2103 Flashcards
The two hemispheres
This is the two halves of the brain which are separated/connected with the corpus callosum. The left side processes info from the right side of the body vice versa.
Hemispheric Lateralisation
The theory that the two halves have different functions, as a function is mainly controlled by one side.
The supposition of hemispheric lateralisation
The left side is language (logical and symbolic) including brocas and wernickes. The right side is perception (Visio spatial and artistic).
What sperry wanted to research
The extent to which functions are localised. He investigated this in those who had their corpus collosum cut due to seizures.
How speedy researched
• Tests of the right hemisphere.
• visual stimuli tests.
• tactile stimuli tests.
Tests of right hemisphere
Puzzles/tests.
Visual stimuli tests
A picture was shown for 1/10 of a second both sides and had to say what it was,
Tactile stimuli test
Had to feel and object and say what it is
Sperry’s research findings
- Naming objects by feeling
- Picking up the object they felt
- Composite words
- Faces
- Drawing abilities
Narumoto’s split brain research
P’s said the emotion on the left of individuals faces as this is where perception is in the brain.
Clarke et al’s research split brain
Lady with right hemisphere damage Could only find her way around familiar places if explained with a visual feature.
Hunger/the cephalic stage as initiation
Hunger is the physiological changes which prepare the body for food which disturbs homeostasis.
The cephalic stage:
1. Senses pick up on food which stimulates the amygdala and hypothalamus.
2. This sends signals to the stomach which via the vagus nerve produces acids as a response
Cephalic stage evidence
• when give animals food stimuli but without food made them hypoglycaemic
• when injected food into animals stomachs caused hyperglycaemia as hadn’t gone through processes
Storing nutrients
• short term - in the liver and muscles as energy for muscles, the liver and converts some into glycogen
• long term - in the adipose tissue in the abdomen which is used when short term energy gets low and then can be used for energy when fasting to nourish brain
Storing nutrients evidence
Glucose detectors were found in the liver for the storing of short term energy which allows maintenance of weight set point
Glucose dual centre model
The liver sends info about glucose to two areas; the VMH and LH.
1. The VMH is activated when glucose levels increase to feel full and stop eating
2. The LH is activated when levels are low to increase eating
Glucose dual centre model evidence
Lesion studies in animals support this
Grehlin for increasing feeding
Grehlin is a hormone produced in the stomach and pancreas which travels to the neurons to activate the LH. This then causes feeding, which is in proportion to hunger.
Grehlin evidence
Blood was tested for levels each 5 mins from lunch to tea on 6 p’s as well as a subjective hunger measure.
This found that after lunch levels were low and high before tea supporting that it acts as a hunger signal.
CCK
Modulates emptying the gall bladder and stomach. This is the opposite of grehlin as reduces feeding, as when food is digested this is released.
PYY - inhibiting eating
A hormone in the gut which is released to suppress appetite in proportion to intake.
PYY evidence
8p’s fasted then had either a saline drip or PYY drip.
This showed those with the PYY drip ate 25% less than saline drip.
Inhibiting eating - leptin & alpha-MSH
Let in is released from adipose tissues which binds itself to receptors in VMH to reduce eating.
Alpha-MSH is then released when strong signals in the VMH are sent. AM is sent to hypothalamus which reduces hunger.
Satiety
• the feeling of fullness after eating
• hunger implicates this
• food tastes better when hungry
• Alliesthesia - a good stimulus can feel in pleasent or pleasant based on fullness