🧢Neuroscience Unit 7 – Learning and Memory

Key Concepts and Definitions

• Learning involves acquiring new knowledge, skills, or behaviors through experience or study
• Memory refers to the process of encoding, storing, and retrieving information in the brain
• Explicit (declarative) memory consists of consciously accessible memories of facts and events
  • Semantic memory stores general knowledge and facts about the world (capital of France)
  • Episodic memory stores personal experiences and events (your 10th birthday party)
• Implicit (non-declarative) memory includes unconscious memories, such as skills and habits (riding a bike)
• Short-term memory holds a limited amount of information for a brief period (phone number)
• Long-term memory stores information for an extended period, potentially lasting a lifetime
• Encoding is the process of converting sensory input into a form that can be stored in memory
• Retrieval involves accessing stored memories and bringing them back into conscious awareness

Brain Structures Involved in Learning and Memory

• The hippocampus plays a crucial role in forming new memories and spatial navigation
  • Damage to the hippocampus can lead to anterograde amnesia, difficulty forming new memories
• The amygdala is involved in processing emotional memories and fear conditioning
• The prefrontal cortex is essential for working memory, decision-making, and executive functions
• The cerebellum contributes to procedural memory and motor skill learning (playing an instrument)
• The basal ganglia are involved in habit formation and reward-based learning
• The temporal lobe is important for long-term memory storage and retrieval
• The neocortex stores long-term memories and is involved in memory consolidation
  • Different regions of the neocortex store specific types of information (visual, auditory, etc.)

Types of Memory

• Sensory memory briefly holds sensory information (iconic memory for visual, echoic memory for auditory)
• Working memory is a limited-capacity system that temporarily holds and manipulates information
  • Consists of the phonological loop (verbal information), visuospatial sketchpad (visual and spatial information), and central executive (attention and control)
• Procedural memory stores learned skills and habits, often acquired through repetition (typing)
• Semantic memory stores general knowledge and facts about the world, independent of personal experience
• Episodic memory stores personal experiences and events, with a sense of time and context
• Prospective memory involves remembering to perform future actions or intentions (taking medication)
• Autobiographical memory stores personal life experiences and self-related information

Learning Processes

• Classical conditioning involves learning an association between a neutral stimulus and a response (Pavlov's dog)
  • The neutral stimulus becomes a conditioned stimulus, eliciting a conditioned response
• Operant conditioning involves learning through consequences (reinforcement or punishment)
  • Positive reinforcement strengthens behavior by providing a rewarding stimulus (praise)
  • Negative reinforcement strengthens behavior by removing an aversive stimulus (taking painkillers)
• Observational learning occurs by observing and imitating others' behaviors (learning a dance move)
• Habituation is a form of learning in which an organism decreases its response to a repeated stimulus
• Sensitization is a form of learning in which an organism increases its response to a repeated stimulus
• Latent learning occurs without obvious reinforcement and is demonstrated later (exploring a maze)

Memory Formation and Consolidation

• Encoding involves converting sensory input into a form that can be stored in memory
  • Elaborative encoding associates new information with existing knowledge, enhancing memory
• Consolidation is the process of stabilizing memory traces over time, making them more resistant to interference
  • Synaptic consolidation occurs within hours of learning, strengthening connections between neurons
  • System consolidation occurs over weeks to years, transferring memories from the hippocampus to the neocortex
• Retrieval involves accessing stored memories and bringing them back into conscious awareness
  • Retrieval cues (sensory, emotional, or contextual) can help trigger memory recall
• Reconsolidation is the process of modifying and strengthening a memory each time it is retrieved
• Interference can disrupt memory formation or retrieval
  • Retroactive interference occurs when new learning interferes with the recall of previously learned information
  • Proactive interference occurs when previously learned information interferes with the acquisition of new information

Neuroplasticity and Synaptic Changes

• Neuroplasticity refers to the brain's ability to change and adapt in response to experience
• Long-term potentiation (LTP) is a persistent strengthening of synaptic connections, associated with learning and memory
  • Involves an increase in the number of AMPA receptors and the size of dendritic spines
• Long-term depression (LTD) is a persistent weakening of synaptic connections, associated with forgetting and memory pruning
• Synaptic plasticity is the ability of synapses to strengthen or weaken over time, based on activity
• Structural plasticity involves changes in the number and structure of neurons and synapses
  • Neurogenesis is the formation of new neurons, which can occur in the hippocampus and olfactory bulb
• Functional plasticity involves changes in the strength and efficiency of synaptic transmission
• Experience-dependent plasticity occurs in response to specific experiences and learning (learning a new language)

Disorders and Dysfunctions

• Alzheimer's disease is a progressive neurodegenerative disorder characterized by memory loss and cognitive decline
  • Associated with the accumulation of amyloid plaques and neurofibrillary tangles in the brain
• Parkinson's disease is a neurodegenerative disorder affecting motor function and procedural memory
  • Caused by the loss of dopaminergic neurons in the substantia nigra
• Huntington's disease is a genetic neurodegenerative disorder affecting movement, cognition, and memory
  • Caused by a mutation in the huntingtin gene, leading to the accumulation of abnormal proteins
• Korsakoff's syndrome is a memory disorder caused by severe thiamine (vitamin B1) deficiency, often associated with chronic alcohol abuse
  • Characterized by confabulation (fabricated or misinterpreted memories) and anterograde amnesia
• Transient global amnesia is a temporary episode of memory loss, often triggered by stress or migraines
• Post-traumatic stress disorder (PTSD) involves intrusive memories and flashbacks of a traumatic event
• Attention deficit hyperactivity disorder (ADHD) can impact working memory and executive functions

Research Methods and Techniques

• Animal models (rodents, primates) are used to study learning and memory processes in controlled settings
  • Morris water maze tests spatial learning and memory in rodents
  • Fear conditioning paradigms investigate emotional memory and the role of the amygdala
• Human studies employ various techniques to investigate learning and memory
  • Neuropsychological tests assess cognitive functions, including memory (Wechsler Memory Scale)
  • Neuroimaging techniques (fMRI, PET) measure brain activity during memory tasks
  • Electroencephalography (EEG) records electrical activity in the brain, providing temporal information
• Optogenetics is a technique that uses light to control the activity of specific neurons, allowing for precise manipulation of neural circuits
• Pharmacological interventions (drugs, neurotransmitter agonists/antagonists) can modulate learning and memory processes
• Computational modeling helps to simulate and understand the complex dynamics of neural networks involved in learning and memory
• Genetic studies investigate the role of specific genes and genetic variations in learning and memory abilities (APOE gene and Alzheimer's risk)