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Chapter 2b CNS Gross Anatomy

Chris RordenUniversity of South CarolinaNorman J. Arnold School of Public HealthDepartment of Communication Sciences and DisordersUniversity of South Carolina

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Brain Sub-Divisions

Telencephalon – Cortex, Limbic system, basal ganglia, olfactory bulb

DiencephalonThalamus, Hypothalamus

MesencephalonTegmentum, Red Nucleus,

ColliculiRhombencephalon

Pons, Cerebellum, MedullaSpinal Cord

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Diencephalon

Diencephalon = thalamus, hypothalamus, epithalamus, prethalamus or subthalamus and pretectum

Thalamus– Oval Mass of Neurons in

the Center of the Brain– Relays Sensorimotor

Information to the Cortex

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Thalamus

Poor contrast on MRI scans – hard to see.

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Thalamic Injury

T2-weighted MRIBilateral injury to parts of

thalamus

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Diencephalon

Hypothalamus– Body Heat, Water intake,

Hormone Production, Emotional Expression, Food Consumption and Reproduction

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Midbrain, Hindbrain

PonsMedulla OblongataFunctions: Automatic

Control Systems

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Ventral Brainstem

Mamillary BodiesMedial SulcusVentral Median FissurePyramidal TractPyramidal Decussation

– Where signals crossVentral lateral sulcus

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Midbrain Dorsal Structures

Superior and Inferior Colliculus – The ‘little hills’.– Superior colliculi – help

initiate eye movements, integrate visual, auditory and tactile information

– Inferior colliculi- audition Aka Corpora

Quadrigemina (four seeds)

Dorsal View of Brainstem

Pineal BodyBrachiumSuperiorColliculus

InferiorColliculus

ColliculusSuperior

Inferior

TrochlearNerve

Colliculi

Superior colliculi: eye movement control. Also maps touch and hearing onto vision

Inferior colliculi: pathway for auditory processing

Sagittal View

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Internal Structures of the Midbrain

Tegmentum Cerebral Aqueduct Red Nucleus Cranial nerve nuclei Reticular Formation Central Gray Area

Transverse Section of Rostral Midbrain

Tectum

Tegmentum

BasisPedunculi

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Internal structures of the pons

Tegmentum– Ascending and Descending Fibers– Medial Lemniscus

Basilar Pons– Cortical Descending Tracts– Pontine Nuclei – Pontocerebellar Fibers

Transverse Section of Mid Pons

Teg-mentum

Basilar

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Medulla Oblongata

Connects to Pontine Protrusion Caudal Portion Contains Pyramidal Decussation Where motor tracts cross over for control of contralateral

side of the body

Tegmentum

Pyramid

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Landmarks of Medulla

Ventral– Ventrolateral Sulcus– Pyramidal Tract– Lateral Corticospinal Motor Tract

Dorsal– Dorsal Median Sulcus– Dorsolateral Sulcus– Olivary Nucleus

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Internal Medulla

Dorsal TegmentumVentral Pyramidal TractReticular Formation

– Cardiac Center– Vasomotor Center– Respiratory Center

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Cerebellum

Modifies Cortical ActivityDistinctive Appearance

– Gyri called Folia– Two Hemispheres

Three Lobes– Anterior– Posterior– Flocculonodular

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CerebellumPosterior lobe

Anterior lobe

Rostral view– (bird’s eye)

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Cerebellum

Caudal view (from the feet)

Posterior lobe

Anterior lobe

Flocculus

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Cerebellum

Anterior view

Nodulus

Flocculus

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Cerebellum

Midsagittal slice

Flocculus

Nodulus