Biopsychology 🧠

Question 1

Outline the human nervous system

Answer 1

• A body wide system of nerve cells that collects information from the environment, processes it and incites a response from body organs and muscles through the transmission of electrochemical messages

• It’s broken into the central nervous system and peripheral nervous system

Question 2

Outline the central nervous system

Answer 2

• Provides complex processing and consists of the brain and spinal chord. The brain contains 100 billion neurones and the spinal chord 1 billion

• The brain’s responsible for all conscious and most unconscious processing and is involved in all psychological processes

• The spinal chord facilitates the transferral of messages to and from the brain to the peripheral nervous system and is involved in reflex actions

Question 3

Identify and outline the lobes of the brain (and the brain stem)

Answer 3

• Frontal lobe: responsible for higher order
functioning eg. planning and abstract thinking

• Parietal lobe: integrates information from the
different senses and plays an important role in
spatial navigation (perception)

• Temporal lobe: auditory information

• Occipital lobe: visual information

• Brain stem: controls involuntary processes eg.
breathing and digestion

Question 4

Outline the peripheral nervous system

Answer 4

• A body wide system of messenger neurones, made up of all nerve endings that aren’t in the brain or spinal chord

• Consists of the somatic and autonomic nervous systems
- The somatic nervous system is responsible for
voluntary movements, controlling skeletal
muscles for movement

• The autonomic nervous system is responsible for
  involuntary actions, controlling internal organs
  and glands and maintenance of homeostasis. It’s
  broken into two parts; the sympathetic and
  parasympathetic nervous systems

Question 5

Outline the sympathetic nervous system

Answer 5

• Responsible for the fight or flight response, increasing bodily activities to prepare the body to face danger

• Releases noradrenaline
• Increased heart rate and breathing rate
• Vasodilation of blood vessels towards active
muscles and vasoconstriction toward less
important processes to slow them down (eg.
digestion)
• Dilates pupils

Question 6

Outline the parasympathetic nervous system

Answer 6

• Returns the body to rest, decreasing bodily activities. Responsible for the body’s rest and digestion response when it’s relaxed, resting or feeding. It effectively undoes the work of the sympathetic division after a stressful situation

• Releases acetylcholine
• Decreased heart rate and breathing rate
• Returns less important processes like digestion
back to normal functioning
(SLUDD- salivation, lacrimination, urination, digestion, deffacation)

Question 7

Describe the structure of neurones in the body

Answer 7

• Cell body that acts as the controls centre of the neurone, protects the nucleus and controls the structure of the neurone. The action potential travels away from the cell body

• Nucleus that contains genetic information (DNA) and controls cell activity

• Dendrites are connected to the cell body and receive electrical signals from nearby neurones or sensory receptors. They cover a large surface area

• The axon is a long slender fibre down which the action potential travels down in one direction

• Myelin sheath protects the axon and increases the speed of action potentials that travel down from the cell body
• Schwann cells create myelin

• Node of Ranvier’s are unmyelinated gaps in the axon that further increase speed of electrical impulse as the action potential jumps from node to node through saltatory conduction

• Axon terminals are at the end of the neurone and are the site of synaptic transmission

Question 8

Describe the function of neurones in the body

Answer 8

• Neurones receive information and transmit it to other cells. This allows us to move, think, experience sensory information etc.

• There are three types; sensory, relay and motor neurones

Question 9

Outline the role of sensory (afferent) neurons

Answer 9

• Inform the brain about the internal and external environment by processing sensory information received via receptors and converting it to action potentials that are passed onto the central nervous system

• Allow the organism to react to a stimulus by sending signals to other neurones via the synapse eg. when touching a hot surface, sensory neurones send signals to the nervous system

Question 10

Outline the function of a relay (interneurone) neurone

Answer 10

• Carry action potentials from one part of the nervous system to another, connecting sensory and motor neurones by relaying signals

• They’re only found in the brain, spinal chord and visual system

Question 11

Outline the function of a motor neurone

Answer 11

• Carry action potentials from the central nervous system to organs and muscles to perform functions

• Controls muscle contraction. When stimulated, they release neurotransmitters that bind to receptors in muscles that trigger a movement response

Question 12

Describe synaptic transmission

Answer 12

• The process of transmitting chemical messages from neurone to neurone

• Action potential arrives at the axon terminal

• This causes vesicles to merge with the membrane of the presynaptic neurone, releasing neurotransmitters into the synaptic fluid of the synapse.

• Neurotransmitters diffuse in one direction across the synapse and bind to receptor sites on the post-synaptic neurone. Enzymes then cause degradation of neurotransmitters that’ve done their action

• Excitatory neurotransmitters depolarise the post-synaptic membrane which increases the likelihood of a threshold being met and therefore an action potential forming
• Inhibitory neurotransmitters hyperpolarise the post-synaptic membrane which decreases the likelihood of a threshold being met and therefore an action potential forming

• Summation is the combined effect of all the excitatory and inhibitory neurotransmitters’ influences on the post-synaptic neurone. If a threshold is reached, a new action potential will form in the postsynaptic cell that will travel down the neurone to the next presynaptic terminal.
• However if the threshold isn’t met, there will be no action potential due to the all or nothing law

• This occurs fast, eg. visual information is mostly encoded in the first 50-100milliseconds of neural activity

Question 13

Outline excitatory neurones

Answer 13

• Stimulate the brain and increase the likelihood of a new action potential forming in the post synaptic cell eg. glutamate

• When detected by receptors in the postsynaptic cell they make the electrical charge inside more positive and more likely to fire

• Incite depolarisation, where positively charged sodium ions (Na+) enter the post synaptic cell

Question 14

Outline inhibitory neurotransmitters

Answer 14

• Relax the brain and create balance, decreasing the likelihood of a new action potential forming in the post synaptic cell eg. serotonin

• When detected by receptors in the post synaptic cell, they make the electrical charge inside more negative and less likely to fire

• Incite hyper polarisation, where positively charged potassium ions (K+) leave the post synaptic cell

Question 15

Outline SSRI’s

Answer 15

Selective serotonin reuptake inhibitors are a class of drug that influence the process of neurotransmission by blocking serotonin being reabsorbed into the presynaptic cell, increasing serotonin levels in the synapse

Question 16

Outline the endocrine system

Answer 16

A collection of glands around the body that regulate bodily functions, growth and psychological factors by releasing chemical messengers called hormones into the bloodstream

Question 17

Outline the pituitary gland in the endocrine system providing an example of a hormone

Answer 17

• The ‘master gland’ that controls the release of hormones from other glands and is split into the anterior and posterior pituitary gland

The anterior pituitary gland releases:
• Adrenocorticotropic hormone that stimulates the release of corticosteroids during the fight or flight response
• Prolactin that stimulates production of milk from mammary glands in the breasts
• Growth hormone for cell growth and manipulation

The posterior pituitary gland releases:
• Anti-diuretic hormone/vasopressin that regulate water balance

• Oxytocin that controls uterine contractions during childbirth. Oxytocin’s improtant for reproductive behaviour and is released following orgasm which aids conception and elicits a feeling of relaxation and calm. It’s thought to be associated with trust, empathy, sexual activity and relationship building.
Females will usually have high levels of oxytocin than males. It can have benefits for treating mental health illnesses e.g. depression.
Kosfield (2005) found high levels of this hormone encouraged strong bonding between couples and Feldman (2007) found it encouraged mother-child bonding

Question 18

Outline the hypothalamus in the endocrine system providing an example of a hormone

Answer 18

• Links the nervous system to the endocrine system in combination with the pituitary gland and maintains homeostasis of bodily systems

• Releases corticotropin-releasing hormone which is the main regulating hormone of the hypothalamic pituitary adrenal (HPA) axis and plays a central role in the adaptation to stress

Question 19

Outline the pineal gland in the endocrine system providing an example of a hormone

Answer 19

• Modulates sleep pattern, keeping the body to a day/night circadian rhythm

• Releases melatonin that manages sleep/wake cycle

Question 20

Outline the thyroid gland in the endocrine system providing an example of a hormone

Answer 20

• Butterfly shaped gland in the front of the neck that modulates metabolism (the rate of energy use in the body)

• Releases thyroxine that regulates metabolic rate and protein synthesis

Question 21

Outline the thymus gland in the endocrine system providing an example of a hormone

Answer 21

• Located in the chest, it stimulates the development of T-cells that work in the immune system helping with disease resistance and is active until puberty

• Releases thymosin that stimulates the development of T-cells and assist in the development of B-cells to plasma cells to produce antibodies

Question 22

Outline the pancreas in the endocrine system providing examples of a hormones

Answer 22

• Located just behind the stomach, regulates blood sugar levels; problems with this system lead to diabetes

• Releases insulin, which enables blood glucose to enter cells where it’s used for energy (stops blood glucose going too high)
• Releases glucagon, which breaks down glycogen to glucose in the liver (keeps blood glucose from dropping too low)

Question 23

Outline the adrenal in the endocrine system providing examples of a hormones

Answer 23

• Regulates biological affects of the fight or flight response, increasing heart rate, breathing rate, blood supply to the muscles and sweating. The adrenal gland’s split into two parts:

• The adrenal medulla, that releases adrenaline, which increases heart rate, oxygen intake and blood flow, and noradrenaline, that maintains blood pressure
• The adrenal cortex, that releases cortisol, which stimulates the release of glucose to provide the body with energy while suppressing the immune system

Question 24

Outline the ovaries in the endocrine system providing examples of a hormones

Answer 24

• Reproductive glands that develop secondary sexual characteristics in females that appear at puberty

• Releases oestrogen which is responsible for female sexual characteristics, menstruation and pregnancy

Question 25

Outline the testes in the endocrine system providing examples of a hormones

Answer 25

• Reproductive glands that develop secondary sexual characteristics in males that appear at puberty

• Releases testosterone that is responsible for male secondary sex characteristics and muscle mass

Question 26

Outline the fight or flight response

Answer 26

• Evolutionary survival mechanism in response to a threat that primes the body and mind for extreme action; fighting for our lives or escaping a threat. Once this threat has passed, the body returns to homeostasis.

• F/F response isn’t designed for the modern world, it’s maladaptive in most situations and can lead to stress (acute or chronic)

Question 27

Identify and explain the two types of stress

Answer 27

• Acute stress is a common response to immediate pressures, which can be exciting in small amounts and give you focus and energy, but exhausting if maintained

• Chronic stress is a long term form of stress in response to prolonged emotional pressure. This often occurs in situations an individual feels unable to control

Question 28

Describe the process of the fight or flight response

Answer 28

• Threat is recognised, causing a stress response

• Hypothalamus activates the sympathetic branch of the autonomic nervous system, a specialised connection from the brain to the adrenal gland called the sympathetic adrenomedullary pathway (SAM) is triggered causing adrenaline and noradrenaline to be released from the adrenal medulla

• Hypothalamus stimulates the pituitary gland in the endocrine system to release ACTH, resulting in the secretion of stress hormone cortisol from the adrenal cortex

Question 29

Identify the roles of adrenaline and noradrenaline in the fight or flight response

Answer 29

• Increased heart and breathing rate to increase blood flow to the brain and skeletal muscles for quick thinking and reactions

• Decreased blood flow to systems that aren’t tike critical such as the digestive system

• Dilated pupils for improved vision and sweating to remove heat

• Psychological effects of increased anxiety, attention and alertness

Question 30

Identify symptoms of stress related illness in relation to the fight or flight response

Answer 30

• Constant triggering of the fight or flight response in chronic stress has long term effects on mental and physical health such as:

• Fight or flight response shuts down the immune and digestive systems, causing high blood pressure
• Increased risk of heart disease obesity and IBS (irritable bowel syndrome) and a general lowering of resistance to disease
• Can lead to anxiety and/or depression

Question 31

Outline localisation of function

Answer 31

• Functions such as movement, speech and memory are performed in distinct regions of the brain (localised). The opposite view is that the brain acts holistically to perform functions

• Key research comes from Sperry (1967)

Question 32

Outline hemispheric lateralisation

Answer 32

• Each hemisphere of the brain is specialised to perform a specific function.

• The brain is contralateral in most people, so parts of the left side of the body are dealt with by the right hemisphere and vice versa

Question 33

Identify the function of the left hemisphere

Answer 33

Language processing; includes areas such as Broca and Wernicke’s areas

Question 34

Identify the function of the right hemisphere

Answer 34

• Visual-spatial processing and creativity

• It’s dominant in recognising emotion in others (Narumoto et al, 2001)

• Clarke, Assal and de Tribolet (1993) found a woman with right hemispheric damage would often get lost, even in familiar situations without verbal instruction containing distinguishable visual features. This highlighted the fact the right hemisphere is more adept at spatial relationships.

Question 35

Define a cortex

Answer 35

• Surface layer of the brain referred to as grey matter (contains mostly cell bodies)

• 2-4mm thick and folded for extra surface area for processings. White matter in the brain’s mostly myelinated axons (subcortex)

Question 36

Identify the key cortecies and areas of the brain

Answer 36

• Visual Cortex
• Visual Cortex
• Motor Cortex
• Somatosensory Cortex
• Auditory Cortex
• Broca’s Area
• Wernicke’s Area

Question 37

Outline the visual cortex and identify the consequences of damage

Answer 37

• Located in the occipital lobe, it’s the brains visual processing centre, each hemisphere’s occipital love received information from the contralateral visual field

• Damage can lead to partial or complete loss of vision (cortical blindness). Damage to one cortex can cause loss of vision in the opposite visual field

Question 38

Outline the auditory cortex and identify the consequences of damage

Answer 38

• Located in both hemispheres at the top of the temporal lobe and it receives and processes auditory information from the ears

Question 39

Outline the motor and somatosensory cortecies

Answer 39

• The motor cortex is located in the posterior frontal lobe and the somatosensory cortex is located in the anterior parietal cortex. They’re divided by a fold called the central sculus and are contra lateral

• The motor cortex is responsible voluntary motor movements and damage leads to loss of muscle function or paralysis

• The somatosensory cortex is responsible for receiving sense impressions and damage leads to loss of sensation, Neglect syndrome (ignoring areas of the body) and Agnosia (loss of ability to recognise objects by their feel)

Question 40

Outline Broca’s area and identify the consequences of damage

Answer 40

• Located in the left frontal lobe, it’s responsible for speech production and was discovered after a case study and post mortem of Louis Leborgne (patient ‘Tan Whon’)

• Damage can cause Broca’s aphasia (expressive/motor aphasia) which refers to a difficulty producing speech; speech lacks fluency and sentences won’t be formed correctly
• Damage to Broca and Wernicke’s area can lead to Global Aphasia

Question 41

Outline Wernicke’s area and identify the consequences of damage

Answer 41

• Located in the left hemisphere at the top of temporal lobe. Wernicke’s area is responsible for speech comprehension; understanding language and assessing the words

• Discovered by Karl Wernicke (1874) who found patents who had damage in areas close to the auditory cortex had specific language impairments including the inability to comprehend language and anomia (struggle to find the words for something)

• Damage causes Wernicke’s aphasia (receptive/sensory aphasia) which refers to difficulty understanding speech or written language, speech sounds fluent and words can be assessed quickly but speech lacks meaning or includes nonsense words
• Damage to Broca and Wernicke’s area can lead to Global Aphasia

Question 42

Outline Global Aphasia

Answer 42

The inability to produce or understand speech, caused by damage to Broca and Wernicke’s area

Question 43

Outline the aim of Sperry (1967)

Answer 43

To show the independent streams of conscious awareness possessed by each hemisphere and to show each hemisphere has it’s own memories

Question 44

Outline the sample and method of Sperry (1967)

Answer 44

• Studied 11 patients who’d had a corpus callostomy (had their Corpus Callosum severed/cut) as a treatment for their epileptic seizures

• Sperry projected information into each visual field, controlling which information each visual field collected/assessed. In a series of tasks/tests, participants would be asked to either say what they saw, draw it or pick it out from hidden objects

Question 45

Outline the findings of Sperry (1967)

Answer 45

Information presented to the left hemisphere could be spoken, but not if it had been delivered to the right hemisphere. However, information presented to the right hemisphere could be drawn or picked out from objects with the left hand

Question 46

Outline the conclusion of Sperry (1967)

Answer 46

• Hemispheres are lateralised and work independently

• Provides evidence for localisation of function as it shows that language centres are localised to the left side of the brain

Question 47

Outline functional recovery of the brain

Answer 47

Following external or internal trauma, unaffected areas of the brain are often able to adapt and compensate for damaged areas.

• External trauma refers to how the environment affects functioning (e.g. physical injury) while internal trauma refers to function being affected by factors within the person (e.g. a stroke)

• The brain’s able to rewrite and reorganise itself by forming new synaptic connections close to the area of damage. Secondary neural pathways that wouldn’t typically be used to carry out certain functions are activated or ‘unmasked’ to enable functioning to continue, often in the same way as before. This is supported by a number of processes.

Question 48

Identify and outline processes that support the functional recovery of the brain

Answer 48

Axonal sprouting
• Secondary nerve cells will grow axons

Reformation of blood vessels
• Blood vessels located near the area of trauma
will direct more blood flow to the area of
damage leading to an increased chance of
recovered functioning

Recruitment of homologous areas of the brain on the opposite side to perform specific tasks
• E.g. if Broca’s area was damaged on the left side,
the right side equivalent would carry out its
functions
• Neuroscientists suggest this process can occur
quickly after trauma (spontaneous recovery) and
then slow down after several weeks or months.
Then the individual may require rehabilitative
therapy to further their recovery

Question 49

Identify the factors affecting functional recovery of the brain

Answer 49

• Perseverence
• Age
• Gender
• Physical exhaustion, stress, alcohol consumption

Question 50

Outline perseverance as a factor affecting functional recovery of the brain

Answer 50

• Defined as the persistence in doing something despite difficult or delay in achieving success

• The faster and more effort someone puts into their recovery (e.g. movement therapy) the faster and more effectively they’ll recover

• Leaving the brines unstimulated is bad as unused neurones will be pruned and will be damaged further or die

Question 51

Outline age as a factor affecting functional recovery of the brain

Answer 51

• The earlier the damage, the better the chance of recovery

• Danelli et al (2013) conducted a case study on patient ‘EB’ and found at 2 1/2 years old, most of his left hemisphere was removed due to trauma. His linguistic abilities disappeared until the age of five which was due to compensation by the right hemisphere after intensive rehabilitation
By 17, he had only minor errors in functioning such as minor grammatical problems and was slow at naming pictured objects

Question 52

Outline gender as a factor affecting functional recovery of the brain

Answer 52

• Due to a stronger Corpus Callosum, females will have a better prognosis than males after trauma
• More nerve fibres connecting the two hemispheres in females means more neurological connections can be made more easily and plasticity has a greater effect

• Ratcliffe et al (2007) examined 325 16-45 year old patients a year after an injury they’d received rehabilitation for on their cognitive skills (e.g. attention/perception/memory)
Women performed better on attention and memory, while men performed better on visual and analytic skills. Overall the results showed a better recovery for women, however they didn’t control for pre-injury performance

Question 53

Outline physical exhaustion, stress and alcohol consumption as factors affecting functional recovery of the brain

Answer 53

• All these risk factors delay or prevent full recovery by using up critical recourses required for recovery

• Physical exhaustion requires growth hormones and proteins to repair muscle tissues rather than the brain
• Stress lowers the efficacy of the immune system by lowering white blood cell count and increases the effect of trauma
• Alcohol consumption dehydrates and damages the brain further and polarises the immune system

Question 54

Identify and explain a case study for localisation of function

Answer 54

• Phineas Gage was a railway worker who used dynamite to blast a clear path for railway construction, he needed to use an iron rod to bed the dynamite in place. One day, the rod caused a spark, blowing the dynamite and sending the iron rod through his chin and out of his forehead

• Immediately after the accident, he was conscious and able to speak and was treated by a doctor and suffered badly over the next few weeks with infection. Eventually he recovered physically with no apparent effects on functioning except losing sight in his left eye

• However, psychologically he changed. Before the accident he was calm and well mannered but after he was unreliable, hostile and rude and used inappropriate language he didn’t tend to before
• The physician who treated Gage believed that there was localisation in the brain and that the area that had been damaged (frontal lobe) affected planning reasoning and control

Question 55

Explain neuroplasticity

Answer 55

• The brain has the ability to change throughout life. During infancy, the brain experiences rapid growth in the number of synaptic connections, peaking at roughly 15,000 at age 2-3, around twice as many as the adult brain.

• Synaptic pruning, where rarely used connections are deleted and frequently used connections are strengthened, occurs as we age

• Functional plasticity refers to the brain’s ability to move functions from a damaged area of the brain to other undamaged areas

• Structural plasticity refers to the brains ability to actually change its physical structure as a result of learning

Question 56

Identify and explain a case study for neuroplasticity

Answer 56

• Eleanor Maguire (2000) conducted a study on London taxi drivers, finding significantly more volume of grey matter in the posterior hippocampus.

• Grey matter stores information and is where cell bodies and nuclei of a cell are found
• The hippocampus is responsible for memory and is associated with the development of spatial memory and navigational skills. As part of their training taxi drivers must take a test called ‘The Knowledge’ which assesses their recall of city streets and possible routes

• Maguire obtained fMRI scans from 16 right handed male London taxi drivers, and compared them to 50 right handed healthy males who didn’t drive taxis. The result of this learning experience is to alter the structure of the taxi drivers brains, and there was a positive correlation between the longer they’d been in the job and more pronounced structural difference

• Concluded that structure differences between the hippocampus of London taxi drivers and control participants suggest extensive practice with spatial navigation affects the hippocampus

Question 57

Identify ways of studying the brain

Answer 57

• Post Mortem Dissection
• Functional Magnetic Resonance Imagining (fMRI)
• Electroencephalogram (EEG)
• Event Related Potential (ERP)

Question 58

Define spatial and temporal resolution

Answer 58

• Spatial resolution refers to the level of accuracy in identifying the exact location of a brain structure or activity in space (where the activity happened)

• Temporal resolution refers to the level of accuracy in identifying the exact location of a brain activity in time (when the activity happened)

Question 59

Outline and evaluate post mortem dissections

Answer 59

• Brains are precisely cut after treatment to give them a firmer texture. Unusual brains are dissected, such as brains that suffered trauma, or from individuals with mental illness and compared with neurotypical brains
• Broca’s area was discovered using a post mortem on patient ‘Tan’, who had Broca’s aphasia and could only say Tan. Damage to an area of the frontal lobe was found after his death

[+] High spatial resolution allows the study of
brain structures down to the neuronal level

[-] Can only show correlations so causation can’t
be determined. Deficits (e.g. inability to
produce speech reported in life could be due to
other reasons (lack of causation decreases
validity) other than damage to the brain (e.g.
damaged Broca’s area)

[+] However, theories can then be generated that
can be tested with other experimental
techniques

Question 60

Outline and evaluate Functional Magnetic Resonance Imagining (fMRI) scans

Answer 60

• fMRI’s detect blood flow in the brain. As more active areas of the brain need more blood that contains oxygenated Haemoglobin, with distinct magnetic properties, they can be compared to lower activation areas displayed on a dynamic fMRI image

[+] High spatial resolution of 1-2mm, precisely
identifying active brain regions and activation
patterns while experimental conditions are
completed
[+] Non-invasive and safe compared to other
options, such as PET scanners that use
radiation

[-] Expensive to build and operate and patient
must be still, experiments with body movement
aren’t possible
[-] Poor temporal resolution (1-5 second time lag)
and don’t provide a direct measure of neural
activity, clinicians can’t be sure that the function
being performed is due to the highlighted brain
area. Lack of causation decreases validity.
[-] Difficult to tell what type of activity’s being
shown on screen as it doesn’t measure
neuronal activity

Question 61

Outline and evaluate Electroencephalograms (EEG)

Answer 61

• A collection of between 22-34 electrodes attached to a cap, and fitted carefully to the scalp with conductive gel. The read out from each electrode is the sum of activation of the brain cortex under the electrode. This is displayed as a series of lines showing brains waves
• Amplitude (size of waves) shows intensity
• Frequency (distance between waves) shows
speed of activation

[+] Cheaper than fMRI’s, safe compared to other
options, such as PET scanners that use
radiation, non-invasive and can be used in
moving experiments
[+] Very good temporal accuracy measured in
milliseconds

[-] Poor spatial activity; generalised activity isn’t
specific to individual areas abnormalities may
be occurring: difficult to pinpoint the exact
source of neural activity which lowers validity

Question 62

Outline and evaluate Event Related Potentials (ERP)

Answer 62

• Uses the same equipment as EEG’s but presents a stimulus many times, creating a smooth curve of activation by combining the data in a process called statistical averaging. This removes background electrical noise unrelated to the stimulus. The waveform’s peaks and dips show exactly when cognitive processes in the brain happen after the stimulus is presented , while EEG’s record general brain activity

[+] Cheaper than fMRI’s, safe compared to other
options, such as PET scanners that use
radiation, non-invasive and can be used in
moving experiments
[+] Very good temporal accuracy with a
millisecond sampling rate
[+] Allows researchers to isolate and study how
individual cognitive processes happen, while
EEG’s record general brain activity

[-] Very poor spatial resolution, can’t study the
same processes as they can’t be presented a
large number of times with the same response
• ERP’s attempt to overcome this issue but it can be difficult for the clinician to tease out and isolate responses meaning the stimuli has to be presented to the participant 100s of times

Question 63

Define and give examples of Cirdacian Rhythm’s

Answer 63

• A biological rhythm that lasts around 24 hours. {Latin: Circa= about, Diem= day}

• Examples of circadian rhythms include the sleep-wake cycle, the release of hormones, body temperature and blood pressure

Question 64

Outline the sleep-wake cycle

Answer 64

• The sleep-wake cycle repeats every 24 hours and it’s believed the ideal sleep wake cycle is to sleep for 7-9 hours and be awake for 15-17 hours

• The endogenous pacemaker (internal body clock that keeps internal processes to time) is the suprachiasmatic nucleus (SCN) which is known as the master clock

• We’re aware of conflicts between the endogenous pacemaker and exogenous zeitgebers (external cues that entrain internal body clocks to match the environment) like social cues in situations such as jet lag; the endogenous pacemaker will be entrained by the exogenous zeitgebers

• Key research comes from Siffre (1975)

Question 65

Define Endogenous Pacemaker

Answer 65

Internal body clocks that keep internal processes to time

Question 66

Define Exogenous Zeitgebers

Answer 66

External cues that entrain internal body clocks to match the environment

Question 67

Outline the suprachiasmatic nucleus

Answer 67

• The SCN is part of the anterior hypothalamus within the lambic system, located at the optic chiasm where the optic nerves from each eye cross over.

• The SCN obtains information about light from the eye via the optic nerve even when our eyes are shut as light penetrates our eyelids

• If our endogenous clock is running slow (e.g. the sun rises slower than the day before) morning light instantly shifts the clock ahead, putting it in rhythm with the world, suggesting exogenous zeitgebers (e.g. light) influence are circadian rhythms

• When light’s detected by the SCN it sends a signal to the pineal gland, stoping melatonin production that results in a sleep response.
• Even when light cues are absent, melatonin is still released in a cyclic manner, yet if the SCN is destroyed then Circadian Rhythms disappear entirely

Question 68

Outline Siffre (1975)

Answer 68

• Tested the endogenous pacemaker of the circadian sleep-wake cycle, which is believed to be free running, maintaining a predictable cycle without constant exogenous zeitgebers

• He tested this by spending 179 days (6 months) in a cave with no natural light or other potential exogenous zeitgebers such as clocks or social cues

• Siffre’s body clock maintained a regular cycle of around 25 hours without exogenous zeitgebers which was longer than the expected 24 hours and suggests the SCN is free running but needs entrainment to stick to a 24 hour cycle

• Siffre went into the cave twice

Question 69

Outline Infradian rhythms

Answer 69

• A biological process that repeats less frequently than every 24 hours {Latin: Infra=below, dian=day}

• The menstrual cycle is a 28 day cycle with a 6 day period of fertility, however cycles can range between 24 up to 36 days (Refinetti, 2006).

• During each cycle, rising levels of oestrogen cause the ovary to develop and release an egg (ovulation). After ovulation, progesterone helps the womb lining grow thicker preparing the body for pregnancy.

• If the egg isn’t fertilised, it’s absorbed into the body and the womb lining comes away and leaves the body which is the menstrual flow. This is regulated by hormones oestrogen (pre-ovulation) and progesterone (post-ovulation). The levels of these act as endogenous pacemakers and its suggested exogenous zeitgebers such as light are also involved.

• Key research comes from McClintock (1971) and Stern and McClintock (1998)

• There are other infradian rhythms aside from the menstrual cycle of fertility, such as hibernation or seasonal affective disorder (SAD). Halbert et at (2002) reported 7 day rhythms of blood pressure and heart rate, although the supporting evidence was weak

Question 70

Outline research into Infradian rhythms

Answer 70

• McClintock (1971) studied 135 women in the same dormitory at university, recording period onset and duration. Results showed women synchronised their cycles with friendship groups, these findings were supported by Russell (1980)

• Further research by Stern and McClintock (1998) investigated if synchronisation was due to sharing pheromones. 20 women were given pads worn for at least 8 hours to wipe on their top lip each day, taken from the armpits of 9 various women at varying menstrual stages. 68% of women experienced changes to their cycle to match the donor.

• This demonstrates the impact of exogenous zeitgebers, such as pheromones on infradian rhythms such as the menstrual cycle

Question 71

Outline seasonal affective disorder (SAD)

Answer 71

• SAD is a circannual infradian rhythm that’s a form of depression where mood decreases during the winter that’s linked to the hormone melatonin

• During the winter, the pineal gland secretes melatonin until dawn, which lasts longer during winter having a knock on effect on the production of serotonin.
• SSRI’s as well as phototherapy are used as treatment to reset melatonin levels, which relieves symptoms in 60% of sufferers (Eastman et al, 1998)

Question 72

Outline Ultradian rhythm

Answer 72

• A biological process that repeats more frequently than every 24 hours {Latin: ultra=beyond, diem= day}

• An example of an ultradian rhythm is that of sleep cycles. Sleep cycles take roughly 90 minutes and repeat 4-5 times a night. They’re made up of four stages. Firstly, the body goes through stage 1 (N1), then stage 2 (N2) and stage 3 (N3), which are all non-rapid eye movement sleep. After passing through these stages, the body passes back through N2, then N1 sleep before transitioning to REM (rapid eye movement sleep) where most dreams occur.

• Sleep cycles are measured by an electroencephalogram which produces brainwaves. Frequency refers to how close the waves are to each other (waves per second in Hz), while amplitude refers to the size of the brain wave (change in voltage)
• The five distinct patterns of brainwave are delta and theta (that distinguish sleep stages) as well as alpha, beta and gamma.

Question 73

Outline N1 sleep

Answer 73

• N1 sleep is known as light sleep

• Easy to wave and the body may move suddenly, referred to as hypnic jerks. There may be a sensation of falling, mild auditory or visual hallucinations referred to as hypnagogic hallucinations.

• The electroencephalogram (EEG) shows theta waves that have a slow frequency, but high amplitude in comparison to being awake

Question 74

Outline N2 sleep

Answer 74

• N2 sleep is a deeper sleep where the individual is harder to wake, but the body’s relaxed. Heart rate and body temperature are lowered and the eyes are still.

• The electroencephalogram (EEG) shows theta waves with occasional activity such as sleep spindles or K complexes

Question 75

Outline N3 sleep

Answer 75

• N3 sleep is the deepest sleep and is referred to as slow wave sleep (SWS). It’s very difficult to wake someone, but the body’s at its most relaxed, where heart rate is at its lowest and has a low metabolic rate

• Growth hormone is released and the immune system’s bolstered

• The electroencephalogram (EEG) shows slow frequency and large amplitude delta waves

Question 76

Outline REM sleep

Answer 76

• Rapid eye movement (REM) sleep is when the brain returns to an active state, passing back through N2 and N1. It’s characterised by rapid eye movement and is associated with dreaming. It’s believed to be essential to cognitive functions such as memory

• The electroencephalogram (EEG) shows REM sleep as similar to wakefulness, however, all non-respiratory muscles experience atonia (temporary paralysis)