Skill Memory Brain Substrates

spinal cord and brainstem

control and coordinate skill movements

basal ganglia

• Relay sensory information from cortex to thalamus and brain stem.

• Involved in activation and control of movement velocity, direction, and amplitude.

basal ganglia damage

impairment of skill learning

Parkinson’s disease

disables basal ganglia circuits => affects basic motor skills

basal ganglia is important for

• performing skills

• forming skill memories

• accessing skill memories

Rodents in a maze with impaired basal ganglia

impaired navigation based on cues such as light

perceptual-motor skill learning in rodents in T-maze

basal ganglia may develop a motor plan consistent with Fittsʼ skills learning model

humans brain activity in cognitive skill learning

basal ganglia shows activity

cortical representation of skill

neuroimaging show cortical regions involved in skill performance expand with extensive practice

cerebellum

important for encoding and retrieving skill memories

• has inputs from spinal cord, sensory systems and cerebral cortex

• has output to spinal cord and cortical motor systems

=> learning precisely timed movement sequences

cerebellum and timing

performing perceptual-motor tasks depends on it

• first brain region affected by alcohol

apraxia

poor coordination of purposeful, skilled movements

• left parietal damage → difficulty imitating actions

• frontal damage - difficulty pantomiming actions with two hands

• cortical damage - difficulties with control and skill execution

cerebellum main function

timing

cerebral cortex main function

controlling complex actions sequences

basal ganglia main function

linking sensory events to responses and automate later sensory-action sequences

transcranial magnetic stimulation

stimulating the brain

Huntington’s disease

neuronal damage in basal ganglia and cerebral cortex

• slow loss of motor abilities

• face twitching/progressive body shaking

• can slowly learn skills (difficulties with mirror reading and weather prediction tasks)

• hindered perceptual-motor skills

Parkinson’s disease

reduction in brainstem neurons (modulating basal ganglia and cerebral cortex)

• muscular rigidity

• difficulty initiating movements

• difficulty learning serial reaction time and rotary pursuit tasks