biopsych Flashcards

Question

ERP disadv

Answer 1

backround noise must be entirely eliminated + lack of standardisation in methodology between studies

Answer 2

- analysis of brain after death to determine whether observed behaviours during lifetime can be linked to brain abnormalities

Answer 3

foundation for key processes in brain eg: wernicke found links between language and brain before scans existed

Answer 4

correlation doesnt equal causation unclear if brain abnormality affected behaviour when alive ethical issues of consent when dead eg: HM

Answer 5

A circadian rhythm is a biological rhythm that lasts for around 24 hours and is governed by internal factors, such as the suprachiasmatic nucleus (endogenous pacemakers), and external factors, such as light (exogenous zeitgebers). eg: sleep/wake cycle and core body temperature. sleep/wake cycle is controlled by our internal biological clock, or SCN, which uses light information (exogenous zeitgeber) to reset itself every day. Siffre conducted a study to investigate the importance of light on our circadian rhythm. He spent several months underground, deprived of natural light and sound. He found that his biological rhythm settled down to around 25 hours SCN lies above optic chiasm providing info about light to the eye (light resets SCN) core body temperature fluctuates by about 2 degree during the course of the day, with its lowest at 4AM and peaks around 6PM folkard et al - 12 ppts placed in dark cave for 3 weeks sleeping and waking at set times -unknown to them - the clock was being sped up to a 22 hour day instead of 24 and only one ppt was able to comfortably adjust to change therefore strong circadian rhythm cant easily be overriden by exogenous zeitgebers

Answer 6

Improve medical treatments: body processes like HR rise and fall during day - linked to circadian rhythm led to chronotherapeutics (treatment corresponding to persons rhythms) eg: taking aspirin at night reduces risk of heart attack occurring in early mornings therefore circadian rhythms can increase effectiveness of drugs Shift school day: delaying start time of school day has been proposed to suit teenagers circadian rhythms proper sleep leads to greater class average BUT isnt suited for everyone affected by individual differences where some people sleep late or wake up early therefore changes wont suit everyone + disruptive to parents critics say teenagers will still sleep later and changes to the day may not actually help

Answer 7

Difficult to make generalisations: A limitation of research into circadian rhythms is that it is difficult to make generalisations For example, Siffre’s study consisted of only himself as the sample and research has shown that there are major individual differences in sleep/wake cycles (between 13 to 65 hours) These differences aren’t just between individuals, but also vary with a person as they age, as Siffre observed his own sleep/wake cycle slowed down as he got older Therefore, it is difficult to make meaningful generalisations regarding sleep/wake cycles based on the research that was done.

Answer 8

infradian = more than 24 hour cycles eg menstruation or SAD menstrual cycle: endogenous system affected by exogenous factors stern + mcklintock - studies 29 women with irregular periods gathered pheromones from 9 women from armpit and treated with alcohol and frozen before being applied to upper lip of ppts found 68% synchronised to odour donors cycle SAD: seasonal affective disorder triggered by shorter daylight hours in winter melatonin secreted from pineal gland until dawn longer nights means more melatonin secreted having knock on effects on serotonin production - depressive symptoms

Answer 9

Menstrual synchrony adaptive: stern and mClintock observed menstrual synchrony which can be explained via natural selection advantageous for women to menstruate + give birth together allows babies who have lost their mothers to survive with others breast milk - improves chances of survival + support for child with large community of mothers to help synchronisation = adaptive strategy

Answer 10

Methodological issues: menstrual cycle is affected by many factors like stress, changes in diet or exercise - acts as confounding variables synchronisation may occur due to chance rather than manipulation of pheromones explains why other studies have been unable to replicate findings - low internal validity + only 68% of women saw synchronisation in periods so not true for all -> unsure how long synchronisation with odour donor lasts for

Answer 11

Real world applications: treatments for SAD= light therapy - box simulates very strong light to reset the body's internal clock reduces effects of SAD in 80% of people safe + no side effects compared to antidepressants BUT causes eyestrain - headaches relapse rate of 46% over successive winters, compared to 27% in a comparison group receiving CBT suggests that light therapy may be an effective short-term treatment but additional treatments may be required for future

Answer 12

Ultradian: ultradian rhythm is anything less than 24 hours sleep wake cycle 5 stages of sleep lasting 90 minutes 1-2 = light sleep but easily woken (1) - high frequency alpha waves and short amplitudes (2) - alpha waves with occasional changes = sleep spindles 3-4 = hard to wake people up - slow wave sleep delta waves with lower frequency + higher amplitude 5 = rapid eye movement paralysed body but brain activity similar to being awake dreams occur

Answer 13

Explains age related changes to sleep: researchers found slow wave sleep reduces with age growth hormones produced during SWS so older people are deficient in this sleep deficit may explain various impairments in old age like reduced alertness practical value as meditation and relaxation techniques can increase SWS to reduce impairments - treatment for older people

Answer 14

Individual differences: significant variation between people tucker - large difference in duration of each sleep stage between people particularly stage 3/4 differences are likely to be biologically determined difficult to determine normal duration of sleep - findings cant be generalised

Answer 15

The suprachiasmatic nucleus (SCN) = endogenous pacemaker, responsible for maintaining circadian rhythms located in the hypothalamus, receives light information from the optic chiasm In the day, the SCN passes light information to the pineal gland which inhibits melatonin production, a hormone which induces sleep. At night, melatonin production increases DeCoursey destroyed SCN inside the brains of 30 chipmunks and returned them to their natural habitats. This greatly impacted their sleep/wake cycle as many of them were killed by predators Exogenous zeitgebers = external factors in the environment that reset biological clocks, such as light and social cues. Research has demonstrated that light can be detected by skin receptors and affect our sleep/wake cycle even when that information isn’t taken up by the eyes 15 ppts woken during night and light shone behind their knee found a deviation of sleep cycle by up to 3 hours = light is a strong exogenous zeitgeber even without the eyes influence on brain Social cues, such as mealtimes and bedtimes, start influencing a baby's sleep/wake cycle around 16 weeks. Adapting to local sleep and bedtimes is an effective way of entraining your circadian rhythm and beating jet lag. e

Answer 16

High internal validity: control over extraneous variables like noise ensures IV affects DV - causal relationship between sleep and behaviour BUT involves being attached to machines which are not representative of ordinary sleeping in people Low external validity: Controlled factors like temperature = artificial conditions hard to generalise data obtained from controlled sleep studies in lab settings to sleep in an everyday context.

Answer 17

Pacemakers cant be studies in isolation: unable to study endogenous pacemakers in isolation total isolation studies like siffres cave study are rare normally endogenous and exogenous factors interact together - doesn't make sense to separate for research absence of one could inhibit the other - untrue findings Lowers validity Exogenous affected by environment: exogenous Zeitgebers dont have same influence in all environments arctic circle inuits have little light in winter and little darkness in summer - but have similar sleep patterns all year around despite half the year in darkness therefore sleep wake cycle is primarily governed by endogenous factors that can override environmental changes in light

Answer 18

Oversimplified (SCN not the only clock): Eg: research has shown that there are many circadian rhythms (peripheral oscillators) in many organs and cells in the body that are influenced by the SCN and can act independently. researchers were able to change the feeding patterns of mice and alter the circadian rhythms of the liver by 12 hours, whilst leaving the SCN rhythm unaffected. suggests the sleep/wake cycle isn’t solely governed by the SCN and there are other complex influences affecting our circadian rhythms.

Answer 19

Case study- social cues couldnt alter sleep wake cycle: man blind from birth (15% of the time cannot detect changes in light) rhythm of 24.9 hours couldnt be changed despite regular meal times and bedtimes therefore it isnt true that social cues compensate for a lack of light both may be needed BUT individual differences can affect results

Answer 20

Ethical issues: mammalian brains in both humans and hamsters mean results can be generalisable BUT most of chipmunks in decourseys study died, were removed from habitat and harmed + ralph destroyed hamsters SCN from foetus and normal hamsters cycle was disrupted unlikely theyd survive in the wild n

Answer 21

Nervous system: collects, responds and processes information in the environment coordinates the working of different cells in the body CNS (central): consists of brain and spinal cord cerebral cortex (3mm thick) covers brain in mammals spinal cord = extension of the brain - passes messages to and from brain + links nerves to PNS PNS (peripheral): transmits messages to (muscles/glands) and from CNS via neurones PNS subdivided into ANS/SNS ANS - autonomic = involuntary actions controlling vital functions of body like breathing/digestion/arousal consists of sympathetic (activates fight or flight) + parasympathetic ( returns body to resting state) nervous systems SNS - somatic = recieves info from sensory receptors and controls voluntary muscle movement

Answer 22

Fight or flight response: endocrine + ANS work together - stressor causes hypothalamus to activate pituitary gland triggering sympathetic branch of ANS change from parasympathetic state to sympathetic state -adrenaline released from adrenal glands causing physiological changes like increased HR for arousal - once threat has passed, body returns to parasympathetic state = rest and digest state n

Answer 23

location: cell body of motor neurones found in CNS but long axons form part of PNS sensory neurones found in PNS in ganglia (clusters) mainly relay neurones in body found in brain + visual system s

Answer 24

Neurones: nerve cells that process and transmit messages through electrical and chemical signals sensory neurons (long dendrites and short axons) motor neurons (short dendrites and long axons) relay neurons (short dendrites and short or long axons) cell body = nucleus containing genetic information dendrites = branches carrying impulses from neighbouring neurones towards cell body axon = carries impulses from cell body down the length of the neuron - covered in myelin sheath speeding up electrical transmission - gaps in myelin sheath = nodes of ranvier speed up transmission terminal buttons = communicate with neighbouring neurones across synapses l

Answer 25

Synaptic transmission: stimulus activates neurone so inside of cell becomes +ve charged momentarily causing an action potential creating an electrical impulse travelling down axon towards neuron end. neighbouring neurones communicate via transmission of impulses across a synapse in groups called neural networks once impulse reaches pre-synaptic terminal (end of neurone) triggering release of neurotransmitter from synaptic vessles neurotransmitter crosses synapse and is taken up by post-synaptic receptor site (one direction) on next neurons dendrites + chemical message converted back into impulse each neurotransmitter has diff structure and functions eg: ACh released at motor neuron meeting muscle causing contractions

Answer 26

Summation: serotonin = inhibitory -> inhibition in receiving neuron makes the neuron more -ve and less likely to fire - decreases likelihood post synaptic neurone will pass on impulse adrenaline = excitatory -> excitation of postsynaptic neurone makes neurone more +ve and more likely to fire - increases likelihood post synaptic neurone will pass on impulse inhibitory and excitatory influences are summed for net effect on post synaptic neuron net effect inhibitory = less likely to fire net effect excitatory = more likely to fire action potential only triggered after summation of influences reaches its threshold to carry impulse forward