BASAL GANG

• Basal nuclei


  - Plays an important role in the control of posture and voluntary automatic movements and skilled volitional movements of the trunk and limbs, including eye movement

  - Applied to a collection of masses of gray matter situated within each cerebral hemisphere.

  - Involved in cognition, such as attention, memory, planning and acts with the limbic system to regulate emotional behavior

  - Made up of amygdaloid nucleus, and the claustrum.
• Cerebral cortex


  - Influences motor function directly through the corticospinal and corticobulbar pathways
• (+) of destruction in the motor cortex


  Will prevent individual from performing fine discrete movements of the hands and feet on opposite side of the body
• (+) destruction of corpus striatum


  Paralysis of movements on opposite side of the body
• CORPUS STRIATUM


  - Divided by a band of nerve fibers, the internal capsule, into the caudate nucleus and the lentiform nucleus.

  - Receives afferent information and are integrated from most of the cerebral cortex, thalamus, subthalamus, brainstem and basal ganglia
• Internal capsule


  - Thin sheet of white matter

  - Projection fibers at the upper part of the brainstem

  - Radiates its nerve fibers in all direction of cerebral cortex forming the "Corona radiata" and to the Calcarine sulcus known as "Optic radiation"
• Caudate nucleus


  C-shaped mass of gray matter that is closely related to the lateral ventricle and lies lateral to the thalamus.
• Head of the caudate nucleus


  Large and rounded and is continuous inferiorly with the putamen of the lentiform nucleus.
• Body of the caudate nucleus


  Long and narrow and is continuous with the head in the region of the interventricular foramen.
• Tail of the caudate nucleus


  Long and slender and is continuous with the body in the region of the posterior end of the thalamus.
• NEOSTRIATUM


  - Constitute the major site of input to the basal ganglia
• Lentiform nucleus


  - Wedge-shaped mass of gray matter whose broad convex base is directed laterally and whose blade is directed medially.

  - Separated from the Claustrum via the EXTERNAL CAPSULE
• GLOBUS PALLIDUS


  - A major outflow nucleus of the basal ganglia

  - Regulate muscle tone required for specific body movements - Plays a role in controlling the axial and girdle movements of the body and positioning of the proximal parts of the limbs
• PUTAMEN


  Activity of the putamen preceedes and anticipates body movement
• Claustrum


  - Separates the external capsule from the subcortical white matter of the insula.

  - Receives all regions of cortex and projects it back

  - Has role in communication between the two hemispheres of the brain, specifically between cortical regions controlling attention

  - thin sheet of gray matter that is separated from the lateral surface of the lentiform nucleus by the external capsule
• AMYGDALOID NUCLEUS


  - Situated in the temporal lobe close to the uncus.

  - Influence body's response to environmental changes

  - considered to be part of the limbic system so it also sense fear, change in heart rate, BP, skin color and rate of respiration

  - Binge drinking, being damaged by repeated episodes of intoxication (such as Alcoholism) and withdrawal.
• KLUVER BUCY SYNDROME


  Increased sexual activity, increase appetite, restlessness, emotional instability and with no evidence of fear or anger
• Substantia nigra


  - Dopaminergic and inhibitory and have many connections to the corpus striatum.

  - Concerned with muscle tone, connected to cerebral cortex, spinal cord, hypothalamus and basal ganglia
• Subthalamic nuclei


  - Glutaminergic and excitatory and have many connections to the globus pallidus and substantia nigra.

  - Receives input from the striatum and cerebral cortex, and projects to the globus pallidus
• CORTICOSTRIATE FIBERS


  Release neurotransmitter: Glutamate
• THALAMOSTRIATE FIBERS


  Sends large number of axons to the caudate nucleus and putamen
• NIGOSTRIATE FIBERS


  Sends axons to the caudate nucleus and putamen; Neurotransmitter: Dopamine
• STRIATOPALLIDAL FIBERS


  Release neurotransmitter: GABA
• STRIATONIGRAL FIBERS


  Release neurotransmitter: GABA, acetylcholine and substance P
• Caudate nucleus and the putamen


  Form the main sites for receiving input to the basal nuclei.
• Globus pallidus


  forms the major site from which the output leaves the basal nuclei.
• Corpus Striatum Afferent Fibers

  Projections to the corpus striatum include corticostriate, thalamostriate, nigrostriatal, and brainstem striatal fibers
• Glutamate


  Neurotransmitter of the corticostriate fibers
• Akinesia


  Disorder of initiation of movement
• CHOREA


  Exhibits involuntary quick, rapid jerky irregular movements of the proximal limbs that are non-repetitive from degeneration of caudate and putamen
• ATHETOSIS


  Slow, writhing, worm like movements with fluctuations in muscle tone usually at the distal segments of the limb from central cortex and globus pallidus involvement
• HEMIBALLISMUS


  Wild, flinging, violent motions due to lesions of the subthalamic nucleus
• DYSTONIA


  Involuntary, twisting sustained movements/muscle contractions resulting in abnormal movements or sustained postures
• PARKINSON'S DISEASE


  Most common degenerative disease involving the basal ganglia due to degeneration of substantia nigra resulting to decrease dopamine
• Bradykinesia


  - slowness of movement
• Rigidity


  Increase resistance to passive motion
• Resting tremor


  Contraction of the agonist & antagonistic muscles during rest characterized by pill rolling of the hand
• SYNDENHAMS CHOREA (a.k.a. St. Vitus Dance)


  Caused by streptococcal bacteria characterized by rapid, uncoordinated jerky movts. primarily affecting face, hands and feet
• HUNTINGTON'S DISEASE


  -Affects the corpus striatum that decreases GABA inhibition

  - characterized by abrupt, clumsy & jerky, irregular choreiform and impaired voluntary movements