Neuroscience of Sensorimotor Function

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Questions and Answers

What occurs during isometric contraction?

Muscle tension decreases while length remains unchanged.

Muscle length remains unchanged and decreases tension.

Muscle tension increases without changing its length. (correct)

Muscle length decreases while exerting force.

Which type of receptor organ primarily senses changes in muscle tension?

Neural Pathways

Muscle Spindles

Joint Receptors

Golgi Tendon Organs (correct)

What is a key characteristic of the stretch reflex?

It involves coordination of opposing muscle groups.

It occurs in response to a relaxing muscle.

It is an automatic response to sudden stretching. (correct)

It is a voluntary response to painful stimuli.

What does motor equivalence allow in the context of central sensorimotor programs?

Adaptation to different movements for the same goal. Signup and view all the answers

Which statement about functional brain imaging of sensorimotor learning is accurate?

Increased activity in sensorimotor areas is observed during learning. Signup and view all the answers

What is the primary function of spinal circuits in sensorimotor function?

They manage basic motor functions independently from the brain. Signup and view all the answers

What role does the posterior parietal cortex play in sensorimotor function?

Integrating sensory and motor information. Signup and view all the answers

Which type of pathways is responsible for controlling fine movements such as those of the hands and fingers?

Dorsolateral pathways. Signup and view all the answers

What is a critical function of the cerebellum in sensorimotor processing?

Coordinating and correcting movements based on sensory feedback. Signup and view all the answers

What is the primary responsibility of the primary motor cortex?

To execute voluntary movements. Signup and view all the answers

What does contralateral neglect refer to in sensorimotor disorders?

Inability to respond to stimuli on the side opposite a brain lesion. Signup and view all the answers

Which type of muscle fibers are best suited for endurance activities?

Slow muscle fibers. Signup and view all the answers

How do mirror neurons contribute to sensorimotor function?

They facilitate understanding of observed actions. Signup and view all the answers

Study Notes

Sensorimotor Spinal Circuits

Spinal circuits control fundamental movements without input from the brain, enabling reflexes and basic actions.

Central Sensorimotor Programs and Learning

Initial motor tasks require conscious effort, but become automated with practice, resulting in smooth and efficient movements.

Sensorimotor Association Cortex

Integrates sensory and motor information to guide behavior and attention.

Posterior Parietal Cortex

Combines spatial information.

Dorsolateral Prefrontal Cortex

Involved in planning and decision-making.

Disorders of Sensorimotor Function

Apraxia is difficulty carrying out voluntary movements independent of motor deficits.
Contralateral neglect involves failure to respond to stimuli on the side opposite a brain lesion.

Secondary Motor Cortex

Receives input from the association cortex and transmits signals to the primary motor cortex, playing a pivotal role in movement planning and coordination.

Mirror Neurons

Fire both when someone performs an action and when they observe the same action taking place, contributing to the understanding of others' movements.

Primary Motor Cortex

Located in the precentral gyrus of the frontal lobe.
Directs voluntary movements.

Motor Homunculus

A map depicting the motor control of different body parts within the cortex.

Effects of Primary Motor Cortex Lesions

Widespread damage may result in less significant impairment than expected, suggesting redundant motor control pathways.

Cerebellum

Coordinates and refines movements based on sensory feedback.
Involved in timing, motor learning, and cognitive and emotional processing.

Basal Ganglia

Regulates motor output and is crucial for habit learning and cognitive functions due to connections with the prefrontal cortex.

Descending Motor Pathways

Dorsolateral pathways control fine movements (e.g., hand and finger movements).
Ventromedial pathways manage posture and whole-body movements.

Types of Muscle Fibers

Fast muscle fibers contract quickly and generate high force but fatigue rapidly.
Slow muscle fibers sustain contractions for longer durations, suitable for endurance activities.

Types of Muscle Contraction

Isometric contraction: Muscle tension increases without shortening (e.g., holding a weight).
Dynamic contraction: Muscle shortens while exerting force (e.g., lifting an object).

Receptor Organs of Tendons and Muscles

Muscle spindles detect changes in muscle length; they trigger reflexes to prevent overstretching.
Golgi Tendon Organs sense muscle tension; They prevent excessive contraction to protect muscles.

Muscle Reflexes

Stretch reflex: Automatic response to sudden stretching (e.g., knee-jerk reflex).
Withdrawal reflex: Rapid response to painful stimuli, involving immediate muscle contraction.

Reciprocal Innervation

Coordination mechanism for smooth movements where opposing muscles work in tandem; One muscle contracts while the opposing muscle relaxes.

Hierarchy of Central Sensorimotor Programs

The sensorimotor system operates hierarchically, with higher levels coordinating complex actions and lower levels functioning autonomously.

Characteristics of Central Sensorimotor Programs

Motor equivalence: Programs can adapt to different movements to achieve the same goal.
Sensory feedback: Programs can develop without practice and improve with experience.

Functional Brain Imaging of Sensorimotor Learning

PET scans show increased activity in sensorimotor areas during learning, with a decrease in activity as tasks become practiced.

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Description

Explore the intricacies of sensorimotor circuits and their role in movement control. This quiz covers the functions of various brain regions involved in motor tasks, learning, and disorders affecting sensorimotor functions. Test your knowledge on how these elements integrate to facilitate movement and coordination.