Biopsychology (paper 2)

Question 1

What is the nervous system

Answer 1

A specialised network of cells that:
1. Collect, process and respond to info in the environment
2. Coordinates the working of organs and cells in the body

Question 2

What are the subsections within the NS (bad diagram but I tried)

Answer 2

Human NS
-Peripheral NS -Central NS
-Autonomic -somatic -Brain
-Sympathetic -Spinal chord
-Parasympathetic

Question 3

A brief description of the brain

Answer 3

-centre of all conscious awareness
-cerebral cortex is the outer layer
-two hemispheres each with 4 lobes:
Frontal, parietal,occipital and temporal.

Question 4

What is the spinal chord

Answer 4

It is an extension of the brain, responsible for reflex actions
It passes messages to and from the brain and connects nerves to the PNS

Question 5

What does the PNS do

Answer 5

It transmits messages via millions of neurons, to and from the CNS.
It is divided into:
autonomic NS
somatic NS

Question 6

What is the role of the Autonomic NS

Answer 6

Governs vital functions ie heart rate (involuntary effects)

Two subdivisions:
sympathetic NS
parasympathetic NS

Question 7

Outline of the sympathetic and parasympathetic NS roles

Answer 7

Sympathetic: activates internal organs and increases bodily activities
Parasympathetic: relaxes internal organs and decreases bodily activities (the opposite)

Question 8

Effects of the sympathetic and parasympathetic ns

Answer 8

Sympathetic: Parasympathetic:
+breathing rate -breathing rate
+heart rate -heart rate
Inhibits sal prod stimulates sal prod
Inhibits digestion stimulate digesti-
Dilates pupils Constricts pupils
Contracts rectum stimulates rectum

Question 9

What is the function of the endocrine system

Answer 9

-instructs glands to release hormones directly into the blood stream.
-hormones are carried towards target organs.
-they can affect any cell in the body that has a receptor for that particular hormone.

Question 10

What are the seven glands and which hormone do they release

Answer 10

Pituitary (master gland) = lots
Pineal = melatonin
Thyroid = thyroxin
Testes = testosterone
Ovaries = oestrogen
Adrenal = adrenaline
Pancreas = insulin

Question 11

What glands/hormones are responsible for

Answer 11

Pituitary - controls/stimulates the release of hormones from other glands

Pineal - biological rhythms eg sleep wake cycle

Thyroid - regulating metabolism

Testes - development of sex characteristics & promoting muscle growth

Ovaries - regulation of female reproductive systems eg menstrual cycle, pregnancy

Adrenal - fight or flight response

Pancreas - allows body to use glucose for energy or to store it for future use, keeps blood sugar levels stable

Question 12

What is fight of flight

Answer 12

When the body becomes physiologically aroused in readiness to fight or flee, the response is reflexive (occurs without conscious awareness)

Question 13

What are the nine steps of flight or fight

Answer 13

1) the hypothalamus recognises a threat in the environment
2) ANS activates the sympathetic nervous system
3)the SNS tells the pituitary gland to release ACTH
4) this sends message to adrenal gland
5) adrenal gland releases adrenaline
6) this travels through the bloodstream to target organs
7) physical changes occur
8) once threat has passed, parasympathetic nervous system brings the body back to normal

Question 14

What are the direct effects of adrenaline

Answer 14

• • heart rate
• constricts blood vessels: + blood flow and pressure
• diverts blood away from the skin, kidneys and digestive system
• +respiration and sweating
• • blood to brain and skeletal muscle
• inhibits saliva production

Question 15

What are the indirect effects of adrenaline

Answer 15

• Prepare body for action (fight or flight)
• increase blood supply/oxygen to skeletal muscle
• increase oxygen to brain for rapid response planning

Question 16

What are neurons?

Answer 16

-nerve cells that process and transmit messages through electrical and chemical signals.
-provide nervous system with its primary means of communication

-There are 100 billion neurons in the human nervous system; 80% of which are located in the brain.

Question 17

What are sensory neurons?

Answer 17

-carry messages from sensory receptors to the spinal cord and brain = from the PNS to the CNS
-have long dendrites and short axons
-located near the body’s surface

Question 18

What are relay neurons?

Answer 18

-connect the sensory neurons to the motor or other relay neurons allows them to communicate
-most common type of neuron in CNS
-have short dendrites and short axons
-located in visual system, brain, and spinal cord

Question 19

What are motor neurons?

Answer 19

-connect the CNS to effectors (ie muscles and glands)
-carry nerve impulses from CNS to PNS
-have short dendrites and long axons
-locatation linked to muscles

Question 20

What is a cell body?

Answer 20

-known as the factory of the neuron
-contains the nucleus
-produces all of the necessary proteins that a neuron required to function

Question 21

What is the nucleus?

Answer 21

-contains the genetic material within the neuron

Question 22

What are dendrites?

Answer 22

-branch-like features protrude from the cell body
-carry nerve impulses from neighbouring neurons, towards the cell body

Question 23

What is an axon?

Answer 23

-carries the electrical impulse from the cell body, down the length of the neuron.
-its covered in myelin sheath

Question 24

What is a myelin sheath?

Answer 24

-a fatty layer, which surrounds and protects the axon
It helps to speed up the electrical transmission of the impulse.

Question 25

What are nodes of ranvier?

Answer 25

-the gaps between the myelin sheath
-Their purpose is to speed up the transmission of the impulse, by forcing it to ‘jump’ across the gaps along the axon.

Question 26

What are terminal buttons?

Answer 26

-also called axon terminal
-located at the end of the axon
-communicate with the next neuron that is on the other side of the synaptic cleft.

Question 27

What is synaptic transmission?

Answer 27

-process by which neighbouring neurons communicate with each other by sending chemical messages across the synaptic cleft them separates them.

Question 28

What is a neurotransmitter?

Answer 28

-Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another
-can be broadly divided into those that perform an inhibitory or an excitatory function

Question 29

What is excitation?

Answer 29

-when a neurotransmitter, (ie adrenaline), increases the positive charge of the postsynaptic neuron*
-This increases the likelihood that the neuron will fire and pass on the electrical impulse.

Question 30

What is inhibition?

Answer 30

-When a neurotransmitter, (ie serotonin), makes the change of the postsynaptic neuron more negative
-This decreases the likelihood that the neuron will fire and pass on the electrical signal.

Question 31

What is a synapse?

Answer 31

-junction between two neurons
-includes the presynaptic neuron, the synaptic clef and the postsynaptic receptor site.

Question 32

What is the synaptic cleft?

Answer 32

-The space between the pre-synaptic and post-synaptic neuron

Question 33

What are synaptic vesicules?

Answer 33

-Small sacs on the end of a presynaptic neuron that contain neurotransmitters that will be released into a synapse.

Question 34

What is the pre-synaptic neuron?

Answer 34

-transmitting neuron, before the synaptic cleft.

Question 35

What is the post-synaptic neuron?

Answer 35

-neuron that is receiving the information at the synapse.

Question 36

What is the post-synaptic receptor site?

Answer 36

-receptor on the post-synaptic neuron.
-neurotransmitter locks into a specific receptor on the post-synaptic neuron and this triggers an electrical impulse in the post-synaptic neuron.

Question 37

What is the process of synaptic transmission?

Answer 37

1) Action potential (electrical impulse) arrives at pre-synaptic neuron
2) as a result of the action potential, vesicles (containing neurotransmitters) diffuse towards the pre-synaptic membrane
3) Vesicles bind to the pre-synaptic membrane and the neurotransmitters are released
4) Neurotransmitters chemically diffuse across the synapse (electrical impulse becomes chemical impulse)
5) Neurotransmitters bind to complementary receptors on the post-synaptic neuron membrane and an electrical impulse is subsequently passed on

Question 38

What are neurotransmitters?

Answer 38

-chemical messengers that relay signals, diffuse across the synapse and elicit an effect
-ie serotonin, GABA

Question 39

Why can neuron’s only transmit in one direction?

Answer 39

-synaptic vesicles containing neurotransmitters are only on the pre-synaptic membrane and the receptors are only on the post-synaptic membrane

Question 40

What is the holistic theory of the brain?

Answer 40

-all parts of the brain are involved in the processing of thought and action

Question 41

What is the theory of localisation?

Answer 41

-specific areas of the brain are associated with particular physical and psychological functions
-damage to these areas cause consequences in behaviour

Question 42

What is phrenology?

Answer 42

-the detailed study of the shape and size of the cranium as a supposed indication of character and mental abilities

Question 43

What are the three layers if the brain?

Answer 43

-central core (or the brain stem
-inc structures such as the hypothalamus in the midbrain, regulates our most primitive and involuntary behaviours (ie breathing, sleeping or sneezing)

-limbi system controls our emotions
-around the central core of the brain.
-inc structures such as the hippocampus which has a key role in memory

-cerebral cortex is the third layer
-divided into two hemispheres; the left hemisphere and right hemisphere. -cortex is about 3mm thick and is what separates us from other animals because the human cortex is much more developed
-both hemisphere is subdivided into four lobes (named after bones they lie beneath: the frontal, the parietal, the occipital and the temporal lobe)
-Each lobe is associated with a different function

Question 44

What is the location and role of the motor cortex?

Answer 44

-back of frontal lobe

-sends nerve impulses to muscles, different areas control different muscle movements
-damage results in loss of muscle movement

Question 45

What is the location and role of the Somatosensory cortex?

Answer 45

-front of parietal lobe

-processes sensory information from the skin (ie pressure, heat, touch)
-damage results in loss of senses

Question 46

What is the location and role of the visual cortex?

Answer 46

-occipital lobe

-receives and processes information from optic nerve
-damage results in loss in visual field

Question 47

What is the location and role of the auditory cortex?

Answer 47

-temporal lobe

-to analyse speech based information
-damage results in loss in hearing

Question 48

What is the location and role of the Wernicke’s area?

Answer 48

-left temporal lobe

-responsible for speech comprehension
-damage results in difficulties understanding speech (Wernicke’s
aphasia)

Question 49

What is the location and role of the Broca’s area?

Answer 49

-left frontal lobe

-responsible for speech production
-damage results in difficulties to speak and write (Brocas aphasia)

Question 50

How are Broca and Wernicke’s areas are examples of localisation?

Answer 50

-located within specific areas of the brain.
Broca - frontal lobe
Wernicke - temporal lobe
-But they only occur in the left hemisphere
-makes them “special”.
(something specialised to one hemisphere, is known as lateralisation)

Question 51

Strengths and limitations of the theory of localisation?

Answer 51

Strengths
-brain scanning evidence
Petersen et al (1988) used brain scans showed Wernicke’s area-active during listening task and Broca’s area-active during reading task, suggests these parts of the brain have different functions, support Wernicke/Broca’s theories increases validity of concept of localisation
-neurosurgical evidence
Dougherty et al. (2002) reported on 44 OCD patients who had cingulotomy (cingulate gyrus is lesioned), 32 weeks post-surgery, showed third of
patients had successful response to surgery and 14% a partial response
suggests symptoms/behaviours associated with OCD are localised
-case study evidence
Phineas Gage accident left his frontal lobe damaged, his personality changed (to quick-tempered and rude)
suggests personality/temperament is localised within the frontal lobe

Limitations
-evidence for some higher cognitive functions distributed in a holistic way
Lashley (1950) removed areas of the cortex (between 10 and 50%) in
rats, No area proved more important than another in rat’s ability to learn a maze, suggests learning is too complex to be localised and involves
the whole brain
-Functional recovery shows localisation of function can change
girl lives with only half a brain as after illness/accident, rest of the brain appears to reorganise itself in an
attempt to recover lost function, supports holistic view of functioning

Question 52

What is an FMRI?

Answer 52

-works by detecting changes in blood oxygenation and blood flow that indicate increased neural activity
-It produces 3-dimensional images (activation maps) shows parts of the brain are involved in particular mental process (important for establishing localisation of function)

-People do a task and it is observed where the brain activity is
-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).

Question 53

What are the strengths and limitations if FMRI’s?

Answer 53

Strengths
-non-invasive (unlike PET scans)
-doesn’t rely on the use of radiation and is safe.
-high spatial resolution. It can show detail by the millimetre. provides clear picture of localised brain activity

Limitation
-expensive compared to other techniques
-only capture an image if the person stays still
-poor temporal resolution as there is a 5 second lag between initial neural activity and image so may not truly represent moment-to-moment brain activity

Question 54

What is an EEG?

Answer 54

-records changes in electrical activity using electrodes attached to thescalp.
-The scan recording represents the brainwave patterns that are
generated from the action of millions of neurons, providing an overall
account of brain activity.

-often used as a diagnostic tool as unusual arrhythmic patterns may indicate neurological abnormalities e.g. epilepsy.

Question 55

What are the strengths and limitations of EEGs?

Answer 55

Strengths
-invaluable in diagnosing conditions (been used to identify epilepsy and also in understanding the stages of sleep)
-extremely high temporal resolution detect brain activity as a resolution of a single millisecond, So its more able to represent moment-to-moment brain activity

Limitation
-produces a *generalised signal from thousands of neurons *this means it’s difficult to know the exact source of neural activity, it cannot distinguish between the activity of different but adjacent neurons.
-do not provide a complete picture of brain activity. They only monitor electrical activity on outer layers of brain so cannot reveal electrical activity deeper in the brain

Question 56

What is an ERP?

Answer 56

-records changes in electrical activity using electrodes attached to the scalp but uses a specific stimulus (sensory, cognitive or motor) to see where the activity is.

-Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out leaving only those responses that related to a specific stimulus or task.
-Research has revealed many different forms of ERP and how these are linked to cognitive processes

Question 57

What are the strengths and limitations of ERPs?

Answer 57

Strengths
-very specific measurement of neural processes. More specific the raw EEG data
-excellent temporal resolution,can detect brain activity as a resolution of a single millisecond. So able to represent moment-to-moment brain activity

Limitation
-lack standardisation in methodology between studies. So its difficult to confirm findings in studies involving ERPs. So reliability of the information regarding the brain’s structure and function is lowered
-background noise and extraneous material must be completely eliminated which is not easyto acheive

Question 58

What is post mortem examination of the brain?

Answer 58

-examine abnormalities in the structure of the brain which try to explain psychological abnormalities that people have before death
-may also involve comparison with a neurotypical (normal) brain in order to ascertain the extent of the difference.

Question 59

What are the strengths and limitations of post mortem Studies?

Answer 59

Strengths
-provided the* foundation for understanding the brain*
(Broca and Wernicke both relied on them) shows they have improved medical knowledge and helped to generate hypotheses for further study.
-allow for in-depth study of the brain. Detailed examinations and measurements of deep brain structures that are not measurable by scans. Provides knowledge of brain that cannot be gained from less invasive options.

Limitations
-causation may be an issue, Observed damage in the brain may not be linked to the deficits under review but some other related to trauma or decay
-raise ethical issues of consent Before death, patients need to give informed consent, but there is a reason that psychologists want to investigate their brains in the first place may mean they are not be able to provide informed consent (eg HM lost ability to form memories so couldn t provide consent)

Question 60

Describe the case study if Phineas Gage

Answer 60

-meter long iron pole went through his left cheek passed behind left eye, and exited his skull at top of head took portion of his brain with it – most of his left frontal lobe
-he survived but the damage to his brain left a mark on his personality (turned from calm/reserved to quick-tempered/rude and ‘no longer Gage’)

-seen as a landmark case in science the change in temperament suggests the frontal lobe may be responsible regulates mood

Question 61

Evaluate the localisation of function

Answer 61

Strength
-brain scanning evidence, Petersen et al (1988), brain scans demonstrated Wernicke’s area active during listening task, Broca’s area active during reading task. suggests these parts of brain have different functions support Wernicke and Broca’s
theories increases the validity
-neurosurgical evidence*, Dougherty et al (2002), 44 OCD patients who had undergone a cingulotomy (procedure where the cingulate gyrus is lesioned). post-surgical 32 week follow-up showed third of patients had a successful response to the surgery and 14% a partial
response, suggests that OCD symptoms/behaviours are localised

Limitations
-evidence suggests some higher cognitive functions distributed in a more holistic way, Lashley (1950) removed areas of the cortex (between 10 and 50%) in rats learning a maze. No area was proven to be more important in rat’s ability to learn the maze, suggests learning is too complex to be localised and involves the whole brain
-Functional recovery shows localisation of function can change, girl who lives with only half a brain after illness/accident the rest of the brain appears to reorganise itself in
attempt to recover lost function, supports that the holistic view of functioning rather than localisation

Question 62

What is Hemispheric lateralisation?

Answer 62

Some mental processes in the brain are mainly specialised to the left or right hemisphere
e.g. Language is specialised to the left and visual-motor tasks.

Question 63

What dies contra-lateral mean in terms of human brains?

Answer 63

This means the opposite side of the
body to the brain hemisphere that controls it.

Question 64

What is the corpus callousm?

Answer 64

Broad band of fibres that
joins the two hemispheres of the brain, thisallows communication to occur.

Question 65

What is splitting the brain?

Answer 65

-cutting of the corpus callosum means that information cannot be passed between the hemispheres.

Question 66

What was Sperry’s (1968) research i to split brain patients?

Answer 66

Aim:
-to examine the extent to which the two hemispheres are specialised for certain functions.

Participants:
-Studied split brain patients and compared them to patients with no hemisphere separation
-11 participants (epileptics who couldn’t be treated with drugs and ALREADY HAD their corpus callosums split to control frequent fits)

Method:
-image/word is projected to the patient’s left visual field (processed by the right hemisphere) or vice versa. When information is presented to one hemisphere in a split-
brain patient, the information not transferred to other hemisphere

Question 67

What was the three variations Sperry and Gazzaniga conducted?

Answer 67

Drawing
-right hemisphere could draw the word ‘saw’, but not say it. suggests right is dominant drawing skills

tactile objects
-right hemisphere could also get left hand to pick up correct object from selection of objects

facial recognition
-right hemisphere was found to be better at recognising faces

Question 68

What was Sperry’s conclusion?

Answer 68

findings of Sperry and Gazzaniga’s research highlights key differences between the two hemispheres

-left hemisphere is dominant in terms of speech and language
-right hemisphere is dominant in terms of visual-motor tasks
-split brain patients their hemispheres of the brain process
information separately
-Hemispheres do seem to have differing functions (e.g language left
and drawing ability right)

Question 69

Evaluation of Sperry’s split brain study?

Answer 69

Strengths
-no ethical issues, patients already had procedure done for seizures, so no harm or deception
-strong methodology experiments had standardised procedure aka patients asked to stare at fixation point one eye blindfolded and image flashes on screen shortly. Ensures one hemisphere received info. Sperry had a controlled and useful procedure

Limitations
-small sample, 11 participants so limits generalisability. patients epilepsy may have influenced findings, control group made of people with no epilepsy history (inappropriate?)
-artificial tasks patients stare at x on screen and cannot move heads, real life they can move/use both eyes. So research lacks mundane realism.
-sample size had both genders
evidence shows there are gender differences in lateralisation of function, not clarified in this study – limits generalisability.

Question 70

What does plasticity mean?

Answer 70

The brain’s tendency to change and adapt (functionally and
physically) as a result of experience and new learning.

Question 71

What is synaptic pruning?

Answer 71

As we age, rarely used connections are deleted and
frequently used connections are strengthened

Question 72

What is axonal sprouting?

Answer 72

Undamaged axons grow new nerve endings to reconnect
neurons whose links were injured or severed.

Question 73

What is bridging (in terms of plasticity)?

Answer 73

-where new connections are created due to use and new stimulus

-During infancy the brain experiences a growth in the number of
synaptic connections peaking at 15,000 at age 2-3 years.
-This is twice as many as there are in the adult brain!

Question 74

What is pruning (in terms of plasticity)?

Answer 74

-where connections are lost due to lack of use.

-As we age, rarely used connections are deleted and frequently used
connections are strengthened (synaptic pruning)

Question 75

How has beliefs of neuroplasticty changed?

Answer 75

-originally thought such changes were restricted to the developing brain within childhood as the adult brain had moved beyond a critical period, so would remain fixed/static in terms of function and structure.
-However, research suggests that at any time in life existing neural connections can change, or new neural connections can be
formed because of learning and experience.

Question 76

What was the aim and method of Maguire et al., (2002, University College London) taxi driver study?

Answer 76

Aim: examine whether structural changes could be detected in the
brain of people with extensive experience of spatial navigation

Method: MRI scans comparing 16 male London Taxi drivers and 50
age-matched male control subjects who did not drive taxis
(part of their training, London cabbies must take test called ‘The Knowledge’ to assess recall of the city streets and possible routes, This learning experience appears to alter structure of the taxi driver’s brains)

Question 77

What was Maguire et al’s findings?

Answer 77

-drivers had significantly larger posterior hippocampi than
control group (posterior hippocampus associated to development of spatial and navigational skills/memory)
-positive correlation between size of posterior hippocampus and the time as a taxi driver (Correlation not causal but implies experience of taxi driving changes brain/hippocampus)

Question 78

What was Maguire et al., (2002) conclusions?

Answer 78

-results provide evidence for structural differences between
hippocampi London taxi drivers and control participants, suggests extensive practice with spatial navigation affects the hippocampus.
(extensive training required to learn the layout of London’s streets)

Question 79

What is functional recovery?

Answer 79

-a form of plasticity
-Following trauma damage, the brain can redistribute or transfer functions (usually performed by damaged area to undamaged area)
-brain learns to COMPENSATE for the area that has lost the
function
-process can occur quickly (spontaneous recovery) and then slow after several weeks or months.
-At this point the individual may require rehabilitation therapy to
further their recovery.

Question 80

How does functional recovery occur?

Answer 80

-Through the law of equipotentiality (secondary neural circuits
surrounding the damaged area become activated)

-brain rewires and reorganises itself by forming new synaptic
connections close to the area of damage
-Secondary neural pathways that would not typically be able to carry
out certain functions are activated or ‘unmasked’ to enable functioning to continue (AKA neural activation of ‘dormant’ synapses to compensate for damaged areas of the brain)

Question 81

What are the additional aspects to functional recovery?

Answer 81

1. Axonal sprouting (growth of new nerve endings, connect with other undamaged nerve cells to form new neuronal pathways)
2. Neural reorganisation (transfer of functions to undamaged areas)
3. Reformation of blood vessels (part of haemodynamic response, where activated areas experience a higher blood deoxygenation level)
4. Recruitment of homologous (similar) areas on opposite side of brain perform specific tasks.
   (E.g Damage to Broca’s area on
   the left could mean right-side equivalent would carry out its functions temporarily)

Question 82

What is the difference between plasticity vs functional recovery?

Answer 82

-Plasticity (neuroplasticity/cortical remapping) describes the brains
tendency to change and adapt (functionally and physically) as a result
of experience and new learning.

WHEREAS…

-Functional recovery is a form of plasticity. Following damage through
trauma, the brain has the ability to redistribute or transfer functions
usually performed by a damaged area(s) to other undamaged area(s).

Question 83

What factors effect functional recovery?

Answer 83

• How much people want to recover
• How tired people are
• How stressed people are
• How much alcohol/drugs people are having
• Age - younger individuals recover more quickly
• Gender - women recover more quickly
• Educational attainment - research has found those with a college degree are more likely to recover faster than those who did not finish high school

Question 84

Evaluation of Plasticity and functional
recovery

Answer 84

Strengths
-case study support, Danelli et al., (2013) describes boy had entire left hemisphere removed age 2 1/2 where language function primarily localised and boy initially unable to speak. But language skills recovered after 2 years. suggests right hemisphere adapted take over function.
-Supporting research, Tajiri et al (2013) evidence for role of stem cells in recovery from brain injury, randomly assigned rats with traumatic brain injury to one of 2 groups. One group received transplants of stem cells to region of brain affected by
injury, control group received a solution infused into brain containing no stem cells. 3 months after brain
injury, stem cell rats showed clear development of neuron-like cells in the area of injury, accompanied by a solid stream of stem cells migrating to the brain’s site of injury. not the case with the control group
-practical application Following illness:injury to brain, spontaneous recovery slows down so forms of physical therapy may be required to maintain function improvements (eg movement therapy and electrical stimulation of brain to counter deficits in motor or cognitive functioning.
Understanding processes involved in plasticity contributed to field of neurorehabilitation.

Limitations
-individual differences in functional recovery Schneider et al. (2014) discovered the more time brain injury patients had spent in education, (taken as indication of
their ‘cognitive reserve’), the greater chances of a disability-free recovery.
shows that educational attainment may influence how well the
brain functionally adapts after injury
-Plasticity can have maladaptive consequences 60-80% of amputees develop phantom limb syndrome (the
continued experience of sensations in the missing limb as if it were still
there), sensations are unpleasant/painful due to cortical reorganisation in somatosensory cortex occurs as result of limb loss

Question 85

What are biological rhythms?

Answer 85

-cyclical changes (go in a cycle) in the way that the our biological systems behave.

• Circadian – 24 hour cycles
• Infradian– over 24 hour cycles
• Ultradian – less than 24 hour cycles

-evolved because the environment which we/other organisms live has cyclical changes:
• Day and night
• Summer and winter

Question 86

What are biological rhythms governed by?

Answer 86

-Endogenous pacemakers
internal body clocks that regulate many of our biological rhythms (eg influence of suprachiasmatic nucleus (SCN) on the sleep-wake cycle)

-Exogenous Zeitgebers
external cues that may affect or entrain our biological rhythms, (eg influence of light on sleep-wake cycle)

Question 87

What are circadian rhythms?

Answer 87

-any cycle that lasts about 24 hours

-These rhythms optimise an organism’s physiology and behaviour to best meet the varying demands of the day and night cycle.
-The rhythm is regulated by an internal system such as the release of
hormones, metabolic rate and body temperature.

-There are numerous examples of circadian rhythms:
• Sleep/wake cycle
• Melatonin production
• Regulation of body temperature

Question 88

What is the sleep wake cycle?

Answer 88

-Light/dark provide signals of we should be awake and asleep.
-Our strongest sleep drive occurs between 2 - 4 am and 1 - 3 pm (post lunch). Sleepiness is less intense with circadian dips if we have had enough sleep the night before.
-Homeostasis also controls need to sleep, need more energy body tells us to sleep (why we get more tired the longer we have been awake)

-These factors combine to control/allow us to sleep during the night
and be awake during the day.
-However, the effect of daylight (exogenous zeitgeber) has an important effect on when we feel drowsy and awake.

Question 89

What was Siffre (1962), initial aim when her went down into the cave and what did he end up discovering instead?

Answer 89

-He wanted to prepare a geological expedition but decided instead to live
without a watch while underground

-investigated what would happen to people’s circadian rhythms if they were cut off from all signals from outside the body that tell us about the time of day (such as light and dark, clocks), and had to rely on internal body clock to tell them to eat/sleep.

Question 90

What was Siffre (1962) method for his cave study?

Answer 90

-descended into a cave on July 16th 1962, completely devoid of
natural light
-stayed there for 63 days (came out September 14th)
-called his team when he woke, ate and before sleep, they couldn’t call him so he wouldn’t know the time
-when his team called him he took his pulse and did ‘psychological test’ (counted from 1 to 120 seconds)

Question 91

What did Siffre find from his study?

Answer 91

-showed humans have a biological clock (his clock was allowed to ‘free-run’, he followed his body’s inclinations, eating and sleeping whenever he chose, with no fixed timetable)
-He was wired up so that some of his body functions could be recorded; a telephone link to the outside world, and monitored by video camera.
-during ‘psychological test’ it took him 5 minutes to count to 120, he experienced 5 minutes as if it were 2

Question 92

What are the conclusions of Siffre’s study?

Answer 92

-prolonged exposure to a strong exogenous zeitgeber (eg light), the sleep-wake cycle is disrupted and there’s disconnection between psychological time and the clock.
-His sleep-wake cycle did not conform to a cyclical 24 hour-period, but around 24 hours and 30 minutes
-Therefore, demonstrateing that there is an internal biological clock.
This describes a ‘free-running’ circadian rhythm i.e. one which is not
affected by exogenous zeitgebers.

Question 93

Evaluate the circadian rhythm

Answer 93

Strengths
-research has practical application circadian rhythms coordinate body’s basic cycles, has implications for pharmacokinetics (action of drugs on body and how well they’re absorbed/distributed, times during day/night when drugs are more effective Guidelines developed for the timing of dosing for a range of drugs including treatments for cancer and epilepsy.
-lack of ethical concerns as Siffre carried out experiment on himself, of his own free will
-High reliability studies support natural light impacting on circadian rhythm (Aschoff and Wever (1976) placed participants in an underground WWII bunker with artificial light, no natural light and complete lack of environmental/social cues for 4 weeks. most participants settled into a sleep/wake cycle between 24 and 25 hours, (some were 29 hours)

Limitations
-research uses small samples/case studies Siffre’s study, case study of himself, may not represent of wider population, limits generalisability as not everyone’s circadian rhythms are
the same. using same person factors prevent general conclusions (Siffre observed his internal clock ticked more slowly at 60 than when younger.
-poor control Siffre had a lamp on from when he woke up til he went to bed (He’d assumed artificial lighting had no effect on free running clock).
But Czeisler et al. (1999) adjusted participants’ circadian rhythms
from 22 to 28 hours using dim lighting. Using artificial light may be like taking a drug that resets the participants’ biological clocks.
suggests that researchers may have ignored an important confounding variable in circadian rhythm research, reducing validity of findings
-individual differences cycles can vary from 13 to 65 hours (Czeisler et al. 1999). Duffy (2001) found some people display natural preference for sleeping:rising early (‘larks’) whilst
others prefer to sleep/rise late (‘owls’). also age differences in sleep/wake patterns. So findings from sleep/wake cycle studies may not be generalisable

Question 94

How are hormones part of circadian rhythms?

Answer 94

-Hormones, like melatonin, increase and decrease as part of your
circadian rhythms.

-Melatonin is produced and released from the pineal gland, levels peak during the hours of darkness.
-By activating synapses in brain, melatonin encourages sleep.
-When dark, more melatonin is produced, and vice versa

Question 95

How is body temperature part of circadian rhythms?

Answer 95

-Internal fluctuations of body temperature regulated by your circadian rhythms.

-one of the best indicators of the sleep wake cycle. It is lowest at
about 4 am and highest at 6pm; varying by around two degrees from
36 degrees centigrade in morning to 38 degrees centigrade in evening.
-Sleep occurs when the body temperature drops.
-Temperature rises during last few hours of sleep causes people to feel alert in morning. Small drops in temperature can occur between 2 and 4 pm which can account for why people sometimes feel sleepy during this time.

Question 96

What ate some examples of the body temperature having effect on our mental abilities?

Answer 96

-the warmer we are (internally), the
better our cognitive performance.

-Folkard et al (1977) found that children who had stories read to them
at 3pm showed superior recall and comprehension after a week
compared to children who heard the same stories at 9am.

-Gupta (1991) found improved performance on IQ tests when
participants were assessed at 7pm as opposed to 2pm and 9am.

Question 97

What are Endogenous Pacemakers

Answer 97

-internal body clocks that regulate many of our biological rhythms,

Eg the influence of the suprachiasmatic nucleus (SCN) on the sleep-wake cycle.

Question 98

What is the Superchiasmatic nucleus (SCN)?

Answer 98

-tiny bundle of nerve cells located in the hypothalamus in each hemisphere of the brain. They are the primary endogenous pacemakers in mammals.

-contains neurons that fire with a 24-hour pattern regardless of any biological or external influences
-Even when eyes are shut the SCN gets info on light from the optic nerve.
(Light can penetrate the eyelids and special photoreceptors in the eye transfer light signals to the SCN)

Question 99

What is the pineal gland?

Answer 99

-another endogenous pacemaker that the SCN sends messages to
-contains light sensitive cells
-When light is sensed melatonin production is inhibited (so light level falls, melatonin production increases)

-Melatonin increases drowsiness and creates biological conditions needed for sleep. This induces sleep by inhibiting brain mechanisms that promote the awake state.

Question 100

What are exogenous zeitgebers?

Answer 100

-external time giving cues, (eg light)
-they set our body clock through entrainment.
-This is synchronisation of body to environment
-This interaction is possible due to the optic nerve registering external cues such as light

-Endogenous pacemakers interact with exogenous zeitgebers

Question 101

What did DeCoursey et al., (2000) do to investigate SCN?

Answer 101

-Destroyed the SCN connections in the brain of 30 chipmunks who were then returned to their natural habitat and observed for 80 days
-The chipmunks sleep-wake cycle disappeared. by end of study a significant proportion of them had been killed by predators cause they were awake and vulnerable to attack when they should’ve been asleep.
-shows how important the SCN is in regulating the sleep wake cycle

Question 102

What did DeCoursey et al., (2000) do to investigate SCN?

Answer 102

-Destroyed the SCN connections in the brain of 30 chipmunks who were then returned to their natural habitat and observed for 80 days
-The chipmunks sleep-wake cycle disappeared. by end of study a significant proportion of them had been killed by predators cause they were awake and vulnerable to attack when they should’ve been asleep.
-shows how important the SCN is in regulating the sleep wake cycle

Question 103

What did Ralph et al., (1990) do to investigate SCN?

Answer 103

-Created ‘mutant’ hamsters who had a 20 hour sleep-wake cycle.
-Transplanted the SCN cells from the mutant hamsters into brains of normal hamsters (24 hour sleep-wake cycle).
-The normal hamsters following transplantation ended up on a 20 hour sleep-wake cycle.
-shows the role of the SCN in establishing and maintaining the sleep-wake cycle.

Question 104

What did Campbell and Murphy prove with their light/sleep study?

Answer 104

-light can be detected by skin receptor sites on the body even when the same information is not received by the eyes.
-15 participants were woken at various times and a light pad shone on the back of their knees.
-researchers could produce a deviation in the participants’ usual sleep-wake cycles (up to 3 hours in some cases)
-This suggests that light is a powerful exogenous zeitgeber that influence our brain and body.

Question 105

What are social clues in the sleep/wake cycle?

Answer 105

-schedules that are imposed on us by society and are key influences on our sleep wake cycle e.g. times to eat, times to go to bed.

-Entrainment of the body following jet lag is quicker when people eat and sleep when the local culture do, rather than responding to your own body and feelings of hunger and fatigue.
-In infants the sleep/wake cycle is initially random but by 6 weeks the circadian rhythms begin and by 16 weeks most babies are entrained.

Question 106

What are social clues in the sleep/wake cycle?

Answer 106

-schedules that are imposed on us by society and are key influences on our sleep wake cycle e.g. times to eat, times to go to bed.

-Entrainment of the body following jet lag is quicker when people eat and sleep when the local culture do, rather than responding to your own body and feelings of hunger and fatigue.
-In infants the sleep/wake cycle is initially random but by 6 weeks the circadian rhythms begin and by 16 weeks most babies are entrained.