Biopsychology Flashcards
What are the 4 ways of studying the brain?
fMRIs
EEGs
ERPs
Post-mortem examinations
What are the strengths and weaknesses of fMRIs?
- Non-invasive, no radiation, easy to use.
- Expensive.
- Poor temporal resolution (so fMRIs may not represent moment-to-moment brain activity.
What are the strengths and weaknesses of EEGs?
- Useful to study stages of sleep and diagnose epilepsy due to high temporal resolution.
- Not useful for pinpointing the exact source of neural activity (can’t distinguish between different activities).
What are the strengths and weaknesses of ERPs?
- Excellent temporal resolution (can be used to study working memory).
- More specificity to the measurement of neural processes.
- Lack of standardisation in methodology.
- Extraneous variables (e.g. background noise) could decrease the accuracy of data.
What are the strengths and weaknesses of post-mortem examinations?
- Vital for early research into newly developed theories (used by Wernicke and Broca to establish links between language, behaviour and the brain.
- Ethical issues (consent).
- Issue of causation: observed brain damage may be due to decay.
How long are Circadian rhythm cycles + examples?
24 hours
- Sleep/wake cycle
- Changes in body temperature during the day
How long are Infradian rhythm cycles + examples?
More than 24 hours
- Menstrual cycle
- Seasonal Affective Disorder (SAD)
How long are Ultradian rhythm cycles + examples?
Less than 24 hours
- Stages of sleep
What makes up the Central Nervous System?
Brain
Spinal Cord
What makes up the Peripheral Nervous System?
Autonomic Nervous System
Somatic Nervous System
What makes up the Autonomic Nervous System?
Sympathetic
Parasympathetic
What is the role of the Sympathetic part of the ANS?
Fight or Flight Response:
- Increased heart rate
- Adrenaline released from medulla
- Slows digestion
- Relaxation of airway muscles to improve oxygen delivery to lungs
- Increased blood pressure
What is the role of Parasympathetic part of the ANS?
Rest and Digest Response:
- Increased digestion
- Slows heart rate
- Increased production of saliva
- Decreased blood pressure
- Acetylcholine released.
What is the role of the pituitary gland?
Known as the ‘master gland’. Controls the release of hormones from all other endocrine glands in the body.
What is the role of the thyroid gland?
Produces thyroxine, responsible for regulation of metabolism, affecting growth rates.
How do hormones operate?
They are released into the bloodstream by glands, affecting any cell in the body that has a receptor for that particular hormone. Hormones act slower than the nervous system but have very widespread and powerful effects.
What are endogenous pacemakers?
Internal body clocks that regulate our biological rhythms.
What are exogenous zeitgebers?
External factors that affect or entrain our biological rhythms.
Endogenous pacemakers examples:
- Suprachiasmatic nucleus
- Pineal gland and melatonin
Exogenous zeitgebers examples:
- Light
- Social cues
What is the role of the suprachiasmatic nucleus?
Receives information about light directly from the optic chiasm, continuing even when our eyes are closed. This enables the biological clock to adjust to changing patterns of daylight whilst we are asleep.
Where is the suprachiasmatic nucleus?
Lies just above the optic chiasm (‘supra’ means ‘above).
Example of an animal study on the SCN (suprachiasmatic nucleus):
Patricia DeCoursey et al (2000):
- Destroyed SCN connections in 30 chipmunks who were returned to their natural habitat and observed for 80 days.
- Sleep/wake cycle disappeared.
- A significant proportion were killed off by predators.
What is the role of the pineal gland?
During the night, it increased production of melatonin (a chemical that induces sleep and is inhibited during periods of wakefulness).
What is a negative side affect of melatonin?
Seasonal Affective Disorder (SAD)
Evaluation of endogenous pacemakers:
- SCN research obscures other body clocks, decreasing internal validity. Damiola et al (2000) demonstrated that circadian rhythms in cells in liver could change whilst SCN rhythm was unaffected.
- Endogenous pacemakers cannot be studied in isolation because in everyday life, pacemakers and zeitgebers interact.
What does light also have an indirect influence on other than the sleep/wake cycle?
- Hormone secretion
- Blood circulation
Example of a study on light as an exogenous zeitgeber:
Campbell and Murphy (1998)
- 15 participants woken at various times and light shone on the back of their knees.
- Managed to produce a deviation in sleep/wake cycle of up to 3 hours.
- Shows that skin receptors also detect light other than the eyes.
How can social cues act as an exogenous zeitgeber?
- By age 16 weeks, babies have been entrained by the schedules imposed by parents (mealtimes and bedtimes).
Evaluation of exogenous zeitgebers:
- Exogenous zeitgebers don’t have same affect in all environments (Arctic Circle people have similar sleep patterns all year round despite having 6 months in darkness). So, endogenous pacemakers = more important.
- Opposing research. Miles et al (1977). A young man with an abnormal circadian rhythm of 24.9 hours could not be adjusted by social cues.
Where is Broca’s Area and what is it responsible for?
- Frontal Lobe
- Speech production
Where is Wernicke’s Area and what is it responsible for?
- Temporal Lobe
- Language comprehension
What is the theory of Localisation of function in the brain?
- Who supports it?
- What is the opposite theory to it?
Different areas of the brain are responsible for specific behaviours, processes or activities.
- Supported by Broca and Wernicke.
- Holistic theory (all parts of the brain are involved in the processing of thought and action).
Where is the motor cortex?
Back of the frontal lobe
Where is the somatosensory cortex?
Front of the parietal lobe
Where is the visual cortex?
Occipital lobe at the back of the brain
Where is the auditory cortex?
Temporal lobe in the middle of the brain
What are the language centres of the brain?
Broca’s Area
Wernicke’s Area
Evaluation of localisation of function in the brain:
- Evidence from neurosurgery: Dougherty et al (2002) found that the cingulotomy procedure was successful in reducing OCD.
- Evidence from brain scans: Petersen et al (1988) used brain scans to show that Wernicke’s Area was active for a listening task, and Broca’s Area was active for a reading task.
- Language localisation is questionable. It isn’t just in the left hemisphere but also the right hemisphere. So, language may be organised more holistically.
What is Hemispheric Lateralisation?
Performed by one hemisphere rather than the other.
What is the left hemisphere known as in terms of language and why?
The Analyser
- Broca’s and Wernicke’s Area are located in the left frontal and left temporal lobes respectively.
What is the right hemisphere known as in terms of language and why?
The Synthesiser
- It contributes emotional context to what is being said.
What is contralateral wiring?
When the right hemisphere controls action of the left of the body and vice versa. (opposite sided)
What sense is both contralaterally wired and ipsilaterally wired?
Vision
What is ipsilateral wiring?
When the right hemisphere controls the action of the right of the body and vice versa. (same sided)
How is vision both contralateral and ipsilateral?
- Each eye receives light from the LVF and RVF.
- The LVF of both eyes is connected to the RH.
- The RVF of both eyes is connected to the LH.
Evaluation of Hemispheric Lateralisation:
- Research shows that the two hemispheres process information differently. Fink et al (1996) used PET scans to show that the RH was more active when looking at the ‘global’ elements of an image over the LH, supporting visual lateralisation.
- LH as analyser and RH as synthesiser may be wrong because there’s no evidence of people being left-brained or right-brained.
What is a split-brain operation?
Involves severing the connections between the RH and the LH, mainly the corpus callosum.
What are split-brain operations used to reduce?
Epilepsy
When was Roger Sperry’s research?
1968
Example of a study on split-brain research:
Roger Sperry (1968)
Sperry (1968) Procedure:
- 11 people who had a split brain operation to reduce their epilepsy studied.
- Participant gazes at a fixation point on a screen. Images projected to either side at a rate of 1 picture per 1/10 second.
Why did Sperry show one image to one side of the visual field and not in the other?
Because if the LH sees an image but not the RH, only the LH will remember it if the corpus callosum is severed.
Sperry (1968) Findings:
- When an object was displayed in the RVF (going to the LH), participants can describe it in speech and writing.
- When an object was displayed in the LVF (going to the RH), participants insist they haven’t seen anything. But, if asked to use the left hand (RH) to point to the object they got it correct.
What did Sperry find when placing objects in either hands of the participants of his study?
- When objects were placed in the right hand (LH), participants could describe the object in speech and writing.
- When objects were placed in the left hand (RH), participants made wild guesses but could pick out the object again with the same hand.
This was because the LH produces language and the RH doesn’t.
What was the conclusion to Roger Sperry’s split brain study (1968)?
The observations showed how certain functions are lateralised. The study supports the view that the LH is verbal and the RH is ‘silent’ but emotional.
Evaluation of Sperry’s research/Split Brain research:
- Research Support: Gazzaniga (1989) found that split brain people perform better on some tasks than others, because in the normal brain the LH’s strong cognition is watered down by the RH.
- Can’t generalise. Sperry’s participants compared to a neurotypical control group (no epilepsy or split brain procedure). Any differences could be due to epilepsy, not the procedure (confounding variable).
How many stages of sleep are there?
5
Stages of sleep can be studied using what?
an EEG
What stage of sleep is REM sleep?
5
What stage of sleep is deep sleep?
3/4
What stage of sleep may someone be easily woken?
1/2
How long in minutes does it take for the 5 stages of sleep to complete one cycle?
90
Evaluation of Ultradian Rhythms:
- Significant variation between people, especially between stages 3 and 4. Tucker et al (2007) suggests that these are biologically determined. This makes it difficult to determine normal sleep in any way.
- Research takes place in labs, limiting extraneous variables. Increases internal validity.
Brainwave patterns for each sleep stage:
1 - Alpha waves
2 - Alpha waves and sleep spindles
3/4 - Delta waves
5 - Theta waves
What is deep sleep also known as?
Slow wave sleep (SWS)
How long is the menstrual cycle in days?
28
At what day in the menstrual cycle does ovulation occur?
14
What causes ovulation to occur in the menstrual cycle?
Rising levels of oestrogen causing the ovary to develop an egg and release it.
What occurs after ovulation in the menstrual cycle?
The hormone progesterone is released to thicken the womb lining, readying it for pregnancy.
What happens if pregnancy does not occur in the menstrual cycle?
The egg is absorbed into the body, the womb lining comes away and leaves the body (menstrual flow).
What are the 2 main hormones involved in the menstrual cycle?
- Oestrogen
- Progesterone
What type of system is the menstrual cycle?
- What is it also influenced by?
Endogenous, but it can be influenced by exogenous factors, such as the cycles of other women.
What causes the menstrual cycles of women to synchronise?
Pheromones
Example of a study on the synchronisation of the menstrual cycle:
Martha McClintock (1998)
Martha McClintock (1998) Procedure and Findings:
- 29 participants
- Samples of pheromones of 9 women were collected and exposed to the other 20 women.
- 68% of women experienced changes to their cycle.
Symptoms of Seasonal Affective Disorder:
- Low mood
- General lack of activity and interest in life
Why does SAD occur?
Due to a decrease in daylight hours during the winter months.
Why is melatonin associated with SAD?
Less daylight hours means melatonin production occurs for longer, having a knock-on effect on serotonin production.
As well as being an infradian rhythm, what is SAD also classed as?
A circannual rhythm (yearly cycle)
Evaluation of Infradian Rhythms/Menstrual Cycle Research:
- Methodological shortcomings of synchronisation studies. Menstrual cycle can also be impacted by stress, changes in diet, exercise (confounding variables). Can’t be replicated.
- Supported by natural selection. Synchronisation has evolutionary value. Survival advantages for women to menstruate and be pregnant at the same time.
What does Siffre’s Cave Study support?
The circadian rhythm of the sleep/wake cycle as a biological rhythm.
What did Siffre’s ‘free running’ sleep/wake cycle settle down to during his time in the cave?
25 hours
Evaluation of Circadian Rhythms:
- Applications: night workers have more health issues, so companies can manage worker productivity better if they avoid giving out night shifts.
- Used to improve medical treatments. Certain drugs (e.g. Aspirin) are most effective if taken at night.
- Can’t generalise. Siffre’s Cave Study is based on one person. Also, sleep/wake cycles vary from person to person.
What is functional recovery a form of?
Plasticity
What is plasticity?
The brain’s tendency to change and adapt as a result of experience and new learning.
- Generally involves the growth of new connections.
Example of a study on plasticity:
Maguire et al (2000)
What year was Maguire’s London Taxi Drivers study
2000
Maguire et al (2000) Procedure and Findings:
- Studied the brains of London taxi drivers.
- Found significantly more volume of grey matter in the posterior hippocampus than in a control group.
- The longer the taxi drivers had been in job = the more structural difference (positive correlation).
Why did Maguire find more grey matter in the posterior hippocampus in London taxi driver’s brains?
The posterior hippocampus is associated with the development of spatial and navigational skills in humans.
Evaluation of Plasticity:
- Plasticity may have negative behavioural consequences. 60-80% of amputees have been known to develop phantom limb syndrome due to somatosensory cortex reorganisation after limb loss.
- Plasticity may be a lifelong ability. Bezzola et al (2012) demonstrated how 40 hours of golf training changed brain structures in participants aged 40 to 60.
What is functional recovery?
The brain’s ability to redistribute or transfer functions usually performed by a damaged area(s) to other undamaged area(s).
What is spontaneous recovery?
When functional recovery occurs quickly after trauma.
When may someone require rehabilitative therapy during functional recovery?
After spontaneous recovery; when the process slows down after several weeks or months.
What are the 3 key processes of functional recovery?
- Axonal Sprouting
- Denervation Supersensitivity
- Recruitment of homologous (similar) areas on the opposite side of the brain.
What is axonal sprouting?
The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
What is denervation supersensitivity?
Occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost.
What is a negative side effect of denervation supersensitivity?
- Oversensitivity to messages such as pain.
Evaluation of Functional Recovery:
- Real-world applications: Neurorehabilitation (constraint induced movement therapy).
- Level of education may influence recovery rates. Schneider et al (2014) found that 40% of those who achieved a disability free recovery (DFR) had more than 16 years education compared to about 10% of those who had less than 12 years education.
What are the 3 types of neuron?
Sensory
Relay
Motor
What neuron type makes up 97% of all neurons in the human body?
Relay
Shared features of all neurons:
- Cell body (with a nucleus)
- Dendrites
- Axon
- Terminal buttons
What are dendrites?
Branchlike structures at the end of neurons which receive messages from other cells.
What is the purpose of the axon?
Passes messages away from the cell body to other neurons.
What is the purpose of myelin sheaths?
Protects the neuron and speeds up the electrical impulse.
What is the purpose of Nodes of Ranvier?
Speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.
What are terminal buttons?
Branches at the end of the axon which communicate with the next neuron to continue the electrical impulse.
Where are sensory neurons found?
Peripheral Nervous System
Where are relay neurons found?
Central Nervous System (specifically the brain and visual systems)
Where are motor neurons found?
- Cell body in the Central Nervous System.
- Axons in the Peripheral Nervous System.
Key features of sensory neurons:
- Receptor cell
- Axon covered with myelin sheaths and Nodes of Ranvier.
- Cell body located in the middle of the axon.
Key features of relay neurons:
- Cell body found next to dendrites.
- Thin axon not covered by myelin sheaths.
Key features of motor neurons:
- Cell body found next to dendrites.
- Axon covered by myelin sheaths and Nodes of Ranvier.
- Effector/Muscle at the end of the neuron.
What is the difference between the autonomic and somatic nervous systems?
Autonomic - involuntary system (not under conscious control).
Somatic - voluntary system (under conscious control).
What hormone does the sympathetic nervous system release?
Noradrenaline
What hormone does the parasympathetic nervous system release?
Acetylcholine
Define homeostasis:
The regulation of our internal environment by a balance between the sympathetic and parasympathetic nervous systems.
What charge is the inside of a neuron during a resting state?
Negative
What happens when a neuron is activated by a stimulus?
The inside of the cell becomes positively charged for a split second causing an action potential to occur (electrical impulse).
Define excitation:
When Excitatory Neurotransmitters (e.g. adrenaline) increase the likelihood of a new action potential forming.
Define inhibition:
When Inhibitory Neurotransmitters (e.g. serotonin) decrease the likelihood of a new action potential forming.
Define summation:
The combined effect of all inhibitory and excitatory influences. Determines whether a new action potential will form.
