Basal Ganglia Lecture Notes PDF

Basal Ganglia Neuroanatomy block-Anatomy-Lecture 17 Editing file  Objectives At the end of the lecture, students should be able to: 01 Define “basal ganglia” and enumerate its components. 02 Enumerate parts of “Corpus Striatum” and their important relations....

Basal Ganglia Neuroanatomy block-Anatomy-Lecture 17 Editing file  Objectives At the end of the lecture, students should be able to: 01 Define “basal ganglia” and enumerate its components. 02 Enumerate parts of “Corpus Striatum” and their important relations. 03 Describe the structure of Caudate and Lentiform (Putamen & Globus Pallidus) nuclei. 04 Differentiate between striatum & paleostriatum in term of connections. 05 State briefly functions & dysfunctions of Corpus Striatum. Color guide Only in boys slides in Green Only in girls slides in Purple important in Red Notes in Grey Basal ganglia (nuclei) ➔ group of nerve cells deeply situated in cerebral hemispheres Caudate Nucleus Are functionally related to each other & called “Corpus Striatum”: Part of CN extrapyramidal motor system, Components Lentiform Nucleus: principally involved in the control of divided into: posture and movements (primarily by LN (Putamen & Globus inhibiting motor functions) Pallidus) AN (part of limbic system) is only Amygdaloid embryologically related to Corpus Nucleus Striatum. Corpus Striatum (Nomenclature): Bands of grey matter pass from lentiform nucleus across the internal capsule to the caudate nucleus, giving the striated appearance hence, the name corpus striatum. 3 Functions Of Basal Ganglia (boys slides) Basal ganglia 1 Design of plans, which convert thoughts and ideas into motor actions: to produce a coordinated organized purposeful movement. e.g. dressing. Corpus Amygdala 2 Determining the timing and scale of movement: to what extent the movement will be striatum fast, and how long it will last. 3 Storage of motor programs of familiar motor actions: e.g. signature. Neostriatum (Striatum) Paleostriatum 4 Planning ,programming and Control of movements Globus 5 Caudate Putamen Cognition Pallidus To sum up 1. Basically the activity of basal nuclei begins by information received from sensory cortex, thalamus, substantia nigra and red nucleus, according to thoughts of mind Lentiform nucleus 2. These information is integrated within corpus striatum and channeled within globus pallidus and outflow back to motor areas of cerebral cortex and other motor areas in brain stem. 3. Thus the basal nuclei can control muscular movement through its effect on cerebral cortex. 4. So basal nuclei assist in regulation of voluntary movement and learning of motor skills 4 Lentiform Nucleus Shape: Three sided, wedge-shaped mass of grey matter, with a convex outer surface and an apex which lies against the genu of the internal capsule. Division: divided into Putamen Globus Pallidus Larger darker lateral portion Smaller, lighter medial portion More closely related to Caudate nucleus The oldest part of corpus striatum and (regarding development, function & is called Paleostriatum or Pallidum. connections) and together constitute the Consists of two divisions, the lateral Neostriatum or Striatum. (L) & the medial (M) segments, Separated from globus pallidus by a thin separated by a thin sheath of nerve sheath of nerve fibers, the Lateral Medullary fibers, the medial medullary lamina. Lamina. The medial segment is similar, in terms The white matter lateral to putamen is of cytology and connections with the divided, by a sheath of grey matter, the pars reticulata of substantia nigra. Claustrum into two layers: ➔ external capsule (❶) between the putamen and claustrum. ➔ extreme capsule (❷) between the claustrum and the insula. 5  Caudate Nucleus Shape Components Head Body Tail Rounded in shape Long & narrow Long & tapering C-shaped Lies anterior to thalamus (in Extends above Descends into mass of frontal lobe). thalamus (in temporal lobe grey Completely separated from parietal lobe) Continuous with matter the putamen by the internal Amygdaloid capsule except rostrally Nucleus. where it is continuous with the putamen. Important relations: Head of Caudate Nucleus Lentiform Nucleus A Lies: Anterior to thalamus P Lateral to thalamus & separated from it Medial to Lentiform & separated by posterior limb of internal capsule.(P) from it by anterior limb of internal capsule.(A) 6 Corpus Striatum Function Dysfunction The corpus striatum assists in regulation of VS It’s dysfunction does NOT cause: paralysis, sensory loss voluntary movement and learning of motor or ataxia. skills as they: It leads to: Facilitate behavior and movement that Abnormal motor control: emergence of abnormal, are required and appropriate. involuntary movements (dyskinesias) Inhibit unwanted or inappropriate Alteration in muscle tone: hypertonia/hypotonia. movement. 7 Corpus Striatum Paleostriatum (Globus Pallidus): Striatum (Caudate & Putamen): The output portion of corpus striatum: The input portion of Corpus striatum. medial segment of G.P. + Pars Reticulata of S.N. Cerebral Cortex Substantia Nigra Thalamus (Pars Reticulata) (Ventral lateral, Ventral anterior, centromedian) icu c sc mi s lu Fa ala Thalamus Th Globus Pallidus (intralaminar Striatum Medial Segment nuclei) Substantia Nigra ic Subthalamic Nuclei (Pars Compacta) Globus Pallidus lam tha s Sub iculu c Afferents (input) Lateral Segment fas Efferents (output) 8  Found only in male’s slides Connection Of Corpus Striatum Afferent Fibers ( Input): Corticostriate fibers Thalamostriate Fibers Nigrostriate Fibers Brain stem Strial Fibers From all parts of cerebral From intralaminar nuclei of Axons from Substantia Ascending fibers from cortex (mostly from thalamus axons pass to nigra of midbrain pass to brain stem end in caudate sensory- motor cortex) caudate nucleus and caudate nucleus and nucleus & putamen. axons pass to caudate putamen. putamen. Serotonin is the nucleus and putamen. Neurotransmitter is neurotransmitter. Glutamate is the Dopamine. neurotransmitter of this fibers. It is believed these 2 groups are inhibitory in function Efferent Fibers ( Output): Striatopallidal fibers Striatonigral fibers These fibers pass from striatum (caudate nucleus & putamen) to These fibers pass from caudate nucleus & putamen to Substantia globus pallidus. nigra. Gamma-aminobutyric acid (GABA) is the neurotransmitter. Some fibers use GABA as a neurotransmitter, and others use P.substance. 9  Found only in male’s slides Parkinson’s Disease ❏ Described by James Parkinson ❏ Degeneration of dopaminergic nigrostriatal neurons (60-80 %) ❏ Methyl-Phenyl-Tetrahydro-Pyridine (MPTP) ❏ The oxidant MPP+ is toxic to SN ❏ Four cardinal symptoms: Tremor, Rigidity, Akinesia & Bradykinesia, Postural Changes, Speech Changes Parkinsonism Parkinson’s disease, paralysis Agitans: Lesion Features Tremors Rigidity Akinesia Pill-rolling, It occurs in both it means lack of involuntary, flexors, and movement; Neuronal degeneration in rhythmic, extensors, but Absence of substantia nigra leading oscillating more in flexors swinging arm to reduction of dopamine movements. It giving flexion during walking within corpus striatum. occurs during rest attitude. mask fac4 it is called static It is called lead low- volume tremors. pipe rigidity. slow monotonous speech shuffling gait. Note: Parkinsonism doesn't mean Parkinson’s Disease, one of the causes of Parkinsonism is Parkinson’s Disease there are many other causes 10  Found only in male’s slides Differences between Parkinson's and Huntington's disease Huntington’s Disease : Parkinson’s Disease: Degeneration of inhibitory pathway from corpus Degeneration of inhibitory pathways from striatum to Substantia nigra. Substantia Nigra to corpus striatum Degeneration of striatum = loss of neurotransmitters, Degeneration of Substantia Nigra = loss of dopamine including GABA, acetylcholine and glutamate 11 Practice Q5: The two division of the globus pallidus are separated by? Q1: Lentiform and Caudate called: A. The medial medullary lamina A. Striatum. B. The lateral medullary lamina B. Neostriatum C. Lateral ventricle C. Corpus striatum D. pars reticulata D. Amygdaloid Q6: what is the input region of corpus striatum? Q2: putamen is Separated from globus pallidus by a thin sheath of nerve fibers called A.internal capsule A. lentiform B. lateral medullary lamina B. Caudate and putamen C. medial medullary lamina C. Putamen only D. Cerebral cortex D. Globus pallidus Q3: The head of caudate nuclei lies anterior to Q7: Which of these is NOT a symptom of Parkinson's Disease? A. Sub thalamus A. Akinesia B. Amygdaloid nucleus B. Rigidity C. Lentiform C. Chorea D. Thalamus D. Bradykinesia Q4: what is the oldest part of corpus striatum? Q8 : One of the major output for basal ganglia is? A. Putamen A. medial segment Globus Pallidus B. Globus pallidus B. Lentiform and Caudate C. Caudate nucleus C. Caudate and globus pallidus D. Amygdala D. Caudate and putamen Answers: Q1(C) Q2(B) Q3(D) Q4(B) Q5(A) Q6(B) Q7(C) Q8(A) 12  Members board Team leaders Abdulrahman Shadid Ateen Almutairi Girls team : Boys team: Ajeed Al Rashoud Mohammed Al-huqbani Taif Alotaibi Salman Alagla Noura Al Turki Ziyad Al-jofan Amirah Al-Zahrani Ali Aldawood Alhanouf Al-haluli Khalid Nagshabandi Sara Al-Abdulkarem Omar Alammari Renad Al Haqbani Sameh nuser Nouf Al Humaidhi Abdullah Basamh Jude Al Khalifah Alwaleed Alsaleh Nouf Al Hussaini Mohaned Makkawi Rahaf Al Shabri Abdullah Alghamdi Danah Al Halees Rema Al Mutawa Amirah Al Dakhilallah Maha Al Nahdi Contact us: Razan Al zohaifi Ghalia Alnufaei Editing file most probably you don't need this