35 Questions
Which cortical area contains neurons that project directly to motor neurons in the brainstem and spinal cord?
Primary motor cortex (M1)
What is the function of the central sulcus in the brain?
It divides the frontal and parietal lobes
Which cortical area is primarily involved in the control of complex, learned movements of the hands and face?
Premotor cortex
What is the purpose of the somatotopic mapping in the primary motor cortex (M1)?
To project directly to motor neurons controlling specific body parts
How are the left and right sides of the spinal cord coordinated for movement?
Due to coordinating fibers connecting the central pattern generators
What is the key evidence that the posterior parietal cortex acts as a spatial map?
All of the above
How do we know that the primary motor cortex (M1) is somatotopically organized?
All of the above
What is the key feature of the somatotopic organization in the primary motor cortex (M1)?
The hands and face have a disproportionately large representation in M1
What is the relationship between the primary motor cortex (M1) and the primary somatosensory cortex (S1)?
All of the above
How does the somatotopic organization of the primary motor cortex (M1) develop?
It is shaped by the patterns of sensory input and motor output during development and learning
What is the primary function of the primary somatosensory cortex (S1)?
Receiving and processing somatosensory information
What is the main function of the premotor cortex?
Planning complex motor acts
Which cortical area provides a spatial map giving information about positioning with respect to a goal object?
Posterior parietal cortex
What is the role of the primary motor cortex (M1) in movement generation?
Directing the execution of tasks
In somatotopic mapping, where are projections from neurons in the primary somatosensory cortex directed to?
Corresponding regions of the primary motor cortex (M1)
What effect does adding glutamate to the bath have on the spinal cord in terms of activity?
Enhances patterned motor output
How does the presence of multiple CPGs in the spinal cord impact motor output coordination?
Leads to uncoordinated motor output from different sides
What happens to the motor output coordination when a thin section of the spinal cord is bisected after generating rhythmic motor output?
Motor output from the two sides is no longer coordinated
How can patterned motor output be produced from a thin slice of spinal cord when placed in a dish?
By stimulating the dorsal roots
What initiates the activity of central pattern generators (CPGs) in the spinal cord?
Sensory stimulation of the ventral roots
What is the primary mechanism by which proprioceptive information regulates the rate of CPG activity?
Proprioceptive feedback alters the sensory input to the CPG, which then adjusts the rate of CPG output.
What evidence suggests that there are multiple, independent CPGs controlling different limb girdles?
Transection of the spinal cord between the lumbar and cervical enlargements results in the front and hind limbs losing coordination, but each limb girdle maintaining its own alternating pattern.
How do the CPGs controlling the fore- and hindlimbs become coordinated during locomotion?
Commissural interneurons with axons crossing the midline provide excitatory connections between the CPGs on each side.
What is the predominant neurotransmitter released by proprioceptive afferents that convey information to the spinal CPGs?
Glutamate
How does stimulation of the dorsal roots influence the activity of the spinal CPGs?
Dorsal root stimulation directly activates the CPG circuits, leading to rhythmic motor output.
What is the primary function of a central pattern generator (CPG) in the spinal cord?
To generate rhythmic motor patterns for coordinated movements, such as walking or breathing, even without input from higher brain regions
How does stimulation of the dorsal roots of the spinal cord affect the activity of a CPG?
It modulates the frequency and amplitude of the CPG's oscillations, allowing for adjustments in the motor pattern
Which statement best describes the role of glutamate in the function of spinal CPGs?
Glutamate excites CPG neurons, contributing to the generation and maintenance of rhythmic motor patterns
How is the coordinated activity of motor neurons on the left and right sides of the spinal cord achieved during rhythmic movements like walking?
By a single bilateral CPG that projects to motor neurons on both sides of the spinal cord
What is the primary mechanism by which sensory input from the periphery modulates the activity of spinal CPGs?
Activation of propriospinal interneurons, which relay sensory information to CPG neurons
What is the primary mechanism for the voluntary initiation of locomotion?
Projections from neurons in the forebrain to command neurons in the mesencephalic locomotor nucleus
What is the role of sensory feedback from moving legs during locomotion?
It turns on the CPGs, which then coordinate the locomotor movements
Which of the following is NOT a type of proprioceptor mentioned in the text?
Golgi tendon organs embedded in muscles
What is the primary function of the proprioceptive information provided by the various sensory receptors mentioned in the text?
To integrate and provide information about the location of body parts
What is the role of the mesencephalic locomotor nucleus in locomotion?
It receives projections from the forebrain to initiate voluntary locomotion
This quiz covers the coordination of alpha motor neurons in the spinal cord before bisection, the presence of central pattern generators (CPGs) on both sides, and the connecting fibers responsible for coordination. It also touches on cortical mechanisms of motor control.
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