Describe EEGs and evaluate it
Use a skull cap to measure how many neurons are firing in the brain. The electrodes pick up the activity of the neurons to see the amplitude and the frequency. Synchronised patterns = waveform, desynchronised = no waveform.
+ helped in identifying epilepsy
+ high temporal resolution
- low spatial resolution as cannot ding exact location
Nervous system overview
CNS = Brain, spinal chord
PNS = autonomous NS - parasympathetic, sympathetic
= somatic NS - afferent pathways, efferent pathways
Describe the autonomous nervous system
Sympathetic
- activated when stimulated
- gives extra energy
- increased heart rate, digestion
- stops digestion, saliva
Parasympathetic
- opposite
- to restore energy
- keeps heart and breathing rate low
- directs blood flow to digestive system
Describe the 2 parts of the peripheral nervous system
Autonomous
- regulates our internal environment (heart rate, digestion etc)
Somatic
- controls muscle movement
- afferent pathways = transits info to CNS (sensory)
- efferent pathways = connected to muscles (motor)
Examples of infradian rhythms
Menstrual cycle
- McClintock studied external factors affecting it with pheromones on 29 women
- cotton pad on armpit of 9 women during different stages of cycle.
- frozen and rubbed in the lip of others
- 68% experienced changes to cycle closer to the person
SAD
- melatonin increased as lack of light means the process continues longer. Affects production of serotonin causing depressive symptoms.
Describe the areas of the brain
Somatosensory cortex - parietal lobe - receives sensory info Motor cortex - frontal lobe - voluntary movement Visual cortex - occipital lobe - visual info Auditory cortex - temporal lobe - language info
Examples of endogenous pacemakers
Melatonin/serotonin
- sleep/wake cycle affected as at night melatonin is secreted while serotonin is decreased causing sleepiness
SCN
- bundle of nerve cells in the brain that receive info about light enabling out body to adjust
What is excitation and inhibiton
Excitation
- when a NT increases the positive charge of the postsynaptic neuron
- increases the likelihood that the impulse will fire
Inhibition
- increases the negative charge of the postsynaptic neuron
- decreases the likelihood that the impulse will fire
Evaluation of endogenous pacemakers and exogenous zeitgebers
- EZ influence overstated
Miles = blind man from birth had rhythm of 24.9hrs, despite social cues, his sleep wake cycle could not be adjusted.
Similarly people that live in the Arctic still sleep regularly despite abnormal light levels
Interactionist approach
- work together
- zeitgebers affects the internal working of your body which regulate
Explain language and the brain
Language only found in the left side of the brain
Broca’s area
- Broca aphid an autopsy on someone who could only say tan
- found damage the the left frontal lobe
- concluded Broca’s area responsible for speech production
- the damage to this is called expressive aphasia
Wernickes area
- studied patients who had no trouble producing speech, but could not produce fluent sentences and were nonsensical
- found auditory cortex damaged
- concluded wernickes area responsible for speech comprehension
Factors that affect functional recovery
Age - children’s pathways are much less fixed
Gender - girls recover slightly better
Education
Describe post mortems and evaluate it
Analysing a dead persons brain. They usually have a rare disorder. Areas of damage are examined to establish the likely cause of affliction.
+ provided a foundation for research into lateralisation etc
- can never be certain of causation
- ethical issues = informed consent
What is plasticity
The brains tendency to change and adapt due to new learning
Evaluation of plasticity and functional recovery
+ practical application after accidents can be things such as cognitive training and re-learning to rebuild the brain.
+ Maguire =
studied brains of London taxi drivers and found significantly larger hippocampus than control group. This is associated with development of spatial and navigational skills.
- phantom limb syndrome where they experience same sensations even if nothing there. These can be very painful and is due to poor reorganisation.
Describe synaptic transmission
Neurotransmitter reaches axon terminal of presynaptic neuron
NT stored in vesicles in presynaptic neuron
NT molecules releases into synapse
NT diffuses across the synaptic cleft
NT bind to receptors on postsynaptic membrane
If threshold is reached the impulse can be fired (excitatory) or inhibitory if not.
Describe fMRIs and evaluate it
detects changes in how oxygenated the blood is. When an area of the brain changes from oxygenated to deoxygenated (consumes oxygen) it shows the area is active. The end result is 3D activation map - helps localisation of function.
+ doesn’t use radiation so risk free
+ high spatial resolution
- low temporal resolution (5 second time lag)
- very expensive
Evaluation of research into circadian rhythms
+ application to
drug treatments = certain times when drugs more effective
shift work = adjusting to the day cause poor performance and heath problems
- generalisations from case studies
What is hemispheric lateralisation
The idea that the two halves of the brain are functionally different and certain behaviours are mainly controlled by one hemisphere
What are exogenous zeitgebers
External cues that affect our biological rhythms
Describe fight or flight
Streets detected
Hypothalamus activated
Sympathetic branch of ANS activated (heart rate increase)
Activates adrenal medula in kidneys
Adrenaline released (oxygen/blood increased to muscles/brain)
Explain the endocrine system
Secretes hormones which are requires to regulate bodily functions. Pituitary gland seen as the master gland as it controls most of the hormones released.
Main example of a ultradian rhythm
Sleep cycle
- stages 1+2 = light sleep, easily awoken
- stages 3+4 = slower waves, difficult to awake
- stage 5 = R.E.M. sleep, body paralysed yet brain active (dreaming)
What is localisation of function
The theory that different areas of the brain are responsible for different behaviours
Evaluation of research into infradian rhythms
+ evolution and menstrual cycles
advantageous to give birth at the same time in past as it increases survival chances
- way too many extraneous variables to know the true causes of change (eg stress, dieting, exercise)
