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Biopsychology Flashcards

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1
Q

What 2 major systems allow us to gain information from the environment and respond?

A

Nervous system

Endocrine system

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2
Q

Describe the endocrine system

A

Endocrine system produces and secretes hormones into the bloodstream, from glands that regulate the activity of target cells/organs through feedback.
~Includes the pituitary gland, adrenal glands and reproductive organs.

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4
Q

Describe the central nervous system

A

Responsible for receiving sensory information and responding accordingly.
Contains the brain and spinal cord.

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5
Q

What 2 systems does the Nervous system consist of?

A

Central Nervous system

Peripheral nervous system

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6
Q

What is the function of the brain and spinal cord?

A
  • Brain is the centre of all conscious awareness - Controls behaviour and psychological processes to maintain life.
  • Spinal cord is the extension of the brain, responsible for reflex actions. Connects PNS to the brain.
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7
Q

Describe the Peripheral nervous system

A

Connects the CNS to the limbs and organs, a communication relay going back and forth between the brain and spinal cord with the rest of the body.

Known for…
~Regulation:
•Somatic nervous system (voluntary, reflex actions without the CNS)
•Autonomic nervous system (involuntary, vital functions of the body)

~Control: (automatic system features)
•Sympathetic nervous system (stress)
•Parasympathetic nervous system (rest)

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9
Q

What are the 4 main parts of the brain?

A
  • Cerebrum - largest part, divides into 4 lobes.
  • Cerebellum - motor skills, balance.
  • Diencephalon - hypothalamus, thalamus.
  • Brain stem - automatic essential functions.
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10
Q

What are the functions of the left brain?

A

Controls activity on the right hand side of the body.

Analytical thought
Logic
Language
Science and Math

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10
Q

What are the functions of the right hemisphere?

A

Controls activity on the left hand side of the body.

Holistic
Intuition
Creative
Art and Music

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11
Q

What are the 4 lobes of the cerebrum and their responsibilities?

A
  • Frontal lobe - thinking/learning, problem-solving, emotions, personality.
  • Parietal lobe - sensory info, perception, spelling, arithmetic.
  • Occipital lobe - vision.
  • Temporal lobe - memory, language, understanding.
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12
Q

What is the purpose of the cerebellum?

A

Receives sensory information and regulates motor and voluntary movement.

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13
Q

What is the purpose of the brain stem (medulla)?

A

Regulates the automatic functions that are essential to life (eg. Breathing).

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14
Q

Describe the hypothalamus

A
  • Regulation of body temp (homeostasis)
  • Hunger and Thirst
  • Link between the endocrine and nervous system
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15
Q

Describe the Thalamus

A

Relays nerve impulses from the senses to the appropriate part of the brain where they can be processed.

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16
Q

What is the neurone route?

A 
Stimulus
Receptors 
Sensory neurone 
Relay neurone (in CNS)
Motor neurone 
Effector
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17
Q

What do all neurones have in common? (Structure)

A

• Axon - carries impulse away from the cell body.
•Dendrites - located at the end of one neurone, receives signals from neighbouring neurones.
• Terminal buttons: communicate with the next neurone across the synapse.
•Cell body - control centre of the neurone, includes the nucleus.
•Myelin sheath - insulating layer which forms around the axon.
•Nodes of ranvier - gaps between myelin sheath.
*action potential.

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18
Q

What is the direction of impulse?

A

Always AWAY from the cell body.

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19
Q

Give 3 examples of neurotransmitters

A

Acetylcholine
Dopamine
Serotonin

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20
Q

Describe an excitatory neurotransmitter

A

Eg. Acetylcholine or Noradrenaline
Increase the likelihood that an excitatory signal is sent/fired to post synaptic neurone, by increasing the postsynaptic neurones positive charge.

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21
Q

What is the role of the anterior pituitary?

A

Targets the adrenal glands and releases ACTH in response to stress which causes the adrenal gland to release cortisol.

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22
Q

Describe an inhibitory neurotransmitter

A

Eg. GABA or Serotonin
Calm the mind, induce sleep and filter out unnecessary excitatory signals. Reduces the likelihood of an excitatory signal firing by making the neurone more negative.

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23
Q

What does the posterior pituitary release which is important in childbirth?

A

Oxytocin which stimulates contraction of the uterus during childbirth and facilitates the bond between child and mother.

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24
Q

Describe the pituitary gland

A
  • Aka master gland.
  • Produces hormones which cause growth.
  • Controlled by the hypothalamus which regulates bodily functions by instructing the pituitary gland to release hormones (ACTH), which will cause other glands to release their hormones.
  • Consists of the anterior (front) and posterior (back).
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25
Q

Define: Hormone

A

Chemical messengers secreted by endocrine glands into the bloodstream where they travel to a target cell and have a particular effect.

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25
Q

Describe the adrenal gland

A
  • Includes the adrenal cortex (outer region) and adrenal medulla (inner region).
  • Adrenal medulla secretes adrenaline or noradrenaline which prepares the body (fight or flight).
  • Adrenal cortex secretes cortisol which responds to stress and aldosterone.
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26
Q

What 2 hormones does the adrenal medulla produce?

A

Adrenaline - increases heart rate and blood flow to muscles and brain.

Noradrenaline- constricts blood vessels, causing blood pressure to increase.

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27
Q

What hormones does the ovaries and testes produce?

A

• Ovaries - oestrogen and progesterone.

Testes - testosterone (causes the development of male characteristics eg growth of facial hair).

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28
Q

Describe the sensory neurone

A
  • Structure: long dendrites, short axon

* Function: conduct impulse (sensory info) from the sensory receptors to the spinal cord/CNS.

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29
Q

Describe the relay neurone

A
  • Structure: short dendrites, long axon.

* Function: interconnect the sensory neurone with appropriate motor neurone.

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30
Q

Describe the motor neurone

A
  • Structure: short dendrites, long axons

* Function: conduct impulse from the CNS to an effector (muscle or gland)

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31
Q

How do neurones transmit signals?

A

Neurones do not make direct contact (they do not touch each other). There is a very small gap between neurones called a synapse. This is done using neurotransmitters.

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32
Q

Describe the reflex arc system

A

A stimulus is detected by sense organs in the peripheral nervous system, which conveys a message along a sensory neurone. The message reaches the CNS where it connects with a relay neurone. This then transfers the message to a motor neurone. This then carries the message to an effector, where a response occurs.

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33
Q

In terms of the fight or flight response, What is chronic stress? (HPA axis)

A

Long term or continuos state of nervous arousal. The stress activates the HPA axis:

~Hypothalamus - releases CRH into the bloodstream.
~Pituitary gland - CRH cause pituitary to produce and release ACTH.
~Adrenal glands - ACTH stimulates the adrenal cortex to release stress related hormones like cortisol.

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34
Q

In terms of the fight or flight response, Describe acute(sudden) stress (SAM)

A

The fight or flight response is an evolved survival mechanism in response to a perceived situation.

  1. Amygdala is activated by a stressor which sends a signal to the hypothalamus.
  2. This triggers the sympathetic nervous system which sends a signal to the adrenal medulla.
  3. Adrenal medulla releases adrenaline into the bloodstream.
  4. Adrenaline and noradrenaline causes physiological changes, helps the body deal with the threat.
  5. After the threat the parasympathetic nervous system calms down the body’s responses.
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35
Q

How do these body parts respond to stress (sympathetic nervous system)?

A)  Eyes
B) Salivary glands 
C) Liver
D) Bladder 
E) Lungs
F) Heart
G) Gut
A 
A) pupils dilate
B) inhibits saliva production 
C) Stimulates glucose production
D) Stimulates urination 
E) Bronchi dilates
F) Increases heart rate 
G) Slows digestion
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36
Q

How do these body parts recover from stress (parasympathetic nervous system)?

A)  Eyes
B) Salivary glands 
C) Liver
D) Bladder 
E) Lungs
F) Heart
G) Gut
A 
A) pupils constrict
B) increases saliva production 
C) stimulates bile production
D) inhibits urination by contracting 
E) bronchi constricts
F) decreases heart rate 
G) increases digestion
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36
Q

Evaluate the fight or flight response

A
  • Taylor et al suggests that for females behavioural responses to stress are more characterised by ‘tend and befriend’ rather than fight or flight. Therefore suffers from gender bias as it only describes male behaviour.
  • Gray (1988)suggests that it doesn’t tell the whole story, eg. doesn’t account for when people ‘freeze’. Shows that there are other responses that occur.
  • The cause and effect between biology and behaviour cannot be established as research is correlational. Therefore fight and flight response is deterministic.
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37
Q

Describe the action potential

A

Neurones must transmit information both within the neurone and from one neurone to the next, via electrical impulses.
The dendrites receive info from sensory receptors or other neurones. This info is then passed down to the cell body and onto the axon.

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39
Q

Describe the synaptic transmission (action potential)

A
  • Each neurone is separated by a synapse - which includes a gap called the synaptic cleft, as well as the presynaptic terminal and postsynaptic receptor site.
  • Signals within neurones are transmitted electrically, but are converted to chemical transmissions when crossing the synaptic cleft.
  • When the electrical impulse (action potential) reaches the end of neurone (the presynaptic terminal), it triggers the release of the neurotransmitter from the synaptic vesicles, via exocytosis.
  • Neurotransmitters are chemicals that diffuse across the synapse to the next neurone in the chain. Once it crosses the synaptic cleft it is taken up by the postsynaptic receptor sites, here the chemical message is converted back into an electrical impulse.
  • The process of transmission will begin again in the postsynaptic neurone. The postsynaptic effect will either be excitatory (depolarisation) or inhibitory (hyperpolarisation).
  • If there are some neurotransmitters left behind in the synaptic cleft, these are taken back into the presynaptic vesicles via re-uptake.
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40
Q

What does a low level of cortisol lead to?

A

Low blood pressure
Poor immune system
Inability to deal with stress

*negative consequence of fight or flight

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40
Q

Describe the somatic nervous system

A

Main role is to transmit and receive information from the senses, controls the movement and the action of muscles including reflex reactions.

12 pairs of cranial nerves, 31 pairs of spinal nerves.

41
Q

How do neurones fire?

A
  • At resting state neurones are negatively charged.
  • When a neurone is activated by a stimulus, it becomes positively charged.
  • This causes an action potential to occur and creates an electrical impulse that travels down towards the end of a neurone.
42
Q

Describe the two theories of localisation of brain functions

A

• The holistic theory:
That all parts of the brain are involved in the processing of thought and action.

• The localisation theory: (cortical specialisation)
That different areas of the brain are responsible for different behaviours, processes or activities. And if a certain area of the brain becomes damaged through injury or illness, it’s function will therefore be affected.

43
Q

Describe the cerebral cortex

A

The outer layer of the left and right hemispheres.
• More developed than other animals
• Appears grey due to the location of cell bodies (grey matter)
• 3mm thick

44
Q

Define: hemispheric lateralisation

A

Some of our physical and physiological functions are controlled or dominated by a particular hemisphere.

45
Q

Describe the motor cortex

A

A region found at the back of the frontal lobe which controls voluntary movement on the opposite side of the body.

Damage to this area of the brain may result in a loss of control over fine movements.

46
Q

Describe the somatosensory cortex

A

A region found at the front of the parietal lobe where sensory information from the skin is processed. E.g. Touch, heat and pressure.

The amount of somatosensory area devoted to a body part denotes its sensitivity.

47
Q

Describe the visual cortex

A

A region found in the occipital lobe that receives and processes visual information.

Damage to the left hemisphere can produce blindness in the right visual field.

48
Q

Describe the auditory cortex

A

A region found in the temporal lobe which analyses speech-based/auditory information.

Damage to this area may produce partial hearing loss.

49
Q

Where is the language area of the brain found?

A

Broca’s area and Wenicke’s area are both found in the left hemisphere.

50
Q

Describe Broca’s area

A

An area of the frontal lobe of the brain in the left hemisphere, responsible for speech production.

Damage to Broca’s area causes Broca’s aphasia which is characterised by speech that is slow and lacking in fluency.

51
Q

Describe Wernicke’s area

A

An area of the temporal lobe (encircling the auditory cortex) in the left hemisphere, responsible for language comprehension.

Damage to Wernicke’s area causes Wernicke’s aphasia which is characterised by the production of nonsense words (neologisms).

52
Q

Phineas Cage case study

A

Supports the localisation theory as personality is associated with the frontal lobe.

During his railroad incident, a metre long pole went through his left cheek and out his skull, taking most of his left frontal lobe out with it. Although he survived, damage to this area resulted in a change in personality (went from calm and reserved to rude and quick tempered).

53
Q

Evaluate localisation of brain functions

A
  • Evidence from brain scans - Peterson (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area during a reading task. Other methods of measuring brain activity support this, e.g. fMRI.
  • Evidence from case studies - phineas gage. Shows that frontal lobe is responsible for personality, social and sexual behaviour. However case studies are idiographic, lack generalisability.
  • Karl Lashley (1950) suggests that basic motor and sensory functions were localised, but not high cognitive functions. Intact areas of the cortex could take over. Effects of damage are determined by the extent rather than the location.
  • Plasticity/cortical remapping - the rest of the brain can sometimes reorganise itself to provide the function. Several documented cases of stroke victims being able to recover previously lost functions. Supports holistic theory.
54
Q

Define: brain plasticity (cortical remapping)

A

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

55
Q

Describe brain plasticity

A
  • Has the ability to change throughout our life.
  • Babies brains experience rapid growth in synaptic connections, as we age rarely used connections are deleted and frequently used ones are strengthened. This is called synaptic pruning.
  • Originally thought that adult brains remained fixed in structure and function, but a wealth of research suggests that at any time in life, neural connections can change as a result of learning and experience.
56
Q

What 4 research examples support the idea of brain plasticity?

A
  • Maguire (2000) - studied brains of London taxi drivers and found they had significantly more grey matter volume in posterior hippocampus (spatial and navigational skills) than control group. ‘The Knowledge’ test assesses their recall of city streets and possible routes, all cabbies must take. As a result of such learning, their brain structure is altered.
  • Draganski (2006) - imaged the brains of medical students 3 months before and after their final exams. Learning-induced changes were seen to have occurred in the posterior hippocampus and parietal cortex, as a result of exam.
  • Mechelli (2004) - found a larger parietal cortex in the brains of people who were bilingual compared to matched monolinguals.
  • Lazar (2005) - used MRI scans to demonstrate how experienced meditators had a thicker cortex than non-mediators, especially in areas related to attention and sensory processing.
57
Q

Define: functional recovery

A

A form of plasticity. Following damage through trauma, the brain redistributes/transfers functions usually performed by a damaged area to a different area of the brain.

58
Q

Explain the processes involved in functional recovery following trauma/injury

A

The brain is able to reorganise itself by forming new synaptic connections close to the area of damage. Secondary neural pathways are activated to enable functioning to continue, often the same way as before.

This process is supported by different structural changes in the brain:
• Axonal sprouting - the growth of new nerve endings which connect with other undamaged nerve cells, to form new neuronal pathways.
• Reformation of blood vessels
• Recruitment of homologous areas on the opposite side of the brain to perform specific tasks.

59
Q

Evaluate brain plasticity (and functional recovery)

A
  • Research has led to real world applications - following brain damage, spontaneous recovery slows down after some time and so forms of physical therapy are required. Techniques such as electrical stimulation of the brain or counter the deficits in motor/cognitive functioning.
  • Age, factor affecting plasticity - research had found that it reduces with age. As a child the brain constantly adapts to new experiences and learning, this reduces with age. However, Bezzola et al (2012) found that after 40hrs of golf training in 40-60y.o, fMRI scans showed a change in motor cortex activity, compared to control group.
  • Cognitive reserve, factor affecting plasticity - Schneider et al (2004) discovered that the more time brain injured patients spent in education (indicating their cognitive reserve), the greater their chances of recovery. 2/5ths of patients who recovered disability-free had more than 16yrs in edu, compared to 10% who had less than 12yrs.
  • Plasticity can sometimes have maladaptive behaviour consequences - negative plasticity. E.g. 60-80% of amputees have been known to develop phantom limb syndrome - the continued experience of sensations in the missing limb. These sensations are usually unpleasant, painful and are thought to be due to cortical remapping in the somatosensory cortex that occurred due to limb loss (Ramachandran and Hirstein, 1998).
60
Q

What are split brain patients?

A
  • In healthy individuals the two hemispheres are connected by the corpus callosum which allows the two hemispheres to communicate.
  • People suffering with severe epilepsy for example may undergo surgery to cut the corpus callosum (commissurotomy).
  • Research on these individuals have allowed researchers to discover specific functions for each hemisphere.
61
Q

What is Sperry’s procedure (how did he investigate hemispheric lateralisation)?

A
  • Sperry devised a general procedure in which an image/word was projected to a patients right visual field (processed by the left hemisphere), and the same or different image/word was projected to the left visual field (processed by the right hemisphere).
  • In a ‘normal’ brain the corpus callosum would immediately share the information between both hemispheres, giving a complete picture of the visual world.
  • However, in a split brain the information could not be converged to give a complete picture.
62
Q

What were the key findings of Sperry’s split brain research into hemispheric lateralisation?

A
  • When patients were asked to describe what they see: right visual field to left hemisphere, patient could describe the object. LVF to RH, they couldn’t describe. This suggests that language is processed in the left hemisphere as there is a lack of language centres in the RH.
  • When patients were asked to recognise objects by touch: LVF to RH, weren’t able to verbally identify the object seen but could select a similar object with their left hand (LVF=RH=left side of body).
  • Drawing task: when 2 words were presented to each eye simultaneously, the patient would write with their left hand the word shown to the LVF and would say the object shown to RVF.
  • Recognising faces: LVF (right hemisphere) was better at selecting faces. RVF (left hemisphere), patients were not able to recognise.
63
Q

What conclusions were made based on the findings of Sperry’s procedure?

A

The left hemisphere is superior at knowledge comprehension and speech production.

The right hemisphere is superior at performing motor skills such as drawing tasks, and at recognising faces.

64
Q

Evaluate split brain research into hemisphere lateralisation

A
  • Sperry’s work provided valuable insight into hemispheric lateralisation of brain functioning. Verbal tasks are dominated by the left hemisphere (analyser) whereas spatial tasks stew dominated by the right hemisphere (synthesiser) of the brain.
  • Procedures in split brain patient research uses scientific methodology. Patients were typically asked to stare at a fixation point whilst one eye was blindfolded. The image projected was then flashed so that patients wouldn’t have enough time to move their available eye across both sides of the visual field. This ensures that only one hemisphere receives info at a time. Easily replicated, high internal validity.
  • Critics argue that results form split brain patients are unique and cannot be generalised (idiographic). Only 11 people took part in all variations of the basic procedure, all of whom had a history of epilepsy. Could be argued that the same findings could not apply to split brain patients without epilepsy. Also some patients had experienced more disconnection of the two hemispheres as part of their surgery. Individual differences.
65
Q

What are the 4 ways of investigating the brain?

A
  • Functional Magnetic Resonance Imaging (fMRI)
  • Electroencephalogram (EEG)
  • Event-related potentials (ERPs)
  • Post-mortems
66
Q

Describe how fMRIs are used to investigate the brain

A
  • fMRIs detect the changes in blood oxygenation and flow that occurs as a result of neural activity in specific part of the brain.
  • The more active a region is, the more oxygenated blood required, hence more flow (haemodynamic response).
  • The fMRI will produce a 3D image showing which part of the brain is activated during a particular mental process.
67
Q

Evaluate the use of fMRI

A

• Unlike other scanning techniques such as PET scans, it does not rely on radiation. If administered correctly it is virtually risk-free and non-invasive.
• Produces high spatial resolution images with a clear picture.
—
• Expensive compared to other neuroimaging techniques and can only capture a clear image if the patient stays perfectly still.
• Can only measure blood flow in the brain, gives no insight into the activity of individual neurones.

68
Q

Describe how EEGs are used to investigate the brain

A
  • EEGs measure electrical activity within the brain via electrodes that are fixed onto the scalp.
  • The scan recording represents the brainwave patterns that are generated from the action potentials of neurones, indicating brain activity.
  • Often used by clinicians as a diagnostic tool, as unusual arrhythmic patterns of activity may indicate neurological abnormality such as epilepsy, tumours or sleep disorders.
69
Q

Evaluate the use of EEGs

A

• Contributed to our understanding of the stages involved in sleep.
• Unlike fMRI, it has extremely high temporal resolution (no time-lag between image on the screen and initial firing of neurone).
—
• EEG signal is not useful for pinpointing the exact source of neural activity, doesn’t allow researchers to distinguish between activities originating in different but adjacent locations.

70
Q

Describe how ERPs are used to investigate the brain

A
  • The brains electrophysiological response to a specific sensory, cognitive or motor event can be isolated though statistical analysis of EEG data.
  • What remains are event-related potentials: types of brainwave that are triggered by particular events.
  • Research has revealed different forms of ERPs and how these are linked to processes such as attention and perception.
71
Q

Evaluate the use of ERPs

A

• Addresses the limitations of EEGs by bringing more specificity to the measure of neural processes that can be achieved using raw EEG data.
• Excellent temporal resolution, unlike fMRI. Because of this, it is known that the P300 component is involved in the allocation of attention and the maintenance of working memory.
—
• Lack of standardisation in ERP methodology between different research studies, difficult to confirm findings.
• In order to establish pure data in ERP studies, extraneous variables such as background noise must be eliminated, difficult to achieve.

72
Q

Describe how post-mortem is used to investigate the brain

A
  • The brain is analysed after death (usually those who had a rare disorder or experienced unusual deficits on mental processes or behaviour).
  • Used as a means of establishing the likely cause of brain abnormality, as it is compared with a neurotypical brain to ascertain the extent of the difference.
73
Q

Evaluate the use of post-mortem

A

• Was vital in providing a foundation for early understanding of the brains processes. E.g. Broca and Wernicke relied on these to establish links between language, brain and behaviour.
• Improve medical knowledge.
—
• Causation is an issue; observed brain damage may not be linked to the deficits under review, but to an unrelated trauma or decay.
• Ethical issue of informed consent; e.g. Patient HM who lost ability to form memories was not able to provide such consent, but a post-mortem was still conducted on his brain.

74
Q

Define: Biological rhythms

A

Cyclical rhythms/time periods that change over time and are influenced by internal body clocks (endogenous pacemakers) and external changes to the environment (exogenous zeitgebers).

I-infradian (>24 hours)
C-Circadian (24 hours)
U-Ultradian (<24 hours)

75
Q

Define: Circadian rhythm

A

A type of biological rhythm, subject to a 24 hour cycle which regulates a number of body processes such as the sleep/wake cycle and changes in core body temp.

76
Q

Describe the sleep/wake cycle (an example of a circadian rhythm)

A

A daily cycle of biological activity based on a 24 hour period (circadian rhythm) that is influenced by regular variations in the environment, such as the alternation of night and day.

  • Siffre’s cave study
  • Bunker study
77
Q

Describe Siffre’s cave study (circadian rhythm)

A
  • Siffre was a self-styled caveman who spent several extended periods underground to study the effects on his own biological rhythms.
  • Deprived of exposure to natural light and sound (but still with access to food and drink), Siffre resurfaced from the cave in mid-September believing it to be mid-August.
  • In this case, his ‘free-running’ biological rhythm settled to around 25 hours, though he did continue to fall asleep and wake up on a regular schedule.
78
Q

Give a research example of entrainment by exogenous zeitgebers on a circadian rhythm

A
  • Aschoff and Wever (1976) convinced a group of participants to spend 4 weeks in a WW2 bunker, deprived of natural light.
  • All but one participant (whose sleep/wake cycle extended to 29 hours) displayed a circadian rhythm of 24-25 hours.
  • Both this bunker study and Siffre’s cave study suggest that the ‘natural’ sleep/wake cycle may be slightly longer than 24 hours, but that it is entrained by exogenous zeitgebers associated with our 24 hour day (e.g. Number of daylight hours or typical meal-times).
79
Q

Evaluate circadian rhythms

A
  • Knowledge of circadian rhythms has given a better understanding of the adverse consequences that can occur when desynchronised - Boivin et al (1996) found that night workers engaged in shift work experience a period of reduced concentration around 6 in the morning, meaning mistakes and accidents are more likely. Economic implications/applications in how best to manage worker productivity
  • Practical application to drug treatments - circadian rhythms control processes such as heart rate, digestion and hormone levels which have an effect on pharmacokinetics. Research has revealed that there are certain peak times during the day/night when drugs are most effective. Led to development of guidelines for timing of drug dosage e.g. In cardiovascular drugs.
  • Limitations associated with the use of case studies and small samples in research - cannot generalise to wider population as it is unrepresentative. Individual differences may be present.
80
Q

Define: Infradian rhythm

A

A type of biological rhythm with a frequency of less than one cycle in 24 hours, e.g. Female menstruation and seasonal affective disorder

81
Q

Describe the female menstrual cycle, include a research example

A

The female menstrual cycle is a type of infradian rhythm, governed by monthly changes in hormone levels which regulate ovulation. The typical cycle takes approx 28 days to complete.

  • McClintock (1998) demonstrated how exogenous factors (female pheromones) can influence a woman’s cycle. Samples of pheromones were taken from 9 of 29 women at different stages of their cycle, who had a history of irregular periods.
  • A cotton pad was placed under these 9 women’s armpit and worn for at least 8 hours. The pads were treated with alcohol and frozen, to be rubbed on the upper lip of participants.
  • McClintock found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’. Suggesting external factors can influence menstrual cycles.
82
Q

Describe SAD (Seasonal Affective Disorder)

A

SAD is a depressive disorder which has a seasonal pattern of onset and is diagnosed as a mental disorder in DSM-5.

  • It is a particular type of infradian rhythm called a circannual rhythm as it is subject to a yearly cycle. But it can also be classified as a circadian rhythm as the experience of SAD may be due to the disruption of the sleep/wake cycle, attributed to prolonged periods of darkness during Winter.
  • Main symptoms include a persistent low mood alongside a general lack of activity and interest in life - generally triggered during Winter when the number of daylight hours becomes shorter.
83
Q

Define: Ultradian rhythm

A

A type of biological rhythm with a frequency of more than one cycle in 24 hours, e.g. The stages of sleep.

84
Q

Describe the stages of sleep

A

Five distinct stages of sleep that altogether span approximately 90 minutes - a cycle which continues throughout the course of the night. Each stage has a different level of brainwave activity so can be monitored using an EEG.

  • Stage 1 and 2: light sleep where the person can be easily woken. Alpha waves so the brainwaves become slower and more rhythmic, stage 2 is theta waves. Characterised by hypnotic jerks and drowsiness.
  • Stage 3 and 4: Deep sleep, delta waves so difficult to rouse someone at this point. Characterised by sleep walking/talking, night terrors and bed wetting.
  • Stage 5: REM sleep, beta waves. The body is paralysed yet brain activity speeds up significantly. Characterised by rapid eye movement, dreaming, increased heart rate and penile erection.
85
Q

How can Seasonal Affective Disorder be treated?

A

Phototherapy:
This involves a light box stimulating very strong light in the morning and evening for around 30 minutes.
This is thought to reset melatonin levels.

86
Q

Evaluate infradian rhythms

A
  • There is an evolutionary basis for the synchronisation of the menstrual cycle - for our ancestors it was advantageous for females to menstruate together and therefore fall pregnant at the same time so that new-borns could be cared for collectively, increasing chances of offsprings survival. However, Schank (2004) argued that synchronisation goes against the sexual selection theory as this would produce competition for the highest quality males, lowering the fitness of potential offspring.
  • Criticisms of early synchronisation studies - confounding variables that affect change in a woman’s menstrual cycle, such as stress or change in diet were not controlled. Therefore any observed pattern of synchronisation may be due to chance. Also McClintock’s study involved a small sample of women relying on them self-reporting the onset of their own cycle.
87
Q

Evaluate ultradian rhythms

A

• Evidence to support distinct stages in sleep - Dement and Kleitman (1957). Monitored sleep patterns of 9 adult participants in a sleep lab. Brainwave activity was recorded in an EEG and variables such as caffeine and alcohol were controlled. REM activity during sleep was highly correlated with the experience of dreaming as those woken at this stage had a more accurate recall of their dream. Suggests that stage 5 exists.

88
Q

Define: endogenous pacemakers

A

Internal body clocks that regulate many of our biological rhythms, such as the influence of the suprachiasmatic nucleus (SCN) on the sleep/wake cycle.

89
Q

Describe the importance of the suprachiasmatic nucleus (SCN)

A
  • The SCN is a tiny bundle of nerve cells located in the hypothalamus in each hemisphere of the brain.
  • It is one of the endogenous pacemakers in the mammalian species and is influential in maintaining circadian rhythms such as the sleep/wake cycle.
  • Nerve fibres connected to the eye cross in an area called the optic chiasm. It receives information about light directly from this structure. This continues even when our eyes are closed, enabling the biological clock to adjust to changing patterns of daylight whilst we are asleep.
90
Q

Describe an animal study investigating the SCN

A
  • DeCoursey et al (2000) destroyed the SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days.
  • The sleep/wake cycle of the chipmunks disappeared and by the end of the study, lots of them had been killed by predators (presumably because they were awake and vulnerable to attack when they should’ve been asleep).
  • Emphasises the role of the SCN in establishing/maintaining this cycle.
91
Q

Describe the association between the pineal gland and melatonin

A

The SCN passes the information on day length and light that it receives to the pineal gland.
During the night, the pineal gland increases production of melatonin - a chemical that induces sleep and is inhibited during periods of wakefulness.
Melatonin has also been suggested as a causal factor in seasonal affective disorder.

92
Q

Define: Exogenous zeitgeber

A

External cues that may affect or entrain our biological rhythms, such as the influence of light on the sleep/wake cycle.

93
Q

Describe light as an external zeitgeber

A
  • Light is a key zeitgeber in humans.
  • It can reset the body’s main endogenous pacemaker - the SCN, and this plays a role in the maintenance of the sleep/wake cycle.
  • Light also has an indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation.
94
Q

Give a research example of light as an exogenous zeitgeber

A
  • Campbell and Murphy (1998) demonstrated that light may 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 was shone on the back of their knees.
  • The researchers were able to produce a deviation in the participants usual sleep/wake cycle, of up to 3 hours.
  • This suggests that light is a powerful exogenous zeitgeber that doesn’t rely on the eyes to exert its influence on the brain.
95
Q

Describe social cues as an exogenous zeitgeber

A
  • About 6 weeks of age, circadian rhythms in human infants begin and by about 16 weeks most babies are entrained.
  • The schedules imposed by parents are a key influence, e.g. Adult-determined meal times and bed times.
  • Research also suggests that adopting to local times for eating and sleeping (rather than doing so on your own instincts), is an effective way of entraining circadian rhythms and beating jet lag.
96
Q

Evaluate endogenous pacemakers

A
  • Animal studies relating to the SCN have associated ethical issues - DeCoursey’s procedure exposed chipmunks to considerable harm and subsequent risk when returned to their natural habitat.
  • Research has revealed that there are numerous circadian rhythms which may also affect the sleep/wake cycle. Damiola et al (2000) demonstrated how changing feeding patterns in mice could alter the circadian rhythms of cells in the liver by up to 12 hours; aside from the SCN.
97
Q

Evaluate exogenous zeitgebers

A
  • The influence of exogenous zeitgebers may be overstated. Miles et al (1977) recount the story of a young man blind from birth with a circadian rhythm of 24.9 hours. Despite exposure to social cues, his sleep/wake cycle could not be adjusted. Similarly, studies of individuals who live in Arctic regions show normal sleep patterns despite the prolonged exposure to light. Both suggest the little influence of exogenous zeitgebers on circadian rhythms.
  • Methodological issues with Campbell and Murphy’s study. Findings are yet to be replicated. Also by isolating one exogenous zeitgeber (light) doesn’t give insight into the many other zeitgebers that influence the sleep/wake cycle, and the extent to which these interact.
98
Q

Define: melatonin

A

A hormone that induces sleep, secreted by the pineal gland.

99
Q

What happens when endogenous pacemakers and exogenous zeitgebers interact?

A

Our body becomes out of sync with the environment we are in and we experience decreased alertness and feel irritable, anxious and tired.

E.g. Night shifts and jet lags.

Psychology (11 decks)

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