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Thalamus and the Internal Capsule MHD - Neuroanatomy Course February 2, 2016 Gregory Gruener, MD, MBA Vice Dean for Education, SSOM Professor & Associate Chair, Department of Neurology LUHS/Trinity and Catholic Health Care East

Outcomes you need to be able to demonstrate List the major subdivisions of the diencephalon and the thalamus Identify the internal medullary lamina and intralaminar nuclei Define the three functional groups of the thalamus Summarize the function of the reticular nucleus of the thalamus List what “afferents” supply individual thalamic nuclei and where those thalamic nuclei project

“Basic” pathway of sensory information to the thalamus Anterolateral tract 1. Information gets collected 2. Transmitted 3. Looked at & analyzed 4. Interpreted Gray’s anatomy: The anatomical basis of clinical practice, 40th edition; Churchill Livingstone, London

Thalamus Lancet Neurol 2014; 13: 100–12

General Anatomical Overview Divisions of the Diencephalon Epithalamus (pineal gland, habenula, stria medullaris) Dorsal thalamus Subthalamus (subthalamic nucleus, zona incerta) Hypothalamus Internal medullary lamina Anterior division nuclei Medial division nuclei Lateral division nuclei Intralaminar nuclei Thalamic reticular nuclei Midline nuclei

Nolte J and Angevine JB. The Human Brain in photographs and diagrams Nolte J and Angevine JB. The Human Brain in photographs and diagrams. 3rd edition, 2007; Mosby Elsevier

Fitzgerald MJT, Gruener G, Mtui E Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 56th Ed., W. B. Saunders 2012

Fitzgerald MJT, Gruener G, Mtui E Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Common functional principles Thalamic nuclei “decide” what information passes Classification of nuclei – location and input/outputs Consist of projection (majority) and inhibitory neurons Inputs into the thalamus Specific – e.g., posterior column/medial lemniscus pathway Use glutamate as their neurotransmitter Regulatory – Majority (Cortex, thalamic reticular nucleus, reticular formation, aminergic projections)

Functional thalamic groups Three groupings Specific or relay nuclei Well defined inputs and projections Anterior, ventral anterior, ventral lateral, ventral posterior, lateral dorsal, medial and lateral geniculate Association nuclei Reciprocally connected to association cortex Lateral posterior, pulvinar, medial dorsal nuclei Non-specific nuclei Not the same point-to-point connections like relay nuclei Intralaminar and thalamic reticular nuclei

Specific or relay nuclei Nolte J . The Human Brain, 6th edition, 2009; Mosby Elsevier

Specific or relay nucleus (specificity) Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Specific or relay nuclei Dorsomedial Lateral Posterior VPL VPM Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Functional thalamic groups Three groupings Specific or relay nuclei Well defined inputs and projections Anterior, ventral anterior, ventral lateral, ventral posterior, lateral dorsal, medial and lateral geniculate Association nuclei Reciprocally connected to association cortex Lateral posterior, pulvinar, medial dorsal nuclei Non-specific nuclei Not the same point-to-point connections like relay nuclei Intralaminar and thalamic reticular nuclei

Association nuclei Nolte J . The Human Brain, 6th edition, 2009; Mosby Elsevier

Association nuclei Lateral Posterior Dorsomedial Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Functional thalamic groups Three groupings Specific or relay nuclei Well defined inputs and projections Anterior, ventral anterior, ventral lateral, ventral posterior, lateral dorsal, medial and lateral geniculate Association nuclei Reciprocally connected to association cortex Lateral posterior, pulvinar, medial dorsal nuclei Non-specific nuclei Not the same point-to-point connections like relay nuclei Intralaminar and thalamic reticular nuclei

Non-specific nuclei Nolte J. The Human Brain: An introduction to its functional anatomy. 6th edition, 2009; Mosby Elsevier Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Non-specific nuclei Nolte J. The Human Brain: An introduction to its functional anatomy. 6th edition, 2009; Mosby Elsevier Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 56th Ed., W. B. Saunders 2012

Lateral Posterior Anterior This is it Internal capsule

Internal capsule AL-Anterior limb, G-Genu, PL-Posterior limb, RL- Retrolentiform part Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2007

(anterior, posterior, superior, inferior) Thalamic peduncles (anterior, posterior, superior, inferior) Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

“The” thalamic nuclei to remember

Blood supply Fitzgerald MJT, Gruener G, Mtui E. Clinical Neuroanatomy and related Neuroscience, 6th Ed., W. B. Saunders 2012

Vascular (stroke) anatomic lesions and syndromes Powell R, et al. Pract Neurol 2014;14:440-445