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Motor Systems Basal Ganglia
Basal Ganglia I
16
Anatomy
Professional
03/26/2011

Additional Anatomy Flashcards

 


 

Cards

Term

 

 

 

Basal Ganglia

Definition

CAUDATE  NU

PUTAMEN

GLOBUS PALLIDUS

AMYGDALA

CLAUSTRUM

Term

 

 

 

Blood Supply: Corpus Striatum

Definition

 

Medial

&

 Lateral Striate

Arteries

Term

 

 

 

Blood Supply: Subthalamus 

Definition

 

 

 

Posteromedial

Arteries

Term

 

 

 

Blood Supply: Substantia Nigra

Definition

 

Posteromedial

 

Posterolateral

 

Ant. Choroidal

Arteries

Term

 

 

 

Motor System: Functions

Definition

Planning, Initiation, Facilitation, and

Suppression of Movement


CAUDATE NU

PUTAMEN

GLOBUS PALLIDUS

Term

 

 

 

Limbic System: Functions

Definition

Mood,  Motivation,  and  Behavior

 

NU ACCUMBENS

AMYGDALA

Term

 

 

 

Basal Ganglia Mechanisms and Concepts

Definition

-No Descending Pathways to

  lower motor neurons

- Connections:

  Basal ganglia connect with

  the cerebral cortex on same

  (ipsilateral) side

- Feedback Circuits: Basal

  ganglia neurons fire

  continually during movement

- Feedforward Circuits: Basal

  ganglia neurons fire prior to

  the upper motor neuron

- Suppression of Movement:

  mediated via striatum and

  subthalamus


- Facilitation of Movement:

  mediated via striatum and

  substantia nigra (dopamine)

Term

 

 

 

Input to Basal Ganglia

Definition

INPUT :Planning & Initiation

 of movement (Glutamate)

Term

 

 

 

Striatum: Mechanisms and Concepts

Definition

Striatum: sporadically active.

Interneurons (Ach) modulate

and suppress dopamine activity.

 

Striatal Output:

 

I = Indirect Pathway suppresses

movement (GABA-Enkephalin)

 

D = Direct Pathway facilitates

      movement (GABA-

      Substance P)

Term

 

 

 

 

Dopamine from substantia nigra ALWAYS

Definition

Dopamine from substantia nigra ALWAYS facilitates movement.

It is excitatory to the striatal Direct Pathway and is inhibitory to the Indirect Pathway.

Term

 

 

 

Basal Ganglia Output

Definition

Basal Ganglia Output:

Medial Globus Pallidus

Inhibits(GABA) movement

and is tonically active.


During movement 20% of

neurons decrease activity;

80% increase activity to inhibit

competing movements.


OUTPUT: Excitation to

upper motor neurons

allowing movement

     (Glutamate)

 

Term




BASAL GANGLIA

 &

 CEREBELLAR

CIRCUITRY  SIMILARITIES

Definition

- Neither  Basal Ganglia nor the

  Cerebellum have any direct

  connections with Lower Motor Neurons. 

 

 - Both Basal Ganglia & Cerebellum

   receive fibers from widespread areas

   of cortex


- Both Basal Ganglia & Cerebellum

   converge on Motor areas of Frontal

   Lobe  via Dorsal Thalamus to

   modulate the Upper Motor Neuron


- Both function as  Feedforward as

   well as Feedback  systems


- Both work in concert to control the

  same Upper Motor Neurons


- GABA inhibition is prevalent in both

   systems

 

Term




HYPOKINESIA

Definition

HYPOKINESIA  =  Movement ↓ Tone↑


Akinesia  =  Absence of movement; Impaired initiation of movement or stopping movement


Bradykinesia  =  Reduced velocity and amplitude of movement


DOPAMINE   <  GABA + ACETYLCHOLINE

 

 

 

Term

 

 

 

Hyperkinesia 

Definition

Hyperkinesia= Movement ↑ Tone ↓


*Note:  Involuntary movements are ARAS dependent and disappear when asleep.

            

Unilateral lesions affect  Contralateral side of body.


DOPAMINE   >  GABA + ACETYLCHOLINE

 

Term

 

 

 

Disorders: Involuntary Movements

Definition

TREMOR   =    Rhythmic oscillatory movement

 

ATHETOID  =  Slow, twisting movements of distal muscles

 

CHOREIFORM  =  Brisk, fast, dance-like

 

BALLISTIC  =  Fast, flailing (flinging) and rotatory movement of proximal extremities

 

DYSTONIA  =  Sustained or repetitive muscular contraction or cramping often resulting in joint distortions

 

* TIC  =  Brief, abrupt spasmodic twitching and other stereotyped movements.

 

* AKATHISIA  =   Movements acted out by an inner feeling for the need  to move.  Often induced by antipsychotic medications

 

 MYOCLONUS  =  Lightning like intermittent muscle jerks (origin unknown)

Term

 

 

 

Parkinson's Disease

Definition

PARKINSONISM  or Paralysis Agitans (“The Shaking Palsy”) is characterized by akinesia,

bradykinesia, festination, resting tremor, rigidity, impaired postural (vestibular)  reflexes as

well as cognitive and emotional disorders.

 

 AKINESIA = difficulty initiating or stopping movement

 

 BRADYKINESIA = slow movement with decreased amplitude and velocity

 

 TREMOR AT REST = Tremor of 3 to 5 CPS involving fingers, wrist, lips, or head RIGIDITY =  Resistance to stretch throughout the range of motion characterized by hypertonia of all muscles, agonists and antagonists, throughout the body.  


-LEAD PIPE (PLASTIC) RIGIDITY = Increased resistance to passive movement throughout the
-range of motion


-COGWHEEL RIGIDITY = Resistance to passive movement suddenly gives way then quickly

  returns and the sequence is repeated like a cogwheel ratchet. Tremor is superimposed on

  rigidity.

 

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