9.0 Motivation, Arousal and Homeostasis Flashcards
(67 cards)
Define consummatory behaviours:
<b>Interaction with goal object (e.g. ingestive responses)</b><br></br>- Inflexible<br></br>- Species specific behaviour
Define appetitive behaviours:
<b>Voluntary behaviour to seek out goal</b> (e.g. food searching)<br></br>- Flexible
What are the different inputs to the hypothalamus?
<b>1) From brainstem</b><br></br>- a) Somatic afferents (somatosensory reflexes)<br></br>- b) Visceral afferents (taste/olfaction)<br></br><b>2) From Amygdala/orbitofrontal cortex</b><br></br>- Motivation/emotional meaning of stimuli<br></br><b>3) Input to neurons that directly respond to hormones</b><br></br>- Steroids e.g. oestrogen (sexual behaviour)<br></br><b>4) Temperature</b><br></br>- Pre-optic area<br></br><b>5) Osmolarity sensitive neurons</b><br></br>- OVLT
Where are the temp. sensitive neurons in the hypothalamus?
Pre-optic area
Where are the osmolarity sensitive neurons in the hypothalamus?
OVLT
What are the outputs of the hypothalamus?
<b>1) Endocrine</b><br></br>- Direct (posterior pituitary)<br></br>- Indirect (anterior pituitary)<br></br><br></br><b>2) Behavioural responses</b><br></br>- Biting/shivering/drinking/mounting<br></br><br></br><b>3) Autonomic responses</b><br></br>- Fight or flight response<br></br>- There are reciprocal connections between NST and hypothalamus for ANS control
What do lesions in the pre-optic area of hypothalamus cause?
Impaired temperature regulation<br></br><br></br>(mice will not shiver but will press button for warm air)
Role of lateral hypothalamus?
Feeding centre
Role of ventromedial hypothalamus?
Satiety centre
Hormones involved in eating/hunger?
<b>NPY</b> increases <b>orexin</b> + <b>melanin concentrating hormone</b> (both found in LH) which both cause hunger<br></br><b>Ghrelin</b> increases NPY<br></br><b>Leptin</b> decreases NPY
Role of arcuate nuclei:
Contain cell bodies of NPY neurons (stimulated by ghrelin and inhibited by leptin)
Role of paraventricular nuclei:
Receive input from NPY. Output to braintsem nuclei to control ANS (reduce metabolic rate and insulin secretion)
What is found in the medial preoptic area (mPOA) of the hypothalamus?
Steroid (androgen) receptors are especially concentrated here<br></br><br></br>Essential for male sexual response
What happens with lesions in the medial preoptic area (mPOA)?
Abolishes consummatory sexual behaviour in male
What is found in the ventromedial nucleus of the hypothalamus (VMH)?
Female sex hormone receptors
What occurs with a lesion of ventromedial nucleus (VMN) of the hypothalamus?
Loss of female sexual behaviour
What region in the hypothalamus is associated with feeding (feeding centre)?
Lateral hypothalamus (actually a tract of fibres that runs through it- median forebrain bundle)
What region in the hypothalamus is associated with satiety?
Ventromedial hypothalamus
What two neuropeptides are important for feeding?
1) Orexin<br></br>2) Melanin concentrating hormone (MCH)<br></br><br></br>Both are activated by Neuropeptide Y
What are the three divisions of the amygdala?
1) Corticomedial<br></br>2) Central<br></br>3) Basolateral
What happens in corticomedial division?
Receives <b>olfactory</b> info<br></br><b>Pheromones</b> elicit social/sexual behaviour
What happens in central division?
Receives info from solitary tract<br></br>Output to hypothalamus/brain stem<br></br><br></br>Controls:<br></br>1) ANS<br></br>2) Endocrine system<br></br>3) Simple motor reflexes
What happens in basolateral division?
Input from higher-order sensory/motivational/emotional assessment<br></br><br></br>Projects to regions of planning and action
What are the effects of amygdala lesions on :<br></br><br></br>1) Sex<br></br>2) Feeding<br></br>3) Fear
<b>1) Sex</b><br></br>- Loss of appetitive motivation. Rats do not press a lever to access the partner (but would still mount the female)<br></br><br></br><b>2) Feeding</b><br></br>- Loss of appetitive motivation. Rats do not press a lever to access the partner (but would eat if food is presented to them)<br></br><br></br><b>3) Fear</b><br></br>- Reduced fear and lack of avoidance of adverse stimuli <br></br>- Prevention and impairment of fear conditioning in humans with Urbach-Weithe disease <br></br>- Overactive in anxiety disorders
1) Ventral striatum
2) Dorsal striatum
2) Dorsal striatum - Activates consumatory behaviours
- Swallowing
- Chewing
- Vomiting
- Sneezing
- Respiratory cycle
- CVS control
2) Regulation of the level of activity of brain
- Sleep and wakefulness
- Activates appetitive and consummatory behaviour
2) Noradrenaline
- Plays a role in attention and orientating
- Released from locus coeruleus
3) Serotonin
- May be involved with behaviour supression
- Deficiency can lead to OCD + impulsive behaviour
4) Acetylcholine
- Associated with learning and memory
Electrophysiologically it is defined by specific brain wave patterns
- Alpha activity (eyes closed)
- Beta activity (eyes open)
Stage 1 (drowsy)
- Theta waves
Stage 2 (light)
Stage 3 (moderate to deep)
- Delta waves
Stage 4 (Deepest)
- Delta waves
REM
- EEG look like awake state
2) Amplitude increases
Until we get to REM which looks similar to awake
1) Cortical regions
2) Extrastriate + some limbic structures
3) Prefrontal cortex
2) Extrastriate + some limbic structures - more active in REM
3) Prefrontal cortex - More active when awake
1) Primary visual cortex
2) Extrastriate cortex
2) Extrastriate cortex - more active in REM
Identify the principal neurotransmitter responsible in each case:
Raphe nuclei - 5HT
Basal forebrain - ACh
Substantia nigra - DA
- VLPA not inhibiting ascending arousal system
- Ascending arousal system inhibiting VLPA
- Awake state
FLIP-FLOP Off
- VLPA inhibiting ascending arousal system
- Ascending arousal system not inhibiting VLPA
- Asleep state
2) MCH (melanin concentrating hormone) - inhibitory for sleep (promotes wakefulness)
2) Narcolepsy
2) Blood pressure
3) Galvanic skin resistance
4) Muscle tension
5) Arousal
""We dont run because we are afraid, we are afraid because we run"""
1) Body changes (heart rate etc) provide substrate for emotion
2) Cognitive factors are important for the interpretation of body changes
Bodily changes (eg heart rate, adrenaline secretion) are necessary and sufficient to determine emotional experience, and depend upon cognitive processes to determine emotional experience.
Anxiety arises from bodily symptoms (hyperventilation, palpitations)
2) Psychic
Anxiety arises from external stressors
Beta-blocker = effective for somatic only
Benzodiazepines = effective for psychic only
2) Hippocampal formation
3) Amygdala
4) Hypothalamus
5) Anterior thalamic nuclei
6) Pre-frontal cortex
Orbitofrontal cortex
Ventral regions of anterior cingulate
Ventral stiatum
Hypothalamus
2) Panic disorder
3) Post-traumatic stress disorder (PTSD)
4) Agoraphobia
5) Generalised anxiety disorders (GAD)
2) Fear is out of proportion to true danger
3) Patient may acknowledge that fear is irrational
4) Patient changes daily routine to avoid
2) Modelling (vicarious conditioning - non fearful response)
3) Systemic desensitisation
- Constantly checking for object, therefore detects it more
2) Thought suppression
- Try hard not to think about it that you think about it more
Prevents fear conditioning in sufferers
1) Medial preoptic area
2) Lateral hypothalamic area
3) Arcuate nuclei
4) Paraventricular nuclei
5) Suprachiasmatic nuclei
6) Ventromedial hypothalamus
7) Supra-optic nucleus
8) Pre-optic
9) OVLT
10) Ventro-lateral pre-optic area
- Male consummatory sexual behaviour
2) Lateral hypothalamic area
- Feeding centre
3) Arcuate nuclei
- Cell bodies of NPY (stimulate LH and PVN to increase feeding)
4) Paraventricular nuclei
- Stimulated by NPY to control ANS via brainstem. Causes reduced metabolic rate and insulin secretion
5) Suprachiasmatic nuclei
- Control of circadian rhythm
6) Ventromedial hypothalamus
- Satiety and female sexual behaviour
7) Supra-optic nucleus
- Cell bodies for ADH and oxytocin secreting neurons
8) Pre-optic
- Thermoregulation
9) OVLT
- Osmoregulation
10) Ventro-lateral pre-optic area
- Sleep promoting (FLIP-OFF)