Biopsychology Flashcards
Commissurotimy (Sperry 1968)
- The corpus callosum connects the two hemispheres of the brain. The procedure would cut through the 2 hemispheres (controls epilepsy)
- Due to the communication line being broken, sperry was able to see the extent to which hemispheres worked independently from each other
Left and right hemispheres
L: More geared towards analytic and verbal tasks
R: More adept at performing spatial tasks and music
- right can only produce rudimentary words and phrases but contributes emotional and holistic content to language
Evaluation of Sperry
+ experiments used highly specialised and standardised procedures
+ method was ingenious, image would be projected for 1/10th of second so that ppts wouldn’t have time to move eyes across both sides of visual field and both sides of the brain
- Puncetti (1977) suggested the hemispheres are so different it is like having 2 minds whereas other researchers believe the 2 hemispheres form a highly integrated system involved in most everyday tasks
- sample was unusual as 11 ppts who all had variations of the basic procedure and had a history of epileptic seizures took part. This means that the findings may be person specific.
- differences in function may be overstated as each hemisphere can do tasks typically associated with the other hemisphere
Core body temp (highs and lows)
Lowest approx 4am
Peak approx 6pm
Folkard (1985)
- Isolated 12 ppts from natural light for 3 weeks, manipulating clocks so that only 22 hours passed in a day.
- one of the participants could adjust comfortably to the pace of the clock, showing the strength of the circadian rhythm and extent to which it can be overridden
- also found primary school children had better recall in afternoon (Gupta found afternoon iq tests were higher on average
Infradian rhythms
- A type of biological rhythm with a frequency of less than one cycle in 24 hours e.g. menstrual cycle
- a type of biological rhythm with a frequency of more than one cycle in 24 hours. Rest + activity cycle
Exogenous
Growing or originating from outside the body
Endogenous
Growing or originating from inside the body
Eastman (SAD study)
- randomly assigned 96 patients one of three bright light treatments, either 1.5 hours in the morning, evening, or palcebo
- found that all showed remision of symptoms but morning then eve then placebo in order (placebo 30%)
Stages of sleep
1 and 2: person may be woken from light sleep
3 and 4: delta waves are slower meaning a deep sleep
5: body is paralysed but brain activity speeds up to resemble awake brain. Dreaming.
- sleep cycle follows an ultradian rhythm of 90 mins
- Kleitman (1969) suggested we move in 90 min needs for rest, fatigue, etc throughout the day
Evolution of the menstrual cycle
- women’s periods are often synced so more mothers would have babies at the same time so they could help each other
- however a woman’s lifestyle, diet, etc. have an effect on the cycle so McClintlocks study would be down to chance
Endogenous pacemakers
Referred to as internal biological clocks e.g. suprachiasmatic nucleus (SCN)
Exogenous zeitgebers
Reset this clock everyday to maintain coordination with the external world
Animal studies
- Decoursey (2000) captured 30 chipmunks and destroyed SCN connections in the brain meaning they had no awareness of sleep wake cycle
- Ralph (1990) bred hamsters with 20 hour sleep wake cycle, heavily effecting the hamsters
- ethical issues as many could not function properly or were killed by predators
Pineal gland
Increases production of melatonin at night as it induces sleep and is inhibited during periods of wakefulness
Burgess (2003)
Exposure to bright light prior to east-west flight decreased rime needed to readjust. Decreased jet lag
Evaluation of endogenous …
+ Burgess (2003) Exposure to bright light prior to east-west flight decreased rime needed to readjust. Decreased jet lag
+ babies circadian rhythm after 6 weeks as parents impose a schedule which has a large influence on meal and bed tiene
- rest of body can function and respond to circadian rhythms without SCN
- Campbell and Murphy (1998) shone light onto the back of the legs of 15 ppts and effected sleep by up to 3 hrs showing the effect of light
- mikes (1997) accounted the life of a blind man who despite social cues couldn’t change his 24.9 hr sleep wake cycle
The brain
Ensures life is maintained Many parts of the brain, concerned with vital functioning like problem solving and thinking
The spinal chord
Facilitates the transferral of messages to and from the brain to the PNS. Also involved in reflex actions
The peripheral nervous system (PNS)
Transmits messages via millions of neurons, to and from the CNS The PNS is divided into the somatic NS and the autonomic NS
The somatic nervous system (SNS)
This is the part of the PNS that is responsible for carrying sensory and motor inform to and from the spinal chord
The autonomic nervous system (ANS)
This governs vital functions in the body such as breathing, heart rare, digestion, sexual arousal and stress responses (fight or flight]
Endocrine system
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream
Hormones
Chemical substances that circulate in the bloodstream, their effects on behaviour can be very powerful
Adrenal medullas
These release adrenaline directly into the bloodstream which prepares the body for fight or flight by constricting blood vessels in the stomach. This inhibits digestion and gives you that sick feeling as well as increasing your heart rate.
Homeostasis
The maintainable of a constant internal environment within the body
Gland
An organ in the body that synthesises substances such as hormones
Pineal gland
Produces and secretes the hormone melatonin which regulates biological rhythms such as sleep cycles
Pituitary gland
Master gland as it controls the release of hormones from all the other endocrine glands in the body
Adrenal glands
Release adrenaline directly into the blood stream which prepares the body for fight or flight by constricting blood vessels to the stomach
Thyroid gland
Produces hormones that regulate the body’s metabolic rate as well as heart and digestive function, muscle control, brain development and mood
Testes
This facilitates the release of the male hormones-testosterone
Ovaries
This facilitates the release of female hormones-oestrogen and progesterone
Gender differences
- Taylor (2000) found that men usually react to stress with a ‘fight or flight’ response but women may show a ‘tend and befriend’ response
- oxytocin as a response to stress had been shown to make people less anxious and more sociable
- however male hormones reduce the effects of oxytocin but female hormones oestrogen amplifies it
- therefore men are more vulnerable to the adverse health effects of stress and more likely to develop stress related disorders
- in contrast women are more likely to ‘tend and befriend’ and this may protect women against stress and thus may explain why women live 7.5 years longer than men
Sensory neuron
- Unipolar neurons - only transmit messages
- Carries messages from the pns to the brain and spinal chord
- Long dendrites and short axons
Relay neuron
- Multipolar neurons - send and receive messages
- Transfers messages from sensory neurons to other interconnecting neurons or motor neurons
- short dendrites and short or long axons
Motor neuron
- Multipolar neurons - send and recieve messages
- Carries messages from the cns ro eddecfirs such as muscles and glands
- short dendrite long axon
Localisation
The theory that specific areas of the brain are associated with particular physical and psychological functions
Process of Synaptic transmission
- Nerve impulse travels down an axon
- Nerve impulse reaches synaptic terminal
- Triggers the release of neurotransmitters
- Neurotransmitters are fired into synaptic gap
- Neurotransmitters bind to receptors on the dendrite of the adjacent neuron
- If successfully transmitted the neurotransmitter is taken up by the post synaptic neuron
- Message continues along via electrical impulses
Excitatory and inhibitory neurotransmitters
- Excitatory neurotransmitters increase the livelihood that an electrical impulse will be triggered in the post synaptic neuron
- inhibitory neurotransmitters decrease the likelihood that an electrical impulse will be triggered in the post synaptic neuron
Acetylcholine
Involved in voluntary movement, memory, learning and sleep. Too much is linked to depression and foo little may result in dementia
Dopamine
Helps movement, attention and learning. Too much is linked with schizophrenia and too little could result in depression and Parkinson’s disease
Noradrenaline
Associated with fight or flight response. Too much linked to schizophrenia, too little may result in depression
Seretonin
Involved in emotion, mood, sleeping and eating. Too little is linked to depression
GABA
Inhibitory neurotransmitter. Tim little is linked to anxiety disorders
Motor cortex
Controls voluntary moment
Broca’s area
Responsible for the production of speech
Auditory cortex
Processes information from our ears
Wernicke’s area
Responsible for understanding language
Visual cortex
Processes information from our eyes
Somatosensory cortex
Processes information about touch, pain, temperature and proprioception (the position of your body)
Plasticity
- The brains ability to alter its structure and function in response to changes in the environment
- information takes a pathway through the brain, travelling form one neuron to the next via synapses
- when we’re presented with new information, new neural pathways begin to form
- using a neural pathway strengthens it- the more a pathway is used the stronger the connections between the neuronsnbecome
- if a neural pathway isn’t used it becomes weaker
Plasticity in musicians (Elbert (1995))
- Nine musicians were compared to 6 non musicians
- the musicians had a larger area of the somatosensory cortex than controls meaning the structure of the brain has changed providing support for plasticity
- however some believe this may be genetic therefore coincidental
Plasticity in brain damage
Plasticity can allow functional recovery after brain damage as ir can recover some of its lower function as due to plasticity the brain begins to rewire itself. Healthier areas nearby take over the damaged area. Method is known as CIMT (constraint-included movement therapy)
Evaluation of CIMT
+ numerous studies have shown that CIMT produces cortical reorganisation which results in regained or improved function
+ patients with aphasia as a result of stroke damage can use the therapy to become functional again
- can be frustrating for patient
- must be very intensive to be effectively
- with lots of damage ir is difficult to regain function
Uses of FMRI scans (functional magnetic resonance imagining)
- are used to research the function of the brain as well as its structure. If a participant carries our a task whilst in the scanner, the part of the brain involved will be more active
- e.g. I’d a participant moves their left hand then the part of the brain involved will show up on the scan
- can be used to diagnose medical problems because they can also show damages or diseases areas of the brain
- also used to study abnormal activity in the brain
Uses of EEGs (electroencephalogram)
- EEGs are commonly used in sleep studies
- they have also been used in the study of conditions such as depression and schizophrenia
- abnormal EEGs have also been identified in patients suffering from eating disorders such as anorexia nervosa
- this means EEGs have the potential to be used as a diagnostic tool
Uses of ERPs
- ERPs have been used a lot in memory research, as they give biopsychologists lots of clues about information processing in the brain
- research has shown differences in the ERPs of people suffering from certain psychiatric disorders compared to healthy individuals. For example, Miltner (2000) found that people with phobias had an ERP or a greater amplitude in response to images of the objects they feared, compared to non-phobic individuals.
Uses of post mortem examinations
- if a person had a medical condition when they were alive, a post-mortem could shop any structural abnormalities is that could explain their condition. For example a study by Brown (1986), which used post-mortem examinations, showed that patients who had suffered from schizophrenia had enlarged ventricles in their brains.
- post-mortems have provided evidence for localisation of function in the brain. For example Paul Broca carried out post-mortem examinations on two patients who developed speech problems as a result of brain damage. Both patients had damage to the same area of the brain, so broca concluded this area was involved in speech production.
Evaluation of brain studies
- An obvious disadvantage of post-mortem examinations is that the person has to die before the examination can be carried out
- A disadvantage of all these methods of studying the brain, is that although they do give us information about what’s going on in the brain, they don’t allow cause-and-effect to be established. For example, the enlarged ventricles in people with schizophrenia haven’t necessarily been caused by schizophrenia
