Motivation, homeostasis and arousal Flashcards
(30 cards)
Pre-optic area
Contains temperature sensitive neurons and is involved in thermoregulatory behaviour
Medial pre-coptic area
Contains steroid receptor neurons
Involved in copulatory behaviour
Lateral hypothalamus
Involved in feeding behaviour that is dependent on motivational state
Hypothalamic inputs
- Brainstem (somatic and visceral afferents, and RF input for taste/olfaction)
- Forebrain (amygdala and orbitofrontal cortex) for emotional significance
- Hormone sensitive neurons
- Temp (pre-optic area) and osmolarity (OVLT; vascular organ of lamina terminalis) sensitive neurons
Starting feeding
Ghrelin activates NPY neutrons in arcuate nucleus
- These activate orexin and MCH neurones in lat hypothalamus
Lack of inhibition on NPY neutrons from leptin also helps
Stopping feeding
Leptin inhibits NPY neurons so get inhibition on the lat hypothalamus and less feeding behaviour
Consummatory sexual behaviours
Male: medial pre-optic area of hypothalamus (testosterone involved)
Female: ventromedial nucleus of hypothalamus (oes involved)
Cortico-medial division of amygdala
Responds to pheromones
Output to hypothalamus for sexual behaviour
Appetitive
Central nucleus of amygdala
Controls autonomic nervous system, endocrine and simple reflexes
Basolat amygdala
For higher order sensory/emotional assessment
Amygdala lesions
Lose lever pressing for mate (appetitive)
Role of dopamine
Provides activation onto motor systems (using input from RF which is activated by motivationally significant stimuli and modified by amygdala and orbitonfrontal cortex)
Dopamine lesions in striatum
Aphagia and adipsia (consummatory loss)
Dopamine lesions in nucleus accumbens (part of reward system)
Loss of appetitive (ear wiggling in female rats)
Arousal system
Ascending reticular activating system
Involves DA, NA, Ash, 5-HT
Functions of reticular formation
To integrate basic, stereotyped responses
To regulate the level of brain activity
Sleep
Active suspension of consciousness and emergence of specific electrophysiological brain activity
Noradrenaline
From Locus Coerulus neurons
Involved in attention
Serotonin
From Raphe nucleus of brainstem neutrons
Involved in behavioural inhibition in averse conditions (so reduced 5-HT linked to impulsivity)
Acetylcholine
From Basal forebrain neurons
Involved in learning and memory
Wakefull EEG
Low amplitude beta activity (for high freq, with active cortex, eyes open etc) Alpha activity (for more quiet wakeful state)
Sleeping EEG
1) Theta waves
2) K complexes
3) Delta rhythms
4) Higher amplitude delta rhythms
REM: beta and alpha rhythms
Changes in neurotransmitter levels during sleep
Non-REM: all levels fall
REM: Ash levels peak to normal levels
Cortical activation in REM/non-REM
Non-REM: visual cortex more active
REM: higher visual areas e.g extra striate cortex more active
