Motor Learning and Control Quiz

Motor Control

• Movement is produced by complex neural networks that activate and coordinate muscles and limbs.
• Motor control involves both reflexive/reactive and voluntary mechanisms.
• Sensory input (afferent) is processed, followed by a motor/action response (efferent).
• Simple behaviors, such as playing tennis, use multiple brain regions for visual processing, planning actions, and integrating sensory information for accurate execution. Specific areas involved include:
  • Visual cortex (processing visual information)
  • Premotor cortex (planning actions)
  • Amygdala and hypothalamus (motivation, alertness)
  • Motor cortex (generating movement commands)
  • Posterior parietal cortex (integrating sensory information about surrounding environment to understand the position of the ball)
  • Basal ganglia (executing a motor task)
  • Cerebellum (error correction in the performance of the motor action)

Nervous System

• The nervous system has central and peripheral components.
• Central nervous system (CNS) includes the brain and spinal cord.
• Peripheral nervous system (PNS) includes peripheral nerves and ganglia.
• CNS and PNS are anatomically separate but functionally interconnected.
• Continuous communication allows the body to sense and react to the environment via motor plans.
• Two major cell types: neurons and glia.
• Neurons are the basic functional units of the nervous system.
  • Neurons have four main components: dendrites, cell body, axon, and terminal.
  • Dendrites receive information, the cell body processes information, the axon transmits information, and terminal sends signals to other cells.

Neuron

• Neurons are functionally classified into sensory, motor, and interneurons.
• Sensory neurons relay information from sensory receptors to the CNS (afferent).
• Motor neurons relay information from the CNS to effectors like muscles (efferent).
• Interneurons connect sensory and motor neurons in the CNS, facilitating complex processing and reflexive actions.
• Sensory neurons provide information about the body's external environment (touch, pressure, temperature, etc) to the CNS.
• Motor neurons transmit instructions from the CNS to muscles or glands, initiating actions.
• Interneurons relay and process information between sensory and motor neurons for complex behaviors.

Central Nervous System (CNS)

• The CNS consists of the spinal cord and brainstem.
• • Spinal Cord
  • Medulla
  • Pons
  • Midbrain
• The cerebellum coordinates fine motor control and balances.
• The thalamus receives sensory information and relays it to the cerebral cortex.
• Cerebral hemispheres (forebrain) are involved in higher-order functions like thought, perception, and language.

Cerebral Cortex Subdivisions

• The cerebral cortex is divided into lobes (frontal, parietal, occipital, and temporal) with different functions.
  • Frontal lobe: Responsible for movement, planning, and reasoning.
  • Parietal lobe: Involved in bodily sensation, spatial processing, and integration of visual and bodily information.
  • Temporal lobe: Processes auditory information, smell, taste, and visual perception.
  • Occipital lobe: Primarily responsible for visual processing.

Cerebral Cortex Continued

• Many areas of the cortex are involved in processing sensory information and motor commands (unimodal).
• Other areas are multimodal association areas, combining diverse information into purposeful interactions, perception of movement and motivation.

Grey and White Matter

• The spinal cord has grey matter (unmyelinated axons and cell bodies) on the inside and white matter (myelinated axons) on the outside.
• Grey matter is involved in processing information, and white matter transmits information.
• Cervical spinal cord segments have more white matter (for relaying information). Lower spinal segments in the vertebrae have less white matter.

Somatotopic Organization

• The organization of the ventral horn is somatotopic, meaning adjacent parts of the body are represented by adjacent neurons.
• Dorsal to ventral direction often maps from flexors to extensors.
• Generally, medial to lateral goes from proximal to distal.

Brainstem

• The brainstem consists of the medulla, pons, and midbrain.
• The brainstem regulates critical life support systems, controls eye movements, and relays sensory and motor information between the brain and spinal cord.
• Also known as a large area involved in the coordination of many fundamental bodily movements, and essential life functions like respiration, heart rate, and blood pressure.

Cerebral Cortex

• The cerebral cortex is the most external layer of the brain, deeply folded to increase surface area.
• It is divided into gyri (bumps) and sulci (grooves) and is vital for higher-order brain functions.
• Subdivisions include frontal, parietal, occipital, and temporal lobes, each with unique tasks.

Summary of Brain Regions

• The cerebral cortex is involved in higher-level processing of sensory and motor information.
• Brainstem functions include fundamental movement interactions and life processes.
• The cerebellum plays a role in motor coordination and error correction.
• The basal ganglia are essential for planning and control of movement.

Action Potential

• An action potential is a rapid change in membrane potential.
• The action potential arises when voltage-gated ion channels open, causing a rapid influx and efflux of ions (sodium and potassium).
• The action potential travels down the axon, leading to neurotransmitter release.
• The propagation of the action potential is affected by myelination.

Synapse

• At the synapse, neurotransmitters are released from the presynaptic neuron, transmitting information to the postsynaptic neuron.
• Drugs can influence this process, either enhancing or inhibiting synaptic transmission. These actions can lead to various behavioral changes.

Postsynaptic Potentials

• Postsynaptic potentials are small changes in membrane potential that summate to trigger an action potential.
• They can be excitatory (depolarizing) or inhibitory (hyperpolarizing) depending on the neurotransmitter released.

Signal Summation

• Signals from multiple presynaptic neurons can summate temporally or spatially to trigger an action potential in the postsynaptic neuron.

Motor Neurons and Motor Units

• Motor neurons control muscle contraction.
• A single motor neuron innervates one or more muscle fibers (a motor unit).
• The size of the motor unit influences the precision of movements; smaller motor units support finer control in movements.
• Different motor neurons are recruited in a specific manner to produce different amounts of force, in which smaller motor units are recruited first followed by larger motor units.

Sensory Receptors

• Specialized structures that detect stimuli from the environment.
• Types include:
  • Cutaneous receptors (detect touch, pressure, temperature, pain)
  • Joint receptors (detect joint position and movement)
  • Muscle spindles (detect muscle length and stretch)
  • Golgi tendon organs (detect muscle tension)
  • Spinal reflex arc

Classification of Skills

• Skills are classified by environmental predictability, organization of the task, the importance of physical vs cognitive components, and the primary muscles involved. Examples of skills are; closed and open skills.
  • Closed skills are performed in stable, predictable environments (e.g., typing, playing a piano).
  • Open skills are performed in moving or dynamic environments (e.g., playing tennis, catching a ball.)
• Discrete skills have a clearly defined beginning and end.
• Serial skills are discrete skills linked together, such as playing a piano, assembling something in a factory or even tying your shoes.
• Continuous skills are ongoing and don't necessarily occur in a distinct beginning and end (e.g., running, swimming)
• Skills can be further described as gross motor (larger muscle use) and fine motor (smaller muscle use).

Stages of Skill Learning

• People acquire skills through different stages: cognitive, associative, and autonomous stages.
• During the cognitive stage, understanding the task and its strategies is crucial.
• The associative stage is about refining movements, and the autonomous stage involves making movements automatic.
• It is worth noting that all these stages are not mutually exclusive and, in fact, they tend to happen simultaneously during practice.

Measuring Performance

• Production measures reflect the movements required to achieve a goal.
• Outcome measures capture the result of the action (eg, whether an arrow hits a target or not).

Sensory Systems

• Sensory systems detect and process information from the environment and from within the body.
• General components include receptors, pathways to the CNS, and integration centers in the brain.
• Receptors encode sensory information, which is relayed to the CNS and processed.
• Important systems are somatosensory, visual, and vestibular systems.

Somatosensory System

• Detects body position and motion.
• Receptors (such as muscle spindles, Golgi tendon organs, and cutaneous receptors) send signals to the CNS.
• Processed information helps to control movements and maintain posture.
• Pathway: periphery to CNS (ascending afferent pathways)
• Important components: proprioception, kinaesthesia and exteroception.

Visual System

• Detects objects and movements in the environment.
• The eye has photoreceptors (e.g. rods and cones) that turn light into signals.
• Signal transmission: retina to optic nerve to brain (optic tract) Important aspects: pathways, interpretation of information.

Visual Pathways

• Visual input travels through various pathways in the brain, with different areas processing different features (location, movement, shape, color).
  • Dorsal stream (where): spatial features.
  • Ventral stream (what): shape, identification and object recognition.

Vestibular System

• Detects head position and movement.
• Receptors (semicircular canals, otolith organs) detect angular and linear acceleration.
• Important in balance and coordination.
• Vestibular information is conveyed via the vestibulo-cochlear nerve (CN VIII) to the brain.
• There are four vestibular nuclei, which relay information to other brain regions.

Sensory System Summary

• Includes different sensory receptors to detect external and internal stimuli, sending signals to the CNS.
• Crucial for coordination and conscious control of body position.
• These interactions between systems are essential for appropriate body response to the environment and performing everyday activities.

Test your understanding of motor learning stages, characteristics, and the role of the brain and nervous system in motor control. This quiz covers key concepts such as the associative and autonomous stages of learning, functions of the motor cortex, and the components of the nervous system. Challenge yourself and deepen your knowledge in this essential area of study.