Biopsychology Flashcards
(15 cards)
The nervous system
A complex network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body and so helps all the parts of the body communicate with each other.Nervous system is controlled by the brain
Central nervous system
compromises the brain and spinal cord has two main functions:control behaviour and regulates the body physiological processes.
-For this to happen the brain must be able to receive information from the sensory receptors and be able to send messages to the muscles and glands of the body.
Spinal cord:
-main function is to relay information between the brain and the rest of the body.Allows brain to monitor and regulate bodily processes eg digestion and coordinate voluntary movements
Brain:
-divided into four areas; cerebrum,cerebellum,diencephalon and brain stem
Peripheral nervous system
Somatic nervous system:made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves.This system is involved in reflex actions without involvement of the CNS which allows reflex to occur quickly
Autonomic nervous system:split into parts sympathetic nervous system and parasympathetic
Neurons
neutrons are cells that are specialised to carry neural information throughout the body.
3 types:sensory, relay and motor neurons
consist of: cell body, dendrites and axon
dendrites are connected to the cell body, the control centre of neurons .From cell body the the impulse is carried along the axon
Sensory neurons:carry nerve impulses from sensory receptors to the spinal cord and brain
Relay neurons: allow sensory and motor neurons to communicate with each other
Motor neurons:directly and indirectly control muscles.When stimulated release neurotransmitter that binds to receptors on the muscle which triggers a response of muscle contraction
Synaptic transmission
- Action potential has been achieved at the end of the axon
- then needs to be transferred to another neutron or to tissue
- for this to happen it must cross gap between between presynaptic neutron and postsynaptic neuron(synapse).
- Action potential reaches the synaptic vesicles it releases their contents
- released neurotransmitter diffuses across the gap between the pre and post synaptic cell
- binds to specialised receptors on the surface of the cell that recognise and are activated by that particular neurotransmitter
Summation
Excitatory neurotransmitters are the nervous systems on switches and increase the likelihood of an excitatory signal being sent to the postsynaptic cell which is more likely to fire.
Inhibitory neurotransmitters are the nervous systems off switches and make it less likely for the cell to fire
net result of this calculation is known as summation
Endorcrine system
-uses hormones transferred through the bloodstream
Pituitary gland: located in the brain,regulates functions of other glands-LH
Adrenal gland:located above kidneys,triggers sympathetic nervous system and increases heart rate-Adrenaline
Testes/Overies:increases secondary male or female sex characteristics-oestrogren or testosterone
fight or flight response
acute stressor:
-threat registered in brain
-activates sympathetic nervous system
-adrenaline released
Chronic stressor:
-if the stressor continues for a long period of time body needs to find new resources
-hypothalamus kicks in and forms the pituitary gland that cortisol is needed
-communicated with adrenal gland and releases cortisol
-suprresses immune system
Ways of studying the brain
FMRI:measures oxygenated and deoxygenated blood using magnetic qualities
+non invasive
-indirect measure of brain
EEG:looks at frequency of brain activity using electrodes to detect electrical impulses triggered in brain activity
+direct measure of brain
-lacks spacial resolution
ERP:similar to EEG,apart from someone is asked to look at stimuli and looks at brain activity,done multiple times
+temporal resolution
-lacks spacial resolution
Post mortem:brain is disected of patients with brain damage or abnormal patients
+direct measure
-invasive
Localisation of function
Motor cortex:located in frontal lobe and responsible for voluntary movement-contralateral
Somatosensory cortex:located in the parietal lobe responsible for sensory information
Brocas area:located in the frontal lobe responsible for speech production
Wernickes area:located in temporal lobe,responsible for speech comprehension
Visual centre:located in the occipital lobe, allows us to see
Auditory centre:processes verbal info
evaluation of localisation of function
+Support from case studies:Aphasia
~aphasia is the inability to understand or produce speech
~consistently found that people with expressive aphasia(unable to produce speech) have damaged their broca’s area.People with receptive aphasia (unable to understand speech) have damage to their wernicke area
COUNTER:only case studies which lack population validity so cannot be applied to everyone
+support from brain scanning techniques
~shows that different regions of the brain are responsible for different tasks in the brain.Shows cause and effect as well as empirical evidence for localisation
STUDY:Beesley found that prefrontal cortex codes for short term memories but not long term
COUNTER:FMRIs lack temporal resolution.Can’t 100% guarantee its cause+effect
-Equipotentiality
~view that basic motor+sensory functions may be localised but higher mental functions are not.EG-cognitive reasoning
COUNTER:initial loss of functions is due to specific damage in the brain for localisation theory
-communication rather than localisation
~ brain functions are not localised
instead it is the communication in the brain which is more important as a result damage to connections between two areas could be more damaging than an injury to one of the areas
COUNTER:people have been able to recover from damage to specific areas(functional recovery).Instead what happened is parts of the brain can take responsibility for these tasks.Brain more likely to work as a unit
hemispheric lateralisation
different halves of the brain have different functions
Sperry:
procuedure 1:asked to stare at dot on screen+words and images are flashed onto each side and asked to write down what they see
procedure 2:objects presented to either right or left side of screen.Participants asked to draw what it was
FINDINGS:
Procedure 1:unable to repeat word or identify image if presented in left visual field (right hemisphere).Could identify is presented in right field (left hemisphere)
procedure 2:
objects in right hand could be described whereas objects in left hand was a guess
evaluation of hemispheric lateralisation
+scientific (cause and effect:valid as it’s a lab experiment so can control it
COUNTER:lacks ecological validity.Tasks done are tasks you wouldn’t do in every day life
-small sample sizes (11 people),severely epileptic.They are unlikely to have right side dominance (3 in 10)
-Turk:discovered ability to speak in right hemisphere as well.Suggests their is language in right side but needs to be trained
-Anderson found that infants who had an entire hemisphere removed were able to recover and develop all normal functions suggesting each hemisphere is able to carry out any function that the other one specialises in
Brain plasticity
Brain plasticity:ability of the brain to adapt and change shape and activity through experience and illness
at any time
Functional recovery:
two processes:
Pruning:neurons and synaptic connections that are not used anymore are destroyed by the brain.This helped the brain work more efficiently
Bridging:neurone make new connections to other neurons
evaluation:
Maguire:correlation between length of service and posterior hippocampus volume
COUNTER:correlation can’t show cause and effect.Omly focuses on one area of the brain
Turk:case study:found a split brain patient was able to read and speak from his right hemisphere
COUNTER:case study lacks population validity and can’t be generalised to everyone
functional recovery
brain loses an ability EG-language and is able to recover that ability overtime.
-recovers if brain has the right connections+can make new ones through bridging
Neural unmasking:
Axon sprouting:axons grow and connect to undamaged areas
Recruitment of homologous areas in the opposite hemisphere:hemispheres are largely symmetrical but each side may have strengths.Involves functions being taken care of by dormant areas of other hemisphere
neurogenesis:birth of new brain cells
stem cells:unspecialised cells which can adapt to carry out any function
Evaluation:
+research support:Tajiri found damaged rats treated with stem cells showed improvement
COUNTER:generalising animals to humans
+scientific:shows clear cause and effect.Objective when considering physical recovery although recovery of function maybe subjective
-age differences:too simplistic to say anyone can refrain functional recovery.Only 20% of over 26s showed functional recovery
