Module 8: Long-Term Memory
Long-term memory is a type of memory responsible for storing information over extended periods, ranging from days to a lifetime. It is divided into two main types: declarative (explicit) and non-declarative (implicit) memory. Each type involves different brain regions and serves distinct functions.
Declarative memory involves conscious recall of facts and events. It is further divided into two subtypes:
Episodic memory is the ability to recall personal experiences and specific events, including the context in which they occurred (time, place, emotions).
Example: Remembering your last birthday party or your first day at school.
Brain Regions: The hippocampus, medial temporal lobe, and prefrontal cortex are critical for episodic memory.
Semantic memory involves the storage of general knowledge about the world, including facts, concepts, and meanings.
Example: Knowing that Paris is the capital of France or that a zebra is an animal with black and white stripes.
Brain Regions: The hippocampus, lateral and anterior temporal cortex, and parts of the prefrontal cortex are involved in semantic memory.
Non-declarative memory involves unconscious recall and is associated with learning and memory that are expressed through performance rather than conscious recollection. It includes several subtypes:
Procedural memory is the memory of how to perform tasks and actions, often developed through repetition and practice.
Example: Riding a bicycle, playing a musical instrument, or typing on a keyboard.
Brain Regions: The basal ganglia, cerebellum, and motor cortex play significant roles in procedural memory.
Classical Conditioning involves learning through association, where a neutral stimulus becomes associated with a meaningful stimulus, eliciting a conditioned response.
Example: A dog salivating when it hears a bell if the bell has been repeatedly associated with food.
Brain Regions: The cerebellum is crucial for classical conditioning, especially for the conditioned responses related to reflexes.
Priming is the unconscious improvement in performance or ability to identify or process a stimulus due to prior exposure to that stimulus.
Example: Faster recognition of the word "nurse" if previously exposed to the word "doctor."
Brain Regions: Various regions of the neocortex are involved in priming, depending on the type of priming.
Non-Associative Learning involves habituation (decreased response to a repeated stimulus) and sensitization (increased response to a stimulus following exposure to a strong stimulus).
Example: Becoming less startled by a loud noise over time (habituation) or becoming more sensitive to pain after a severe injury (sensitization).
Brain Regions: Reflex pathways, including the spinal cord and brainstem, are involved in non-associative learning.
Summary
Declarative (Explicit) Memory: Conscious recall of facts and events.
Episodic Memory: Personal experiences (hippocampus, medial temporal lobe, prefrontal cortex).
Semantic Memory: General knowledge (hippocampus, temporal cortex, prefrontal cortex).
Non-Declarative (Implicit) Memory: Unconscious recall and performance.
Procedural Memory: Skills and tasks (basal ganglia, cerebellum, motor cortex).
Classical Conditioning: Learning through association (cerebellum).
Priming: Improved processing due to prior exposure (neocortex).
Non-Associative Learning: Habituation and sensitization (reflex pathways, spinal cord, brainstem).