Psychology: Brain areas involved in long-term implicit and explicit memories

Brain areas involved in memory

- hippocampus
- amygdala
- neocortex
- cerebellum
- basal ganglia

Consolidation

A neurobiological process of making a newly formed memory stable and enduring following a learning experience.

Reconsolidation

During memory retrieval, it is open to further consolidation and has to be 're-stabilised'. If the original memory is changed when we rehash a memory, the revised version is 'reconsolidated'.

Hippocampus

A structure in the medial temporal lobe that plays a role in the formation, encoding and consolidation of new long-term explicit memories and their transfer to the neocortex for storage.

Role of the Hippocampus

- plays a major role in the formation and encoding of semantic and episodic (explicit) memories
- ensures theses memories are neurologically stable and long lasting
- important for spatial memory, an explicit memory for the physical location of objects in space

Amygdala

A small structure in the medial temporal lobe involved in emotional reactions (particularly fear and anger) relating to implicit memory and the formation of a wide variety of emotional memories.

Role of the Amygdala

- processing and regulating emotional reactions and classically conditioned fear responses involving implicit memory
- formation and consolidation of events that evoke an emotional reaction
- helps detect danger

Hippocampus vs Amygdala

- hippocampus consolidates explicit LTM where as the amgydala consolidates implicit LTM
- people with damaged hippocampi can form procedural memories (implicit) but will not remember the event where the performed the skill (episodic, explicit)
- people with damaged amgydalae are incapable of forming new phobias (implicit)

Neocortex

The largest and most recently evolved part of the brain's cerebral cortex.

Role of the Neocortex

- long term explicit memories are widely distributed and stored throughout the neocortex
- role in interaction with the hippocampus in the formation, consolidation, storage and retrieval of long term explicit memories
- acts as part of a larger interconnected learning and memory system

Cerebellum

It is a major structure of the hindbrain with connections to basal ganglia and prefrontal cortex. In relation to memory, it is involved in formation of long-term motor skill memories and stores implicit memories of conditioned reflexes.

Role of the Cerebellum

- directly involved in the encoding of implicit procedural motor memories when learning voluntary movement of new motor skills
- forms and stores implicit memories of simple reflexes acquired through classical conditioning
- coordinates fine muscle movements, regulates posture and balance

Basal Ganglia

Structures in the brain involved in the generation of voluntary movements and long-term implicit memories involving motor skills. It is also involved with the process of habituation.

Role of the Basal Ganglia

- forms and stores implicit procedural memories of habits
- inhibits unwanted movements, resulting in a smooth sequence of movements that can be stored as a procedural memory
- involved with habituation, as this occurs without awareness, memories associated with habituation are implicit memories

Aphantasia

A term used to describe the absence of visual imagery.

Alzheimer's Disease

A neurodegenerative disorder characterised by the gradual widespread degeneration of brain neurons, progressively causing memory decline, deterioration of cognitive and social skills and personality changes.

Features of Alzheimer's Disease

- episodic and semantic memories are primarily affected (explicit memory)
- degeneration often starts at the hippocampus and progresses outwardly
- initially affects only the STM but as it progresses, it affects LTM

Amyloid Plaques

Clumps of insoluble plaques that form in the spaces between nerve cells, thereby impairing synapses and inhibiting communication between neurons.

Tau neurofibrillary tangles

Are tangles that form inside neurons, inhibiting the transport of essential substances throughout the neuron. This failure of the transport system is believed to kill neurons.