The Structure and Functional Localization of the Cerebral Cortex

Flashcards based on lecture notes about the structure and functional localization of the cerebral cortex.

What was the neurologist's diagnosis for the 19-year-old woman experiencing jerking movements in her leg?

Jacksonian epileptic seizures caused by cerebral scarring secondary to an automobile injury.

Cerebral Cortex

Highest level of the central nervous system, functions in association with lower centers, receives vast amounts of information, and responds in a precise manner.

What are the five types of nerve cells present in the cerebral cortex?

Pyramidal cells, stellate cells, fusiform cells, horizontal cells of Cajal, and cells of Martinotti.

Betz Cells

Located in the motor precentral gyrus of the frontal lobe, cell bodies measure as much as 120μm.

Stellate Cells

Small, polygonal shape, multiple branching dendrites and a relatively short axon, which terminates on a nearby neuron.

Radial Fibers

Terminates within the cortex, and the axons of pyramidal,stellate,and fusiform cells

Nerve fibers of the cerebral cortex

Arranged both radially and tangentially

Tangential fibers are most concentrated in layers 4 and 5

Outer and inner bands of Baillarger, respectively.

What are the six layers of the cerebral cortex?

Molecular layer, external granular layer, external pyramidal layer, internal granular layer, ganglionic layer, and multiform layer.

Molecular Layer

A dense network of tangentially oriented nerve fibers derived from apical dendrites, axons of stellate cells, and cells of Martinotti.

External Granular Layer

Small pyramidal cells and stellate cells

External Pyramidal Layer

Pyramidal cells, whose cell body size increases from the superficial to the deeper borders of the layer

Internal Granular Layer

Closely packed stellate cells.

Ganglionic Layer

Very large and medium-size pyramidal cells

Multiform Layer

Majority of the cells are fusiform, cells of Martinotti are conspicuous in this layer.

Heterotypical areas

Areas of the cortex in which the basic six layers cannot be recognized

Granular type

The granular layers are well developed and contain densely packed stellate cells

Agranular type of cortex

The granular layers are poorly developed, so layers 2 and 4 are practically absent

Functional organization of the cerebral cortex

The cerebral cortex is organized into vertical units or columns of functional activity.

Main areas of the frontal lobe

Precentral area, premotor area, supplementary motor area, and frontal eye field.

Precentral area

Contains giant pyramidal cells of Betz

Primary motor area

Found in the precentral gyrus extending over the superior border into the paracentral lobule

Premotor area

Occupies the anterior part of the precentral gyrus and the posterior parts of the superior, middle, and inferior frontal gyri.

Motor speech area of Broca

Located in the inferior frontal gyrus, important for speech formation

Primary somesthetic area

Located in the postcentral gyrus, concerned with sensory information from the opposite half of the body

Secondary somesthetic area

In the superior lip of the posterior limb of the lateral fissure

Somesthetic association area

Occupies the superior parietal lobule, integrates different sensory modalities

Primary visual area

In the walls of the posterior part of the calcarine sulcus, receives afferent fibers from the lateral geniculate body

Secondary visual area

Surrounds the primary visual area, relates visual information to past visual experiences

Primary auditory area

Includes the gyrus of Heschl, receives projection fibers from the medial geniculate body

Secondary auditory area

Situated posterior to the primary auditory area, necessary for the interpretation of sounds

Cerebral Dominance

Dominant hemisphere for speech, spatial perception, recognition of faces, and music are interpreted by the nondominant hemisphere

Sensory speech area of Wernicke

Localized in the left dominant hemisphere, mainly in the superior temporal gyrus, permits the understanding of written and spoken language

What was the neurologist's diagnosis for the 19-year-old woman experiencing jerking movements in her leg?

Jacksonian epileptic seizures caused by cerebral scarring secondary to an automobile injury.

Cerebral Cortex

Highest level of the central nervous system, functions in association with lower centers, receives vast amounts of information, and responds in a precise manner.

What are the five types of nerve cells present in the cerebral cortex?

Pyramidal cells, stellate cells, fusiform cells, horizontal cells of Cajal, and cells of Martinotti.

Betz Cells

Located in the motor precentral gyrus of the frontal lobe, cell bodies measure as much as 120μm.

Stellate Cells

Small, polygonal shape, multiple branching dendrites and a relatively short axon, which terminates on a nearby neuron.

Radial Fibers

Terminates within the cortex, and the axons of pyramidal,stellate,and fusiform cells

Nerve fibers of the cerebral cortex

Arranged both radially and tangentially

Tangential fibers are most concentrated in layers 4 and 5

Outer and inner bands of Baillarger, respectively.

What are the six layers of the cerebral cortex?

Molecular layer, external granular layer, external pyramidal layer, internal granular layer, ganglionic layer, and multiform layer.

Molecular Layer

A dense network of tangentially oriented nerve fibers derived from apical dendrites, axons of stellate cells, and cells of Martinotti.

External Granular Layer

Small pyramidal cells and stellate cells

External Pyramidal Layer

Pyramidal cells, whose cell body size increases from the superficial to the deeper borders of the layer

Internal Granular Layer

Closely packed stellate cells.

Ganglionic Layer

Very large and medium-size pyramidal cells

Multiform Layer

Majority of the cells are fusiform, cells of Martinotti are conspicuous in this layer.

Heterotypical areas

Areas of the cortex in which the basic six layers cannot be recognized

Granular type

The granular layers are well developed and contain densely packed stellate cells

Agranular type of cortex

The granular layers are poorly developed, so layers 2 and 4 are practically absent

Functional organization of the cerebral cortex

The cerebral cortex is organized into vertical units or columns of functional activity.

Main areas of the frontal lobe

Precentral area, premotor area, supplementary motor area, and frontal eye field.

Precentral area

Contains giant pyramidal cells of Betz

Primary motor area

Found in the precentral gyrus extending over the superior border into the paracentral lobule

Premotor area

Occupies the anterior part of the precentral gyrus and the posterior parts of the superior, middle, and inferior frontal gyri.

Motor speech area of Broca

Located in the inferior frontal gyrus, important for speech formation

Primary somesthetic area

Located in the postcentral gyrus, concerned with sensory information from the opposite half of the body

Secondary somesthetic area

In the superior lip of the posterior limb of the lateral fissure

Somesthetic association area

Occupies the superior parietal lobule, integrates different sensory modalities

Primary visual area

In the walls of the posterior part of the calcarine sulcus, receives afferent fibers from the lateral geniculate body

Secondary visual area

Surrounds the primary visual area, relates visual information to past visual experiences

Primary auditory area

Includes the gyrus of Heschl, receives projection fibers from the medial geniculate body

Secondary auditory area

Situated posterior to the primary auditory area, necessary for the interpretation of sounds

Cerebral Dominance

Dominant hemisphere for speech, spatial perception, recognition of faces, and music are interpreted by the nondominant hemisphere

Sensory speech area of Wernicke

Localized in the left dominant hemisphere, mainly in the superior temporal gyrus, permits the understanding of written and spoken language

Frontal Lobe

Located in the frontal lobe, responsible for executive functions, planning, decision-making, and working memory. Consists of several key areas:

• Prefrontal Cortex (PFC): The largest region responsible for higher cognitive functions.

  • Dorsolateral PFC (DLPFC): Important for working memory, cognitive flexibility, and planning.
  • Ventrolateral PFC (VLPFC): Involved in response inhibition and attentional control.
  • Orbitofrontal Cortex (OFC): Plays a role in decision-making and emotional regulation.
  • Anterior Cingulate Cortex (ACC): Involved in error detection and conflict monitoring.

Parietal Lobe

Located behind the frontal lobe, responsible for processing sensory information such as touch, temperature, pain, and spatial awareness. Key regions include:

• Primary Somatosensory Cortex (S1): Receives tactile information from the body.
• Secondary Somatosensory Cortex (S2): Processes additional sensory input.
• Parietal Association Cortex: Integrates sensory information with motor and cognitive functions.

Occipital Lobe

Located at the back of the brain, primarily involved in visual processing. Contains:

• Primary Visual Cortex (V1): Receives direct input from the retina and processes basic visual features.
• Secondary Visual Cortex (V2): Further processes visual information and sends it to other visual areas.
• Visual Association Areas: Involved in higher-level visual processing, such as object recognition.

Located on the sides of the brain, involved in auditory processing, memory, and language comprehension. Key areas include:

• Primary Auditory Cortex (A1): Receives auditory information from the inner ear.
• **Secondary Auditory Cortex (A