Postural Control and Muscle Function Quiz

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Questions and Answers

What role does the soleus muscle play in maintaining posture?

It offsets the center of mass with excessive torque.

It enables fast reflexive actions during balance.

It initiates voluntary movements.

It is tonically active to maintain posture and balance. (correct)

What must happen if the center of mass moves outside the base of support?

The individual should maintain the current position.

No adjustments are necessary.

The center of pressure can remain static.

The base of support must be changed to prevent falling. (correct)

Which statement best describes the role of muscle activity in balance?

Muscle activity is unnecessary for postural adjustments.

Passive forces are sufficient for maintaining balance.

Muscle activity is required to offset torque moments caused by misalignment. (correct)

Muscle activity can inhibit anticipatory adjustments.

What is the center of pressure?

The location maintained within the base of support. Signup and view all the answers

What is ‘anticipatory postural adjustment’?

A feedforward activation of postural muscles prior to a voluntary movement. Signup and view all the answers

What typically happens prior to lifting the swing foot while walking?

The center of pressure shifts toward the supporting leg. Signup and view all the answers

What is a common misconception about passive forces in maintaining balance?

They are completely sufficient for balance. Signup and view all the answers

What is the average variance of the center of mass when standing?

10 mm Signup and view all the answers

What are automatic postural reactions (APRs)?

Highly stereotyped patterns of muscle activity triggered by instability Signup and view all the answers

What characterizes fixed support reactions?

They occur without any changes to the base of support Signup and view all the answers

Which of the following components contribute to maintaining stability during postural reactions?

Ocular information and vestibular information Signup and view all the answers

What triggers a change in support reactions?

An unexpected loss of balance necessitating support changes Signup and view all the answers

What role does proprioception play in automatic postural reactions?

Proprioception gives a clear image of body state Signup and view all the answers

How does the amplitude of electromyographic activity relate to support reactions?

Amplitude changes correlate with balance recovery strategies Signup and view all the answers

What happens during an unexpected perturbation to stability?

Automatic postural reactions are initiated Signup and view all the answers

In which scenario would a change in support reaction be necessary?

When maintaining balance after a sudden shift in body position Signup and view all the answers

What role do the basal ganglia play in movement initiation?

They initiate and modulate postural adjustments. Signup and view all the answers

Which pathway is involved in modulating flexor and extensor muscle tone?

Corticorubral tract Signup and view all the answers

How are neurons in the primary motor cortex organized?

They are organized based on movement properties rather than individual muscles. Signup and view all the answers

What is the function of the pontine tract?

To coordinate voluntary motor functions. Signup and view all the answers

Which area is involved in mapping visual information to arm movements?

Medial intraparietal area (MIP) Signup and view all the answers

What does lesion to the basal ganglia typically disrupt?

The ability to initiate and sense postural adjustments. Signup and view all the answers

Which tract is responsible for cognitive motor integration?

Corticostriate tract Signup and view all the answers

What is a characteristic of mirror neurons?

They relate the actions of others to one's own actions. Signup and view all the answers

What role do AMPA receptors play in synaptic transmission?

They are activated by glutamate to allow sodium influx. Signup and view all the answers

What is the function of NMDA receptors in the postsynaptic neuron?

They allow calcium and sodium influx following depolarization. Signup and view all the answers

What is the significance of calcium influx in the context of synaptic transmission?

It leads to the translocation of AMPA receptors to the membrane. Signup and view all the answers

What aspect of memory is most directly driven by the emergence of new dendritic spines?

It enhances learning and memory formation. Signup and view all the answers

What distinguishes long-term potentiation (LTP) in synapses?

It is an intermediary step toward the permanence of synaptic changes. Signup and view all the answers

Which process combines the action of multiple inputs at a synapse?

Spatial summation Signup and view all the answers

What is symptogenesis in relation to memory?

The process of making a memory more resilient to forgetting. Signup and view all the answers

What can inactivity and learned non-use lead to in the context of neural plasticity?

A decrease in synaptic connections. Signup and view all the answers

What defines the center of gravity of the human body?

The average position of the entire body's mass Signup and view all the answers

What is meant by the 'flight period' in terms of gait?

The time when both legs are off the ground Signup and view all the answers

Which factor is crucial for controlling gait?

Dynamic balance control Signup and view all the answers

What is the role of a central pattern generator?

To produce rhythmic muscle activation patterns spontaneously Signup and view all the answers

How does the nervous system contribute to gait?

Through a network of interneurons for rhythmic control Signup and view all the answers

What is primarily responsible for the initiation and modulation of gait?

Peripheral and central influences Signup and view all the answers

What does 'rhythmical collimating limb control' refer to?

Consistent and synchronized limb movement Signup and view all the answers

What is indicated by the term 'alternating placement of feet'?

The typical pattern of walking or running Signup and view all the answers

What is the principle of multimodal integration primarily based on?

Probability and schema rules Signup and view all the answers

Which area of the brain is involved in the 'where/how' pathway of visual processing?

Posterior parietal cortex Signup and view all the answers

What is prosopagnosia commonly known as?

Face blindness Signup and view all the answers

Which visual area is primarily responsible for object recognition?

Inferior temporal lobe Signup and view all the answers

What aspect does the integration of sensory modalities primarily depend on?

Spatiotemporal congruency Signup and view all the answers

What does the dorsal stream primarily contribute to in visual processing?

Movement control and perception Signup and view all the answers

Which term describes the brain's tendency to integrate information received simultaneously from the same spatial location?

Multimodal processing Signup and view all the answers

What is the role of V2 and V6 in visual processing?

They are involved in face and object recognition. Signup and view all the answers

Study Notes

Lecture Notes Summary

Goal-directed movement: A behavioral goal-oriented action guided by neural coordination of multiple small movements within an environmental context.
Motor program theory: Proposes goal-directed movements result from learned motor programs, which are pre-determined sequences of muscle commands executed without sensory feedback. However, this theory faces challenges in explaining the flexibility and novelty of movements.
Generalized motor programs: Abstract representations of movement sequences with invariant features (like timing) and variable features (like speed and force). These programs allow for adapting movements across different effectors.
Methods for assessing motor control: Single-cell studies, fMRI, EEG, TMS, and lesion studies. Non-invasive methods have limitations in measuring both spatial and temporal resolution.
FMRI: Measures brain activity by analyzing the levels of oxygenated and deoxygenated hemoglobin.
EEG: Measures electrical activity in the brain using electrodes placed on the scalp.
TMS: Alters brain activity by inducing short-term changes in excitability of neurons using magnetic pulses.
Lesion studies: Involve creating controlled brain damage to study the impact on movement control.
Postural orientation: Relative positioning of body segments concerning each other and the environment.
Postural stability: Maintaining the body's center of mass within the base of support despite disturbances.
Balance/equilibrium control: The nervous system control of postural stability.
Center of mass (COM): The average location of the body's mass.
Base of support (BOS): The area of the body in contact with supporting surfaces.
Center of pressure (COP): The point of application of the overall ground reaction force vector between a person and the base of support.
Static stability: Maintaining COM within a stationary BOS.
Dynamic stability: Maintaining the relationship between COM and BOS during changes in either or both.
Reactive balance control: Responding to a sensed moment of instability by stabilizing the body.
Predictive balance control: Anticipating potential instability and proactively adjusting body position.
Passive forces are not sufficient to maintain balance, therefore active muscle control is important.
Passive forces and torque moments affect balance; muscle activity to overcome these is crucial for stability.
Anticipatory postural adjustments (APAs): Preemptive postural muscle activation before voluntary movements to maintain balance.
Postural set: A state of increased muscle tone that prepares the body for movement or response, reducing expected instability.
Methods to assess balance: Measurement of the center of pressure and variance of the COM.
Sensorimotor learning: The process of improving skilled movement through practice.
Neural plasticity: The ability of the nervous system to respond to experience and modify its structure/function.
Neurogenesis: The formation of new neurons.
Synaptogenesis: The formation of new synapses.
Long-term potentiation (LTP): A persistent strengthening of synaptic efficacy, fundamental to memory and learning.
Working memory: A limited capacity cognitive system responsible for holding information temporarily during processing.
Perception: Recognition and interpretation of sensory stimuli.
Attention: Focusing on specific stimuli while ignoring others.
Top-down control: Intentional attentional focus.
Bottom-up control: Involuntary attention directed by sensory input.
Schemas: Mental representations of objects, events, or actions.
Sensory modalities: Different ways of receiving sensory input (visual, auditory, tactile, etc.).
Multimodal sensory integration: Combining information from multiple sensory modalities.
Neurological disorders: Conditions that affect sensory perception or motor control, including agnosia and prosopagnosia.
Perception and action are closely linked: Perceived information influences actions, and actions influence perception.
Central pattern generators (CPGs): Neural networks in the spinal cord that generate rhythmic motor patterns for tasks like locomotion. Invariant rhythmical behaviours.
Propriospinal tracts: Interconnect various spinal cord levels for interlimb coordination and adaptation in gait. Allow for coordinating the actions of different limbs in locomotion.
Sensory inputs influence and maintain the CPG. Inter-limb/intra-limb coordination.
MLR (Mesencephalic lococoto region): Important for CPG activation.
Functional neuroplasticity: Changes in the strength of synaptic connections in response to experience.
Experiences are a necessary part of the development and maintenance of the nervous system. Includes learned non-use (deprivation) and plasticity that's dependent on experience.
Executive functions: High-level cognitive processes including planning, decision-making, problem-solving, and action sequencing. Prefrontal cortex, specifically DLPFC, plays an important role in these functions.
Working memory: Active mental holding and processing of information. Crucial for tasks such as ordering. Corsi blocks test, N-back type tasks.
Neuroanatomical structures: Key areas in the brain involved in processing sensory information and executing movements discussed in the lectures. DMPFC, VMPFC, OFC, and ACC are noted in conjunction with executive functions, along with the frontal, parietal, and occipital lobes.

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Description

This quiz explores the roles of muscles in maintaining posture and balance, focusing on the soleus muscle, anticipatory adjustments, and automatic postural reactions. Understanding these concepts is crucial for analyzing how stability is maintained during various movements, including walking and responding to perturbations.