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
Satiety neural substrates
Linked to the hypothalamus
Satiety neural substrates research
Monkeys stop reacting to smell of food when have enough
Satiety OFC
Links to reward and when full it no longer feels like a reward
Satiety OFC evidence
• OFC activates less when sniffing bananas after satiety
• PET scan showed activation when found chocolate pleasant
Satiety - opioids actions
The more palatable a food is the more options are released, so niceness links with wanting it
Sensory specific satiety
Not all foods loose their pleasantness which can encourage over eating, but when they do it encourages varied eating
Mood in eating
Mood effects eating as stress/anxiety can cause under eating but depression can cause over for the energy in carbs
Serotonin hypothesis - eating behaviours and research
This says when carbs are eaten Thai increases insulin which reduces amino acids in the blood except from tryptophan. This goes to the brain and releases serotonin reducing stress.
• research shows when overweight women were either given a high protein or carb drink and they rated carb better for improving mood
Role of stress
When the individual is stressed this links to high cortisol which causes eating to secure food in times of stress
Dopamine hypothesis - eating behaviours and research
This says when eating carbs they feel better due to the dopamine in these.
• shows when watching g a sad and happy film more choc was eaten in happy
• however another piece showed when shown funny/sad clip and offered popcorn, more ate when sad
Cog aspects - obesity and research
Memory and attention
• can affect memory
- r - those with memory problems may eat more
• when distracted can eat more
- r - number of people correlated with meal size
- r - eat more with people present
Obesity
A >30kg/m3 which can cause strokes, cancer, diabetes etc and has been increasing. Doubled since 1980’s.
Leptin - obesity
Leptin is stored in adipose cells and released into blood when full/at satiety to reduce intake. When dieting and not full, less leptin is released so generates hunger.
Explanations of weight gain - obesity
Thrifty gene, genetic drift, protein leverage.
1. When go through famine, they learn to deposit fat and this often doesn’t come, can also be passed onto offspring (dutch famine study).
2. Genetic drift - animals that’s suffer high predation eat lots to maintain weight and have back up
3. Protein leverage - protein heals through energy intake but can cause obesity
Risk factors for obesity and research
Early development, taste (liking and sensitivity), externality, trauma
1. Thrifty gene babies are smaller and then become obsese to make up for it
2. The CD36 gene can affect pleasantness of food so either need a low amount or a high amount to get this causing obesity (research).
3. Some respond to smell/taste more
4. Trauma correlated. 60% of observe were abused (research).
Sleep- what is sleep
A natural reoccurring altered state of consciousness where muscles movement is reduced as well as reduces interacting with environment
Arousal stages
Arousal - physiologically awake and alert
Sleep - altered states of consciousness
Coma - period of unconsciousness due to tbii
Vegetative state - altering between sleep and moderate arousal
Minimally concious- brief stages of purposeful actions
Brain death - no brain activittyy
Sleep stages
- Awake and alert - beta waves - aware.
- Awake and drowsy - Alpha waves - drowsy but muscles work
- Sleep - light, heavy and dreaming
- • NREM 1 - alpha and theta waves - easily awoken and some dreams
• 2 - bursts of brain activity to respond to stimuli
• 3 - Thelma and delta waves -
• 4 - give off low frequency waves - loss of xoncousness - REM - no dreaming, twitching, muscle paralysis, irregular breathing
Each is 90 mins
Functions of sleep
Is the only universal behaviour which has no clear underlying function
However must do because other wise it would be eliminated and not universal (universal behaviour).
However is fatal without and is used for concentration and mental health
Theories of sleep
Hibernation theory and conservation theory
Hibernation theory - sleep and evidence
It is a way to conserve energy, which the sleep pattern links to energy intake such as size and diet.
• carnivores eat more than herbivores
• Smaller animals need more sleep
• those aware of predators all the time get less sleep
• increased periods of sleep in energy shortages
Restoration theory and evidence - sleep
Sleep is for the repair and regrowth of cells, as REM restores brain cells and more rem is used in brain growth
• less sleep as brain stops growing
• when rats were deprived of sleep for 4 weeks they ate more for more energy but there immune systems failed after 3 weeks
• 50% of REM is restored
Ultradian Cycle - BRAC: biological mechanisms of sleep
90 min cycle unaffected by light, eating, sleep cycles etc. however other bio tyhtms are these bio rhythms however are controlled by endogenous pacemakers (internal clock) and exogenous zeitgebers (external changes). And sleep is controlled by these changing