Implicit vs. Explicit Memory in Animals and Humans Lecture

Vocabulary flashcards covering key terms from the lecture on implicit (nondeclarative) memory, hippocampal lesions, and comparative memory tasks in humans and animals.

Implicit (Nondeclarative) Memory

Memory for skills, habits, and conditioned responses that occurs without conscious awareness; supported by multiple distributed brain systems.

Explicit (Declarative) Memory

Conscious recollection of facts and events; chiefly depends on the medial temporal lobe memory system, including the hippocampus.

Medial Temporal Lobe (MTL) Memory System

Brain network (hippocampus + surrounding rhinal cortex) essential for explicit memory formation in humans and many animal species.

Hippocampal Lesion ("an lesion")

Experimental ablation or destruction of the hippocampus, commonly used in animal studies to test memory function.

Pattern Discrimination Task

Simple learning task where an animal distinguishes between two patterns (e.g., X vs. O); humans learn in one trial with explicit memory, monkeys learn slowly via implicit systems.

Delayed Non-Matching to Sample (DNMS)

Task in which an animal must choose the novel object after a delay; performance requires the hippocampus in both monkeys and humans.

Delayed Matching to Sample (DMS)

Variant of DNMS where the subject selects the previously seen object; procedure is identical, only the required choice differs.

Concurrent Discrimination Task

Learning eight object pairs in parallel; monkeys solve it gradually via habits (implicit) and are unaffected by hippocampal lesions, whereas humans use explicit memory.

Basal Ganglia

Subcortical structures that support habit learning and many forms of implicit memory, especially in tasks like pattern or concurrent discrimination.

Evolutionary Continuity

Idea that hippocampal functions are conserved across species; some tasks engage the hippocampus in both rats and humans.

Sea Slug (Aplysia) Studies

Early work on implicit memory showing classical conditioning in a simple nervous system without a hippocampus (Eric Kandel’s research).

Cellular Connection (Connectionist) Approach

View that different circuits mediate different forms of implicit learning depending on the learning situation.

Quick and Dirty Route (Low Road)

Fast, unconscious pathway from sensory thalamus to amygdala producing immediate emotional reactions.

Slow but Accurate Route (High Road)

Pathway from sensory cortex to amygdala that processes stimuli more fully before generating an emotional response; still implicit.

Amygdala

Almond-shaped medial temporal structure mediating emotional learning; operates both within and outside conscious awareness.

Unconscious Key Presses

Motor responses triggered by stimuli outside awareness, illustrating implicit processing in the cortex.

Classical Conditioning

Associative learning where a neutral stimulus becomes linked to a reflexive response; a form of implicit memory.

Eric Kandel

Neuroscientist who won the Nobel Prize for work on the neural basis of learning in Aplysia; author of "In Search of Memory."

Implicit Processes

Cognitive operations that occur without conscious awareness, distributed across many brain circuits rather than one dedicated system.

Explicit vs. Implicit Memory Distinction

Explicit memory relies on a single MTL system, whereas implicit memory comprises many specialized systems spread throughout the brain.