brain learning and motivation: brain behaviour-motivation Flashcards
we are motivated to..
eat sleep drink regulate body temperature etc…
variations in moticated behavious
food intake
sexual behaciour
bible reading
…all varyupon individual differences
what is motivation
A process/condition that influences our behaviours to fulfill both physical and psychological needs/desires
driving force behind:
emerging: initiating actions/behaviours
directing: guides behaviour toward a goal
persistance: keep going until need is satisfied
needs and drives
Drives are psychological states that create arousal which motivates and organism to satisfy a need
needs and drives: origin
all drives ar not equal:
the wisdom of the body
• Homeostasis (Cannon, 1932)
homeostasis
A state of internal physiological equilibrium that the body strives to maintain
why we ar motivated to meet our needs
physiological basis for motivation
psychological experience of motivation
these both equal back to drive reduction returning the balance
eating
regulation of food intake
when it goes wrong this is called regulation failures
eating: physiological regulation of food intake
all different parts of the body play a roll e.g. stomach small intestine
adepose tissue and liptin enzyme that monitors fat as well as glucose monitoring in liver
the hypothalamus
consists of : lateral region (go centre) hypothalamic nuclei ventromedial region (stop center) contains over 20 clusters of neutrons (nuclei) all implicated in eating
regulation of food intake and the hypothalamus
sensitive to glucose levels in the blood
sensitive to leptin
sensitive to external stimuli
hpothalamus is brain structure that most influences eating
brain damage and body weight
hyperphagia: excessive hunger
aphagia: refusal to swallow
when the system is all going well
we eat what we need
calorie intake remains constant
metabollism etc lowers when activity level lowers
while all keeping weight constant
when things go wrong: obesity
men 5-23%
women 7-36%
obesity causes
physiological: no constant changes
Genes: eg (e.g. Sørensen et al., 1992; Bouchard et al., 1990; Maes et al., 1997)
food availibility and sedentary lifestyle
eg Wadden et al, 2002)
when things go wrong: Anorexia Nervosa
1%in industrialised societies enviromental causes: westernised society psychological: perfectionist personality biological: genetic predisposition
what do different motivations have in common
External cues/incentives provide the pleasure that we take in eating
pleasure center in the brain
accidentally discovered by (Olds, 1953; Olds & Milner, 1954; Olds, 1958)
While stimulating the bran, one electrode missed its target and suddenly his rat started repeating its behaviour.
Obsessively pressed a lever 5-7 thousand times an hour for the same stimulation
similar results have been seen in other species
medial forebrain bundle (MFB)
consists of: Axons from nucleus accumbent Dopamine interaction nucleus accumbens medial forebrain bundle
biological basis of reward
Perhaps this brain-stimulation reward is what motivates us do to things that are good for us?
– Brain stimulation more likely if natural motivation strong (Olds & Fobes, 1981)
Dopamine released naturally when need met (e.g. Phillips et al., 1991)
– Blockade of dopamine reduces behaviour (Wise & Rompre, 1989)
drugs and motivation
- Drugs affect dopamine levels in MFB (see, e.g. Di Chiara, 1998; Kelley, 2004; Drevets et al., 2001 )
- Perhaps also affects over-eating (Davis et al., 2004, 2007) and under-eating (Davis & Woodside, 2002; Eiber et al., 2002)?
