Most people move throughout the day without thinking about how their bodies accomplish these actions. Movements such as brushing teeth or walking are possible because of constant communication between the brain, muscles, and sensory systems.
James David Guest, M.D., PhD., FAANS, a professor of neurological surgery at the University of Miami’s Miller School of Medicine and a scientific faculty member with The Miami Project to Cure Paralysis, explains how this process works. Dr. Guest’s research focuses on helping individuals regain movement after spinal cord or brain injuries.
Dr. Guest describes the process by which thoughts become coordinated movements: “The transformation from thought to movement involves multiple parallel pathways that use the brain, spinal cord, muscles, and sensory mechanisms.” Voluntary movement begins with an intention in the brain’s premotor and supplementary motor areas. These regions plan which muscles need to move and in what order. Commands travel through nerve fibers called the corticospinal tract to reach nerves and muscles responsible for action.
Some parts of the premotor cortex help determine spatial responses—such as how far to step—while others focus on details like grip strength or adjusting steps on uneven ground. Many adjustments happen automatically through the spinal cord.
Interneurons in the spinal cord play a role in controlling rhythmic movements like walking by acting as pattern generators that shift weight between legs. Other neural pathways assist with posture and coordination so that precise movements can occur.
The cerebellum is responsible for predicting and correcting movements in real time. According to Dr. Guest: “The cerebellum compares your intended movement with incoming sensory feedback and generates error signals. It serves a regulatory and monitoring function. Your movements are responsive to changing visuals, sounds, the sense of physical contact, and joint positions, as well as warning signals like pain,” he says. “These predictive loops allow you to make smooth movements, even when sensory feedback is delayed. The cerebellum has already calculated where your limb should be.”
When visual input conflicts with physical reality—such as when looking at a reversed reflection in two mirrors—the brain must quickly decide which information to trust. Dr. Guest explains: “Normal spatial coordination depends on reference frames that are computed by the brain’s posterior parietal cortex,” he says. “This region of the brain integrates predictive data from your eyes (retinas) and your balance system (inner ear) and combines them with muscle and joint data to create a sense of your body in space.” He adds: “Mirror reversal creates a conflict between visual feedback (your hand moving right in the mirror) and proprioceptive feedback (your hand actually moving left). The parietal cortex must perform a rapid coordinate transformation, essentially applying a mental rotation.”
Sensory illusions further show how vision can influence bodily perception. Dr. Guest notes: “When someone watches a rubber hand being stroked synchronously with their hidden real hand, they begin to ‘feel’ the stroking on the rubber hand and misjudge their actual hand position by several centimeters. This illusion engages the brain’s premotor and parietal cortex, areas that maintain body schema.” With prism glasses shifting vision off target during an activity: “Initially, they miss the target. But, within 20 to 30 attempts, their cerebellum adjusts the mapping between visual targets and motor commands,” he says. When prisms are removed there is an aftereffect until normal vision readapts.
Practice helps improve bodily awareness over time by building muscle memory for complex skills such as riding a bicycle or playing piano—even after long periods without practice.
“Early attempts at learning a new skill rely heavily on conscious control and visual guidance,” Dr. Guest says.“With repetition, your nervous system builds statistical expectations about how your muscles, joints, and sensory feedback behave… This early practice heavily engages your brain’s prefrontal and parietal areas…”
He continues: “With repeated practice, your brain creates memory circuits that act like predictive models… While you sleep these motor memories transfer from cortical areas… stored as loops in… cerebellum and basal ganglia…. This is why skilled movements consolidate… Individual elements merge into fluid sequences….”
Neuroplasticity supports this process by forming new connections within the brain through synapses—the points where electrical signals release neurochemicals.“With extensive practice,the cerebellum’s predictive maps become more accurate,reducing need for conscious error correction…. Studies of musicians show expanded cortical representations… increased gray matter density…. Expert pianists show more precise somatosensory discrimination…” Dr.Guest adds,“An experienced mechanic can make adjustments using their hand when it’s inside a tight box.This means they’ve essentially increased resolution of their body maps.”
Once learned,movements become automatic; overthinking can interfere.“In your muscles,muscle memory is a cellular mechanism that describes capacity of skeletal muscle fibers to respond differently…when those stimuli have been previously encountered,”says Dr.Guest.“In your brain,muscle memory involves long-term procedural memory circuits in cerebellum,motor cortex,and basal ganglia.”
He explains:“Once you have learned …coordinated series of movements,…‘subcortical’ loops can execute it automatically,…little involvement from conscious prefrontal cortex…. But when you overthink,your prefrontal cortex … sends top-down signals that compete with automatic programs — breaking … confidence.This can happen with excess anxiety.”
Performance errors may result because conscious thinking uses slower networks than automatic movement systems; too much focus interrupts fast timing needed for practiced skills.
As people learn new skills,cortical activity increases;as tasks become routine,the activity shifts toward subcortical regions reflecting transfer from conscious control to automatic execution.
Disruptions due to injury can affect these processes.The Miami Project to Cure Paralysis conducts research aimed at understanding such injuries better.Click here to learn more about The Miami Project’s life-changing work.
Written by Dana Kantrowitz.
Medically reviewed by James David Guest,M.D.,PhD.,FAANS,in November 2025.
