Basic movements

Motor cortex

The region of the cerebral cortex involved in the planning, control and execution of voluntary movements

Basal ganglia

a group of subcortical nuclei responsible for action selection, motor control, and procedural learning

Availability Heuristic

A mental shortcut relying on immediate examples that come to mind when evaluating a specific topic or decision

Anchoring and adjustment

a cognitive bias where individual decisions are disproportionately influenced by an initial piece of information

Repetitiveness heuristic

assessing probability by comparing an object or event to a prototype or stereotype already existing in mind

Action selection

The task of resolving conflicts between competing behaviours and choosing the appropriate motor outcome

Simple reflex

mediated at the level of the spinal cord

Locomotion

Walking, running

Sensory orientation

Head turning, eye fixation

Voluntary movements

Those that are under conscious control by the brain

Rhythmic movements

timing and spatial organisation is to a large extent is controlled autonomously by spinal or brain stem circuitry. They are produced by local spinal cord circuits known as central pattern generators

central pattern generators

produce rhythmic movements

Reflexes

stereotyped involuntary responses to specific stimuli that are generated by simple neural circuits in the spinal cord or brain stem.

leprosy

Caused by bacterium infection - thermal sensation first to go followed by pain and touch

Striated/skeletal muscles

when at least one end (origin) is connected to a bone through a tendon and involved in voluntary movement

smooth muscle

around blood vessels glands, the gut and in the brochioles

Myosin

form thin filaments in the sarcomere

fibrous tail and globular head that goes into the actin

Actin

Form thick filaments in the sarcomere

Sarcomere

The basic functional unit for contraction in striated muscle

Acetylcholine

The neurochemical responsible for helping generate movement, triggers the release of calcium ions into the muscle cell calcium binds to regulatory protein that allows for muscle movement

ion channels

open allowing calcium ions to enter the muscle triggering a contraction

Innervation

a single motor neuron will control several muscle fibres

Motor unit

the motor neuron and all the fibres it controls

Proximal

towards the midline

Distal

Away from the midline of the body

Curare toxin

• made from various plants

• inhibits muscles within 25 mins

• inability of the muscles to respond to motor nerve stimulus

• no contraction of muscle fibre

• suffocation - muscle paralysis including breathing muscles often used in blow darts

Myasthenia gravis

• Abnormality in acetylcholine receptors. - muscle movement ments voluntary movements made more difficult

• People with this condition are very weak as they can only activate a few of their striated muscle fibers.

• Trouble smiling. Difficulty chewing and blinking in severe cases 

A congenital issue

present from birth

Tetanic contractions

Multiple motor neurons activating many muscles fibres simultaneously

Motor unit pool

motor neurons in the spinal cord that supply a single muscle

Henneman’s size principle

Motor recruitment is from smallest to largest

Slow twitch fibres

• fatigue resistant

• higher excitability

• activated first

Fast twitch fibres

• high force output

• requires stronger input

• recruited later as task intensity rises

Temporal summation

• wave summation

• muscle contraction where a muscle receives multiple stimuli of equal intensity in quick succession

Spatial summation

Overall recruitment of all the potential

Hypotonia

Decreased muscle tone due to lack of NS input

Flaccid paralysis

The loss of your ability to perform voluntary movement

Denervation atrophy

The shrinkage and weakening of muscle fibres that occurs after loss of nerve supply leading to rapid fibre loss

Amyotrophic lateral sclerosis (ALS)

a progressive neurodegenerative disorder affecting nerve cells in the brain and spinal cord, leading to muscle weakness and atrophy

Fasciculation

• muscle twitching

• involuntary

• triggered by stress, fatigue or caffeine

Motor programs

Abstract neural commands stored in the CNS that execute actions independently of specific muscle groups and without requiring continuous peripheral sensory feedback.

Motor equivalence

• The ability of different motor systems to achieve the same behaviour

• suggests that purposeful movements in your brain are therefore represented abstractly rather than the specific sets of programs assigned to given limb

Supplementary motor cortex (SMA)

Premotor region specialized for self-initiated, internally guided movement sequences independent of external sensory cues.

Primary motor cortex (PMC)

Responsible for the execution of all voluntary movements of the body

Posterior parietal cortex

• Planning areas for sequencing spatial reasoning and attention

• links action with visual objects

Transmission stimulation

Trigger movement by magnetic stimulation

Pyramidal (voluntary) pathway

• originates in the PMC

• projecting to cranial nerve VII (facial nucleus) in the pons

• superior facial muscles receive bilateral cortical innervation

• inferior facial muscles receive contralateral innervation

Emotional (Extrapyramidal) Pathway

• Originates in prefrontal cortex/basal ganglia

• projecting through the hypothalamus and reticular formation to the facial nucleus.

•  Mediates involuntary emotional facial expressions.

Somatotropic organisation

The precise mapping of the body’s surface onto regions of the CNS particularly the primary somatosensory and moto cortices

Motor Homunculus

A model representing particular parts of the brain's response to electrical stimulation made by Penfield and Rasmussen (mapping out electrical stimulation of the cortex)

Motor apraxia

Inability to perform a learned action when presented with target objects or imitate observed actions.

Ideational apraxia

Disruption in sequencing multi-step tool/object interactions (e.g., placing a letter in an envelope before folding it).

Verbal apraxia

Impairment in motor planning for speech production.

Lower motor neurons

• located in the ventral horn of the spinal cord and cranial nerve nuclei in the brainstem

• Directly innervate skeletal muscle fibers

FIne motor control neurons

• (e.g., ocular or finger muscles)

• innervate few muscle fibers,

Gross movement neurons

• (e.g., leg muscles)

• innervate hundreds of muscle fibres

Local circuit neurons

• Interneurons supplying synaptic input to LMNs;

• essential for local reflex loops and coordinating rhythmic behaviors.

Upper motor neurons

• Reside in the cerebral cortex (primary motor, premotor) and brainstem

• project descending axons to local circuit neurons and LMNs.

Spinal locomotor circuits

Rhythmic behaviors like locomotion, swimming, and swallowing rely on autonomous spinal/brainstem circuits termed Central Pattern Generators (CPGs)

Central pattern Generators

autonomous spinal/brainstem circuits that generate rhythmic movements

Population coding theory

• a framework in neuroscience that suggests that information is represented not by individual neurons but by the joint activity of many neurons.

• posits that the collective firing rates of a population of neurons can convey information about stimuli, decisions and actions