Neural Mechanisms Contributions and Control

The Nervous System— Central Nervous System (CNS) Brain and spinal cord Processes: Sensory information is integrated Decisions are made Signals are generated and sent to muscles and glands to carry out responses

The Nervous System— Peripheral Nervous System (PNS) Nerves that extend from brain and spinal cord, linking body and CNS Afferent division: Detects changes in the environment and conducts nerve impulses from sensory receptors to CNS Efferent division: Transmits nerve impulses away from the CNS

Sensory Receptors Exteroceptors: Detect stimuli outside the body Provide information about the external environment Interoceptors: Detect stimuli from internal viscera Provide information about the internal environment Proprioceptors: Provide information regarding body position and movement Detect changes in muscle tension, joint position, and equilibrium

Vision Predominant sensory receptor: 70% of all the body’s sensory receptors are located in the eyes 40% of the cerebral cortex is thought to be involved in some aspect of processing visual information Sport vision: Focuses on investigating visual contributions to performance

Basic Structures of the Eye

Visual Fields of the Eyes and Associated Neural Pathways

Focal vs. Ambient Vision Focal system: Functions to identify objects located primarily in the center of the visual field Linked to consciousness Operates under voluntary control Ambient system: Thought to be responsible for spatial localization and orientation Functions at a subconscious level Serves both central and peripheral visual fields

Your Perspective When you are out walking or bike riding in the woods, what do you pay attention to and what other things are you just vaguely aware of? How does this differ when you are walking down a city street at night?

Visual Abilities in Performance Eye dominance Spotting Fixating Visual search

Eye Dominance One eye processes information and transmits it to the brain more quickly than the other Same-side dominant Cross-dominant

Visual Search Strategies Quiet eye Targeting skills: Archery, rifle shooting, putting, free throws in basketball, etc. Interceptive skills: Striking, catching, landing, avoiding a collision Tactical skills: Quick, accurate situational decision making Attention to relevant environmental cues Pattern recognition

Vision Tips for Practitioners Develop effective visual search strategies: Instruction and feedback should direct learners to areas where critical cues occur Appropriate learning experiences should provide extensive practice opportunities Video training—with challenges to anticipate an opponent’s actions Context of learning situations should include a good deal of variability

Proprioception The continuous flow of sensory information received from receptors in muscles, tendons, joints, and inner ear regarding movement and body position. Types: Golgi tendon organs Muscle spindles Joint kinesthetic receptors Vestibular apparatus

Proprioception and Performance Makes the motor control system more efficient and flexible Provides information about initial body and limb position, which serves as the basis of programming of motor commands Evaluates movement for correctness: Compares proprioceptive feedback to the intended goal Makes adjustments

Transmission of Information via the Spinal Cord

Sensory and Motor Pathways Sensory (ascending) pathways: Spinothalamic and posterior or dorsal column pathway Conduct impulses related to pain, temperature, touch, pressure, and vibrations Motor (descending) pathways: Pyramidal and extrapyramidal pathways Conduct impulses related to voluntary and subconscious movements

Spinal Reflexes An automatic, involuntary response to stimuli Reflex arc—simplest pathway by which a reflex occurs Types: Monosynaptic reflex Polysynaptic reflex

Reflexes Monosynaptic reflex loop Withdrawal and crossed extensor reflex arc

Damage to the Spinal Cord Types of injury: Complete Incomplete: Effects depend on the area of the spinal cord affected Level of injury: In general, the higher up the spinal cord that injury occurs, the greater the extent of the injury.

Parts of the Brain Brain stem Diencephalon Cerebrum Cerebellum

Areas of the Cerebral Cortex Sensory areas Motor areas Association areas Basal ganglia

Functional Areas of the Cerebral Cortex

Cerebellum Monitors movement by comparing what was intended with what is actually taking place Plays a key role in detecting and correcting errors Works with motor cortex to produce smooth, coordinated movements Plays a key role in maintaining posture and balance

Memory Systems

Subsystems of Long-Term Memory Episodic memory: Information about personal experiences and events Semantic memory: General, factual knowledge Procedural memory: Skills, operations, and actions

Your Perspective Sometimes it is much easier to remember events from our childhood than to remember what we had for breakfast the day before yesterday. Why do you think that is? Why do you think certain smells or songs have such a strong effect on our ability to remember people and events?

Forgetting Decay theory Interference theory: Proactive interference Retroactive interference

Proactive and Retroactive Interference

Memory Tips for Practitioners Keep instructions and feedback short and simple Provide ample opportunities for physical rehearsal Relate a skill being learned to previously learned skills Use meaningful labels and analogies to strengthen associations Group several movements together