BASAL GANGLIA Flashcards by KIRK IBARRA

Collection of gray matter nuclei located deep within the cerebral white matter

BASAL GANGLIA

How well did you know this?

Not at all

Perfectly

Main 5 Components that participate in regulation of movement:

Caudate nucleus
Putamen
Globus pallidus (GP)
Subthalamic nucleus (STN)
Nucleus accumbens

How well did you know this?

Not at all

Perfectly

Nucleus Accumbens parts

Ventral Striatum
Similar embryonic development and input/output connections
Limbic system

How well did you know this?

Not at all

Perfectly

Other parts involved: amygdaloid nuclear complex (limbic system) and claustrum

Amygdaloid nuclear complex - does not participate in the modulation of movement as well as claustrum; only included d/t its location (on tail of caudate) and Claustrum (on side of basal ganglia)

How well did you know this?

Not at all

Perfectly

Primary Components of Basal Ganglia

Caudate
Putamen
Globus Pallidus
Subthalamic nucleus (nucleus of Luys)
Substantia nigra is divided into
reticula and compacta
Globus pallidus = aka paleostriatum or pallidum

How well did you know this?

Not at all

Perfectly

Neostriatum

Caudate & Putamen

How well did you know this?

Not at all

Perfectly

Lentiform Nucleus

Putamen & Globus Pallidus (more medial)

How well did you know this?

Not at all

Perfectly

Corpus Striatum

Caudate, Putamen, Globus Pallidus

How well did you know this?

Not at all

Perfectly

HORIZONTAL SECTION FROM LATERAL TO MEDIAL

INSULA
EXTRE CAP (extreme capsule)
CLAUSTRUM
EXTER CAP (external capsule)
PUTAMEN
EXTER ML ( external medullary lamina)
GPe (globus pallidus externa)
INTER ML (internal medullary)
GPi (globus pallidus interna)
INTER CAP (internal capsule)

How well did you know this?

Not at all

Perfectly

Elongated arched gray cellular mass related throughout its extent to the lateral ventricle
C-shaped

CAUDATE NUCLEUS

How well did you know this?

Not at all

Perfectly

Most lateral part of the corpus striatum
Darker and larger

PUTAMEN

How well did you know this?

Not at all

Perfectly

Wedge shaped with apex directed medially
Kind of cone shaped
Broad convex base is directed laterally

LENTIFORM NUCLEUS

How well did you know this?

Not at all

Perfectly

C-shaped
Lies lateral to the thalamus

CAUDATE NUCLEUS

How well did you know this?

Not at all

Perfectly

Outer putamen, inner globus pallidus
Between the internal and external capsule

LENTIFORM NUCLEUS

How well did you know this?

Not at all

Perfectly

Between the external capsule and the lateral medullary lamina of the globus pallidus

PUTAMEN

How well did you know this?

Not at all

Perfectly

Lateral surface is related to internal capsule which separates it from lentiform nucleus

CAUDATE NUCLEUS

How well did you know this?

Not at all

Perfectly

Related medially to internal capsule
Related laterally to external capsule which separates it from claustrum

LENTIFORM NUCLEUS

How well did you know this?

Not at all

Perfectly

Rostral part is continuous ventromedial with the head of the caudate

PUTAMEN

How well did you know this?

Not at all

Perfectly

enlarged, protrudes into anterior horn of lateral ventricle (part of caudate nucleus)

Head

How well did you know this?

Not at all

Perfectly

follows the curvature of the inferior horn of lateral ventricle and enters the temporal lobe; terminates in the region of the amygdaloid complex
(part of caudate nucleus )

Tail

How well did you know this?

Not at all

Perfectly

dorsolateral to the thalamus near the lateral wall of the lateral ventricle (part of caudate nucleus )

Body

How well did you know this?

Not at all

Perfectly

What separates 2 segments of globus pallidus (interna/externa)

medial / internal medullary lamina

How well did you know this?

Not at all

Perfectly

Receives inputs to basal ganglia

STRIATUM

How well did you know this?

Not at all

Perfectly

Lateral to the thalamus

CORPUS STRIATUM

How well did you know this?

Not at all

Perfectly

Most medial part of the lentiform nucleus Lighter, inner portion

GLOBUS PALLIDUS

CORPUS STRIATUM: Almost completely divided by __________ into: Caudate nucleus Lentiform nucleus

Internal Capsule

High concentration of myelinated fibers Diencephalic origin

GLOBUS PALLIDUS

Anteriorly and ventrally, putamen is fused with head of the caudate

ventral striatum

Caudate and putamen separated by internal capsule but remain joined in some places by cellular bridges

STRIATUM

Stripes or striations

STRIATUM

part of anterior part of striatum (ventral striatum)

Nucleus accumbens

Dorsal to the crus cerebri (found in midbrain)

SUBSTANTIA NIGRA

NEURO TRANSMITTER of Substantia Nigra

Dopamine

lies Under the thalamus Spindle- or cigar-shaped

SUBTHALAMIC NUCLEUS

Ventral portion Cells are similar to cells of globus pallidus interna (GPi) Bc it is close to GPi Separated by internal capsule from GPi

Substantia nigra pars reticulata

Dorsal secretes Darkly pigmented dopaminergic neurons

Substantia nigra pars compacta

Main input/receptive site of basal ganglia

striatum (caudate, putamen) motor, mainly goes to putamen

Main output site of basal ganglia

GPi and substantia nigra pars reticulata

Excitatory NT

Glutamate

Other input sources of basal ganglia

Intralaminar nuclei of thalamus (mainly centromedian and parafascicular nuclei) - released (+) glutamate Raphe nuclei serotonin in reticular formation releases serotonin

Inhibitory NT

GABA

Where does GPi and SNPR sends their axons ?

Thalamus

associated with motor output of the rest of the body

GPi

leads and necessitates output

Substantia nigra pars reticulata

GPi and SNPR both releases

GABA

All the outputs are sent to

ventral lateral (VL) and ventral anterior (VA) of thalamus via thalamic fasciculus

Anterior part of thalamic fasciculus send out to:

anterior portion of VL (VL pars oralis)

Posterior part of thalamic fasciculus send out to:

posterior portion of VL (VL pars caudalis) from cerebellum

Thalamus convey information from basal ganglia to entire....

frontal lobe especially premotor cortex, supplementary motor area and primary motor cortex.

After outputs were sent to thalamus it goes to...

Intralaminar nuclei of thalamus (centromedian and parafascicular) project back to striatum Mediodorsal nucleus - limbic pathways To pontomedullary reticular formation influencing reticulospinal tract To superior colliculus - influencing tectospinal tract

from striatum directly to GPi or substantia nigra pars reticulata

Direct pathway

striatum to GPe to STN to GPI

Indirect pathway

The net effect of direct pathway

excitatory which facilitates movement in targeted muscles/ wanted movements

Indirect pathway and Hyperdirect pathway

Inhibitory = inhibition of unwanted movement

Net effect of both pathway

Coordinated, smooth movement

Activates ST directly from motor cortex without intervening striatum Inhibitory

Hyperdirect pathway

Rom cortex to subthalamic nucleus to striatum STN releases glutamate to GPi and SNR which will stimulate cortex

Hyperdirect pathway

excitatory; stimulates adenyl cyclase; stimulates the direct pathway

D1 receptor

inhibitory; inhibits the indirect pathway

D2 receptor

TRIAD for parkinson's disease

Bradykinesia, Rigidity and Rest Tremor

Dopamine-containing neurons in substantia nigra pars compacta degenerate

Parkinson's Disease

Increase inhibition of thalamic nuclei and reduce excitation of cortical motor system

Parkinson's Disease

Degeneration of striatal neurons Indirect pathway is more severely affected

Huntington's Disease

Regulation of eye movements

Oculomotor Channel (VA, MD)

Limbic regulation of emotions and motivational drives

Limbic Channel (MD, VA)

“Brake and Switch” concept of movement

Motor Channel (VI, VA)

Passes slightly rostrally as it loops around the inferior medial edge of the internal capsule, and it then turns back towards the thalamus

Ansa lenticularis

Sweeps around the internal capsule

Ansa lenticularis

Traverse the internal capsule in a number of small fascicles and then continues medially and caudally to join the ansa in the prerubral field

Fasciculus lenticularis

Penetrate straight through the internal capsule

Fasciculus lenticularis

Looping course ventrally under the internal capsule before passing dorsally to thalamus

Ansa lenticularis

Then pass dorsal to the subthalamic nucleus and ventral to the zona incerta before turning superiorly and laterally to enter the thalamus

Fasciculus lenticularis

thalamic fasciculus

lenticular fasciculus that is dorsal to the subthalamic nucleus

carries fibers of the indirect pathway from GPe and STN, and from STN to GPi

Subthalamic fasciculus

region where the ansa lenticularis and lenticular fasciculus join together

H (prerubral field)

Brake

tonic inhibitory action preventing unwanted motor activity

Switch

select which of the available motor programs will be active at a given time

FUNCTIONAS OF BASAL GANGLIA

Acts as "brake or switch" Initiation, sequencing, modulation of motor activity (motor programming) Participate in constant priming of motor systems for rapid execution of motor acts without premeditation

corticospinal or upper motor neuron pathways (Type of movement disorder)

Pyramidal

from disorders of basal ganglia

Extrapyramidal

Unilateral movement disorders

Unilateral movement disorders because it crosses

Most obvious movement abnormalities cease during sleep except....

palatal myoclonus, periodic leg movement of sleep and some tics

Increased resistance to passive movement of the limb Matigas siya all throughout the movement Vs Spasticity - UMN lesion

RIGIDITY

more continuous throughout attempts to bend the limb

Lead pipe rigidity

ratchet-like interruptions in tone

Cogwheel rigidity

frontal lobe dysfunction actively resist movement of their limbs; more active, inconsistent or almost voluntary quality

Paratonia or gegenhalten

Assumes abnormal, often distorted positions of limbs, trunk or face that are more sustained or slower than athetosis

DYSTONIA

Generalized, unilateral or focal Focal - torticollis, blepharospasms, spasmodic dysphonia, writer's cramp Spasm of eyelids - blepharospasms Generalized - XDP XDP is generalized type

DYSTONIA

slow, writhing, twisting movements usually of the fingers and extremities (can also be seen on face, trunk) that sometimes merge with faster choreic movements (choreoathetosis)

Athetosis

"dance", characterized by nearly continuous involuntary movements that have a fluid or jerky, constantly varying quality

Chorea

Movement of the proximal limb muscles with large-amplitude or more rotatory flinging quality

BALLISMUS

unilateral flinging movements of extremities contralateral to the lesion in basal ganglia

Hemiballismus

leading to decreased pallidal inhibition of the thalamus

Subthalamic nucleus lesion

Becomes subtler choreoathetotic movements over days or weeks after infarct

BALLISMUS

Sudden brief action preceded by urge to perform it and is followed by a sense of relief Sequence of movements identical each time

TICS

more often face or neck, less often extremities

Motor tics

brief grunts, coughing, sounds, howling, barking or vocalizations (coprolalia - obscene words)

Vocal tics

persistent motor and vocal tics; most common

Tourette's syndrome

Fastest of all movement disorders Fastest type of motor problem Sudden, rapid muscular jerk Shock-like, lightning fast contractions of muscles or groups of muscles

MYOCLONUS

intermittent brief flexion movements of the wrists bilaterally as patient attempts to hold "stop the traffic" position; caused by brief interruptions in contraction of the wrist extensors = negative myoclonus; hepatic encephalopathy, other metabolic-toxic encephalopathies and other structural lesions of cerebello-thalamo-cortical circuits

Asterixis (flapping tumor)

Causes of myoclonus

anoxic brain injury, encephalitis, toxic/metabolic encephalopathies primary is brain injury

most prominent when limbs are relaxed, decreases or stops when patient moves their limbs

Resting tremor (3-5Hz)

most prominent when limbs are actively held in a position, disappears at rest

Postural tremor

familial, benign, or senile tremor Most commonly involves the hands or arms, can also affect jaw, tongue, lips, head, vocal cords and legs or trunk

Essential tremor (5-8 Hz)

No problem in basal ganglia

Physiological tremor (8-13 Hz)

occurs as patient attempts to move their limb toward a target and has irregular, oscillating movements in multiple planes throughout trajectory; cerebellar disorder

Intention tremor or ataxic tremor (2-4Hz)

low amplitude at rest but becomes more violet as limbs are abducted slightly or attempts are made to hold a position or perform a movement lesion in superior cerebellar peduncle or cerebellar circuitry

Rubral tremor (2-4 Hz)

marked psychomotor retardation in patients with schizophrenia or severe depression; not a basal ganglia lesion

CATATONIA

BASAL GANGLIA Flashcards

(110 cards)