Brain White Matter Tracts and Fibres Quiz

18 Questions

Which white matter tract connects the frontal to occipital and temporal lobes?

Superior longitudinal fasciculus

What type of fibres connect corresponding areas of the two hemispheres in both directions?

Commissural fibres

What is the main function of the Corpus callosum?

Required for the 2 hemispheres to operate cooperatively at the superficial subconscious level

Which white matter tracts connect the cortex to the spinal cord?

Cortico-spinal tract

What is the role of the Anterior commissure in the brain?

Plays an important role in unifying the emotional responses of the 2 hemispheres

What is the function of the Inferior longitudinal fasciculus?

Connects temporal to occipital lobe

What is the primary function of the primary motor area in the brain?

To control voluntary movements by sending neural signals to the skeletal muscles.

Explain the role of primary sensory areas in the brain.

To receive and process sensory information from the environment, such as touch, temperature, and pain.

What distinguishes secondary areas from primary sensory areas in the brain?

Secondary areas further process and interpret sensory information received from the primary sensory areas.

Describe the function of association areas in the brain.

Association areas integrate information from different parts of the brain to perform higher cognitive functions such as problem-solving and memory.

What are granular neurons and where are they typically found?

Granular neurons are small neurons found in the cerebral cortex, primarily in the sensory areas.

How do myelin sheaths contribute to the propagation of action potentials?

Myelin sheaths allow for faster and more efficient transmission of action potentials along the axon.

What is the main function of primary sensory areas?

Detect specific sensations transmitted to the brain from peripheral sensory organs.

How do granular neurons mainly function in the brain?

As interneurons that transmit signals only short distances.

Which areas of the brain receive and analyze signals simultaneously from multiple regions of the motor and sensory cortices?

Association areas.

What distinguishes secondary areas from primary sensory areas?

Secondary areas make sense of the signals received by the primary areas.

Where are high concentrations of granular neurons found in the brain?

In sensory areas as well as association areas between sensory and motor areas.

What is the role of white matter tracts in the brain?

To serve as connections between different parts of the brain.

Study Notes

White Matter Tracts

Connect different parts of the same hemisphere, different hemispheres, or cerebral regions to lower brain centers.
Three types of communication tracts: association, commissural, and projection fibers.

Association Fibers

Connect different areas of the same hemisphere.
Short fibers connect adjacent gyri and long fibers connect distant parts of the same hemisphere.
Examples:
- Uncinate fasciculus: connects temporal lobe to Broca's area and orbitofrontal cortex (associated with emotion and representation of reward value and non-reward).
- Cingulum: connects the orbitofrontal cortex along the dorsal aspect of the corpus callosum to the temporal lobe.

Commissural Fibers

Connect corresponding areas of the two hemispheres in both directions.
Ensure integration of information from all functional areas.
Examples:
- Corpus callosum: required for the two hemispheres to operate cooperatively at the superficial subconscious level.
- Anterior commissure: plays an important role in unifying the emotional responses of the two hemispheres of the brain.
- Posterior commissure, hippocampal commissure, habenular commissure, hypothalamic commissure, and cerebellar commissure.

Projection Fibers

Bundles of white matter that connect the cerebral cortex to other parts of the CNS, such as the brain stem and spinal cord, in both directions.
Examples:
- Cortico-spinal tract: connects the cortex to the spinal cord.
- Cortico-posterior tract: connects the cortex to the pons of the brainstem.

Longitudinal Fasciculi

Superior longitudinal fasciculus: connects the frontal to occipital and temporal lobes.
Inferior longitudinal fasciculus: connects the temporal to occipital lobe.

Nervous System

Afferent division: transmits information from the environment to the CNS.
Efferent division: transmits messages from the CNS to effector organs.
Somatic nervous system: consists of fibers that innervate skeletal muscles.
Autonomic nervous system: consists of fibers that innervate smooth muscle, cardiac muscle, and glands.
Subdivisions of autonomic nervous system:
- Sympathetic nervous system: responsible for the fight, flight, or fright responses.
- Parasympathetic nervous system: controls the rest and digest functions.
- Enteric nervous system: controls the functioning of digestive activities, along with the autonomic nervous system and hormones.

Neurons

Afferent neurons (sensory neurons): transmit information from the environment to the CNS.
Efferent neurons (motor neurons): transmit information from the CNS to effector organs.
Glial cells: support and maintain neurons.
Two types of propagation methods for action potentials:
- Myelin sheath presence: impulse transferred much further.
- Contiguous conduction.

Functional Areas of the Cortex

Primary sensory areas: detect specific sensations (visual, auditory, or somatic) transmitted to the brain from peripheral sensory organs.
Secondary areas: make sense of the signals received by the primary areas.
Association areas: receive and analyze signals simultaneously from multiple regions of the motor and sensory cortices, as well as subcortical structures.
Granular (stellate) neurons: multipolar neurons with short axons, function mainly as interneurons, transmitting signals only short distances.

Test your knowledge on brain white matter tracts and fibres including the Superior and Inferior Longitudinal Fasciculus, Projection Fibres like Cortico-spinal tract, and more.

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