Biopsychology Flashcards
1
Q
What’s the nervous system?
A
A network of cells in the human body
The body’s internal communication system
2
Q
What’s the function of the nervous system?
A
To collect, process and respond to information from the environment.
To control organs and cells in the body.
3
Q
The Nervous System: Two Main Parts
A
The central and peripheral nervous system.
4
Q
The Nervous System: What’s the Central Nervous System made up of?
A
Made up of the brain and spinal chord.
Brain’s responsible for higher mental functioning.
Spinal chord’s responsible for reflex actions and transmitting info to and from the brain.
5
Q
The Nervous System: What’s the Peripheral Nervous System made up of?
A
Sub-divided into the autonomic and somatic nervous system.
6
Q
The Nervous System: What’s the Autonomic Nervous System responsible for?
A
Responsible for involuntary functions e.g. breathing and digestion.
ANS can be further sub-divided into sympathetic (responsible for fight or flight response) and parasympathetic (conserves and restores body energy when relaxed) branches.
7
Q
The Nervous System: What’s the Somatic Nervous System responsible for?
A
Responsible for voluntary movements e.g. walking.
Transmits info from the brain to the skeletal muscles/ effectors.
8
Q
Structure and Function of Neurons: What are Neurons?
A
Neurons are cells that make up the nervous system.
They communicate with each other using a mixture of electrical and chemical signals.
9
Q
1) Structure and Function of Neurons: Dendrites
A
Located at the post-synaptic membrane.
Where the neurotransmitter receptors are found.
Once receptor and neurotransmitter bind, causes a new electrical impulse to occur.
10
Q
2) Structure and Function of Neurons: Cell Body
A
Includes the nucleus which contains the genetic material of the cell.
11
Q
3) Structure and Function of Neurons: Axon
A
Sends a nerve impulse (action potential) through the neuron to transmit a message to the next neuron.
12
Q
4) Structure and Function of Neurons: Myelin Sheath
A
Protect the axon and helps to speed up transmission of the message.
13
Q
5) Structure and Function of Neurons: Nodes of Ranvier (the gap)
A
Speeds up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.
14
Q
6) Structure and Function of Neurons: Terminal Button (pre-synaptic membrane)
A
The end of the neuron.
Sends information through to the next neuron, through the release of neurotransmitters.
15
Q
Sensory Neuron: Location
A
The PNS in clusters known as ganglia.
16
Q
Sensory Neuron: Function
A
Send info from the senses (PNS) towards the brain (CNS).
Receptors found in eyes, ears, tongue, skin.
17
Q
Sensory Neuron: Structure
A
Have long dendrites and short axons.
18
Q
Relay Neuron: Location
A
In the brain and the visual system.
19
Q
Relay Neuron: Function
A
Found in the CNS (brain/ visual system/ spinal chord).
Carry nerve impulses between neurons allowing sensory and motor neurons to communicate.
Involved in analysing sensations from these neurons and deciding how to respond.
20
Q
Relay Neuron: Structure
A
Have short dendrites and short axons, and no myelin sheath.
21
Q
Motor Neuron: Location
A
Cell bodies are found in the CNS
Long axons form part of the PNS.
22
Q
Motor Neuron: Function
A
Send info via long axons from the brain/ spinal chord (CNS) through to effectors such as muscles/ glands.
23
Q
Motor Neuron: Structure
A
Have short dendrites and long axons.
24
Q
Process of Synaptic Transmission: What are neurotransmitters?
A
Chemical messengers within the brain.
Their role is to transmit info from one neuron to another so a person performs an action e.g. movement or has an emotional response.
25
The Process of Synaptic Transmission
1) Begins at pre-synaptic neuron, action potentials (electrical nerve impulses) sent down axon until they reach presynaptic terminal.
2) Causes neurotransmitters stored in vesicles (only located in presynaptic neuron) to be released into synaptic cleft (gap between each neuron).
3) Neurotransmitters diffuse across synapse (high to low concentration) and bind with specific receptor sites only present in post-synaptic neuron.
4) Enough neurotransmitters attached to receptor sites on post-synaptic neuron, two possible outcomes:
- Next neuron's ready to fire an impulse, depending on whether neurotransmitter has excitatory or inhibitory effect.
- Neurotransmitters are recycled to be stored back in the vesicles in pre-synaptic neuron in a process called reuptake.
26
Neurotransmitters Effect on the Next Neuron: Excitatory Neurotransmitter (Adrenaline)
When excitatory transmitter bind to post-synaptic receptors the post-synaptic cell (next neuron) becomes positively charged.
Makes it more likely that the post-synaptic cell will fire so an impulse will travel down the axon.
Increases brain activity in CNS.
27
Neurotransmitters Effect on the Next Neuron: Inhibitory Neurotransmitter (Serotonin)
Inhibitory neurotransmitter binds to post-synaptic receptors the post-synaptic cell (next neuron) becomes negatively charged.
Prevents/ reduces likelihood that post-synaptic cell will fire.
Decreases brain activity in CNS.
28
Neurotransmitters Effect on the Next Neuron: Summation
Occurs when excitatory & inhibitory influences are added together.
If overall effect's mainly inhibitory/ negatively charged, reduces likelihood the neuron will fire an impulse down post-synaptic neuron.
If overall effect's mainly excitatory/ positively charged, neuron will fire impulse down post-synaptic neuron.
29
The function of the endocrine system
Endocrine system provides chemical system of communication within blood stream to regulate activity of cells/ organs in the body.
It's slower than the nervous system but its effects are more widespread and powerful.
Chemical messengers are hormones which are released by glands within endocrine system to regulate bodily function.
30
The role of glands in the endocrine system: What is a gland?
An organ that releases hormones that control/ regulate bodily functions.
Many different glands in the body.
31
The role of glands in the endocrine system: Pineal Gland
Secretes hormone melatonin, involved in regulating the sleep-wake cycle by making a person feel tired and ready to sleep.
32
The role of glands in the endocrine system: Pituitary Gland
Master gland.
Controls functions of other glands.
Secretes many different hormones that control function of other glands.
33
The role of glands in the endocrine system: Adrenal Gland
Releases adrenaline which causes physiological changes involved in the fight or flight response e.g. increased blood flow to transport oxygen to brain for rapid response planning.
34
The role of glands in the endocrine system: Ovaries
Anterior pituitary gland releases LH and FSH
Encourages ovaries to release oestrogen and progesterone which regulate female menstrual cycle and prepares body for reproduction.
35
The role of glands in the endocrine system: Testes
Anterior pituitary gland releases LH and FSH.
Encourages testicles to release testosterone which is involved in creating male characteristics and the production of sperm.
36
The Fight or Flight Response
The ANS and the endocrine system plays major role in stress response in producing fight or flight response.
When stressor's identified by brain it activates sympathetic branch of ANS.
1) Stressor's identified by hypothalamus and activates pituitary gland which triggers activity in sympathetic branch of ANS.
2) Adrenaline's released by adrenal medulla into bloodstream.
3) 'Fight or flight' response is produced, preparing body for sudden physical action, produces physiological reactions e.g. increased heart rate - this is an immediate and automatic response.
4) Parasympathetic branch returns the body back to normal once stressor's been removed (homeostasis e.g. heart rate decreased).
37
Role of Adrenaline in Fight or Flight Response
Adrenaline's the hormone released from the adrenal medulla.
Travels through bloodstream and activates heart and circulatory system, increases heart rate and blood pressure.
Changes are important in fight or flight response.
38
Direct effect of Adrenaline in Fight or Flight Response
Increased heart rate increasing blood flow and blood pressure.
Increases blood flow to brain and skeletal muscles.
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Indirect effect of Adrenaline in Fight or Flight Response
Prepares body for action e.g. fight or flight.
Increases blood supply yo skeletal muscles for physical action, stops digestion and saliva production.
Increased oxygen to brain for rapid response planning.
40
What happens once stressor's removed: Parasympathetic Branch
Once stressor's passed, parasympathetic Branch of ANS takes over.
Main function's to activate 'rest and digest response' and return body to homeostasis after fight or flight response.
41
AO3: Fight or Flight Response: Stress Response in Females (Tend and Befriend)
P: Issue is that it doesn't explain stress response in females.
E: Research's found women are more likely to protect offspring (tend) and form alliances with other women (befriend) than to fight or run away.
E: Suggests there's gender bias as fight or flight response assumes men and women respond to threatening situation in same way prior to research.
L: Limits explanation for fight or flight.
42
AO3: Fight or Flight Response: Limited to Two Responses
P: Issue, human behaviour's not limited to two responses.
E: Psychologists argue first response to danger's to avoid confrontation altogether through 'freeze' response.
E: During 'freeze' response humans consider best course of action for threat they're faced with.
L: Suggests fight or flight response doesn't consider other factors such as thought process.
43
Localisation of Function in the Brain and Hemispheric Lateralisation: Introduction
Localisation of Function: Specific areas of the brain specialised for certain functions (jobs) e.g. motor cortex is responsible for voluntary movements- only this area of the brain's responsible for this job.
Hemispheric Lateralisation: Brain's split into two symmetrical halves called left and right hemisphere. Idea that two different hemispheres are responsible for different mental processes e.g. left responsible for language, right responsible for creativity.
Holistic theory: Before investigations into localisation and lateralisation, scientists believed all parts of brain worked together when processing information.
44
Localisation of Function in the Brain and Hemispheric Lateralisation: Broca's Area
Left hemisphere.
Involved in production of spoken and written language.
Damage to area can cause 'Broca's aphasia, person may show slow speech which requires a great deal of effort, speech lacks fluency, or complete loss of speech)
45
Localisation of Function in the Brain and Hemispheric Lateralisation: Motor Cortex
Both hemispheres.
Involved in creation of voluntary motor movements.
Each hemisphere controls movement of opposite side of body.
Damage can cause loss of control over fine movements or can cause small movements on opposite side of body).
46
Localisation of Function in the Brain and Hemispheric Lateralisation: Somatosensory Cortex
Both hemispheres.
Processes information from senses in the skin.
Includes touch, pressure, pain, temperature from all areas in body.
Damage can cause problems in perceiving touch, failure to recognise an object by touch).
47
Localisation of Function in the Brain and Hemispheric Lateralisation: Visual Cortex
Both hemispheres.
Area of brain receives info directly from eyes. Processes info such as eye colour and shape.
Damage can cause blindness, hallucinations or inability to see colour/ motion.
48
Localisation of Function in the Brain and Hemispheric Lateralisation: Wernicke's Area
Left hemisphere.
Area involved in understanding language.
Damage can cause Wernicke's aphasia where indivudals cannot understand spoken language or where person produces nonsense words).
49
Localisation of Function in the Brain and Hemispheric Lateralisation: Auditory Cortex
Both hemispheres.
Analyses speech based info e.g. hearing pitch and volume.
Damage could cause partial/ full hearing loss.
50
AO3: Localisation of Function in the Brain: Research to Support by Broca
P: Research to support, Broca.
E: Reported case study of man who lost ability to speak, except one word 'tan' although he could understand language.
E: Post mortems showed damage in one area in left hemisphere, now called Broca's area.
L: Shows language production's localised to one specific brain area as theory predicts.
51
AO3: Localisation of Function in the Brain: Research to Contradict on EB
P: Research to Contradict, patient EB.
E: EB suffered brain damage, resulted in removal of left hemisphere and therefore language centres.
E: Despite this, after some time EB managed to regain some language ability that wouldn't be possible if language centres were completely localised to left hemisphere.
L: Demonstrates that language must be in more areas than just left hemisphere suggesting holistic explanation of brain functioning's more appropriate than localisation of function.
52
AO3: Localisation of Function in the Brain: Case Studies Lack Pop Val
P: Both case studies lack pop. val.
E: May not be appropriate to generalise findings on localisation of function to whole population.
E: These are unique case studies where brain damage may have affected the way in which brain functions and some individuals may be able to process language in other brain areas.
L: Suggests more research is needed with more diverse samples before firm decision's on localisation of language areas are possible.
53
AO1: Hemispheric Lateralisation: What is Hemispheric Lateralisation?
The idea that the left and right hemispheres of the brain are responsible for different functions.
The two hemisphere have different functions and roles.
54
AO1: Hemispheric Lateralisation: Left Hemisphere
Responsible for language
Two main language centres located in left hemisphere:
Broca's area: responsible for speech production.
Wernicke's area: responsible for understanding of language.
55
AO1: Hemispheric Lateralisation: Right Hemisphere
Responsible for recognition of faces, places, objects, creativity.
Can only produce basic words/ phrases but contributes to emotional context of what's being said.
56
AO1: Hemispheric Lateralisation: Areas that aren't lateralised
Many functions aren't lateralised e.g. vision, motor, somatosensory areas that occur in both hemispheres.
57
AO1: Hemispheric Lateralisation: Contralateral Wiring
Brain has contralateral wiring.
Left hemisphere receives information from right visual field, and controls right side of the body.
Right hemisphere receives information from left visual field and controls left side of the body.
58
AO3: Hemispheric Lateralisation: Research to support
P: Research to support conducted by Sperry using split brain patients with severed corpus collosum.
E: Found when ppts were shown image of object in right visual field, patient could name it verbally, but when presented to left visual field, couldn't name it verbally but could identify object through pointing.
E: Supports the idea that the brain's lateralised and that the hemispheres are responsible for different functions e.g. left being responsible for language abilities.
L: Therefore split brain research supports theory of hemispheric lateralisation.
59
AO3: Hemispheric Lateralisation: Research to contradict
P: Research to contradict comes from case study on patient EB.
E: EB suffered from brain damage that resulted in removal of left hemisphere and therefore his language centres.
E: Despite this after some time EB managed to regain some language ability which wouldn't be possible if brain was completely lateralised.
L: Demonstrates how language must be in more areas than just the left hemisphere, arguing against lateralisation of function in the brain.
60
AO3: Hemispheric Lateralisation: EB lacks pop val
P: Case study of EB lacks pop val
E: May not be appropriate to generalise findings on lateralisation of function to whole population.
E: These are unique case studies where brain damage may have affected the way in which brain functions and some individuals may be able to process language in other brain areas.
L: Suggests more research is needed with more diverse samples before firm decision's on lateralisation of language areas are possible.
61
AO1: What's Split Brain?
Split brain patients have had surgery (normally to treat epilepsy) to cut the area that connects the two areas of the brain (corpus callosum).
Surgery may relieve epilepsy, has a major side effect: two hemispheres become functionally separate (act as two separate independent brains).
62
AO1: Outline Split Brain Research
Aim was to investigate the effect of severing the connection between the two hemispheres of the brain (the corpus callosum) on functioning.
It was a natural experiment.
Studied 11 individuals who had their corpus callosum severed due to surgery.
Procedure:
1) Ppts sit in front of a screen, while fixating gaze on a spot in the middle of a screen.
2) Ppts were presented with visual information to either their left/ right visual field for 1/ 10th of a second (so there's not enough time for the other visual field to switch focus to the visual image).
Results:
Objects seen in right visual field named verbally and in writing as the image would be processed by language centres in left side of the brain.
If objects only seen in left visual field they can only be identified through pointing but can't be named by ppt.
Conclusion:
Two hemispheres in brain have different abilities and functions; but only left's able to produce language.
Right hemisphere can recall and identify information, but can't verbalise this.
63
AO3: Split Brain Research: Scientific Methods
P: Strength of research, uses scientific methods.
E: Based on objective and empirical techniques such as controlled laboratory settings.
E: Used in order to identify which hemisphere of brain's responsible for which task, e.g. patients could only say what image was when presented in right visual field, suggesting left hemisphere's activated during language tasks.
L: Arguably increases overall internal val of hemispheric lateralisation research, raising psychology's scientific status.
64
AO3: Split Brain Research: Individual differences
P: Limitation's individual differences in ppts in relation to how lateralised their brain was.
E: Degree to which corpus callosum was severed for each ppt varied greatly with some having greater disconnection between two hemispheres than others.
E: Weakness because research may not be measuring effects of lateralisation effectively.
L: Reduces internal val of split brain research.
65
AO3: Split Brain Research: Research to contradict
P: Research to contradict comes from case study on patient EB.
E: EB suffered from brain damage that resulted in removal of left hemisphere and therefore his language centres.
E: Despite this after some time EB managed to regain some language ability which wouldn't be possible if brain was completely lateralised.
L: Demonstrates how language must be in more areas than just the left hemisphere, arguing against lateralisation of function in the brain.
66
AO1: What is Plasticity and Functional Recovery of the Brain after trauma?
Brain's ability to change and adapt its structures and processes as a consequence of experience and new learning.
67
AO1: Plasticity: Synaptic Pruning
During infancy the brain experiences a rapid growth in the number of synaptic connections it has peaking at approx 15,000 at the age of 2-3 years (around twice as many as an adult brain).
Synaptic Pruning: as we age connections that aren't used regularly are deleted and one that are used regularly are strengthened.
68
AO1: Research investigating Plasticity: Maguire et al
-Brains of London taxi drivers studied.
There was greater volume of grey matter in posterior hippocampus (responsible for spatial and navigational skills) in those who had been a taxi driver for a long time in comparison to those who had been taxi drivers for a short time.
Difference was due to their greater knowledge of the roads which suggests the structure of their brain's been altered by their experience = plasticity.
69
AO1: Example of Plasticity: Functional Recovery
Type of plasticity which refers to recovery of abilities and mental processes (e.g. movement/ language) that have been affected as a result of brain damage or disease.
Brain's able to rewire itself by forming new synaptic connections close to the damaged area of the brain.
Secondary neural pathways that wouldn't typically be used to carry out certain functions are activated to enable functioning to continue, often in the same way as before. This process creates a number of 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.
Recruitment of Homologous (similar) areas: areas from opposite side of the brain take over the function of the damaged area of the brain e.g. if Broca's area's damaged in LH, right side equivalent would carry out its functions.
70
AO2: Affects of Recovery After Trauma: Perseverance
Takes a great deal of effort to recover from trauma and research shows that some people may appear to lose function but the reason may be that the person's not trying because they believe that it's unrecoverable, not due for any biological reason.
71
AO2: Affects of Recovery After Trauma: Age
Younger people are more likely to recover from damage that older individuals (40+). There's a deterioration of the brain in old age which affects the extent and speed of recovery.
72
AO2: Affects of Recovery After Trauma: Gender
Evidence on gender differences is mixed but some research suggests that females are more likely to recover than males.
73
AO2: Affects of Recovery After Trauma: Education
Research found the more time people spent in education the greater their chance of a disability free recovery.
Those who achieved a DRF had 16+ years of education compared to those who had less than 12 years of education.
This suggests that other factors such as education can affect the plasticity of the brain and reduce functional recovery of the brain.
74
AO2: Affects of Recovery After Trauma: Stress and Alcohol
After recovery from trauma it takes a great deal of effort to regain the ability to function so alcohol and stress can make it more difficult for an individual.
75
AO3: Plasticity and Functional Recovery: Research to Support
P: Research to support comes from case study on patient EB.
E: EB suffered from brain damage that resulted in removal of left hemisphere and therefore his language centres.
E: Despite this after some time EB managed to regain some language ability which wouldn't be possible if brain was completely lateralised.
L: Demonstrates how brain can adapt to produce language even when left hemisphere isn't present/ functioning, supports idea of plasticity and functional recovery.
76
AO3: Plasticity and Functional Recovery: EB Lacks pop val.
P: Case study of EB lacks pop val, only one ppt, EB who had severe brain damage.
E: An issue as it may have caused unique changes in the brain that may have influenced plasticity and functional recovery of the brain.
E: Limits how well the research can be generalised to the wider population as different genders and age groups may experience different levels of plasticity in the brain.
L: Lowers external val of research into plasticity and functional recovery.
77
AO3: Plasticity and Functional Recovery: A strength of the Maguire research
P: Has practical applications.
E: Principles of theory that it's possible for an individual for an individual's brain to recover from damage through axonal sprouting has led to development of neurorehabilitation.
E: This is where the patient practices repeatedly using the affected side of their body e.g. their affected arm.
L: Important area of applied psychology as it helps treat people in the real world.
78
Ways of Studying the Brain: Functional Magnetic Resonance Imaging (fMRI scans)
-Identifies changes in the levels of oxygen in blood that occurs due to brain activity in specific areas.
-When brain area's more active it leads to more oxygen being used so there's an increase of blood flow to this active area.
-fMRI produces 3D image showing which part of brain's active, called an activation map.
-Been used to identify which specific parts of the brain are active in particular mental processes.
79
AO3: fMRI strength
-Much safer technique to measure brain activity, non-invasive and doesn't use radiation to identify the differences in brain area.
-Unlike PET scans which use radiation.
-fMRI's a more appropriate technique to use that could reduce the risk of potential harm to individuals.
80
AO3: fMRI weakness
-Has poorer temporal resolution as there's around a 5 second time lag behind the image on the screen and the initial firing of neuronal activity.
-fMRI's may not truly represent moment-to-moment brain activity.
81
Ways of Studying the Brain: Electroencephalograph (EEG)
-EEG's a brain scanning technique that works by electrodes being placed on the scalp using a skull cap.
-They detect small electrical changes resulting from activity of brain cells.
-Electrical signals are graphed over a period of time to see a person's general brain activity.
-EEG's are used to detect sleep patterns and states such as sleep/ arousal.
-Used as a diagnostic tool to help diagnose conditions e.g. brain tumours and epilepsy.
82
AO3: EEG strength
P: High temporal resolution, enables researcher to take a real time recording of brain activity rather than a still image of the brain.
E: Researcher can gain more accurate measure of brain activity in particular task.
E: Provides greater insight into processes of the brain e.g. activity of brain during sleep.
L: Increases EEG's validity as way of studying the brain.
83
Ways of Studying the Brain: Event-Related Potentials (ERPs)
-Like with EEG, electrodes are placed on the scalp, but unlike EEG, ERP shows SPECIFIC brain activity.
-Stimulus is presented to an individual many times and their brain activity's measured in same way as an EEG.
-All extraneous brain activity from original EEG recording's filtered out leaving only responses that link to presentation of stimulus/ task.
-Once extraneous activity is filtered, only ERP's remain.
84
AO3: ERP's strength
P: High temporal resolution, enables researcher to take a real time recording of brain activity rather than a still image of the brain.
E: Researcher can gain more accurate measure of brain activity in particular task.
E: Provides greater insight into processes of the brain e.g. activity of brain during sleep.
L: Increases ERP's validity as way of studying the brain.
85
Ways of Studying the Brain: Post-Mortems
-Brain of a dead patient's examined and dissected to see if there's any physical/ structural abnormalities.
-Brain can be compared with brain that doesn't show particular behaviour/ mental process.
-Mainly used on people who have rare disorder/ defects.
-One area of research has been identification of Broca's area as important brain area for speech production.
86
AO3: Post-Mortems strength
P: Only invasive way to study the brain.
E: Possible to get a more detailed examination of the brain than would be possible through solely using brain scanning techniques such as EEG and ERPs.
E: e.g. it's meant researchers have been able to study deeper areas of the brain such as the hypothalamus.
L: Helped understand brain functioning in may different areas.
87
AO3: Post-Mortems Weakness
P: Hard to establish cause and effect with post-mortem studies.
E: Many cofounding variables which can't be easily controlled E: e.g. how long a person's had a particular eating disorder.
L: Limits internal val of findings of the studies and therefor the appropriateness of using post-mortems to study the brain.
88
What is a Biological Rhythm?
Biological rhythms have an important influence of the way in which body systems behave.
All biological rhythms are controlled by:
Endogenous pacemakers = internal body clock,
All biological rhythms are influenced by:
Exogenous zeitgebers = external changes in the environment.
89
Biological Rhythms: What is an Ultradian Rhythm?
A cycle that's less than 24 hours e.g. stages of sleep which last approx 90 minutes.
90
Biological Rhythms: What is a Circadian Rhythm?
A cycle that lasts 24 hours e.g. sleep wake cycle.
91
Biological Rhythms: What is an Infradian Rhythm?
Cycle that lasts longer than 24 hours e.g. female menstrual cycle which operates on a 28 day cycle.
92
AO1: Circadian Rhythms: The Sleep Wake Cycle
1) One example of a circadian rhythm is the sleep wake cycle which is controlled by the master endogenous pacemaker, the suprachiasmatic nucleus (SCN) found in hypothalamus.
2) Eyes notice a change in light as it gets dark, less light's received by the retina.
3) Sends info to SCN which stimulates the pineal gland to release melatonin and promote sleep.
4) Eyes detect light (exogenous zeitgeber) the SCN's reset which maintains the sleep wake cycle to around 24 hours so we can be in synchrony with the outside world.
93
AO3: Circadian Rhythms: Research to support
P: Research to support circadian rhythms lasting around 24 hours conducted by Siffre.
E: Isolated himself in a cave for 6 months where his biological body clock was able to be free running and unaffected by exogenous factors e.g. clocks, natural light.
E: Found within a few days he'd developed consistent 25 hour cycle and continued to fall asleep and wake up on regular schedule.
L: Supports the sleep wake cycle's a circadian rhythm which is mainly controlled by an endogenous pacemaker, the SCN, to maintain a circadian rhythm.
94
AO3: Circadian Rhythms: Limitation of Siffre research
P: Low pop val.
E: Conducted as a case study, Siffre was the only ppt.
E: May not be appropriate to generalise findings on sleep wake cycle beyond Siffre due to individual differences in sleep wake cycle and circadian rhythms. e.g. older people's circadian rhythms may be slower and more easily influenced by exogenous zeitgebers.
L: Lowers external val.
95
AO3: Circadian Rhythms: Strength of Siffre research
P: Has prac apps.
E: Basic principles of theory (circadian rhythm's around 24 hours and maintained by endogenous pacemakers, given researchers better understanding of negative consequences that can occur as a result of disrupting their rhythm.
E: e.g. night workers who experience shift work have a period of reduced concentration around 6am meaning mistakes and accidents are more likely, used y employers to manage work productivity.
L: Research is important part of applied psychology.
96
AO1: Infradian Rhythms: Menstrual Cycle
-Menstrual cycle's an endogenous system which typically lasts between 28-35 days.
-Begins on the first day of a woman's period, when womb lining's shed, to the day before her next period.
-In the brain, pituitary gland releases FSH which activates the release of oestrogen from the ovaries and causes egg to mature.
-Increased oestrogen increases levels of LH (released by pituitary gland) promote the release of an egg.
-Oestrogen develops in womb lining and progesterone helps it grow thicker, readying womb for pregnancy.
-If pregnancy doesn't occur, the egg's absorbed into body, womb lining comes away and leaves the body and cycle begins again.
-Although menstrual cycle's mainly and endogenous system that maintains infradian rhythm, affected by exogenous factors e.g. stress and pheromones (chemical scents given by males and females).
97
AO3: Infradian Rhythms: Research
P: Infradian rhythms are mainly governed by endogenous system conducted by Russell.
E: Asked a sample of women to wear cotton pads under their arms, pads were rubbed on upper lip of 5 sexually inactive women, process repeated daily for 5 months.
E: Found 4 out of 5 women developed menstrual cycles that synchronised within one day of cycle donor.
L: Suggests infradian rhythm of menstrual cycle can be affected by exogenous factors/ controlled by endogenous factors which may influence length of infradian rhythm.
98
AO3: Infradian Rhythms: Russell Research Limitation
P: Russells research was a field experiment, low control over extraneous variables.
E: Research took part in ppts natural environment, exogenous factors e.g. light, diet, stress could affect infradian rhythm.
E: Difficult to establish cause and effect between influence of heromones on maintaining infradian rhythm.
L: Weakens reliability of research.
99
AO3: Infradian Rhythms: Russell research strength
P: Research findings can be explained by evolutionary psychologists.
E: Would've been advantageous in our evolutionary past for social group to synchronise pregnancies
E: so many women would be breast feeding at same time so one mother could take over caring for an orphaned child, to improve survival chances.
L: Synchronisation of infradian rhythms e.g. menstrual cycle, is an adaptive strategy and supports exogenous factors influencing infradian rhythms.
100
AO1: Ultradian Rhythms: Stages of Sleep
The cycle lasts approx 90 minutes and consists of 5 stages and alternates between REM sleep and NREM sleep.
It's known as the sleep staircase, a person can experience up to 5 cycles per night that repeat in a rhythmic pattern.
-Research using EEG, into ultradium rhythms has shown there to be 5 distinct stages of sleep, characterised by difference in brain, muscle, eye activity:
-Stages 1 and 2 (Light sleep - NREM): Light sleep where a person may be easily woken.
-Stage 1 = experience alpha waves
-Stage 2 = Alpha waves continue but there are occasional random changes in pattern called sleep spindles (high frequency - protect brain from awakening).
-Stage 3 and 4 (Deep sleep - NREM): Known as deep sleep, brain waves are delta waves with lower frequency and higher amplitude, difficult to wake someone up at this point.
-Stage 5 (REM) - Body is paralysed, brain activity closely resembles that of awake brain. Brain produces theta waves and eyes ocassionally move around - called rapid eye movement (REM).
Dreams often experienced at this stage, may also occur in deep sleep.
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AO3: Ultradian Rhythms: Strength of Research: Practical apps
P: Strength of research- has prac apps in understand age-related changes in sleep.
E: Knowledge that growth hormone's produced during stage 4 of sleep's been associated with sleep deficit in old age as research has found older people experience less stage 4 sleep.
E: Result of research: medication and relaxation techniques have been developed to increase stage 4 sleep in older individuals and therefore, prevent some issues associated with old age such as reduced alertness.
L: Research is important part of applied psychology.
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AO3: Ultradian Rhythms: Strength of Research: Scientific Methods
P: Strength of research- uses scientific methods.
E: Because it's based on objective and empirical techniques e.g. EEGs to measure brain activity and controlled lab settings.
E: Scientifically measure activity of the brain throughout 5 stages of sleep to identify length of rhythm and how many times rhythm occurs throughout duration of sleep whilst excluding extraneous variables e.g. noise.
L: Increases overall internal val of research, raising psychology's status.
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AO3: Ultradian Rhythms: Limitation of Research
P: Low eco val.
E: Research conducted in artificial lab setting.
E: And so sleep experienced by ppts in studies may not reflect genuine sleep patterns due to unfamiliar setting, and because they're attached to electrodes.
L: May alter the length of ultradian rhythm, making it difficult to generalise findings to explain how ultradian rhythms work in real life.
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What are endogenous pacemakers?
Endogenous pacemakers are internal factors which help us maintain our biological rhythms. it's also thought our rhythms are synchronised by exogenous zeitgebers (external factors) e.g. light, meal times.
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Effect of Endogenous Pacemakers on Sleep Wake Cycle
1) Sleep wake cycle's produced by master endogenous pacemaker, the suprachiasmatic nucelus.
2) Eyes notice a change in light as it gets dark and less light's received by retina.
3) Sends info to SCN, which stimulates pineal gland to release melatonin and promote sleep.
4) Eyes detect light again (exogenous zeitgeber) the SCN's reset which stimulates SCN and pineal gland, inhibits release of melatonin to promote wakefulness. Suggests sleep wake cycle's controlled by endogenous factors.
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Effect of Exogenous Zeitgebers on Sleep Wake Cycle
-Exogenous zeitgebers are external factors which re in environment which can influence our sleep wake cycle through entrainment e.g. light, resets SCN suggesting our sleep wake cycle's not only influenced by endogenous pacemakers (internal factors).
-Social cues such as meal times and social interaction can influence sleep wake cycle, making us less alert once we've finished our evening meal.
-research suggests adapting to local eating and sleeping times before travelling to different time zone can prevent jet lag, suggesting exogenous zeitgebers can influence sleep wake cycle.
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Biological Rhythms Affected by Exogenous Zeitgebers
Biological rhythms can be affected by exogenous zeitgebers and these can make it difficult to maintain a consistent cycle. When these external factors override our natural rhythm, it can lead to disruption, which can have a range of consequences.
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What happens when sleep wake cycle's disrupted?
Can occur for many resons e.g. jet lag and through shift work. Can produce many negative consequences such as:
-Difficulty sleeping
-Decreased attention
-Digestive problems
-Tiredness and poorer reasoning skills
-Increased anxiety and irritability
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AO2: How could we maintain our sleep wake cycle
-Keep to local times for eating
-Keep to local times for sleeping e.g. sleeping when dark, waking up when light.
-Stimulate yourself during the day by being social and active
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AO3: Research to support effect of endogenous pacemakers on sleep wake cycle: Decoursey
P: DeCoursey et al
E: Destroyed SCN connections to brains of 30 chipmunks who were returned to natural habitat and observed for 80 days.
E: Sleep way cycle of chipmunks disappeared and by end of study a significant proportion had been killed by predators- maybe because they were awake, vulnerable to attack when they were supposed to be asleep.
L: Supports influence and importance of endogenous pacemakers e.g. SCN on maintenance of sleep wake cycle, as exogenous zeitgebers alone weren't able to maintain sleep wake cycle of chipmunks.
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AO3: DeCoursey Research Limitation
P: Animal bias
E: Potential problem as humans may have more complex biological rhythms to animals as they have higher mental functioning.
E: Issues with generalising findings to humans
L: Limits extend to which DeCoursey's findings support endogenous pacemakers on sleep wake cycle
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AO3: Research to support Endogenous Pacemakers on Sleep Wake Cycle: Siffre
P: Research to support endogenous pacemakers on sleep wake cycle, conducted by Siffre
E: Isolated himself in a cave for 6 months where his biological body clock was able to be free running and unaffected by exogenous factors e.g. clocks, natural light.
E: Found within a few days he'd developed consistent 25 hour cycle and continued to fall asleep and wake up on regular schedule.
L: Supports the sleep wake cycle's mainly controlled by an endogenous pacemaker, the SCN, rather than exogenous zeitgeber.
