Gross Brain Overview: Part II

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Gross Brain Overview Part II

• Basic Neuroscience
• James H. Baños, Ph.D.

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Overview

• Organization
• Morphology
• Developmental/Evolutionary
• Cytoarchitectural
• 3-D Orientation to Internal Structures

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• How do we organize and characterize different
  parts of the brain?

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• How do we organize and characterize different
  parts of the brain?
• Morphology
• Developmental/Evolutionary Origins
• Cytoarchitecture
• Function

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Morphology External Features
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Frog
Rat
Whats changing?
Cat
Monkey
Human
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• Sulci - The valleys on the surface of the brain
• Gyri - The Hills

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The term gyrus is sometimes used broadly and
doesnt always refer to a single well-defined
ridge on the surface of the brain. The
distinctions between large gyri are sometimes
better seen in coronal sections.
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Hemispheres
Longitudinal Fissure
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Lobes
Central (Rolandic) Sulcus
Lateral (Sylvian) fissure
Parieto-occipital fissure
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Lobes
Cingulate Gyrus Limbic Lobe
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Brain Stem
Thalamus
Hypothalamus
Midbrain
Pons
Medulla
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Cerebellum Superior Aspect

• 2 Hemispheres
• Vermis

Ant
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Cerebellum Posterior Aspect
Anterior Lobe
Primary Fissure
Posterior Lobe
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Cerebellum Mid-Saggital
Anterior Vermis
Posterior Vermis
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Developmental and Evolutionary Origins The
Cephalons
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Developmental Origins

• Areas of the Brain can be characterized by the
  embryonic origins of the tissue.
• Nervous system begins as a tube that
  differentiates into three vessicles
• Prosencephalon
• Mesencephalon
• Rhombencephalon

Three Vessicle Stage
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Developmental Origins

• Prosencephalon differentiates
• Telencephalon -- beginnings of hemispheres
• Diencephalon
• Rhombencehphalon differentiates
• Metencephalon
• Meyelencephalon
• We use this terminology to describe the parts of
  the brain that develop from these vessicles

Five Vessicle Stage
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Developmental Origins
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Organization

• Telencephalon
• Cortex
• Basal Ganglia
• Limbic System
• Hippocampus

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Organization

• Diencephalon
• Thalamus
• Hypothalamus

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Organization

• Mesencephalon
• Midbrain

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Organization

• Metencephalon
• Cerebellum
• Pons

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Organization

• Myelencephalon
• Medulla

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Cytoarchitectural Organization
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Brodmanns Areas
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Internal Structure
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Major Internal Structures

• Ventricular System
• Amygdala (helpful landmark)
• Thalamus/Hypothalamus/brain stem
• Basal Ganglia
• Caudate Nucleus
• Putamen
• Globus Pallidus
• Hippocampal formation
• Hippocampus
• Fimbria
• Fornix
• Major white matter landmarks
• Corpus callosum
• Internal capsule

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Evolution and Development
Frog
Rat
Cat
Monkey
Human
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Evolution and Development
Frog
Rat
Cat
Monkey
Human
?
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Evolution and Development
Ventricles
Basal Ganglia
Hippocampus
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Evolution and Development
Why not the thalamus?
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The Ventricular System
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Ventricles
Lateral Ventricles
Third Ventricle
Fourth Ventricle
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Ventricles

• Ventricles are connected (communicate)
• Intraventricular Foramina (of Monroe)
• Lateral Ventricles to Third Ventricle
• Wide, oval hole
• Cerebral Aqueduct (of Sylvius)
• Third Ventricle to Fourth
• Long, thin channel
• Foramen of Magendie
• Median aperture -- Fourth ventricle to
  subarachnoid space
• Foramina of Luschka
• Lateral apertures -- Fourth ventricle to
  subarachnoid space

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Ventricles
Foramen of Monroe
Aqueduct of Sylvius
Foramina of Luschka
Foramen of Magendie
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Ventricles
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Ventricles
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Ventricles
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Ventricles
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Choroid Plexus and CSF

• Choroid Plexus
• Spongy tissue located in the ventricles
• Rich capillary bed
• Pia Mater
• Choroid endothelial cells
• Produces CSF
• About .35 ml per minute
• Total volume 70-120 ml

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Choroid Plexus
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CSF Flow

• Lateral ventricles
• Foramina of Monroe
• 3rd ventricle
• Aqueduct of Sylvius
• 4th Ventricle
• Foramen of Magendie/foramina of Lushka
• Subarachnoid Space
• Arachnoid granulations (absorption)
• Superior sagittal sinus

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CSF Flow
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CSF Absorption

• CSF flows to the dorsal surface of the brain,
  where arachnoid granulations form a one-way valve
  and let the excess CSF enter the veinous drainage
  of the superior sagittal sinus

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CSF Absorption
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Arachnoid Granulations
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Ventricular System plus Amygdala
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Ventricular System plus Thalamus
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Ventricular System plus Thalamus
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Ventricles, Brainstem, and Thalamus
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Ventricles, Brainstem, and Thalamus
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Basal Ganglia -- Caudate Nucleus

• Basal Ganglia
• Caudate Nucleus
• Putamen
• Globus Pallidus
• Sometimes Amygdala

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Basal Ganglia -- Caudate Nucleus
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Basal Ganglia -- Caudate Nucleus
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Basal Ganglia -- Caudate Nucleus
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Basal Ganglia -- Putamen Globus Pallidus
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Basal Ganglia -- Putamen Globus Pallidus
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Basal Ganglia
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Basal Ganglia
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Basal Ganglia
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Internal Capsule
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Hippocampus

• Hippocampal formation
• Fimbria
• Fornix
• Anterior Commissure
• Amygdala

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Hippocampus
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Hippocampus
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Coming up

• Spinal cord
• Basic Spinal Pathways