Module 3: Sensory Motor System

8.1 Introduction and Organization
- Overview of sensory systems functioning as interfaces between the internal and external environments.
8.2 The Sensory System: Vision
- Mechanisms of vision processing and its neuroanatomy.
8.3 The Sensory System: Audition
- Understanding auditory perception including the anatomy of the ear and auditory pathways.
8.4 The Sensory System: Tactition-Pain
- Exploration of tactile sensation and pain perception processes.

A. Three Principles of Function
- 1. Hierarchical Organization
  - Information processing occurs at multiple levels of the nervous system.
- 2. Motor Output Guided by Sensory Input
  - Movement is continually modified based on sensory feedback.
- 3. Impact of Learning
  - Learning changes sensorimotor relationships, affecting both motor commands and sensory processing.

Posterior Parietal Association Cortex
- Function: Integrates sensory input for action.
- Disorders:
  - Apraxia: Difficulties in the execution of movements despite having the capacity.
  - Contralateral Neglect: Ignoring one side of the body or space, often due to right hemisphere lesions.
Dorsolateral Prefrontal Association Cortex
- Involved in planning and decision-making.

Inputs: Receives information from various sensory modalities and other motor areas.
Function: Important for planning and coordination of complex movements.
Mirror Neurons: Activate when an individual performs an action or sees another perform that same action.

Precentral Gyrus: The area of the brain responsible for generating movements.
Somatotopic Organization: The organization of the primary motor cortex that reflects the arrangement of body parts—specific areas correspond to specific body regions.

Cerebellum (Location): Situated at the back of the brain, beneath the cerebral hemispheres; major role in motor control and learning.
Basal Ganglia: Group of nuclei involved in the regulation of voluntary motor movements and procedural learning.
Striatum: Major input nucleus of the basal ganglia, consisting of the caudate nucleus and putamen.
Globus Pallidus: Part of the basal ganglia that regulates voluntary movement.

Overview: Complex networks that control reflexes and motor actions at the spinal level.

Integrate sensory information and motor commands, facilitating movement responses.

Golgi Tendon Organs: Receptors located at the junction of tendons and muscles; sensitive to changes in muscle tension.
Muscle Spindles: Sensory receptors located within the belly of muscles; detect changes in muscle length and the rate of length change.

Patellar Tendon Reflex Example: A monosynaptic reflex that occurs when the patellar tendon is tapped, causing the extension of the lower leg.
General Function: Maintains posture and helps coordinate movement.

How it Differs from Stretch Reflex: Involves multiple synapses and is a polysynaptic reflex that results in the withdrawal of a limb from a painful stimulus.
Site of Transduction: The point where sensory stimuli are converted into neural impulses, typically within sensory neurons.
Afferent Pathway: The pathway that carries sensory signals to the central nervous system.
Efferent Pathway: The pathway that transmits motor commands from the central nervous system to muscles.

Role of Inhibition and Excitation: Reflex responses are modulated by both excitatory and inhibitory connections in the nervous system.
Reciprocal Innervation: A process where the contraction of one muscle is accompanied by the relaxation of its antagonist; essential for coordinated movement.
Recurrent Collateral Inhibition: A feedback mechanism where a neuron inhibits itself or surrounding neurons to refine motor commands and maintain balance in neural output.