Med 7107: The Cerebrum Lecture 1

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Questions and Answers

Which part of the frontal lobe is situated most anteriorly?

Middle frontal gyrus

Superior frontal gyrus

Inferior frontal gyrus (correct)

Precentral gyrus

What separates the frontal lobe from the temporal lobe?

Cingulate sulcus

Lateral sulcus (correct)

Precentral sulcus

Central sulcus

Which gyrus is located anterior and parallel to the central sulcus?

Middle frontal gyrus

Precentral gyrus (correct)

Inferior frontal gyrus

Superior frontal gyrus

Which part of the inferior frontal gyrus is considered the opercular part?

Part of the frontal operculum Signup and view all the answers

What structure lies medially to the frontal lobe?

Cingulate sulcus Signup and view all the answers

Which part is located most medially in the frontal lobe?

Gyrus rectus Signup and view all the answers

Which structures are divided by the intraparietal sulcus?

Superior and inferior parietal lobules Signup and view all the answers

What is the posterior boundary of the parietal lobe determined by?

Imaginary line connecting the top of the parietooccipital sulcus Signup and view all the answers

Which sulcus separates the postcentral gyrus from other regions in the parietal lobe?

Central sulcus Signup and view all the answers

Which gyrus is NOT part of the inferior parietal lobule?

Precuneus Signup and view all the answers

Which sulcus serves as the superior boundary of the temporal lobe?

Lateral sulcus Signup and view all the answers

What distinguishes the occipitotemporal (fusiform) gyrus from the limbic lobe?

It is separated from the limbic lobe by the collateral sulcus. Signup and view all the answers

Which structure connects the parietooccipital sulcus with the preoccipital notch posteriorly?

Line forming inferior boundary of parietal lobe Signup and view all the answers

Which gyrus continues onto the inferior surface of the temporal lobe?

Inferior temporal gyrus Signup and view all the answers

Which of the following describes the cuneus?

It is the wedge-shaped area between the parietooccipital and calcarine sulci. Signup and view all the answers

What is the anterior boundary of the occipital lobe?

Parietal lobes on medial surfaces Signup and view all the answers

Which of the following structures is found on the lateral surface of the occipital lobe?

Occipital gyri Signup and view all the answers

What part of the temporal lobe is situated inferior to the calcarine sulcus?

Lingual gyrus Signup and view all the answers

What anatomical feature encircles the junction of the telencephalon and diencephalon?

Limbic lobe Signup and view all the answers

Where is the cingulate sulcus located in relation to other lobes?

Between the corpus callosum and frontal/parietal/occipital lobes Signup and view all the answers

Which sulcus is mentioned alongside the subparietal sulcus?

Parieto-occipital sulcus Signup and view all the answers

What layer encircles the temporal lobe?

Limbic lobe Signup and view all the answers

What structure is located between the corpus callosum and the frontal/parietal/occipital lobes?

Cingulate sulcus Signup and view all the answers

Which lobe is NOT involved in the encirclement described in the content?

Cerebellum Signup and view all the answers

The limbic lobe is located between which two structures?

Corpus callosum and temporal lobe Signup and view all the answers

What role does the cingulate sulcus play in brain anatomy?

Marks the boundary between limbic and non-limbic structures Signup and view all the answers

What is the primary function of the cerebrum in the central nervous system?

Information processing Signup and view all the answers

Which structure connects the right and left hemispheres of the cerebrum?

Corpus callosum Signup and view all the answers

Which lobe of the cerebrum is primarily responsible for processing visual information?

Occipital lobe Signup and view all the answers

What is a gyrus in the context of brain anatomy?

A ridge or bump Signup and view all the answers

Which term describes a collection of nerve cell bodies within the central nervous system?

Nucleus Signup and view all the answers

What is the main difference between gray matter and white matter?

Gray matter consists of nerve cell bodies, while white matter consists of axons. Signup and view all the answers

Which region of the brain includes structures such as the thalamus and hypothalamus?

Forebrain Signup and view all the answers

Which area of the cerebral cortex is involved in motor control?

Primary motor area Signup and view all the answers

What does the term 'somatotropic organization' refer to?

The spatial organization of body functions in the cortex Signup and view all the answers

Which of the following correctly describes subcortical gray matter?

It contains basal ganglia and nuclei. Signup and view all the answers

Which of the following is NOT a lobe of the cerebrum?

Cerebellar Signup and view all the answers

What is the primary structure responsible for communication between the central nervous system and peripheral nervous system?

Spinal nerves Signup and view all the answers

Which of the following describes the role of the internal capsule?

It contains fibers connecting the cortex with subcortical structures. Signup and view all the answers

What term describes the layer of the cerebral cortex that contains a high density of pyramidal cells?

Neocortex Signup and view all the answers

Which layer of the neocortex primarily receives input from the thalamus?

Layer IV Signup and view all the answers

Which of the following is NOT a type of white matter fiber in the brain?

Radial fibers Signup and view all the answers

What is the role of the uncinate fasciculus within the brain?

Connects the inferior frontal gyrus to the anterior temporal lobe Signup and view all the answers

What functional area is primarily located in Brodmann area 4?

Primary motor cortex Signup and view all the answers

Which structure is involved in the coordination of movement and is part of the basal ganglia?

Putamen Signup and view all the answers

What is the primary function of the internal capsule in the brain?

Conducting both ascending and descending neural signals Signup and view all the answers

In terms of organization, what is the primary feature of the somatosensory cortex's representation of the body?

Somatotopic organization Signup and view all the answers

Which gyrus is situated immediately superior to the corpus callosum?

Cingulate gyrus Signup and view all the answers

Which layer of the neocortex includes predominantly fusiform-shaped modified pyramidal cells?

Layer VI Signup and view all the answers

What does the term 'fasciculus' generally refer to in the context of white matter connections?

A bundle of axons that have a common origin and destination Signup and view all the answers

Which of the following areas corresponds to the olfactory cortex?

Brodmann area 11 Signup and view all the answers

What does the term 'corticonuclear fibers' refer to in the context of the brain’s anatomy?

Fibers connecting the cortex to cranial nerve nuclei Signup and view all the answers

Study Notes

Lecture 1: The Cerebrum

The lecture is on the cerebrum, part of the neuroscience course (Med 7107).
The instructor is Savannah Newell, PhD, Assistant Professor of Anatomical Sciences at Edward Via College of Osteopathic Medicine (VCOM) in Louisiana.
The lecture date is Block 3, 2025.

Learning Objectives

Students will recall the cerebrum's function within the nervous system's macroscopic organization.
Students will locate lobes of the cerebral hemisphere.
Students will recognize major gyri and sulci of the cerebral cortex.
Students will recognize the histological organization of the cortex.
Students will recognize the concept of Brodmann areas.
Students will identify primary motor, primary somatosensory, and association areas of the cortex.
Students will recognize somatotropic organization of the somatosensory cortex.
Students will recognize the somatotropic organization of the primary motor cortex.
Students will locate the subcortical gray matter (basal ganglia).
Students will recognize white matter fiber tracts connecting cortical areas.
Students will recognize the somatotopic organization of fibers traversing the internal capsule.
Students will learn directional, descriptive, and laterality terms in relation to the nervous system and clinical imaging.
Recommended reading materials include Moore, Dalley, and Agur (pp. 886); Blumenfeld (pp. 24-32); and Schuenke, et al. (pp. 266-269).

Announcements

Clinical cases and quizzes continue with the same expectations as Block 2.
Ultrasound content will be added.
A detailed schedule for ultrasound will be provided soon.
Invitations to use "Butterfly" ultrasound technology, housed in the Sim Center, have been sent.
Images from ultrasound are part of the exam material.

Structural Division of the Nervous System

The Central Nervous System (CNS) processes information and includes the brain, brainstem, cerebellum, diencephalon (thalamus and hypothalamus), and basal ganglia, and spinal cord.
The Peripheral Nervous System (PNS) communicates with the CNS and organs, with minimal processing occurring in ganglia. It includes cranial nerves, spinal nerves, autonomic ganglia, and sensory ganglia and splanchnic and pelvic splanchnic nerves.

Gray Matter & White Matter

Gray Matter: Contains nerve cell bodies, responsible for neural processing, includes nuclei (clusters of nerve cell bodies in the CNS) and ganglia (clusters of nerve cell bodies outside the CNS).
White Matter: Facilitates conduction using axons (bundles of nerve fibers in the CNS) organized as tracts (axons connecting neighboring or distant nuclei of the cerebral cortex).

Overview of the Brain

The forebrain is composed of the cerebrum (telencephalon) and the diencephalon (thalamus, hypothalamus).
The cerebellum is located at the back of the brain.
The brainstem includes the midbrain, pons, and medulla.

Overview of the Cerebrum

The cerebrum has two hemispheres (R+L) connected by the corpus callosum.
Four paired lobes: frontal, parietal, temporal, and occipital.
Sulci are grooves, gyri are ridges on the cortex.
The cerebellum has two hemispheres connected by the vermis.

Direction in the CNS

Forel Axis: Refers to the cerebrum.
Maynert Axis: Refers to the spinal cord, brainstem, and cerebellum.
Directions in the CNS: Cranial/oral/rostral/anterior, caudal/posterior, dorsal/superior, and ventral/inferior.

Cerebrum (Detailed)

Contains two hemispheres (R and L), connected by the corpus callosum.
Four major paired lobes (frontal, parietal, temporal, occipital), plus limbic lobe and insular cortex.
Sulci and gyri are the grooves and ridges in the cerebral cortex.
White matter, grey matter, and deep nuclei compose the cerebrum's components.

Lobes of the Cerebrum (Detailed)

The frontal lobe extends from the frontal pole to the central sulcus.
The lateral sulcus separates the frontal from the temporal lobe.
The frontal lobe's orbital part is inferior.
The parietal lobe starts at the central sulcus and extends to the imaginary line connecting the top parietooccipital sulcus to the pre-occipital notch.
The lateral sulcus, extending inferiorly, forms a boundary for the parietal lobe.
The medial surface of the parietal lobe is bounded by the subparietal sulcus, parietooccipital sulcus, marginal branch of cingulate sulcus, and part of the calcarine sulcus.
The temporal lobe's superior boundary is formed by the superior lateral sulcus and the inferior boundary from the parietal boundary.
The line connecting the parietooccipital sulcus and the pre-occipital notch defines a posterior boundary.
The medial surface moves toward the corpus callosum’s splenium.
The collateral sulcus is superior to the medial surface.
The occipital lobe extends from the posterior boundary to the anterior boundary, limited by the parietal lobe.
The lateral surface includes occipital gyri, and the Cuneus is wedge-shaped, located between the parietooccipital sulcus and calcarine sulcus.
The lingual gyrus is located on the temporal lobe, inferior to the calcarine sulcus, connecting with the parahippocampal gyrus.

Limbic Lobe (Cortex)

The limbic lobe encircles the telencephalon-diencephalon junction.
It is located on the medial surface of the temporal lobe.
It's bordered by the corpus callosum and other lobes.
It includes the cingulate gyrus, parahippocampal gyrus, and subparietal sulcus.

Insula

The insula is also known as the insular cortex or lobe.
It is within the lateral fissure.
The insula is covered by the frontal, temporal, and parietal opercula.

The Cerebral Cortex

It is a thin layer of gray matter.
Has a surface area of 1800 cm².
Comprises approximately half the brain's weight.
Contains about 25 billion nerve cells and a substantial amount of axons (around 100,000 km).
The neocortex is the major part of the cerebral cortex and consists of six distinct cortical layers.
The mesocortex and allocortex also exist in other areas of the brain, differing in internal layer structures.

Histological Organization of the Cortex

The neocortex has six distinct layers of horizontal lamination.
The relative thickness of cortical layers can vary depending on the brain area's function.
The cortical layers exhibit their own internal vertical bundles.
Layer I is the most superficial, with layer VI being the deepest.
Layers II-V demonstrate a variation in cell structures (small, medium, and large pyramidal cells).

Layers of the Cortex

Layer I consists of few neurons, mainly axons, and dendrites from deeper cortical layers.
Layers II and III contain small to medium-sized neurons connecting to other cortical areas.
Layer IV receives input primarily from the thalamus.
Large pyramidal neurons, composing layer V, project to subcortical structures (e.g., brainstem, spinal cord, and basal ganglia).
Layer VI neurons project to the thalamus.

Korbinian Brodmann

Brodmann categorized brain regions based on neuron shape and arrangement.
A map of the brain, established in 1909, classified brain regions based on cytoarchitecture.
The map comprises 52 distinct regions; many correlate with specific brain functions, called Brodmann areas.

Brodmann Areas (Detailed)

The Brodmann areas are divisions of the cerebral cortex based on cytoarchitectural features.
The numbers correlate with specific functions in the brain.

Primary Motor & Sensory Cortexes

The primary motor cortex, located in the precentral gyrus, controls voluntary movements.
The primary somatosensory cortex, in the postcentral gyrus, processes sensory information.
Both areas have somatotopic organization, meaning areas of the cerebral cortex correspond to specific body areas.

Somatotopic Organization of Primary Motor Cortex, Somatosensory Cortex

Precentral gyrus (area 4) contains the primary motor cortex, organizing body parts for motor functions. The areas in this region correlate with the parts of the body controlled.
Postcentral gyrus (areas 3, 1, and 2) contains the primary somatosensory cortex, involved in sensory information processing. Specific regions correlate to specific body areas.

Subcortical Grey Matter

Basal ganglia, deep brain clusters, are associated with motor control and limbic systems.
Major components of basal ganglia include the caudate nucleus, putamen, globus pallidus, substantia nigra, and subthalamic nucleus.

White Matter Connections

White matter forms fasciculi based on connections (association and commissural).
Association fibers connect areas within the same hemisphere.
Commissural fibers connect to the opposite hemisphere.
Projection fibers connect cortical areas with subcortical structures.

White Matter Connections (Detailed)

Association fibers include short U-fibers (connecting gyri within a hemisphere) and long, named fasciculi (connecting different lobes—frontal, parietal, occipital, temporal).
Commissural fibers are long bundles connecting the two hemispheres, including the corpus callosum (largest) and anterior and posterior commissures.
Projection fibers connect the cortex to other parts of the CNS (e.g., brainstem, spinal cord, thalamus, or other structures outside the cortex).

Projection Fibers

Corona radiata: descending and ascending axons from cortical neurons and lower areas to the cortex, respectively.
Internal capsule: converging fibers from the corona radiata coming to the brainstem.
Cerebral peduncles: contain the corona radiata and connect to subcortical structures.

Somatotopic Organization of Internal Capsule

Internal capsule is organized somatotopically and contains ascending and descending projection fibers.
It connects the frontal lobe to lower brain structures; different nuclei of the basal ganglia and other fibers.
Anterior limb: contains motor fibers (face, arm, and legs) from the primary motor cortex to respective body areas.
Posterior limb: contains sensory fibers (face, arm, and legs) from the thalamus to the sensory cortex.

References

A list of recommended neuroanatomy textbooks and articles for further study is included in the slides.

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Description

This quiz covers the cerebrum and its significant anatomical features within the neuroscience course (Med 7107). It focuses on the functions, lobes, gyri, sulci, histological organization, and the important concepts of Brodmann areas. Prepare to identify the primary motor and somatosensory areas, as well as the organization of the cerebral cortex.