7 - learning and memory

• Memories are crucial to existence
• Learning


  A behavioural experience associated with change, where the change allows some form of adaptation. It is not change incurred by brain damage
• Memory


  The encoding of the learning experience, the physical basis of memory is the change in the brain
• The task of a biological psychologist is to link three different levels of description


  • The psychology of these phenomena
  • The brain regions involved
  • Their cellular basis in terms of neurons and the connections between them
• Types of learning


  • Associative learning
  • Non-associative learning
• Associative learning


  • Based on associating two things in the environments
  • Based on associations between different phenomena
• Non-associative learning


  • A change within yourself - habituation; repeated exposure to a stimulus that offers no threat/benefit
  • Not based on environment/associations
• Both types of learning offer an adaptive advantage, allow organisms to respond to the environment, develop efficient responses to positive stimuli, and develop efficient avoidance of negative stimuli
• Associative learning


  • Classical conditioning
  • Operant conditioning
• In classical conditioning, the strengthened connection is between the conditioned stimulus (CS) and the unconditioned stimulus (UCS)
• Lashley's experiments showed that there is no one area responsible for learning, and that all parts of the cortex contribute equally to complex behaviours
• The modern understanding is that the engram is the physical representation for storing memories
• Richard Thompson's classical conditioning experiments

  • The lateral interpositus nucleus (LIP) in the cerebellum is used in the process of learning
  • The red nucleus (midbrain motor area) is crucial for the performance of a conditioned response but not for learning
• Types of memory


  • Short-term memory
  • Long-term memory
• Short-term memory


  Limited capacity, lost after a few seconds
• Long-term memory


  Unlimited capacity, hints help you reconstruct, meaningful context helps us to remember
• Shifting from one memory to another is called consolidation
• Working memory


  Stored information that is still in use, information that is still relevant, information crucial for complex cognitive activities
• The pre-frontal cortex is associated with complex, executive cognitive functions and is involved in working memory
• Habituation


  Decrease in response to a stimulus that is presented repeatedly
• Sensitization


  Opposite of habituation, increased responses to unpleasant stimuli after a shock
• Changes in synaptic activity produce behavioural plasticity, allowing organisms to respond appropriately to the environment
• Hebbian synapse


  Simultaneous activity in the presynaptic and postsynaptic neurons increases the effectiveness of each action potential
• Long-term potentiation (LTP)


  Axons bombard a dendrite with a rapid series of stimuli which leaves the synapses more responsive for a period of time
• Long-term depression (LTD)


  Where axons are active at low frequency, response reduces
• The hippocampus is important for new declarative, explicit memories, but not for old implicit memories
• Damage to the hippocampus leads to anterograde amnesia (loss of memory for events after brain damage) and retrograde amnesia (loss of memory for events before brain damage)
• Individuals with Korsakoff's syndrome have damage to the mammillary bodies, parts of the hippocampus, and the dorsomedial thalamus, leading to amnesia, confusion, and confabulations (remembering guesses as true memories)
• Alzheimer's disease is associated with the accumulation of amyloid protein, causing widespread atrophy of the cerebral cortex, hippocampus, and other brain areas, leading to memory loss and cognitive decline
• Differences between Korsakoff's syndrome and Alzheimer's disease


  • Korsakoff's has more prefrontal cortex damage, leading to confabulations
  • Alzheimer's has more widespread cortical and hippocampal damage
• Both Korsakoff's syndrome and Alzheimer's disease are associated with the loss of previous memories and the inability to form new ones
• Brain areas involved in two types of learning

  • Basal ganglia - integrates information over many trials, learns habits, requires immediate feedback
  • Hippocampus and cerebral cortex - can learn in a single trial, more flexible responses, can connect information over time, can learn from delayed feedback
• Damage to the basal ganglia impairs well-learned motor patterns and skill learning, while damage to the hippocampus and cortex impairs declarative memory, especially episodic memory
• Habituation


  A decrease in responsiveness to a stimulus after repeated exposure; not based on associations or consequences.
• Sensitization


  An increase in responsiveness to a stimulus after repeated exposure; often based on associations or consequences.
• Working memory


  The system that actively holds multiple pieces of transitory information in the mind where they can be manipulated. Limited in capacity and duration.
• Semantic memory


  The memory for facts, concepts, and knowledge independent of personal experience. Relatively permanent and not limited by capacity.
• Interaction between working memory and semantic memory

  1. Accessing semantic memory from working memory. 2. Transferring information from working memory to semantic memory. 3. Using semantic memory to maintain working memory.
• Factors influencing transfer from working memory to semantic memory

  1. Attention. 2. Meaningful encoding. 3. Elaborative rehearsal. 4. Consolidation. 5. Sleep.
• Impact of attention on transfer from working memory to semantic memory

  1. Focused attention. 2. Capacity of working memory. 3. Inhibition of irrelevant information. 4. Working memory resources.