DiencephalonDiencephalon

DiencephalonDiencephalon Thalamus  dorsal thalamus Thalamus  dorsal thalamus Hypothalamus Hypothalamus pituitary gland Epithalamus Epithalamus habenular nucleus and commissure pineal gland Subthalamus  ventral thalamus Subthalamus  ventral thalamus subthalamic nucleus (STN) subthalamic nucleus (STN) field of Forel field of Forel

Diencephalon dorsal surface

Diencephalon ventral surface

Diencephalon Medial Surface

THALAMUS

Classification of Thalamic Nuclei I. Lateral Nuclear Group I. Lateral Nuclear Group II.Medial Nuclear Group II.Medial Nuclear Group III.Anterior Nuclear Group III.Anterior Nuclear Group IV.Posterior Nuclear Group IV.Posterior Nuclear Group V.Metathalamic Nuclear Group V.Metathalamic Nuclear Group VI.Intralaminar Nuclear Group VI.Intralaminar Nuclear Group VII.Thalamic Reticular Nucleus VII.Thalamic Reticular Nucleus

Classification of Thalamic Nuclei

LATERAL NUCLEAR GROUP Ventral Nuclear Group Ventral Nuclear Group Ventral Posterior Nucleus (VP) Ventral Posterior Nucleus (VP) ventral posterolateral nucleus ventral posterolateral nucleus ventral posteromedial nucleus (VPM) ventral posteromedial nucleus (VPM) ventral posteroinferior nucleus (VPI) ventral posteroinferior nucleus (VPI)

LATERAL NUCLEAR GROUP Ventral Lateral Nucleus (VL) Ventral Anterior Nucleus (VA, L.po.)

LATERAL NUCLEAR GROUP Ventral Ventral Nuclear Group TTT ML, STT CbllGPi SNr Prefrontal SMA MI, PM SI

LATERAL NUCLEAR GROUP Dorsal or Lateral Nuclear Group Lateral Dorsal Nucleus (LD, D.sf.) Lateral Dorsal Nucleus (LD, D.sf.) Lateral Posterior Nucleus (LP, D.im. & Z.im.) Lateral Posterior Nucleus (LP, D.im. & Z.im.) Pulvinar (P, Pu.) Pulvinar (P, Pu.)

LATERAL NUCLEAR GROUP SC, Pretectal HF VisualAssociationarea SomestheticAssociationArea cingulate gyrus, precuneus

MEDIAL NUCLEAR GROUP Dorsomedial Nucleus (MD) - pars magnocellularis - pars magnocellularis - pars parvocellularis - pars parvocellularis Midline Nuclear Group

ANTERIOR NUCLEAR GROUP anteroventral nucleus (AV, A.pr.) anterodorsal nucleus (AD, A.d.) anteromedial nucleus (AM, A.m.) POSTERIOR NUCLEAR GROUP suprageniculate nucleus (SG, Li.) nucleus limitans (Lim, Li.) posterior nucleus (PO, Li.por.)

MEDIAL & ANTERIOR NUCLEAR GROUP MB, HF PrefrontalCortex Frontal Eye Field MedialFrontalGyrus cingulategyrus Basalforebrain SNr, SC, RF

METATHALAMIC NUCLEAR GROUP Medial Geniculate Nucleus (MG) ventral nucleus dorsal nucleus medial nucleus Lateral Geniculate Nucleus (LG) dorsal nucleus ventral nucleus

INTRALAMINAR NUCLEAR GROUP Rostral Intralaminar Nuclei central lateral nucleus, central medial nucleus, paracentral nucleus, Caudal Intralaminar Nuclei (CM-PF nuclear complex) (CM-PF nuclear complex) centre median nucleus, parafascicular nucleus,

THALAMIC RETICULAR NUCLEUS Cerebral Cortex Subcortical Structure ThalamicReticularNucleusThalamicReticularNucleus ThalamocorticalNeuronThalamocorticalNeuron

Summary of Thalamic Connectivity I.Sensory Input I.Sensory Input general sensation general sensation special sensation special sensation taste, equilibrium, hearing, vision II.Motor Input II.Motor Input cerebellum, basal ganglia cerebellum, basal ganglia III. Reticular Formation III. Reticular Formation IV.Limbic System IV.Limbic System mammillary nucleus mammillary nucleus hippocampal formation hippocampal formation

Sensory Input (1) General Sensation 1. Medial lemniscus 1. Medial lemniscus VPLc S I, S II VPLc S I, S II 2. Spinothalamic tract 2. Spinothalamic tract VPLc S I, S II VPLc S I, S II POm retroinsular cortex POm retroinsular cortex Sm frontal lobe(?) Sm frontal lobe(?) CL diffuse cortical areas CL diffuse cortical areas 3. Trigeminothalamic tract 3. Trigeminothalamic tract VPM S I, S II VPM S I, S II

Sensory Input (2) Taste sensation VPM pc gustatory area (Brodmann area 43) VPM pc gustatory area (Brodmann area 43) (3) Sense of equilibrium VPLo S I VPLo S I (4) Auditory sensation MGv A I (Brodmann area 41, 42) MGv A I (Brodmann area 41, 42) MGd A II MGd A II (5) Vision LGd V I (Brodmann area 17) LGd V I (Brodmann area 17) Pi, Pl V I, V II (Brodmann area 17, 18, 19) Pi, Pl V I, V II (Brodmann area 17, 18, 19)

Motor Input (1) Cerebellum VLc, VPLo, - M I (Brodmann area 4), Premotor area VLc, VPLo, - M I (Brodmann area 4), Premotor area (2) Basal ganglia 1. GPi (internal segment of globus pallidus) 1. GPi (internal segment of globus pallidus) SMA (supplementary motor area) frontal cortex frontal cortex 2. SNr (pars reticularis of substantia nigra) 2. SNr (pars reticularis of substantia nigra) - fronal cortex - fronal cortex medial frontal cortex medial frontal cortex frontal eye field (Brodmann area 8) frontal eye field (Brodmann area 8)

Reticular Formation & Limbic System Reticular formation rostral intralaminar nuclei (CL, Cem, PC), Rh rostral intralaminar nuclei (CL, Cem, PC), Rh diffuse cortical areas diffuse cortical areas thalamic reticular nucleus (R), LGv thalamic reticular nucleus (R), LGv adjacent thalamic nucleus adjacent thalamic nucleus Limbic System Mammillary Body Mammillary Body AV, AD, AM cingulate gyrus AV, AD, AM cingulate gyrus Hippocampal Formation Hippocampal Formation AV, AD, AM cingulate gyrus AV, AD, AM cingulate gyrus LD cingulate gyrus, precuneus Re medial cortex, entorhinal cortex Re medial cortex, entorhinal cortex

Clinical Syndromes of the Thalamus Posterolateral thalamic syndromes sensory disorders sensory disorders Thalamic (Dejerine-Roussy) syndrome Thalamic (Dejerine-Roussy) syndrome VP nucleus - pain VP nucleus - pain Medial thalamic syndromes disorders of consciousness disorders of consciousness thalamic neglect, thalamic amnesia, thalamic neglect, thalamic amnesia, akinetic mutism akinetic mutism Anterolateral thalamic syndromes motor disorders motor disorders paresis, ataxia, motor incoordination, dysphagia paresis, ataxia, motor incoordination, dysphagia

Thalamic (Dejerine-Roussy) Syndrome Joseph Jules Dejerine ( ) Gustave Roussy ( )

Modality: Vision Modality: Vision Receptor: Photoreceptor Cell of Retina Receptor: Photoreceptor Cell of Retina Cranial Nerve: II (Optic nerve) Cranial Nerve: II (Optic nerve) 1st Neuron: Bipolar Cell 1st Neuron: Bipolar Cell 2nd Neuron: Ganglion Cell 2nd Neuron: Ganglion Cell optic nerve optic nerve optic chiasm optic chiasm optic tract optic tract 3rd Neuron: Lateral Geniculate Nucleus 3rd Neuron: Lateral Geniculate Nucleus optic radiation optic radiation Termination: Visual Areas (V I, V II) Termination: Visual Areas (V I, V II) Brodmann area 17 (V I), 18, 19 (V II) Brodmann area 17 (V I), 18, 19 (V II) Modality: Vision Modality: Vision Receptor: Photoreceptor Cell of Retina Receptor: Photoreceptor Cell of Retina Cranial Nerve: II (Optic nerve) Cranial Nerve: II (Optic nerve) 1st Neuron: Bipolar Cell 1st Neuron: Bipolar Cell 2nd Neuron: Ganglion Cell 2nd Neuron: Ganglion Cell optic nerve optic nerve optic chiasm optic chiasm optic tract optic tract 3rd Neuron: Lateral Geniculate Nucleus 3rd Neuron: Lateral Geniculate Nucleus optic radiation optic radiation Termination: Visual Areas (V I, V II) Termination: Visual Areas (V I, V II) Brodmann area 17 (V I), 18, 19 (V II) Brodmann area 17 (V I), 18, 19 (V II) Visual (Optic) Pathway Visual (Optic) Pathway

1. Pigment Epithelium - retinal detachment - retinal detachment 2. Neuronal Layer (1) Photosensitive Cell Layer (1) Photosensitive Cell Layer Rod Cell, Cone Cell Rod Cell, Cone Cell (2) Bipolar Cell Layer (2) Bipolar Cell Layer Bipolar Cell Bipolar Cell Horizontal Cell Horizontal Cell Amacrine Cell Amacrine Cell (3) Ganglion Cell Layer (3) Ganglion Cell Layer Ganglion Cell Ganglion Cell Optic Nerve (II) Optic Nerve (II) RETINA - Pars Nervosa

VisualPathway 1. Optic nerve 2. Optic chiasm 3. Optic tract 4. Lateral geniculate geniculate body body 5. Optic radiation 6. Visual cortex

Visual (Optic) Pathway

Visual Pathway Lateral Geniculate Nucleus (LGd) Visual Pathway Lateral Geniculate Nucleus (LGd) Dorsal Nucleus (LGd) Magnocellular Part Magnocellular Part 1, 2 1, 2 Parvocellular Part Parvocellular Part 3, 4, 5, 6 3, 4, 5, 6 contralateral afferents contralateral afferents 1, 4, 6 1, 4, 6 ipsilateral afferents ipsilateral afferents 2, 3, 5 2, 3, 5 Ventral Nucleus (LGv) part of thalamic part of thalamic reticular nucleus reticular nucleus dorsolateral ventromedial

Optic Radiation (Geniculocalcarine Tract) Meyer’s loop

Clinical Features of Visual Pathway Lesion Clinical Features of Visual Pathway Lesion 1. optic nerve 2. optic chiasm 3. optic tract optic radiation A. unilateral blindness B. bitemporal hemianopsia C. left homonymous hemianopsia hemianopsia D. left inferior homony- mous quadranopsia mous quadranopsia E. left superior homony- mous quadranopsia mous quadranopsia

Signs of Visual Pathway Lesion Optic nerve - ipsilateral blindness - ipsilateral blindness Optic chiasm - bitemporal hemianopsia - bitemporal hemianopsia Optic tract - contralateral homonymous hemianopsia - contralateral homonymous hemianopsia Optic radiation - contralateral homonymous quadranopsia - contralateral homonymous quadranopsia - intact light reflex - intact light reflex Visual Cortex - contralateral homonymous quadranopsia - contralateral homonymous quadranopsia - macular sparing - macular sparing

Visual Field Defect left inferior optic radiation lesion right superior quadranopsia

Hypothalamus  Limbic System

Epithalamus  Limbic System Habenular Nucleus Medial Habenular Nucleus Medial Habenular Nucleus Lateral Habenular Nucleus Lateral Habenular Nucleus Habenular Commissure Pineal Gland

Subthalamus  Basal Ganglia Subthalamic nucleus zona incerta Field of Forel H ansa lenticularis H ansa lenticularis H1thalamic fasciculus H1thalamic fasciculus H2lenticular fasciculus H2lenticular fasciculus