Neuroplasticity and Behavior

Neuroplasticity and Behavior

1. Learning

   • Learning: The acquisition of an altered behaviorual response due to an environmental stimulus
   • Unconscious Learning
     • Subject to Conscious Recall
       • Trace Conditioning
       • Operant Conditioning
       • Contextual Fear Conditioning
         • Training: freezing increases in response to tone-shock pairings  Test: we don't present shocks or tone rat freezes 50-60% of the time, shows that it remembers  Contiguity is difficult here because temporal association is weak  contingency is strong - the context is always here, it follows the shock 
       • Taste Learning / Taste Aversion
         • Neophobia: measure increased consumption as index of long-term memory of novel taste  Taste aversion: measure decreased consumption as index of long-term memory of novel taste 
     • Unconscious Recall
       • Non-associative Learning
         • Habituation
           • Habituation = leads to weaker response (low stimulus, weak) 
         • Sensitization
           • Sensitization = leads to larger response (strong stimulus)
         • Dishabituation
       • Associative Learning
         • Delay Eye-Blink Conditioning
         • Pavlovian Conditioning
           • CS is neutral before conditioning  US has a value attached to it (punish / reward) - by nature the animal has an instinct to perceive and it produces an UR that can be measured  Co-presenting two stimulus multiple times: the animal will associate CS with US and now the CS is not neutral, it's associated and the animal will respond to it (this is proof of learning) 
           • Delay conditioning: CS and immediately present US after CS  - no delay, CS and US end together  - contiguity (temporal association) is strong  Trace conditioning: CS is presented, US presented after a temporal gap  - contiguity is weak / non-existent  contingency (order) is the same in both 
         • Cued Fear Conditioning
           • Training: we present 3 cue-shock pairings and freezing increases in response to shock  Test: after training, present tone-cue only (chamber is different)  rat remembers the cue because of increased freezing  Freezing is the natural fear response (UR)  shock pairing is the US  tone cue is the CS 
       • Motor Learning
         • Motor learning – shows improvement over time Rotor rod: electric motor can rotate the rod and the task is..  If the animal is unable to keep up with the speed, it will fall (signals timer) The rod measures time Animals can learn to cope with higher speeds over time Wild type = healthy, no issues After training trials, speed can be increased until a plateau (max speed they can accomplish after multiple exposures) Other mice are dysfunctional in En2 protein – En is expressed in normal mice in the cerebellum (cerebellum deficit – involved in motor involvement, coordination, balance) If you knock out both copies of En2 – they improved but not at the same level Heterozygous mice are in-between in function The mice performance is proportional to how much En2 is in the cerebellum Both hetero- and homo- mice do not have properly developed cerebellum (development alteration)  
   • Conscious Learning
     • Declarative Learning
     • Spatial Learning
       • Large water tank is not a pleasant environment (CS) - the only way to escape is to find a platform  after training, the mice find the platform much more quickly - it learns the complex association relationships 
       • Barnes Maze - land version of the water maze  task is: various holes, one with a hidden chamber (rodents like to hide in the holes but don't want to just fall)  There isn't a single cue that marks the hidden chamber, BUT the animal learns that there are holes around the perimeter and that one is safe  they can use a chain strategy to check for the safe hole  We rotate the table so that the animal can't follow it's sent 

2. The Neuron