9.0 Motivation, Arousal and Homeostasis Flashcards
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
Through which neural pathway does the amygdala control voluntary action?
Output to ventral striatum (nucleus accumbens and ventral caudate + putamen)
What is the role of dopamine on the<br></br>1) Ventral striatum<br></br>2) Dorsal striatum
<b>1) Ventral striatum</b> - Activates appetitive behaviours<br></br><b>2) Dorsal striatum</b> - Activates consumatory behaviours
Where is the location of the reticular core?
Medially in brainstem
Function of reticular formation:
<b>1) Basic pattern generation</b><br></br>- Swallowing<br></br>- Chewing<br></br>- Vomiting<br></br>- Sneezing<br></br>- Respiratory cycle<br></br>- CVS control<br></br><b>2) Regulation of the level of activity of brain</b><br></br>- Sleep and wakefulness
What are the four chemically defined components of the reticular formation:
<b>1) Dopamine</b><br></br>- Activates appetitive and consummatory behaviour<br></br><br></br><b>2) Noradrenaline</b><br></br>- Plays a role in attention and orientating<br></br>- Released from locus coeruleus<br></br><br></br><b>3) Serotonin</b><br></br>- May be involved with behaviour supression<br></br>- Deficiency can lead to OCD + impulsive behaviour<br></br><br></br><b>4) Acetylcholine</b><br></br>- Associated with learning and memory
What is the behavioural definition of sleep?
Normal suspension of consciousness<br></br><br></br>Electrophysiologically it is defined by specific brain wave patterns
What nucleus in the hypothalamus controls circadian rhythmicity?
Suprachiasmatic nucleus
What are the different stages of sleep:
<b>Awake</b><br></br>- Alpha activity (eyes closed)<br></br>- Beta activity (eyes open)<br></br><br></br><b>Stage 1 (drowsy)</b><br></br>- Theta waves<br></br><br></br><b>Stage 2 (light)</b><br></br><br></br><b>Stage 3 (moderate to deep)</b><br></br>- Delta waves<br></br><br></br><b>Stage 4 (Deepest)</b><br></br>- Delta waves<br></br><br></br><b>REM</b><br></br>- EEG look like awake state
Summarize the EEG changes as we progress through sleep:
1) Frequency decreases<br></br>2) Amplitude increases<br></br><br></br>Until we get to REM which looks similar to awake
Define REM sleep:
Sleep state following slow-wave sleep characterised by rapid-eye movement, beta rhythms (EEG), paralysis of large muscles, increase in BP, HR and metabolic rate
Compare activity of the following regions in REM sleep vs Awake:<br></br><br></br>1) Cortical regions<br></br>2) Extrastriate + some limbic structures<br></br>3) Prefrontal cortex
1) Cortical regions - Equal activity<br></br>2) Extrastriate + some limbic structures - more active in REM<br></br>3) Prefrontal cortex - More active when awake
Compare activity of the following regions in REM sleep vs Non-REM sleep:<br></br><br></br>1) Primary visual cortex<br></br>2) Extrastriate cortex
1) Primary visual cortex - more active in Non-REM<br></br>2) Extrastriate cortex - more active in REM
What is the relationship between neuronal firing in the thalamus and the cortex during the sleeping state?
Becomes synchronised in intrinsic burst-firing mode, disconnecting cortex from outside world
Name the brainstem structures responsible for modulation of sleep and attention.<br></br>Identify the principal neurotransmitter responsible in each case:
Locus coreleus - NA<br></br>Raphe nuclei - 5HT<br></br>Basal forebrain - ACh<br></br>Substantia nigra - DA
What happens to serotonin and ACh levels during wakefulness, sleep and REM sleep?
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Which sleep promoting region in the hypothalamus is important in providing the switch between the awake and sleeping state (FLIP-FLOP)?
Ventrolateral pre-optic area (VLPA)
Brief overview of FLIP-FLOP model:
<b>FLIP-FLOP On</b><br></br>- VLPA not inhibiting ascending arousal system <br></br>- Ascending arousal system inhibiting VLPA<br></br>- Awake state<br></br><br></br><b>FLIP-FLOP Off</b><br></br>- VLPA inhibiting ascending arousal system <br></br>- Ascending arousal system not inhibiting VLPA<br></br>- Asleep state
What neurotansmitters can modulate the activity of the ventrolateral pre-optic area (VLPA)?
1) <b>Orexin</b> - excitatory for VLPA (promotes sleep)<br></br>2) <b>MCH</b> (melanin concentrating hormone) - inhibitory for sleep (promotes wakefulness)
Name two sleeping disorders:
1) Insomnia<br></br><br></br>2) Narcolepsy
What is narcolepsy caused by?
Mutation in orexin gene
What light sensitive pigment is involved in circadian entrainment?
Melanopsin
What physiological parameters can we measure as emotional indices?
1) Heart rate<br></br>2) Blood pressure<br></br>3) Galvanic skin resistance<br></br>4) Muscle tension<br></br>5) Arousal
What is the James-Lange theory of emotion?
“Emotional experiences are derived from bodily experience<br></br><br></br>"”We dont run because we are afraid, we are afraid because we run”””
What is the Schachter-Singer theory of emotion?
Two factors:<br></br><br></br>1) Body changes (heart rate etc) provide substrate for emotion<br></br>2) Cognitive factors are important for the interpretation of body changes<br></br><br></br>Bodily changes (eg heart rate, adrenaline secretion) are necessary and sufficient to determine emotional experience, and depend upon cognitive processes to determine emotional experience.
What are the different forms of anxiety?
<b>1) Somatic</b><br></br>Anxiety arises from bodily symptoms (hyperventilation, palpitations)<br></br><b>2) Psychic</b><br></br>Anxiety arises from external stressors
What drugs work on the different forms of anxiety?
Diazepam = effective for both psychic and somatic<br></br><br></br>Beta-blocker = effective for somatic only<br></br><br></br>Benzodiazepines = effective for psychic only
What structures form the limbic system?
1) Cingulate gyrus<br></br>2) Hippocampal formation<br></br>3) Amygdala<br></br>4) Hypothalamus<br></br>5) Anterior thalamic nuclei<br></br>6) Pre-frontal cortex
What are the principle components of emotional circuit (modern definition)?
Amygdala<br></br>Orbitofrontal cortex<br></br>Ventral regions of anterior cingulate<br></br>Ventral stiatum<br></br>Hypothalamus
Define anxiety disorder:
Healthy response to, and the anticipation of, fear becomes dysfunctional
What are the main anxiety disorders?
1) Phobias<br></br>2) Panic disorder<br></br>3) Post-traumatic stress disorder (PTSD)<br></br>4) Agoraphobia<br></br>5) Generalised anxiety disorders (GAD)
Define agoraphobia:
Fear of crowds/public places
Characteristics of phobias:
1) Fear of situation/object that people find tolerable<br></br>2) Fear is out of proportion to true danger<br></br>3) Patient may acknowledge that fear is irrational<br></br>4) Patient changes daily routine to avoid
What is biological preparedness with regards to anxiety?
A proposed explanation as to why some associations can be learned more easily compared to other associations. For example evolutionary bias can mean that phobias are more likely to form to objets/situations that were harmful to our ancestors.
Define vicarious conditioning:
Learning to respond in a particular way by watching others. E.g individual can develop a fearful response by watching others react fearfully to that response.
Different treatments of phobias:
1) Flooding<br></br>2) Modelling (vicarious conditioning - non fearful response)<br></br>3) Systemic desensitisation
What two cognitive biases can actually be maintaining factors for phobias:
<b>1) Hyper-vigilance</b><br></br>- Constantly checking for object, therefore detects it more<br></br><br></br><b>2) Thought suppression</b><br></br>- Try hard not to think about it that you think about it more
What is the behavioural account of phobias?
Conditioning occurs with minimal awareness of the situation
What is the cognitive account of phobias?
A persons interpretation of CS-US pairings are central to phobia developments.
Where brain structure is associated with fear?
Amygdala
Through which pathway does amygdala control voluntary action?
Stria terminalis (to ventral striatum)
What is Urbach-Weithe disease?
Rare disease causing calcification of the amygdala<br></br><br></br>Prevents fear conditioning in sufferers
How do benzodiazepines work?
Increase GABA transmission (inhibitory neurotransmitter thus causes sedation)
Role of the following hypothalamic nuclei:<br></br><br></br>1) Medial preoptic area<br></br>2) Lateral hypothalamic area<br></br>3) Arcuate nuclei<br></br>4) Paraventricular nuclei<br></br>5) Suprachiasmatic nuclei<br></br>6) Ventromedial hypothalamus<br></br>7) Supra-optic nucleus<br></br>8) Pre-optic<br></br>9) OVLT<br></br>10) Ventro-lateral pre-optic area
<b>1) Medial preoptic area</b><br></br>- Male consummatory sexual behaviour<br></br><br></br><b>2) Lateral hypothalamic area</b><br></br>- Feeding centre<br></br><br></br><b>3) Arcuate nuclei</b><br></br>- Cell bodies of NPY (stimulate LH and PVN to increase feeding)<br></br><br></br><b>4) Paraventricular nuclei</b><br></br>- Stimulated by NPY to control ANS via brainstem. Causes reduced metabolic rate and insulin secretion<br></br><br></br><b>5) Suprachiasmatic nuclei</b><br></br>- Control of circadian rhythm<br></br><br></br><b>6) Ventromedial hypothalamus</b><br></br>- Satiety and female sexual behaviour<br></br><br></br><b>7) Supra-optic nucleus</b><br></br>- Cell bodies for ADH and oxytocin secreting neurons<br></br><br></br><b>8) Pre-optic</b><br></br>- Thermoregulation<br></br><br></br><b>9) OVLT</b><br></br>- Osmoregulation<br></br><br></br><b>10) Ventro-lateral pre-optic area</b><br></br>- Sleep promoting (FLIP-OFF)
