Psych 251: Understanding Human Motor Systems and Control

The question is specifically asking about actions in the Somatic system, which involves voluntary control of skeletal muscles to move limbs.

The Autonomic system primarily deals with involuntary actions such as regulating blood pressure, digestion, heartbeat, hormonal secretion, and glandular activities. It is not responsible for voluntary muscle movements, sensory perception, or conscious control of breathing.

Actions within the Central Nervous System (CNS) involve internal processes such as memory update and task switching, which do not occur in the external environment. Processing sensory information, controlling voluntary movements, and regulating heart rate are functions typically associated with other parts of the nervous system.

The supplementary motor cortex is located rostrally to the primary motor cortex and dorsally to the premotor cortex. The incorrect answers provide alternative directions that do not accurately describe the relative positions of the supplementary motor cortex in comparison to the primary motor cortex and premotor cortex.

Motor control being hierarchical means that it is organized in a step-by-step manner, with each level of control building upon the previous one.

The correct answer provides evidence that motor plans can be abstract by showcasing the ability to draw with different body parts controlled by different muscles, emphasizing motor equivalence and a hierarchical control system.

Inverse models are used to determine how to move from a current position to a desired position, by generating motor commands. They are essential for planning and executing movements to reach specific goal states.

Forward models play a crucial role in motor control by helping to evaluate motor plans and actions, compare desired outcomes with actual outcomes during movement, and quickly detect errors in motor execution.

An efference copy is a neural copy of a motor command sent to another part of the brain for prediction purposes.

Feed forward control involves sending a command to a limb without waiting for feedback in the hopes that it will be executed correctly. This approach is faster but less accurate compared to feedback control. It is often utilized for rapid movements such as eye movements (saccades).

Feedback control involves sending motor commands to muscles, comparing the actual state to the desired state, and making adjustments based on errors. This process is slower but more accurate compared to direct control or immediate adjustments without evaluation.

In feedforward control systems, an inverse model is commonly used to generate control inputs based on a desired state. This is because the system works backward from the desired state to determine the necessary actions. The use of an inverse model allows for more precise control in feedforward systems.

Forward models are used in the feedback state during feedback control to predict the state of a system based on input and to adjust control actions accordingly.

The premotor cortex is specifically responsible for selecting goals and planning actions at a conceptual level, particularly in response to external stimuli.

The correct answer is 'goals' because setting specific objectives or desired outcomes helps guide the planning process.

Readiness potential refers to the brain activity leading up to a voluntary action, occurring before the conscious decision to move is made. It is not the immediate action taken once the decision is conscious, a measure of muscle tension, or a measure of the time taken to respond to a stimulus.

The Supplementary Motor Cortex (SMA) is primarily involved in selecting goals and planning actions at a conceptual level, especially when those plans involve sequences of actions. It is more related to complex motor tasks rather than basic functions like walking, emotional regulation, or visual processing.

The motor cortex is responsible for coordinating and executing voluntary movements of body parts. It does not control specific muscle actions, sensory perception, or cognitive functions.

The premotor cortex has the ability to plan for multiple actions simultaneously, as demonstrated by studies like the monkey example provided in the correct answer.

Mirror neurons are a specific type of neuron found in the premotor cortex that play a role in understanding and imitating the actions of others. These neurons fire both when a person performs an action and when they observe someone else performing the same action, hence the term 'mirror' neurons.

The correct answer explains the role of Peristimulus time histogram in representing motor sequences and highlights the specific firing pattern of a SMA neuron in anticipation of movements.

Muscimol is a GABA agonist that inhibits the SMA, affecting the ability to perform sequences of actions. The incorrect answers describe effects opposite to the actual impact of muscimol injection into the SMA.

Correct answer explains that certain neurons in the motor cortex have directional selectivity, firing more intensely when movements are made in specific directions. This selectivity is not influenced by factors like randomness, speed of movement, or consistent activity regardless of direction.

A tuning curve summarizes the relationship between response rate and direction of movement in motor directional selectivity.

A population vector refers to a method used in neuroscience to accurately represent actual movement direction by treating the firing of each neuron as a vector and adding up vectors for all neurons.

Population vectors are representations of motor plans, which are neural signals responsible for coordinating movement.

Population vectors are formed by combining the responses of multiple neurons with different tuning curves, not by simply averaging the firing rates or considering only a single neuron's tuning curve.

Areas in IP (Inferior Parietal) play important roles in guiding movements, correcting location, orientation, and configuration by integrating sensory information and coordinating motor actions.

The Lateral Intraparietal Sulcus (LIP) specifically deals with representing space for eye movements, retina-centered receptive fields, and the location relative to where the eyes are looking. The incorrect answers provided do not align with the known function of LIP.