BIOPSYCHOLOGY: CONCEPTS

1. when neuron is in resting state inside is negative compared to outside. when activated by stimulus inside becomes more positive for a second. this causes action potential which creates electrical impulse
  1. when impulse reaches end of neurone it triggers neurotransmitters to be released and travel across synaptic cleft,when they reach postsynaptic neurone receptor sites, the chemical message in converted back into an electrical impulse
hypothalamus triggers sympathetic branch causing physical arousal, adrenaline is released + changes physiological changes which are needed for fight or flight. after parasympathetic branch kicks in and reduces changes made earlier
different parts of the brain perform different tasks and are involved with different parts of the body, so if a certain area of the brain is damaged the function associated with that part will also be affected
1. cerebral cortex is outer layer of brain 3mm thick in humans and its what makes us better than animals as ours is very developed
2. 1. 1. at back of frontal lobe is the motor area which controls voluntary movement
    2. front of parietal lobe is somatosnesory area which processes sensory info e..g touch + heat. the more sensitive a body part is the more space it takes up in this area
    3. occipital lobe is the visual area which recieves + processes visual info
    4. temporal lobe is the auditory area which analyses speech based info, Wernicke's + Broca's area is found HEAR
3. Broca's area in left temporal lobe controls speech production damage to this area causes speech to be slow and not fluent
4. Wernicke's area also in the left temporal lobe controls language comprehension, damage to this area means you can still speak fluently but its nonsense
the brain is able to change and adapt as a result of experience and learning regardless of age
1. cabbies have to complete The Knowledge which tests their recall of London's street's + routes have more grey matter volume in their hippocampus that a matched control group
2. healthy areas of the brain are able to take over functions of areas that are damaged or missing. e.g after a stoke
  1. the brain rewires and reorganises itself by forming new synaptic connections and activating secondary neural pathways that aren't usually used.
    1. growth of new nerve endings, which connect with other nerve cells to form new pathways, and reforming of blood vessels
    2. getting homologous areas on the other side of the brain to perform the specific tasks the damaged part used to do
Certain mental processes are controlled by only one of the hemispheres and not both.
1. corpus callosum cut separating the 2 hemispheres, so we c
  1. patients that saw image on right eye (controlled by left hemi) easily described it. Same image couldn't be described when the saw it on left eye (right hemi). this is cause right hemi doesn't have language processes.
    1. patient were able to pick matching object or associated object with left hand when shown image to left eye,
  2. when word 'key' was shown to left eye and 'ring' was shown to right eye, they would write key with left hand and say ring
    1. right hemisphere was also better at recognising + matching faces
WAYS OF INVESTIGATING THE BRAIN
1. when area of brain is more active it needs more oxygen + so more blood flow is directed there, these changes in blood flow are detected by fMRI which makes 3D image of this
2. EEGs measure brain's electrical activity via electrodes fixed to scalp by skull cap. this provides overall brain activity as patterns are generated from millions of neurons
3. all extraneous brain activity from original EEG is filtered out by statistical averaging technique so only represenataions of responses to specific task or stimulus are left. these are ERPs
4. analysis of brain after death, usually brain of those with disorders+ defects in mental processes , damaged areas are examined to see if it caused the disorder
Siffre spent 2 months in a cave he left in sept but thought it was august. he had no natural light
1. a group spent 4 weeks in bunker with no natural light, all but one of them had a rhythm of 24-25 hrs
2. 12 people in cave for 3 weeks they slept when clock said 11:45pm + woke up at 7:45am, clock was gradually sped up so 24 hrs became 22hrs
3. suggests that natural sleep/wake cycle is just over 24hrs but is shortened by exogenous zeitegebers. but circadian rhythm is not easily overridden by external environment
menstruation is a infradian rhythm, although its an endogenous system its can be influenced by exogenous factors
1. pheromones from 9 women with irregular periods were collected + rubbed on the upper lip on 20 women with irregular periods, on day 1 they would receive pheromones from day 1 of the menstruation and so on. in 68% the cycles moved closer to that of their pheromone donor.
light sleep you're easily woken, brainwave patterns are slow + rhythmic
1. deep sleep ,hard to wake up from delta waves which are slower than before and have greater amplitude
  1. brain activity spikes almost as if you're awake , there's rapid eye movement under eyelids, highly correlated with dreaming
SCN is a primary endogenous pacemaker in mammals,it receives info about light from the optic chiasm even when our eyes are closed
1. when SCN connections were destroyed in chipmunks their sleep/wake cycle vanished + most of them died
2. when tissue from mutant hamsters that had 20 hr sleep/wake cycle was transplanted into normal hamsters it changed their cycle to 20 hrs too
3. SCN passes its info on light and day length to pineal gland, at night pineal gland increases melatonin production, which induces sleep
light is a key EZ, it can reset SCN to affect sleep/wake + indirectly influences processes
social cues act as EZ as they help to entrain rhythms e.g. mealtimes + baths help

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BIOPSYCHOLOGY: CONCEPTS

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	Created by Ma-adjoa Akwah about 7 years ago