Cerebrum - Chapter 17 Quiz

Cerebrum - Chapter 17 Ekman

• The cerebrum is the largest part of the brain, comprising 80-83% of the brain's mass.
• It's responsible for complex aspects of consciousness such as memory, personality, and intelligence.
• The cerebrum contains the cerebral hemispheres and subcortical structures (e.g., hippocampus, basal ganglia, olfactory bulb).

Contents

• The cerebrum is divided into structures, lobes, white matter, and lesions.
• Diagrams and charts detail the different components and locations of these elements.

Different Types of Cortex

• Neocortex (new cortex): Six layers, examples include primary motor and sensory cortex, association areas.
• Mesocortex (middle cortex): 3-6 layers, associated with the limbic system (cingulate gyrus, parahippocampal gyrus).
• Allocortex (other cortex): Three layers. This includes archicortex (hippocampal formation), and paleocortex (piriform cortex). Each area of the allocortex has a specific role and can be affected by a lesion.

Neocortex Cellular Layers

• The neocortex comprises approximately 90% of the cortex and displays six identifiable cellular layers.
• Key neuronal types include pyramidal cells and granule cells.
• The cellular layers are described and illustrated, noting their functions and connections (e.g., layers 3, 5, and 6 are output layers). Layer 4 receives thalamocortical axons.

Cerebral Cortex Areas

• Sensory areas perceive sensory information.
• Motor areas control voluntary movements.
• Association areas integrate complex functions.
• Each hemisphere primarily controls the opposite side of the body.
• Conscious behavior requires the entire cortex.

Functional Areas of the Cerebral Cortex

• Specific areas (e.g., primary motor cortex, premotor cortex, frontal eye field, Broca's area, primary somatosensory cortex, visual cortex, auditory cortex, Wernicke's area) are detailed and shown on diagrams.

Brodmann Areas

• Brodmann areas are noted for their association with different functions of the brain (e.g., primary motor cortex in area 4).
• Diagrams depict the locations of these areas.

Homunculus

• The primary sensory and motor areas are topographically organized, reflecting the organization of ascending and descending pathways within the dorsal thalamus.
• Specific parts of the cortex control specific motor and sensory functions on the contralateral side of the body.
• The amount of cortical space dedicated to a body part varies. This is illustrated in a diagram.

Internal Capsule Organization

• The internal capsule's structure and components are described and illustrated, including its connections to different brain regions. (e.g., frontothalamic, frontopontine tracts, and connections to visual and auditory regions)

Lobes of the Cerebrum

• Brain lobes (frontal, parietal, occipital, temporal, insula) and their locations are outlined.
• Important sulci and fissures are identified (central sulcus, lateral fissure, parieto-occipital sulcus)
• Diagrams illustrate these structures and boundaries.

Insula

• The insula is a cone-shaped portion of the cortex.
• Its location is described, and its possible involvement in consciousness, emotions, and regulation of homeostasis is explained.

Frontal Lobe

• The frontal lobe's functions include executive functions, motor performance, speech (e.g., in Broca's area), and the coordination of voluntary movement in the primary motor cortex.
• The prefrontal cortex is associated with executive functions.
• Diagrams and descriptions of different areas within the frontal lobe are available.
• Testing of frontal lobe function, including the Wisconsin Card Sorting Test, is detailed.

Parietal Lobe

• The parietal lobe is involved in integrating sensory information, spatial orientation, and language comprehension.
• Structures within the lobe are detailed (e.g., postcentral gyrus, somatosensory area, Wernicke's area, angular and supramarginal gyri).
• Specific processes are illustrated (two-point discrimination, graphesthesia).
• Areas within the lobe and their role in receiving input from the posterior parietal cortex and related visuospatial processing ("where" stream, "how" stream) are discussed

Temporal Lobe

• The temporal lobe contains the primary auditory cortex and Wernicke's area.
• It's important in memory, areas within the lobe associated with memory are detailed in an illustration.
• Heschl's gyrus is a crucial structure for auditory processing.

Occipital Lobe

• The occipital lobe contains the primary visual cortex, crucial for visual processing.
• Structure and function of primary and secondary visual cortex locations are illustrated.

Limbic System

• The limbic structures, not considered a true lobe, work in conjunction with other structures, playing a critical role in emotion, memory, aggression (e.g., in the amygdala) and controlling the body's homeostasis (e.g., the hypothalamus, fornix).

White Matter

• White matter's organization is illustrated, detailing different fiber types (projection, commissural, association); which are categorized based on their function and where they connect.

Lesions of the Cerebrum

• The presentation briefly touches on several neurological deficits that may result from brain lesions (e.g., apraxia, aphasias, agnosia, contralateral neglect).