Telencephalon White matter. Basal ganglia

Telencephalic white matter Projection fibers Corona radiata Commissural fibers Corpus callosum rostrum, genu, trunkus, splenium Commissura anterior Commissura fornicis Association fibers Fibrae arcuatae breves Fibrae arcuatae longi

Association fibers 1. Fasciculus longitudinalis superior 2. Fasciculus longitudinalis inferior 3. Cingulum 4. Fasciculus uncinatus 5. Fibrae arcuatae brevae

1. Fasciculus longitudinalis superior 3. Fasciculus uncinatus 2. Fasciculus occipitofrontalis 4. Fasciculus perpendicularis inferior occipitalis Association fibers (lateral aspect)

1. Cingulum 4. Fasciculus occipitofrontalis superior 2. Fasciculus uncinatus 5. Fasciculus perpendicularis occipitalis 3. Fasciculus longitudinalis inferior Asociation fibers (medial aspect)

Speech areas

Commissural fibers Corpus callosum symmetrical areas of the hemispheres symmetrical areas of the hemispheres splenium, corpus, genu, rostrum splenium, corpus, genu, rostrum Commissura anterior temporal lobes temporal lobes olfatory bulbs olfatory bulbs Commisssura posterior left and right parts of tectum & tegmentum of midbrain left and right parts of tectum & tegmentum of midbrain Commissura fornicis between both crura of fornix between both crura of fornix

Corpus callosum - forceps minor - forceps minor - forceps major - tapetum Commissura anterior - pars anterior - pars anterior - pars posterior Commissura anterior (frontal section)

Commissural fibers 1.Corpus callosum 3. Forceps minor 2.Commissura anterior 4. Forceps major

Lateralisation of functions

А. Dominant hemisphre - mention the stimulus B. Nondominant hemisphere - points the stimulus points the stimulus C. Anomia – can not name stimuli on the left hand D. Alexia in the left visual fields E. Test – hybrid face - the patient answers man, but point the woman Split brain syndrome

Projection fibers

1. Crus anterior between nucl. caudatus и nucl. lentiformis - stripes of grey matter 2. Genu 3. Crus posterior Pars thalamolentiformis - between thalamus & nucl. lentiformis Pars retrolentiformis Pars sublentiformis Capsula interna

1. Tractus corticonuclearis 2. Tractus corticospinalis 3. Fibrae corticothalamicae 4. Fibrae thalamocorticales 5. Radiatio acustica 6. Radiatio optica 14. Fibrae corticorubrales

White matter (frontal section) 1. Corpus callosum 2. Capsula interna 3. Fasciculus occipitofrontalis superior 4. Fasciculus longitudinalis superior 5. Fasciculus occipitofrontalis inferior 6. Cingulum 7. Fasciculus uncinatus 8. Fasciculus longitudinalis inferior

Basal ganglia

Location Section through the base of hemisphere exposes a. Paired nuclear masses within the hemispheres. b. Surounded by white matter (capsula interna, capsula externa, capsula extrema)

Components of the Basal ganglia Components of the Basal ganglia Corpus Striatum Striatum Caudate Nucleus & Putamen Striatum Caudate Nucleus & Putamen Pallidum Globus Pallidus (GP) Pallidum Globus Pallidus (GP) Substantia Nigra Pars Compacta (SNc) Pars Compacta (SNc) Pars Reticulata (SNr) Pars Reticulata (SNr) Subthalamic Nucleus (STN) Ventral Striatum и Ventral Pallidum Nucleus Accumbens Septi Nucleus Accumbens Septi Noncholiergic part of Substantia Innominata Noncholiergic part of Substantia Innominata Basal ganglia Components Basal ganglia Components

STRIATUM STRIATUM Nucleus Caudatus Caput, (Corpus), Cauda Caput, (Corpus), Cauda Caudolenticular bridges of grey matter Caudolenticular bridges of grey matterPutamen Striatum Ventralis: Nucleus Accumbens (Septi) Basal ganglia Components Basal ganglia Components

Striatal Compartments Striatal Compartments (Mosaic or Modular Organization) (Mosaic or Modular Organization) 1. Striosome (Patches) % of total striatal mass % of total striatal mass - low acetylcholinesterase (AchE) activity - low acetylcholinesterase (AchE) activity - high substance P (SP), neurotensin (NT), tyrosine hydroxylase - high substance P (SP), neurotensin (NT), tyrosine hydroxylase - high expression of D 1 dopamine receptor - high expression of D 1 dopamine receptor - high opiate receptor - high opiate receptor 2. Matrix - high acetylcholinesterase (AchE) activity - high acetylcholinesterase (AchE) activity - high somatostatin (SRIF) activity - high somatostatin (SRIF) activity - high D 2 dopamine receptor - high D 2 dopamine receptor Basal Ganglia Components Basal Ganglia Components

Traditional Concepts of Basal Ganglia Traditional Concepts of Basal Ganglia Corpus Striatum Caudate Nucleus Caudate Nucleus Lenticular Nucleus Putamen Lenticular Nucleus Putamen Globus Pallidus Paleostriatum Pallidum Globus Pallidus Paleostriatum Pallidum Corpus Amygdaloideum Archistriatum Neostriatum Striatum Basal Ganglia Introduction Basal Ganglia Introduction

1. Putamen 2. Tail of caudate nucleus 3. Caudatolenticular gray bridge 4. Amygdaloid body 5. thalamus Lateral surface of basal ganglia

1. head of caudate nucelus caudate nucelus 2. body of caudate nucelus caudate nucelus 3. caudatolenticular gray bridge gray bridge 4. putamen 5. tail of caudate nucleus caudate nucleus 6. external segment of globus pallidus 7. internal segment of globus pallidus 8. amygdaloid body 9. nucleus accumbens septi Medial surface of basal ganglia

Putamen Globus pallidus external segment external segment internal segment internal segment Subthalamic Nucleus Substantia nigra Internal capsule Components of Basal Ganglia

Input Portion Input Portion STRIATUM STRIATUM (Caudate Nucleus and Putamen) (Caudate Nucleus and Putamen) Output Portion Output Portion 1. PALLIDUM (Globus Pallidus) 1. PALLIDUM (Globus Pallidus) 2. SNr (Substantia Nigra, Pars Reticulata) 2. SNr (Substantia Nigra, Pars Reticulata) Basal Ganglia Connections

Basal ganglia Connections А. Striatum (nucl. caudatus + putamen) 1. Afferent fibers а. Cortex (sensimotor – gyrus paracentralis) b. Thalamus – nucl. centromedianum, NVL, NVA c. Substantia nigra d. Nuclei raphe 2. Efferent fibers [ a. Pallidum [striopallidal] SN b. SN [strionigral]

B. Globus pallidus (pallidum) 1. Afferent fibers а. Striatum (striopallidal fibers) b. Nucleus subthalamicus (fasciculus subthalamicus) c. Cerebral cortex d. Substantia nigra e. Nuclei raphe 2. Efferents fibers a. Common final pathway to thalamus b. Ansa lenticularis, fasciculus lenticularis, fasciculus subthalamicus Basal ganglia Connections

Basal Ganglia (Main Motor Circuit) Connections Supplementary Motor Area (SMA) Primary (M I) THALAMUS (VLo, VApc, CM) STRIATUM(Putamen) PALLIDUM(GPi) pyramidal tract tract LMN ansa ansalenticularis lenticular lenticularfasciculus

SMA (supplementary motor area) (supplementary motor area)SMA Basal Ganglia and Pyramidal Tract upper motor neuron upper motor neuron UMN UMN lower motor neuron lower motor neuron LMN LMN pyramidal tract tract BASAL BASALGANGLIA CIRCUIT CIRCUIT

Functional role Regulate the motor activity by intrinsic and extrisic feed-back circuits  Role in the control of movements  Suppress the motor tone  Suppress the excesive and unnecessary movements

Signs in lesion of basal ganglia 1. Akinesia & bradykinesia - difficulty in initiation and cessation of movement 2. Rigidity of muscles 3. Involutary movements (hyperkinesia) – tremor, tics, balism, chorea, atetosis, distonia

Basal Ganglia Functional Consideration Functional Consideration Functional Consideration 1. Selection of “Preprogramed (learned) motor plans” Basal Gangla Circuit ---- Selection Mechanism Basal Gangla Circuit ---- Selection Mechanism Selection Inability Akinesia and Hypokinesia Selection Inability Akinesia and Hypokinesia Faulty Selection Hyperkinesia Faulty Selection Hyperkinesia 2. Generation (learning) of motor programs Programming of several motor fragments into Programming of several motor fragments into complex motor routines complex motor routines Cerebral Palsy Disordered motor program Cerebral Palsy Disordered motor program

SYDENHAM’S CHOREA - Complication of Rheumatic Fever Rheumatic Fever - Fine, disorganized, and random movements of random movements of extremities, face and extremities, face and tongue tongue - Accompanied by Muscular Hypotonia Muscular Hypotonia - Typical exaggeration of associated movements associated movements during voluntary activity during voluntary activity - Usually recovers spontaneously spontaneously in 1 to 4 months in 1 to 4 months Clinical Feature Principal Pathologic Lesion: Corpus Striatum

Clinical Feature Principal Pathologic Lesion: Corpus Striatum (esp. caudate nucleus) Corpus Striatum (esp. caudate nucleus) and Cerebral Cortex and Cerebral Cortex - Predominantly autosomal dominantly inherited chronic fatal disease inherited chronic fatal disease (Gene: chromosome 4) (Gene: chromosome 4) - Insidious onset: Usually Choreic movements in onset - Frequently associated with emotional disturbances emotional disturbances - Ultimately, grotesque gait and sever dysarthria, progressive dementia dysarthria, progressive dementia ensues. ensues. HUNTINGTON’S CHOREA