Podcast
Questions and Answers
Which area of the brain is responsible for cognitive functions like intellect, judgment, and planning of behavior?
Which area of the brain is responsible for cognitive functions like intellect, judgment, and planning of behavior?
Where do the subcortical afferents that connect with the prefrontal cortex mainly arise from?
Where do the subcortical afferents that connect with the prefrontal cortex mainly arise from?
Which motor neurons are responsible for directly innervating skeletal muscles?
Which motor neurons are responsible for directly innervating skeletal muscles?
Where do the cell bodies of lower motor neurons originate from?
Where do the cell bodies of lower motor neurons originate from?
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Which nucleus of the thalamus is involved in providing afferents to the prefrontal cortex?
Which nucleus of the thalamus is involved in providing afferents to the prefrontal cortex?
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Which descending tract is among the most important for controlling movement and runs through the brainstem and spinal cord?
Which descending tract is among the most important for controlling movement and runs through the brainstem and spinal cord?
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Which nucleus provides the principal subcortical input to premotor cortical regions?
Which nucleus provides the principal subcortical input to premotor cortical regions?
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What percentage of corticospinal and corticobulbar fibres originate in the premotor cortex?
What percentage of corticospinal and corticobulbar fibres originate in the premotor cortex?
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Which region lies immediately in front of the premotor cortex and controls voluntary conjugate deviation of the eyes?
Which region lies immediately in front of the premotor cortex and controls voluntary conjugate deviation of the eyes?
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Where is the motor speech area (Broca's area) typically located?
Where is the motor speech area (Broca's area) typically located?
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Which area is involved in the programming of and preparation for movement?
Which area is involved in the programming of and preparation for movement?
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Through which fibers does the premotor cortex exert some of its actions towards the primary motor cortex?
Through which fibers does the premotor cortex exert some of its actions towards the primary motor cortex?
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Which region of the brain is functionally known as the primary motor cortex?
Which region of the brain is functionally known as the primary motor cortex?
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Stimulation of the primary motor cortex elicits contraction of muscle groups on which side of the body?
Stimulation of the primary motor cortex elicits contraction of muscle groups on which side of the body?
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What percentage of corticospinal and corticobulbar fibers arise from neurons of the primary motor cortex?
What percentage of corticospinal and corticobulbar fibers arise from neurons of the primary motor cortex?
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Which subcortical structure provides the principal afferents to the primary motor cortex?
Which subcortical structure provides the principal afferents to the primary motor cortex?
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The motor homunculus is a topographic representation located along which part of the cerebral cortex?
The motor homunculus is a topographic representation located along which part of the cerebral cortex?
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Where do the afferents to the primary motor cortex mainly originate from?
Where do the afferents to the primary motor cortex mainly originate from?
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What is the primary function of the prefrontal cortex?
What is the primary function of the prefrontal cortex?
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Where do the cell bodies of upper motor neurons originate from?
Where do the cell bodies of upper motor neurons originate from?
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Which part of the brain constitutes the 'final common pathway' for controlling movement?
Which part of the brain constitutes the 'final common pathway' for controlling movement?
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What is the function of lower motor neurons?
What is the function of lower motor neurons?
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Where do subcortical afferents that connect with the prefrontal cortex mainly arise from?
Where do subcortical afferents that connect with the prefrontal cortex mainly arise from?
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Where does the decussation of the pyramids occur?
Where does the decussation of the pyramids occur?
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Which region controls the voluntary conjugate deviation of the eyes?
Which region controls the voluntary conjugate deviation of the eyes?
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From where do the corticospinal fibers control trunk and limb muscles originate?
From where do the corticospinal fibers control trunk and limb muscles originate?
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Which area is functionally known for intellect, judgment, and planning of behavior?
Which area is functionally known for intellect, judgment, and planning of behavior?
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Which fibers control the activity of motor neurons located in cranial nerve nuclei for head and neck muscles?
Which fibers control the activity of motor neurons located in cranial nerve nuclei for head and neck muscles?
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What is the function of the primary motor cortex?
What is the function of the primary motor cortex?
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Where do the principal subcortical afferents to the primary motor cortex originate from?
Where do the principal subcortical afferents to the primary motor cortex originate from?
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Which part of the brain is involved in providing afferents to the prefrontal cortex?
Which part of the brain is involved in providing afferents to the prefrontal cortex?
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Where do the upper motor neurons originate from?
Where do the upper motor neurons originate from?
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Which area of the brain is typically associated with the motor speech area (Broca's area)?
Which area of the brain is typically associated with the motor speech area (Broca's area)?
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Study Notes
Prefrontal Cortex
- Rich connections with parietal, temporal, and occipital cortex through long association fibers in the subcortical white matter
- Subcortical afferents arise mainly in the medial dorsal and anterior nuclei of the thalamus
- Cognitive functions of a high order: intellect, judgment, predictive faculties, and planning of behavior
Motor Systems
- Upper motor neurons: control activity of lower motor neurons, do not transmit impulses directly to muscles
- Cell body originates in cerebral cortex or brainstem, also known as second-order neurons
- Form descending tracts that run through brainstem and spinal cord, including corticospinal and corticobulbar tracts
Lower Motor Neurons
- Directly innervate skeletal muscle
- Cell bodies originate in grey matter of spinal cord, brain stem, or cranial nerve nuclei
- Constitute the 'final common pathway' by which the nervous system controls movement
- Also known as second-order neurons
Premotor Cortex
- Functions in programming and preparation for movement and control of posture
- Exerts actions via primary motor cortex and corticospinal and corticobulbar fibers
- 30% of corticospinal and corticobulbar fibers originate in premotor cortex
- Principal subcortical input from ventral anterior nucleus of thalamus
Frontal Eye Field and Motor Speech Area
- Frontal eye field: controls voluntary conjugate deviation of the eyes
- Motor speech area (Broca's area): important interconnections with temporal, parietal, and occipital lobes involved in language function
Primary Motor Cortex
- Functionally known as primary motor cortex
- Stimulation elicits contraction of discrete muscle groups on opposite side of body
- Controls voluntary, skilled movements (fractionated movements)
- 30% of corticospinal and corticobulbar fibers arise from neurons of primary motor cortex
- Principal subcortical afferents from ventral lateral nucleus of thalamus
Cortical Homunculus
- Represents motor or sensory distribution along cerebral cortex of brain
- Motor homunculus: topographic representation of body parts along precentral gyrus of frontal lobe
- Sensory homunculus: topographic representation of body parts along postcentral gyrus of parietal lobe
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Description
Test your knowledge on the anatomy of the prefrontal cortex and motor pathways in the brain. Learn about the rich connections of the prefrontal cortex with other areas of the brain and its cognitive functions. Explore the gross anatomy of motor pathways.
