W6 Emotional Motivation, Memory, Sleep Flashcards
Internal states
Influences behaviour. 4 F’s: Feeding, Fleeing,Fighting, Mating.
Sensory imputs => Internal states => Behaviour
Homeostatic Systems (behavioural and physiological)
Perturbation => Controlled variable => Sensor = error signal = Effector ==> Controlled variable
Negative feedback loops, always odd number. Signal occurs neuropeptides, hormones (slow)
Hypothalamus - Hunger
Lateral Hypothalmus (hunger, orexigenic) = promotes hunger
Ventromedial nucleus (satiety, anorexigenic) = suppress feeding/hunger
Hypothalamus = key center controlling appetit
Neuropeptides hormones) = orexin, MCH
Leptin
Body fat => Leptin =| body fat
ob/ob mutant, mice lack leptin got obeses.
GLP-1
peptide, promotes production of insuline. Reduce appetite. Pharmaceutical: reduce weigth reverse when off drug.
CCK
Hormone sends signals to brainstem and suppress feeding.
Amygdala
Required for fear conditioning (CS + US = CR). If lesioned, loss of fear.
Central nucleus, Basolateral nuclei, Cortoico medial nuclei.
Brain areas: Aggression
Cerebral Cortex => Amygdala => Hypothalamus = affective aggression.
Cerebral Cortex => Amygdaka => PAG, Ventrak tagmental area (VMHvl) = preditory aggression
Dopamine Reward (wanting vs liking)
Rats w/out mesolimbic dopaminergic projection still enjoyed tasty food but lack of motivation.
Somatic marke hypothesis
embodied decision making = emotions, gut feeling
Common Sense, ‘folk’ theory - Emotion
Sensory imput => Emotional Experience => Physiological reaction
James Lange Theory - Emotion
Sensory input => Physiological reaction => Emotional expeirence
Cannon-Bard theory - Emotion
Sensory imput => Emotional experience
Sensory imput => Physiological reaction
Thalamus signal to neocortex while physiological reaction increse from thalamus signal to hypothalamus.
Singer-Schachter Theory - Emotion
Sensory input => Physiological reaction =(ambigious signal) => Cog. I
Sensory input => Cog. interpretation => Emotional experience
Constructiveist theories - Emotions
Sensory input => Physiological reaction =(ambigious signal) => Cog. I <= culture
Sensory input => Cog. interpretation => Emotional experienceC
Definition of Sleep
reduced motor activity, reduced response to stimulation, stereotypic postures (eye closed in humans), relatively easy reversibility (waking up)
Differenty phyiological activity is measured with what?
Physiological activity can be measured using electrical recordings:
Muscle movements with electromyography
Eye movements with electro-oculography
Brain activity with electroencephalography.
EEG (electroencephalogram)
Measures the synchronous, electrical activity from large populations of neurons in the brain. Caused by cellular, ionic movements, which creates an electric field.
Electrodes placed on the surface of the scalp etect these electric fields. Linked to an electrical amplifier.
Properties of EEGs
Non invasive, easy to administer, data easily gathered. High temporal resolution, low spatial resolution. Electric fields follow an inverse square law so only cortical activity is detectable.
Non-REM sleep
Neuronal activity is low, metabolic rate and brain temperature is at theri lowest, heart rate and blood pressure decline, decreased sympathetic nervous system outflow. Inceease in parasympathetic nervou ssytem. Muscel tone and reflect are intact.
Stages:
1- Drowsiness
2- Light sleep
3- Deep Sleep
4- Very deep Sleep
5- REM sleep (rapid eye moevement)
Non-REM sleep - Drowsiness
Awakened easily, eyes move slowly, msucle activity slows down. People expeirene sudden muscle contractions preceded by a sensation fo failing. Transition from Wakefulness to onset of sleep.
Non-REM sleep - Ligh sleep
Eye moevemnt stops, brain waves become slower with only one occasional burt of rapid brain waves. Body prepares for deep sleep temperature drops, heart rates slow.
Characterised by burst of sinusoidal waved called sleep spindles and biphasic waves called K complexes.
Non-REM sleep - Deep Sleep
Slow Delta waves are interpersed with smaller, faster waved. Sleepwalking, Night terrros, tlaking during one’s sleep.
Non-REM sleep - Very deep Sleep
Brain produces delta waved almost exclusively. Disorientation for several minutes, following arousal from Stage 4. Slow wave actiivty increases and dominate the EEG recordings.
During REM sleep
Brain temperature and metabolic rate rise, consistent with increased neural activity. In some areas, geater than in waking. All skeletal msucles are atonic flaccid and paralysed. Muscle controlling movements of the eyes, middle ear ossicles adn diaphragm remain active.
Thoeries of Dreaming
Strange imagery-brain not fully functioning (philosophical).
Exercises synapses when no external activity.
Circuit testing.
Memory consolidation.
Circadian Rhythms
Circadian rhythms are endogenous and persist without environmental cues. However, they are modulated by external timing cues ‘zeitgebers’ These adapts the rhythm to the environment.
Visual System - Circadian Rhythm
Intrinsically photosenstive Ganglion cells provide input to te Suprachiasmatic Nucleus.
Role of Suprachiasmatic Nucleus.
SCN is the major internal clock of anterior hypothalamus.
Lesioning of the suprachiasmatic tract dampens down the circadian rhythm of sleep.
Suprachiasmatic nucleus regulates timing of sleep. Not responsible for sleep itself.
Wakefullness - Brain stem (Locus Coeruleus)
Lesion of the brain stem can cause sleep and coma. Activation of neurons in brain stem (locus coeruleus- NE, raphe nuclei- TH) precedes awakening.
Stimulation of brain stem causes awakening. Depolarising effect.
Normal Sleeping Patterns in Humans
Non-REM and REM sleep alternate cyclically.
70-80min returns to S2/3 => REM phase (8-10m).
S1 => REM last 90-110mins. x 4/5 per night, during each rep, S3/4 decrease and REM increase in duration.
Young Adult Sleep Stages (duration, in %)
S1: 5%
S2: 50-60%
S3/4:15-20%
REM: 20-25%
Regulation of Sleep
Diffuse modulatory neurotransmission system. NE and 5-HT neurons in the brain stem. Diffuse modulatory system controls rhythmic behaviour in the Thalamus. Inhibition of motor neurons.
Definition of Learning
Aquisition of information
Definition of Memory
Storage of learned information
Definition of Recall
Reacquisition of stored informaiton
Definition of the Engram
Physical embodiment of a memory
Independent Memory systems
Differnt forms of memory stored in different ways/regions/pathways (playing piano (auditory) and passing exams (frontal cortex)
Procedural vs Declarative and Implicit and Explicit.
Procedural Memory
Skills and associations largely unavailable to conscious mind = learning how to ride a bike, you can’t explain how to do it but you can do it.
Declarative Memory
available to conscious mind, can be encoded in symbols and language.
Explicit Memory
Memory that can be consciously recalled
Implicit Memory
Memory that cannot consciously be recalled, different types:
Procedural Memory
Classical Conditioning
Priming
Memory Duration
Immediate memory – few seconds.
Short-term memory – seconds or minutes. = Working memory.
Long-term memory – days, months, years.
Temporal Lobe and Memory
Electrical stimulation – hallucinations and recollection of the past experiences.
Epileptic seizures – complex sensations and memories
Temporal Lobectomy - Patient HM
8 cm of the medial temporal lobe was removed;
Intelligence, personality, etc. was intact.
Extreme anterograde amnesia.
Hippocampus
Essential for converting STM to LTM.
Lessions cause memory loss.
3 layered cortex:
Inputs from entorhinal cortex and beyond.
Outputs => many regions.
Enlarged in people whose work requires good spatial memory.
Amydgala
Multiple processed sensory inputs (smell), implict, emotional, learnt (fear)
Mechanism of memory
Long-term storage seems to be distributed.
Reverberating circuits.
The Hebbian synapse concept = activity modifiable, plastic synapse.
Memory and Synaptic plasticity
Synaptic strenght changes. Facilitation / depression = Short-term (mins / hours) + Ca2+ availability / vesicle depletion.
Long-term facilitation / depression = change the structure of the synapse to increase/decrease the strength of the synapse long term.
Long term depression
short stimulation of pre-synapti neuron and measure the epsp amplititude. Strenght of synapse decrease. In the hippocampus
Long term Potentiation: in hippocampal slices
Post ‘tetanic’ LTP. High frequency burst, LTP in specific pathways.
Paired LTP, coioncident stimulus and depolarization, associativity.
Aplysia Californica
See snail, with big neurons, easily recorded.
Gill: delicate tissue, when animal reachs a rough surface it hides the Gill, Gill withdrawal refelct, they can form certain memories.
Long-term-Potential and Long-term-Depression and Aplysia
Require receptor activation (glutamate/serotonin), altered synaptic responsivity, mediated by second messengers (Ca2+/cAMP). Require portein phosphorylation changes in early stages, require protein synthesis for alte stages.
Involve biochemical and structural pre and post-synaptic changes
How does Long-term-Potential occur?
Evidence suggest often a post-synaptic event. Most indicates a critical role for Ca2+. Involves trafficking of AMPA receptors to the postsynaptic membrane.
