for certain tasks BUT NO EVIDENCE OF A DOMINANT SIDE
SUGGESTS NOTION OF RIGHT OR LEFT BRAINED PEOPLE IS WRONG
88
how is it a strength that there is support from more recent split brain research?
gazzaniga (1989) showed split brain ppts acc perform better than connected controls on certain tasks e.g faster at identifying off one out in array of similar objects)
in normal brain LHs better cognitive strategies are watered down by inferior RH
this supports sperry’s earlier findings that left brain and right brain are distinct
89
How is it a limitation of sperrys research that casual relationships are hard to establish?
compared to a neurotypical control group but none had epilepsy therefore is a CONFOUNDING VARIABLE
any differences observed may be caused by epilepsy and not split brain
MEANS SOME UNIQUE FEATURES OF SPLIT BRAINS COGNITIVE ABILITIES MIGHT BE DUE TO EPILEPSY
90
what are the different ways to study the brain?
fMRI: functional magnetic resonance imagine
EEG: electroencephalogram
ERPs: event related potentials
post mortem examinations
91
what do fMRIs produce?
3D Images (activation maps) showing which parts of the brain are involved in a particular mental process
has important implications for our understanding of localisation of function
92
how do fMRIs work?
detects changes in both blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain
93
what happens in an fMRI when a brain area is more active?
it consumes more oxygen and to meet this increased demand, blood flow is directed to the active area -> haemodynamic response
94
what do EEG’s measure?
electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap
95
what do EEG scan recordings represent?
the brainwave patterns that are generated from the action of thousands of neurons, providing an overall account of brain activity
96
who are EEGs used by and why?
clinicians as a diagnostic tool as unusual arrhythmic patterns of activity -> may indicate neurological abnormalities e.g epilepsy tumours or sleep disorders
97
what are event related potentials?
types of brainwave that are triggered by particular events
98
how do researches find ERPS?
using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out leaving responses that show the PRESENTATION OF A SPECIFIC STIMULUS or PERFORMANCE OF A SPECIFIC TASK
99
what are post mortem examinations?
analysis of a persons brain following death
A means of establishing the likely cause of affliction the person experienced -> may involve comparison with a neurotypical brain to ascertain the extent of the difference
100
what does it mean if an individuals brain is subject to a post mortem examination?
they are likely to be those who have a rare disorder or have experienced unusual deficits in cognitive processes or behaviour during their lifetime
101
how is it a strength of fMRI that is does not rely on the use of radiation?
unlike other scanning techniques e.g PETs does not rely on radiation:
virtually risk-free, non-invasive and straight forward to use
produces images that have high spatial resolution, provides clear picture of how brain activity is localised
fMRIs CAN SAFELY PROVIDE A CLEAR PICTURE OF BRAIN ACTIVITY
102
how is it a limitation of fMRI: that it is expensive in comparison to other neuroimaging techniques?
has poor temporal resolution: 5 second time lag behind the image on screen and the initial firing of neuronal activity
MEANS fMRI MAY NOT TRULY REPRESENT MOMENT TO MOMENT BRAIN ACTIVITY
103
how is it a strength of EEGs that it has been useful in studying the stages of sleep and in diagnosis of conditions such as epilepsy?
EEG tech has extremely high temporal resolution, can accurately detect brain activity at a resolution of a single millisecond
SHOWS REAL WORLD USEFULNESS OF THE TECHNIQUE
104
how is it a limitation of EEGs is it’s generalised nature of information?
EEG signal is not useful for pinpointing the exact source of neural activity
therefore does not allow researches to distinguish between activities
originating in different but adjacent locations
105
how is it a strength of ERPs that they bring more specificity to the measurement of neural processes that could be achieved with raw EEG data?
have excellent temporal resolution
means ERPs are frequently used to measure cognitive functions and deficits e.g allocation of attentional resources and maintenance of working memory
106
how is it a limitation that there is a lack of standardisation in ERP methodology between different research studies?
makes it difficult to confirm findings
in order to establish pure data, background noise and extraneous material must be eliminated
-> not easy to achieve
107
how is it a strength of post mortem examinations is that it is vital in providing a foundational for early understanding of key processes in the brain?
broca and wernicke relied on PMEs to establish links between language, brain and behaviour
PMEs also used to study HM’s brain to identify the areas of damage (then associated with his memory deficits)
PMEs provide USEFUL INFORMATION
108
how is it a limitation of post mortem evaluations that causation is an issue and there are ethical issues?
observed damage to the brain may not be linked to the deficits under review but to other unrelated trauma or decay
raises ethical issues of consent from the individual before death: participants may not be able to provide informed consent
challenges the usefulness of postmortem studies in psychological research
109
what are circadian rhythms?
biological rhythms subject to a 24hr cycle, which regulate a number of body processes such as sleep/wake cycle and changes in core body temperature
110
what are endogenous pacemakers?
body’s internal biology clocks
111
what are exogenous zeitgebers?
external changers in the environment e.g daylight, noise, temperature
112
how does the sleep wake cycle work?
governed by an internal pacemaker, SCN
SCN provides information from the eye about light (exogenous zeitgeber)
113
what was siffre’s cave study?
spent several extended periods underground in the alps to study effects of his own biological rhythms
deprived or exposure to natural light and sound, he resurfaced in mid sept 1962 believing it was mid august
his biological rhythms settled down to one that was just beyond the 24 hours (25hrs) -> fell asleep and woke up on a regular schedule
114
115
what was folkard et al. 's (1985) study and why does it show we should not overestimate the influence of exogeneous zeitgebers on our internal biological clock?
studied 12 ppl: lived in a dark cave for 3 weeks, sleeping when clock said 11.45pm and waking up at 7.45am.
over course of study: researchers gradually sped up the clock so 24hr day lasted 22hrs
only 1 ppt could comfortably adjust to regime
suggests the existence of a strong free-running circadian rhythm that cannot be easily overridden by exogeneous zeitgebers
116
what is desynchronisation?
consequences that occur when circadian rhythms are disrupted?
117
how is it a strength that research into circadian rhythms provides an understanding of desynchronisation?
e.g night workers engaged in shift work experience a period of reduced concentration around 6 in the morning therefore mistakes and accidents are more likely (boivin et al 1996)
relationship between shift work and poor health: shift workers 3x more likely to develop heart diseases than ppl working regular shift patterns (knutsson 2003)
SHOWS RESEARCH INTO SLEEP/WAKE CYCLE MAY HAVE REAL-WORLD ECONOMIC IMPLICATIONS IN TERMS OF HOW BEST TO MANAGE WORKER PRODUCTIVITY
118
How is it a counterpoint that there may be other factors to explain the effects of shift work?
studies investigating shift work tend to use correlational methods: means it is difficult to establish whether desynchronisation of sleep/wake cycle is acc cause of negative effects
solomon 91993): high divorce rates in shift workers may be due to strain of deprived sleep and other events e.g missing out on family events
SUGGESTS IT MAY NOT BE BIOLOGICAL FACTORS THAT CREATE THE CONSEQUENCES ASSOCIATED W SHIFT WORK
119
what is chronotherapeutics?
medical treatment administered in a way that correspnds to a person's biological rhythms?
120
How is it a strength of circadian rhythms that it has been used to improve medical treatments?
CR's coordinate some of the body's basic processes e.g heart rate, digestion and hormone levels -> rise and fall during day leading to chronotherapeutics e.g aspirin more effective at night as heart attacks likely to occur in the morning
SHOWS CIRACDIAN RHYTHM RESEARCH CAN HELP INCREASE THE EFFECTIVENESS OF DRUG TREATMENTS
121
how is it a limitation of research into circadian rhythms is that generalisations are difficult to make?
studies (siffre, aschoof + wever) based on small sample of ppts -> sleep/wake cycles may range widely from person to person
czeisler et al found individual differences in S/W cycles varying from 13-16hrs
duffy et al found ppl have preferences for going to bed early (larks) / sleeping late (owls)
MEANS IT IS DIFFICULT TO USE RESEARCH DATA TO DISCUSS ANYTHING MORE THAN AVERAGES WHICH MAY BE MEANINGLESS
122
what is an infradian rhythm?
type of biological rhythms subject it’s a frequency of less than one cycle of 24hrs e.g menstruation or seasonal affective disorder
123
what is the menstrual cycle?
infradian rhythm governed by monthly changes in hormone levels which regulate ovulation
refers to time between first day when womb lining is shed to the day before her next period
approx 28 days to complete
124
what happens during each menstrual cycle?
rising levels of oestrogen cause the ovary to develop an egg and release it (ovulation)
progesterone helps womb lining to grow thicker readying womb for pregnancy
if pregnancy does not occur, egg is absorbed into the body -> menstrual flow
125
126
although the menstrual cycle is an endogenous system, evidence suggests it may be influenced by
exogenous factors e.g cycles of other women
127
what was the study by stern and McClintock (1998) that demonstrates how menstrual cycles may synchronise as a result of the influence of pheromones?
29 women with irregular periods studied
samples of pheromones gathered from 9 at different stages of their cycle (via cotton pad from armpit worn for 8hrs then treated w alcohol and frozen) -> rubbed on upper lip of other ppts
on day 1 pads from start of cycle were applied to all 20 women, on day 2 they were all given pads from second day of cycle etc.
128
what were the findings of the study by stern and McClintock (1998) that demonstrates how menstrual cycles may synchronise as a result of the influence of pheromones?
found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their “odour donor”
129
what is seasonal affective disorder?
SAD = depressive disorder which has a seasonal pattern onset and is described and diagnosed as a mental disorder in DSM-5
130
what are the symptoms and characteristics of SAD?
persistent low mood
lack of general activity and interest in life
symptoms are triggered during the winter months when number of daylight hours becomes shorter
called circannual rhythm as it is subject to a yearly cycle
131
why have psychologists hypothesised that the hormone melatonin is implicated in the cause of SAD?
during night the pineal gland secretes melatonin until there is an increase in light
during winter lack of light in morning means secretion process continues for longer -> knock on effect on production of serotonin in the brain (linked to onset of depressive symptoms)
132
what is an ultradian rhythm?
type of biological rhythms which a frequency of more than one cycle in 24hrs e.g stages of sleep
133
what are the stages of sleep that altogether span approx 90 minutes?
(different levels of brainwave activity monitored using EEG)
stages 1 and 2: alpha waves
stages 3 and 4: delta waves
stage 5 (REM sleep): theta waves
134
what happens in stage 1 and 2?
Light sleep: person may be easily woken
stage 1: alpha waves (high frequency short amplitude)
stage 2: alpha waves with sleep spindles
135
what happens in stage 3 and 4?
deep sleep/slow wave sleep
(Difficult to wake person)
delta waves (low frequency high amplitude)
136
what happens in stage 5 (REM sleep)?
body = paralysed yet brain activity closely resembles awake brain
brain produces theta waves and eyes occasionally move around (rapid eye movement REM)
dreams are often experienced during REM and also deep sleep
137
