12 Pages
Unlock Document

University of Toronto Scarborough
Rutsuko Ito

lec07 hypothalamus and motivation lecture overview 1. focus on hypothalamus as a motivation center a. known as a motvation center b. evidence for this c. also have different functions (refer to lec08) 2. regulation of feeding behavior a. long term regulation i. hunger vs satiety centers b. short term regulation 3. weight loss, exercise and food regulation a. practical applications motivation center in brain 1. involved in control of 4 Fs a. feeding b. fucking c. fighting d. flight 2. ability to sense deviations from set point 3. want specific receptors to sense changes (osmolarity) 4. highly integrated with other centers a. correct errors 5. hormonal regulation 6. control over output to sympathetic and parasympathetic responses 7. what makes the hypothalamus fit its functions? a. comparative point of homeostasis i. maintaining homeostasis the case for hypothalamus as the brain center for motivational control hypothalamus as the motivation / drive center 1. known to coordinate the endocrine / autonomic systems to motivate homeostasis 2. maintains body's internal environment within a narrow physiological range hypothalamic functions 1. sleep and wakefulness 2. etc anatomical features 1. many nuclei 2. most of them are bathed in CSF a. third ventricle containing CSF i. nuclei located around the third ventricle principal hypothalamic nuclei 1. anterior hypothalamic area 2. suprachiasmic nucleus 3. paraventricular nucleus 4. arcuate nucleus 5. ventromedial nucleus 6. lateral hypothalamic area 7. posterior hypothalamic area anatomical features 1. access to CSF a. so that nuclei will be able to sense changes in chemical and hormonal levels 2. hypothalamic capillaries are fenestrated a. allows large molecules to enter into the nucleus b. useful in being able to detect changes in chemical concentrations neural connections - inputs 1. well connect to subserve regulatory function a. gustatory/sensory information i. retina ii. olfactory iii. cutaneous 1. noxious response on skin iv. visceral 1. internal states 2. important in parasympathetic and sympathetic systems 2. noradrenaline / 5HT 3. limbic structures a. hippocampal b. amygdala hypothalamic outputs 1. affect endocrine control over behavior 2. pituitary gland large output structure  release of hormones  regulation over various functions a. what types of hormones are released? b. anterior vs posterior pituitary gland 3. neural control a. division of autonomic system i. rest and digest 1. parasympathetic ii. flight or fight 1. sympathetic 2. changes according to stressful situations intrinsic sensitivity of hypothalamic neurons 1. how hypothalmic neurons respond to various variables a. osmotic pressure (osmotic receptors) b. temperature c. glucose / fatty acid d. hormones three important functions 2. what the hypothalamus does a. three modes i. feedback system 1. deviation from a certain setpoint 2. fix the error ii. feedforward system 1. stressful situation 2. body overrides feedback system and feed forwards hormonal response 3. similar to anticipation 4. e.g. fever a. body raises temperature to combat virus iii. anticipation 1. hypothalamus can adjust its output to meet future needs 2. e.g. insulin secretion happens prior to food intake (in anticipation of the food) interim summary 1. hypothalamus as motivational center 2. different motivational states associated with different hypothalamic nuclei 3. but must remember that hypothalamus functions as a circuitry a. manipulation one neuronal population can lead to suppression or activation of feeding regulation of feeding behavior regulatory mechanisms for feeding 1. food intake controlled by reflexive mechanisms 2. hunger signal from stomach to brain  leading to change in behavior  eating 3. stomach gives us the cue that we're hungry 4. two aspects of regulation a. long term i. tonic regulatiion ii. wanting to lose wait b. short term i. episodic regulation ii. associated with episodes of eating and signalling of satiety energy balance 1. catabolism vs anabolism a. store energy i. maintain energy and store it at a homeostatic level b. catabolism i. ... c. anabolism i. ... dual center hypothesis 2. suggests that hypothalamus has two centers that are responsible for hunger and satiety a. lateral hypothalamus as hunger center i. electrolytic lesion here resulted in loss of interest in food ii. stimulation of lateral hypothalamus resulted in food eating b. ventromedial hypothalamus as satiety center i. electrolytic lesion here resulted in overeating and rapid weight gain ii. stimulation of VMH lead to abandoning eating (even if hungry) iii. what does satiety mean? 1. ... 3. glucostatic theory a. eating  increase glucose  excite VMH / inhibit LH  satiety  stop eating  decrease glucose  excite LH / inhibit VMH  hunger  issues with LH = hunger center 1. rats with LH lesions kept alive by force feedings resulted in recovered voluntary eating a. by recovered function b. or other centers of the brain involved in hunger 2. stimulation did not only induce feeding a. induced other behaviors associated with feeding 3. stimulation of LH resulted in general increase in motivational behavior 4. electrolytic lesions are aspirative a. affects other neuronal circuits  non-specific what does the LH do? 1. winn and dunnet a. LH involved in some aspects of appetite control 2. edmund rolls a. LH neurons respond to taste and sight of food b. responsive of LH neurons to sight and taste of preferred food diminished as satiety increased i. most
More Less

Related notes for NROC61H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.