The Nature of Elicited Behaviour Flashcards
brain stem structures
- medulla oblongata
- pons
- midbrain
- reticular formation
medulla oblongata function
essentials for survival
- heart rate
- respiration
- blood pressure
pons function
- sleep + wake cycle
- respiration
midbrain function
- hearing
- motor control
- alterness
reticular formation function
alertness
thalamus
- gateway to the brain
- receives almost all incoming sensory information before it reaches the cortex
- except olfactory information
hypothalamus
- brain structure that is involved in regulation of bodily functions
- includes:
1. body temperature
2. body rhythm
3. blood pressure
4. blood glucose level - influences basic motivated Bs (aggression, hunger, thirst, sex)
hippocampus
- associated with formation of new memories
- memory of arrangements (places, objects)
- volume of gray matter found highly with years of experience as taxi driver (navigation)
amygdala
- vital role in learning to associate things with emotional responses and in processing emotional information
- special role in:
1. responding to fear eliciting stimuli
2. evaluating facial expression of emotional significance
3. intensification of memories associated with emotional arousal
nature of elicited behaviour
- learning that occurs depends on preexisting behavioural organization
- preexisting behavioural tendencies limit how learning occurs + extent of learned B change
- most B is elicited
- simplest form of elicited B = reflexive b
reflex
- involves eliciting a stimulus + corresponding linked response
- consequences of nervous system organization
types of neurons
constitute the reflex arc
1. sensory/afferent neuron
- transmits info to spinal cord
2. motor/efferent neuron
- activates muscles involved in refelx
3. interneuron
- passes info from one neuron (sensory) to another neuron (motor)
reflex arc
- excitatory pathway, sensory neurons activates motor neurons supplying flexor muscles, which withdraw limb from noxious stimuli
- inhibitory interneurons ensure that motor neurons supplying antagonist muscles that are inactive during reflex response
- at same time, motor neurons supplying extensor muscles are excited to provide support during withdrawal of the limb
the reflex arc: pathway to the brain?
most sensory neurons do not pass directly into the brain
- synapse in the spinal cord
- permits faster reaction time
- brain receives input while reflex is being carried out
- brain analyses the info after the reflex action
suckling and rooting reflex in babies
- innate respone due to stimulation of the face, mouth, cheek by touching/stroking
- brainstem mediated primitive motor reflex
respiratory occlusion reflex in babies
- if baby’s breathing = inhibited
- head pulled back, wiping face, crying
motor neuron types
- upper motor neurons
- originates in cerebral cortex
- travel to the brainstem and spinal cord
- glutamate = NT - lower motor neurons
- originate in spinal cord + innervate glands+mucles
- Ach = NT - autonomic + somatic motor neurons
- somatic = alpha, beta, gamma motorneurons
sensory neuron types
- mechanoreceptors
- thermoreceptors
- nociceptors, electromagnetic receptors
- chemoreceptors
autonomic reflexes
largely unconsciously regulate internal organs smooth muscles + glands
mediating a reflex
reflexes can be modified by descending brainstem and cortex pathways
mediating a reflex: carrying a kitten example
“If you are carrying a kitten and trip and fall…”
- automatic reflexes would normally move to break the fall
- BUT you do not want to drop the kitten
- within 30 ms, the cortical motor centers would mordify reflexes to allow you also to protect the kitten
Modal Action Patterns
- response sequence typical of a particular species
- many stimuli elicit different responses
- sign stimulus + supernormal stimulus
sign stimulus
- specific stimulus that elicits certain response
- when chicks peck at their parents’ beak to get them to regurgitate, red spot near the tip = sign stimulus
supernormal stimulus
exaggerated stimulus used to cause extremely vigourous response
sequential organization of B
behaviour sequence
- sequential series of actions to achieve organism’s goal
appetitive B
- early component of B sequence
consummatory
- end components of B sequence
repeated stimulation
- simple reflex response does not automatically occur the same way each time the eliciting stimulus is presented
- B varies; can be modified (IMPORTANT slide 25)
- visual attention in infants (slides 26-27)
startle response
- defensive reaction to potential/actual attack
- with repeated starting stimuli, the startle response will progressively diminish
- spontaneous recovery
- repeated presentations of stimulus do not always result in both long-term + short-term habituation effects
spontaneous recovery
wait for period of time before presenting the startling stimuli again, startle response returns
sensitization effect
if already aroused…
- same eliciting stimulus will trigger a much stronger reaction
supermarket vs dark alley example
sensitization and modulation of elicited B
eyeblink startle response study (slide 30)
adaptiveness and pervasiveness of habituation and sensitization
habituation:
- when your mind tunes out certain stimuli so you can focus on other, presumably more important stimuli
sensitization:
- when your mind specifically targets stimuli that it deems more important and makes you more attentive
habituation and sensitization can occur with repeated exposure to stimuli
habituation vs sensory adaption and response fatigue
NOT ALL instances of repetitious stimuli response decline are due to habituation
habituation vs sensory adaption and response fatigue: components of reflex
- stimulus
- sensory-motor nerve relay of a signal via an interneuron
- motorneurons activate muscle response
habituation vs sensory adaption and response fatigue: sensory adaptation
- when the sense organs become temporarily disabled due to stimuli overload
- e.g. temporarily deafened by loud noise
habituation vs sensory adaption and response fatigue: response fatigue
- when sensory receptors won’t receive stimuli because they are fatigued
- fatigue is outside the nervous system
habituation vs sensory adaption and response fatigue: sensory adaptation and fatigue
involve sense organs + muscles outside the nervous sytem
habituation vs sensory adaption and response fatigue: sensitization and habituation
- involves decrements in the responsiveness of interneurons
effects: - outward
- can be explained by repetition of a stimulus
- can be explained partly by the enhanced effect of arousal
dual process theory of habituation and sensitization assumptions
- different types of underlying neural processes are responsible for increase/decrease in responsiveness to stimulation
- habituation = less response / sensitization = more response
- habituation + sensitization are not mutually exclusive (concurrent activation of each other)
- habituation processes assumed to occur in S-R system are activated every time eliciting stimuli are produced
- S-R can be viewed as a reflex arc - each stimulus contributes to some build-up of habituation
- sensitization processes are assumed to occur in state system, which activates only in presence of arousing stimuli
- refer to slide 35
state system structures
- determine level of responsiveness and arousal
- limbic structure involvement
NTs of learning
- acetylcholine
- motor control over muscles
- learning, memory, sleeping and dreaming - dopamine
- reward and motivation
- motor control over voluntary movement - endorphins
- painreduction and reward - GABA
- inhibition of action potentials
- anxiety reduction - glutamate
- enhancement of action potentials
- learning and memory - serotonin
- emotional states and impulsiveness
- dreaming
agonists vs antagonists
drugs and toxins can alter NT action
1. agonists - enhance actions
- increase production of NT in the presynaptic neuron
- block reuptake receptors on the presynaptic cell
- mimic action ofNT on the post-synaptic cell
- e.g. heroin mimics naturally-occurring endorphins and binds to endorphin receptors
2. antagonists - inhibit actions
- decrease the production of NTsinpresynaptic neuron
- facilitates the destruction of NT
- block postsynaptic receptors, and prevent NT from activating them
dopamine and Parkinson’s
- because dopamine affects motor activity, this is why some patients with this disorder shake, have tremors, etc.
- may require agonist DA drug to increase dopamine levels
dopamine and Schizophrenia
- research implicates caudate DA cell dysfunction
- cell is unable to control dopamine levels
- schizophrenia meds: DA receptor antagonist that destroys dopamine in synapse when there is too much (overactive)
dopaminergic neurons
- initiation of movement; habit learning
- motivating effects
- recreational drugs often increase DA neurotransmission in the brain
norepinephrine
- regulation of heart rate
- beta blockers, historically, prescribed after heart attack
- alertness, attentiveness, and mood
serotonin
- regulation of blood pressure
- serotonergic neurons have big effect on arousal, mood, sleep
- most anti-depressants regulate serotonin transmission
- ecstacy in high doses may increase anxiety and slow reaction
glutamate
- important for neuroplasticity; learning; memory
- neuroplasticity mod of structure and function in brain
GABA
- predominant inhibitory NT in brain and spinal cord
- decreases anxiety and sedative (put to sleep)
cellular messaging: second messengers
released by cell from exposure to extracellular signaling molecules
1. cAMP
- transferring effects of hormones into cells
- protein kinase activation
2. adenylate cyclase
- regulates physiological responses
- accelerates conversion of ATP to cAMP
3. protein kinase A(PKA) enzyme
- regulates sugar + lipid metabolism
- alters K+ channels and decreases amount of K+ outside of cell
- prolongs action potential
neural circuits of habituation and sensitization
refer to YoutTube video “Sensitization in Aplysia”
emotional reactions and aftereffects
- concepts of habituation and sensitization have been extended to complex emotions and motivated B
- intense emotional reactions = often biphasic; 1 emotion during eliciting stimulus, opposite emotion stimulus terminated
- emotional reactions change with experience; primary reaction becomes weaker and after reaction becomes stronger
opponent process theory of motivation (OPTM)
requires:
1. biphasic emotional reactions
2. weakened primary reactions to repeated simulations
3. strengthening after reaction
- based on how emotional B serves to maintain emotional stability
- opponent process: activated with an emotional shift away from neutral
OPTM processes
emotionally arousing stimulus will elicit
1. process A (primary process)
- process A is unopposed
- primary emotional reaction rises to a peak
2. process B
- elicited by process A (opposite reaction)
- not sufficiently strong to counteract A
- when stimulus ceases, process A quickly returns to baseline
- process B lingers longer (drug consumption)
opponent aftereffects and motivation
- a highly familiar stimulus does not elicit a strong emotional response
- BUT affective after-reaction tends to be much stronger
- process B becomes strengthened with repeated use
- process B becomes activated sooner after stimulus onset
- process B then can effectively counteract process A response
- refer to diagram in notebook
why continue the addiction to drugs?
- main effect of psychoactive drug is gone for habitual drug users
- to escape the misery of withdrawal
- extensive drug use results in :
1. reduced reward NT function
2. heightened antireward system
3. drug use continues to reduce withdrawal pains (negative reinforcement)
