Telencephalon White matter Basal ganglia Telencephalic white matter

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

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

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

Speech areas

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

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

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

Lateralisation of functions

Split brain syndrome А. Dominant hemisphre - mention the stimulus B. Nondominant hemisphere 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

Projection fibers

Capsula interna 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 extrema)

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

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

Basal Ganglia Components Striatal Compartments (Mosaic or Modular Organization) 1. Striosome (Patches) - 10 -20% of total striatal mass - low acetylcholinesterase (Ach. E) activity - high substance P (SP), neurotensin (NT), tyrosine hydroxylase - high expression of D 1 dopamine receptor - high opiate receptor 2. Matrix - high acetylcholinesterase (Ach. E) activity - high somatostatin (SRIF) activity - high D 2 dopamine receptor

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

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

1. head of caudate nucelus 2. body of caudate nucelus 3. caudatolenticular gray bridge 4. putamen 5. tail of 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

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

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

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] [ b. SN [strionigral]

Basal ganglia Connections 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 subthalamicus

Basal ganglia Connections

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

Basal Ganglia and Pyramidal Tract SMA (supplementary motor area) upper motor neuron UMN pyramidal tract lower motor neuron LMN BASAL GANGLIA 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 1. Selection of “Preprogramed (learned) motor plans” Basal Gangla Circuit ---- Selection Mechanism Selection Inability ---- Akinesia and Hypokinesia Faulty Selection ------ Hyperkinesia 2. Generation (learning) of motor programs Programming of several motor fragments into complex motor routines Cerebral Palsy ------- Disordered motor program

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

HUNTINGTON’S CHOREA Clinical Feature - Predominantly autosomal dominantly inherited chronic fatal disease (Gene: chromosome 4) - Insidious onset: Usually 40 -50 - Choreic movements in onset - Frequently associated with emotional disturbances - Ultimately, grotesque gait and sever dysarthria, progressive dementia ensues. Principal Pathologic Lesion: Corpus Striatum (esp. caudate nucleus) and Cerebral Cortex