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Neuroanatomy II: Systems, Pathways and Tracts
Marc Norman, Ph.D., ABPPAmanda Gooding, Ph.D., ABPP
Department of PsychiatryNeuropsychology Clinical Training Seminar (NCTS)
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2Courtesy of Erin Bigler, Ph.D.
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Neostriatum or striatum
• Caudate + Putamen– Receives all input to BG– Most cortical input is
excitatory (glutamate)– Output is GABA
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Lentiform
• Globus Pallidus + Putamen
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BG Pic
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Connections
• Commisure• Faciculus
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Homonculus
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Limbic• Homeostasis• Olfaction• Memory• Emotion
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Getting� Limbic• Limbic Function Key Structure• Homeostasis, autonomic Hypothalamus & neuroendocrine control• Olfaction Olfactory Cortex• Memory Hippocampal Formation• Emotions and drives Amygdala
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Limbic System• Olfaction and regulation of emotions, memory, appetite
drives, and autonomic and neuroendocrine control• These areas are interconnected by a variety of
pathways, including the fornix- connecting the hippocampal formation to the hypothalamus and septal nuclei
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Limbic Structures• Medial and anterior
temporal lobes• Anterior insula• Inferior medial frontal
lobes• Hippocampal formation• Basal ganglia
• Cingulate gyri• Amygdala • Medial thalamic nuclei • Hypothalamus• Septal area• Brainstem
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Sensory• Posterior Column pathway - proprioception, vibratory,
fine touch• Anteriolateral- pain, temperature, and crude touch
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Spine: Everyone should get one
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Motor Neurons• Upper motor neurons
– From cortex to spinal cord or brainstem• Lower motor neuron
– Out of CNS via anterior spinal roots (cranial nerves) to muscles in periphery
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Crossover• Medulla/spinal cord junction• 85% of motor fibers cross over• Contralateral/ipsalateral
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Motor System (medial)
• Anterior Corticospinal tract• Vestibulospinal tract• Reticulospinal tract• Tectospinal tract
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Corticospinal• Major motor tract• Most important pathway - pyramidal tract• Voluntary movement• From cortex to anterior horn cells in spinal cord
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Corticospinal Tract
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Internal Capsule• Corticospinal/corticobulbar fibers form part of it• From cortex to brainstem = corticobulbar
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Rubrospinal Tract• Small, unclear clinically• Rubrospinal tract decussates in the ventral tegmentum at
the level of the midbrain to the red nucleus• A portion of the anterior corticospinal tract decussates at
the level of the cervical spinal cord, just below the Pyramid
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Rubrospinal
• May play role in decorticate posturing
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The End is Here• Repent, for the time is Nigh