Neuroanatomy: Cerebrum and Higher Cortical Functions

Cerebrum

Largest brain part, responsible for higher functions.

Forebrain

Region containing the cerebrum and diencephalon.

Diencephalon

Part of forebrain including thalamus and hypothalamus.

Thalamus

Relay station for sensory information in the brain.

Hypothalamus

Regulates autonomic functions and homeostasis.

Internal Capsule

Main conduit for ascending and descending tracts.

Sulcus

Groove separating gyri in the cerebral cortex.

Gyrus

Raised fold of the cerebral cortex.

Lateral Cerebral Fissure

Separates temporal lobe from frontal and parietal lobes.

Insula

Cortex portion lying deep within the lateral fissure.

Circular Sulcus

Surrounds the insula, separating it from adjacent lobes.

Longitudinal Cerebral Fissure

Divides the right and left cerebral hemispheres.

Central Sulcus

Separates frontal lobe from parietal lobe.

Parieto-occipital Fissure

Separates parietal lobe from occipital lobe.

Calcarine Fissure

Located near the occipital pole, involved in vision.

Corpus Callosum

Connects left and right cerebral hemispheres.

Genu

Anterior curved portion of the corpus callosum.

Splenium

Thick posterior portion of the corpus callosum.

Frontal Lobe

Responsible for initiative, judgment, and creativity.

Precentral Sulcus

Located anterior to the precentral gyrus.

Superior Frontal Sulcus

Divides superior frontal gyrus from middle frontal gyrus.

Cingulate Gyrus

Convolution between cingulate sulcus and corpus callosum.

Prefrontal Cortex

Involved in complex cognitive behavior and decision-making.

Higher Order Association Cortex

Involved in judgment, reasoning, and social behavior.

Parietal Lobe

Extends from central sulcus to parieto-occipital fissure.

Postcentral Sulcus

Located behind the postcentral gyrus.

Intraparietal Sulcus

Horizontal groove connecting with postcentral sulcus.

Superior Parietal Lobule

Located above the intraparietal sulcus.

Inferior Parietal Lobule

Located below the intraparietal sulcus.

Supramarginal Gyrus

Arches above the posterior ramus of lateral fissure.

Angular Gyrus

Arches above superior temporal sulcus, connects to middle temporal gyrus.

Occipital Lobe

Houses primary visual cortex behind parieto-occipital fissure.

Temporal Lobe

Lies below lateral cerebral fissure, extends to parieto-occipital fissure.

Transverse Temporal Gyrus

Occupies posterior part of superior temporal surface.

Hippocampal Gyrus

Extends along inferomedian aspect of temporal lobe.

Uncus

Most medial part of temporal lobe, hook-shaped.

Limbic System

Includes cingulate, parahippocampus, subcallosal gyri, hippocampal formation.

White Matter of Cerebrum

Contains myelinated nerve fibers and neuroglia.

Centrum Semiovale

Myelinated fibers in the white matter of cerebrum.

Transverse (Commissural) Fibers

Interconnect both cerebral hemispheres.

Anterior Commissure

Connects olfactory bulbs and temporal lobe structures.

Projection Fibers

Connect cortex to lower brain or spinal cord.

Association Fibers

Connect various portions of a cerebral hemisphere.

Pyramidal Cells

Type of neuron in the cerebral cortex.

Stellate Neurons

Another type of neuron in the cortex.

Fusiform Neurons

Third type of neuron in the cortex.

Allocortex

Found in limbic system, fewer layers than isocortex.

Isocortex (Neocortex)

Common in cerebral hemisphere, contains six layers.

Juxtallocortex (Mesocortex)

Transition area between allocortex and isocortex.

Molecular layer

Layer I of the isocortex, superficial layer.

External granular layer

Layer II of the isocortex, contains small neurons.

External pyramidal layer

Layer III of the isocortex, contains pyramidal neurons.

Internal granular layer

Layer IV of the isocortex, receives sensory input.

Internal pyramidal layer

Layer V of the isocortex, sends output to subcortical areas.

Fusiform layer

Layer VI of the isocortex, involved in integration.

Brodmann's Classification

System for naming functional areas of the cortex.

Area 4

Primary Motor Area for voluntary muscle activation.

Corticospinal Tract

Pathway for voluntary motor control from the brain.

Motor homunculus

Representation of body parts in the motor cortex.

Area 6

Premotor Area for planning and organizing movements.

Area 8

Frontal Eye Field, controls eye movements.

Broca's area

Areas 44 and 45, involved in speech production.

Areas 3, 1, 2

Primary Sensory Area for processing sensory information.

Sensory homunculus

Representation of body parts in the sensory cortex.

Area 17

Primary Visual Cortex, processes visual stimuli.

Area 41

Primary Auditory Cortex, processes auditory stimuli.

Area 42

Associative Auditory Cortex, enhances auditory processing.

Heschl's gyrus

Combined areas 41 and 42 for auditory processing.

Area 22

Auditory Association Cortex, involved in language comprehension.

Planum Temporale

Region for language and music processing.

Primary Motor Cortex

Located in precentral gyrus, controls voluntary movements.

Giant pyramidal cells

Betz cells controlling skeletal muscle movements.

Jacksonian epilepsy

Focal twitching progressing to larger muscle involvement.

Contralateral flaccid paresis

Weakness on opposite side due to lesions.

Primary Sensory Cortex

Processes sensory information from body and face.

Somatesthetic area

Located in postcentral gyrus, processes touch sensations.

Cortical Taste Area

Processes gustatory information from the body.

Irritative lesions

Cause abnormal sensations like tingling or numbness.

Destructive lesions

Lead to impaired sensory perception and localization.

Primary Visual Cortex

Located in occipital lobe, processes visual information.

High-resolution macular vision

Posterior portion of Primary Visual Cortex function.

Peripheral vision

Anterior portion of Primary Visual Cortex function.

Visual Association Area

Includes Areas 18 and 19 for visual processing.

Visual hallucinations

Irritative lesions cause flashes or bright lights.

Contralateral homonymous defects

Destructive lesions affect visual fields opposite side.

Visual disorganization

Injury to Areas 18-19 affects spatial orientation.

Primary Auditory Receptive Cortex

Located in transverse temporal gyrus, processes sound.

Low tones representation

Frontolateral portion of Area 41 for low frequencies.

High tones representation

Occipitomedial portion of Area 41 for high frequencies.

Wernicke Area

Area 22, crucial for speech comprehension.

Buzzing sensations

Irritation of auditory cortex causes abnormal sounds.

Unilateral lesion effects

Results in mild hearing loss on one side.

Bilateral lesion effects

Causes complete deafness in both ears.

Wernicke's Aphasia

Damage to Area 22 leads to pure word deafness.

Basal Ganglia

Gray matter masses essential for motor control.

Corpus Striatum

Combined term for caudate nucleus and putamen.

Striatum

Caudate nucleus and putamen develop together.

Lenticular Nuclei

Putamen and globus pallidus form lensed shape.

Caudate Nucleus

Elongated mass, major input site for basal ganglia.

Lenticular Nucleus

Divided by External Medullary Lamina into two parts.