Untitled Deck Flashcards
(42 cards)
What is the resting state in an action potential –> 1
Neuron at rest is at about -70 mV
Outside of neuron is positive, inside is negative
Membrane is polarised (charge difference across membrane)
Ion distribution:
* Outside = lots of Na+ (sodium) and Cl- (chloride)
* Inside = lots of K+ (potassium) and negatively charged proteins (P-)
What is the threshold state in an action potential –> 2
Stimulus (like another neuron firing) causes membrane to depolarise a little
If membrane potential reaches about -55 mV (threshold), action potential is triggered
This is an all-or-nothing process → once threshold is hit, it goes the whole way
What is the depolorisation + peak phase in an action potential –> 3
Voltage-gated Na+ channels OPEN
→ Na+ RUSHES INTO the neuron because:
Electrical gradient: inside is negative, attracts positive Na+
Concentration gradient: more Na+ outside than inside
Inside of the neuron becomes positive
Membrane potential rises rapidly up to about +30 to +40 mV
Peak
At the peak (~ +30 to +40 mV):
Na+ channels CLOSE
K+ channels OPEN
Repolarisation action potential –> 4
K+ EXITS the neuron:
Electrical gradient: inside is positive, repels K+
Concentration gradient: more K+ inside than outside
Membrane potential becomes negative again → moves back toward -70 mV
Hyperpolarisation + return to normal action potential –> 5
Hyperpolarisation
K+ channels stay open a bit too long → too many K+ leave
Membrane becomes more negative than resting → ~ -80 mV
Neuron is briefly more negative than usual → refractory period (can’t fire again immediately)
Na+/K+ pump restores resting state:
Pumps 3 Na+ OUT, 2 K+ IN (uses ATP)
Restores balance → back to -70 mV
What are the two parts of simple learning?
- Habituation
When an organism responds less and less to a repeated stimulus
Example: You stop noticing the sound of the air conditioner after a while.
- Sensitisation
When an organism responds more and more to a repeated stimulus
Example: If someone taps your shoulder again and again, it starts feeling more annoying.
What makes simple learning different?
Involuntary (automatic, reflex-based)
Short-lasting
Specific to certain systems (like sea slug gill withdrawal reflex)
Describe general learning: classical conditioning
Classical Conditioning (Pavlov)
Event → consequence
Steps:
unconditioned stimulus → unconditioned response (Food → Salivation)
conditioned stimulus + unconditioned stimulus → unconditioned response (Bell + Food → Salivation)
conditioned stimulus alone → conditioned response (Bell → Salivation)
Key points:
Response is involuntary (reflexes)
Learns association between 2 events
Describe general learning: operant conditioning
Operant Conditioning (Skinner & Thorndike)
Action → consequence
Learns that behaviour leads to outcome
Response is voluntary
Thorndike’s Law of Effect:
Behaviour followed by positive consequence → more likely to repeat (reinforcement schedules see other slide)
Explain reinforcement schedules
Fixed Ratio (FR)
* Reward after a set number of actions.
* You know exactly how many times you must do the action to get the reward.
* Example: Paid for every 10 items you make at work.
* Result: You tend to respond FAST, then pause a little after each reward
Variable Ratio (VR)
* Reward after an unpredictable number of actions.
* You don’t know when the reward is coming — but it’s based on how many times you do the action.
* Example: Slot machines — pull lever, sometimes win, sometimes not — could be after 2 pulls, could be after 20.
* Result: Respond VERY FAST and constantly, because “it might be the next one!” - VERY resistant to extinction (hard to stop behaviour — why gambling is addictive).
Fixed Interval (FI)
* Reward is given for the first action after a fixed period of time has passed.
* No matter how many times you act, you’ll only get rewarded once the time is up.
* Example: Paycheck every Friday — you get paid at the end of the week, no matter how much or little you worked each day.
* Result: Response rate is low after the reward, but speeds up as the reward time approaches → scalloped pattern.
Variable Interval (VI)
* Reward is given for the first action after a random/unpredictable amount of time.
* You don’t know when it will happen — but it’s based on time passing, NOT how many actions you do.
* Example: Checking phone for new messages — you don’t know when a message will come, so you check occasionally.
* Result: Steady, moderate response rate — because checking all the time is tiring but you also don’t want to miss the reward.
Key difference between classical and operant
Classical: response is automatic
Operant: response is voluntary and shaped by consequences
Define superior/inferior
Superior = toward top of head
Inferior = Toward feet
Define anterior/posterior
Anterior = Front of body/brain
Posterior = Back of body/brain
Define Dorsal (brain) and Ventral (brain)
Dorsal (brain) = Top
Ventral (brain) = Bottom
Define Medial and lateral
Medial = Toward midline
Lateral = Toward sides
What are the brain slices?
Sagittal = divides left/right
Coronal = divides front/back
Horizontal = divides top/bottom
Brain lobes and their functions
Frontal = Motor, planning, judgement, personality
Parietal = Sensory info: touch, pain, proprioception
Occipital = Vision
Temporal = Hearing, memory, language
Role of Broca’s area and Wernicke’s area
Broca’s area = Speech production
Wernicke’s area = Language comprehension
Role of the prefrontal cortex and the primary motor cortex and the primary somatosensory cortex
Prefrontal cortex = Decision making, impulse control
Primary motor cortex = Controls movement
Primary somatosensory cortex = processes touch
What is the role of the cerebellum, medulla, pons
Cerebellum = coordination, balance
Medulla = heart rate, breathing
Pons = sleep, facial expressions
What is the role of the midbrain, corpus callosum, hypothalamus and olfactory bulb
Midbrain = Vision, hearing, alertness
Corpus Callosum = Connects brain hemispheres
Hypothalamus = Hormones, hunger, body temp
Olfactory bulb = Processes smell
Describe the basic neuron structure
Soma (cell body) → keeps neuron alive
Dendrites → receive signals
Axon → sends signals
Presynaptic terminals → release neurotransmitters to next neuron
Two different neurons transferring signals
Afferent neuron → carries signal to CNS
Efferent neuron → carries signal from CNS to body
Types of operant conditioning (punishment etc)
Positive Reinforcement → adding something pleasant to increase behaviour
e.g. Giving a child a sticker for doing homework
Negative Reinforcement → removing something unpleasant to increase behaviour
e.g. Taking an aspirin to remove a headache
Positive Punishment → adding something unpleasant to decrease behaviour
e.g. Giving a child extra chores for being rude
Negative Punishment → taking away something pleasant to decrease behaviour
e.g. Taking away phone privileges after missing curfew
TRICK
Positive = adding something
Negative = taking something away
Reinforcement = increases behaviour
Punishment = decreases behaviour
