311 Session 4 Brain Organization and Neural Pathways (Lobes - limbic system - basal ganglia - cerebellum)

What are the four lobes of the brain

Frontal

Parietal

Temporal

Occipital

Identify this structure

Insula

Identify this sulcus

Longitudinal fissure: divides cerebrum into left and right hemispher

Identify orange and yello

Orange: parieto-occipital fissure

Yellow: Calcarine sulcus

Why does the corpus callosum contain white matter and what does it connect

Connectes left and right hemispheres of brain

Contains white matter because it is made primarily of myelinated axons travelling between the two hemisphere

Where does the primary visual cortex lie

along the banks of the calcarine sulcus

Where does the primary auditory cortex lie

Superior temporal surface of the lateral sulcus

What are the limbic structures

Hippocampus: new memory formation + learning

Amygdala: Emotion + emotional memory

Hypothalamus: Homeostasis + motivaiton

Mammillary bodies: memory/ recall

Cingulate gyrus: Emotion + Motivaiton

What does this image show? Identify the structures

Limbic system

How are the mamillary bodies related to the hypothalmus?

Mammillary bodies are part of the hypothalamus, they’re small rounded structures on the inferior surface of the hypothalamus

Where is the hypothalamus relative to the third ventricle

The hypothalamus forms the inferior (lower) floor and the side walls of the third ventricle

What exactly is the basal ganglia

A group of subcortical nuclei (a collection of interconnected clusters of gray matter neurons) located deep within the brains white matter

What is the main function of the basal ganglia

Control and fine-tune voluntary movements by promoting desired motor actions while suppressing unwanted ones

What are the structures of the basal ganglia

Caudate nucleus

Putamen

Globus pallidus

Where can you see the caudate nucleus in a transverse vs a coronal section

Identify this structure

Internal Capsule

What structures form the Lentiform nucleus

Putamen and Globus Pallidus

What is the most medial vs lateral part of the lentiform nucleus

Medial: globus palligus

Lateral: Putamen

What structures make up the dorsal Striatum (aka striatum)

Caudate Nucleus

Putamen

What does this image show and identify the structures

Basal ganglia

Identify this sturcture

Substantia Nigra

Identify this structure

Subthalamus

What are the surrounding structures relative to the subthalamus

Anterior: Thalamus

Lateral and posterior: hypothalamus

How does the basal ganglia influence movement

Influence movement INDIRECTLY by influencing the motor cortex via the thalamus

• information enters the B.G → corpus striatum → leaves through GPi → thalamus

How does the caudate nucleus relate to the lateral ventricle?

The caudate nucleus follows the C-shaped curve of the lateral ventricle. Its head lies beside the anterior horn, its body runs along the lateral wall/floor of the body of the ventricle, and its tail curves inferiorly with the temporal horn toward the amygdala.

Which basal ganglia components lie in the cerebrum, diencephalon, and midbrain

Cerebrum: caudate nucleus, putament, GP

Diencephalon: Subthalamic nucleus

Midbrain: substantia nigra

Identify this structure

Vermis

Name this structure

Tonsils

Name the following structures

Name these structures

What is the cerebellums main role

Plays a role in coordinating voluntary muscle movements, maintain balance, and regulate posture

How does the cerebellum play a role in movement coordination

Coordinates the timing, force, and sequence of muscle activity so movements are smooth and precise. Without proper cerebellar funciton, muscles can still contract, but movements may be poorly timed or inaccurate

How does the cerebellum play a role in balance / posture

Uses information about body position and head movement to help maintain balance, posture, and stability

How does the cerebellum play a role adjusting movements

Recieves feedback about how a movement is actually happening and helps correct errors while the movement is occuring

Which features of the cerebellum identify the midline, inferior surface, and branching internal white matter? What does each help explain

Midline: Vermis = midline structure connecting the two cerebellar hemispheres

Inferior surface: Tonsils = rounded structure on the inferior, near the foramen magnum

Arbor Vitae: Internal white matter = inside the cerebellum, carries information between the cerebellar cortex and other regions

What does the primary fissure of the cerebellum separate?

Separates the anterior lobe from the posterior lobe

What are the main function of the cerebellar peduncles

The cerebellar peduncles are white matter tracts that connect the cerebellum to the brainstem, carrying information into and out of the cerebellum for the coordination and adjustment of movement

Where are the fourth ventricle and brainstem relative to the cerebellum? Why do the tentorium, posterior cranial fossa, and tonsils matter?

Cerebellum lies posterior to the brainstem, with the fourht ventricle between the pons and the cerebellum

• Tentorium cerebelli → dural fold that separates the cerebellum from the occipital lobes.

• Posterior cranial fossa → bony compartment containing the cerebellum and brainstem.

• Cerebellar tonsils → inferior portions of the cerebellum near the foramen magnum. Increased intracranial pressure can push them downward through the foramen magnum (tonsillar herniation), potentially compressing the brainstem.

Why can movement be poorly coordinated even when the muscles can still contract

Because the cerebellum doesnt initiate muscle contraction, it coordinates and fine tunes movement. It compares intended movement with what is actually occuring and hleps adjust timing,force, accuracy, balance, and posture