Coordination.br

8/11/2019 Coordination.br

1/14

COORDINATION

DR.FITRI


2/14


3/14

Anatomy

Occupies most of the posterior cranial fossa

Dorsal to the brainstem and attached to it by cerebellar

peduncles :

Superior cerebellar peduncle (Brachium conjunctivum)midbrain

Middle cerebellar peduncle (Brachium pontis)pons

Inferior cerebellar peduncle (restiform body)medulla oblongata

Other relationship :

The fourth ventricle

Tentorium cerebelli


4/14

Anatomy (ctnd)

Composition Cerebellar hemispheres

Vermis : cortex and medulla (incl. Nuclei)

Lobes

Anterior lobe (palaocerebellum) C/o most of the vermis and anterior aspect of hemispheres

Associated with proprioceptive (spinecerebellar) and exteroceptive input

Significant role in regulation of muscle tone (maintain posture)

Posterior lobe (neocerebellum)

The largest part; c/o main bulk of hemisphere and part of vermis

Receive connections of cerebrum through nuclei & brachium pontis

Role in muscular coordiantion of phasic movement

Flocculonodular lobe (archicerebellum)

C/o paired flocculi of hemispheres and unpaired nodulus

Cerebellar portion of vestibular system (somatic afferent collumn)

Significant role in muscle tone, equilibrium, and posture (trunk muscles)


5/14


6/14

Anatomy (ctnd)

Cerebellar cortex (ctnd)

Cell and Nerve types

Granule cells, Purkinje cells, Basket cells, Golgi cells

Mossy fibers

Primary cerebellar input from pontine nuclei andspinocerebellar pathways

Function : to excite the granule cell

Climbing fibers (Cf)

Its cell bodies located in the inferior olivary nucleus Synapse with primary and secondary dendritic branches of

Purkinje cells at many sites

each action potential in Cf cause a giant EPSP

a burst of repetitive Purkinje cell firing


7/14

Anatomy (ctnd)

Subcortical cerebellar nuclei

Dentate nuclei

Emboliform nuclei*

Globose nuclei

Fastigial nuclei*

Relationship of cerebellar cortex and subcortical nuclei

Lateral areas of cortex to dentate nuclei

Paramedian areas to emboliform and globose nuclei

Median area (vermis) to globose and fastigial nuclei

* The emboliform and globose nuclei are collectively called the nucleusinterpositus


8/14

Anatomy (ctnd)

Cerebellar connectionsAll fibers carrying information to and from cerebellum do so by way

of the cerebellar peduncles

Incoming (afferent) fibers

Superior cerebellar peduncle : anterior spinocerebellar tract (paleo-),tectocerebellar tract (midbrain tectum to neocerebellum),trigeminocerebellar tract

Medial cerebellar peduncle (entirely afferent!!) : corticopontocerebellartract

!! Each cerebellar hemisphere monitors the activity of the oppositecerebral hemisphere

Inferior cerebellar peduncle : conveys unconscious exteroceptive andproprioceptive fibers from the spinal cord and vestibular system :

Dosrsal spinocerebellar (to paleo-)

Vestibulocerebellar (to archi- of the same and opposte sides)


9/14

Anatomy (ctnd)

Cerebellar connections

Outgoing (efferent) fibers : No direct cerebellospinal pathways exist !!

Superior cerebellar peduncle : primarily c/o the efferent fibers from

dentate (-rubral, -thalamic,-reticular), emboliform and globose nuclei

(the last two project to red nucleus, inferior olive, reticular formation)

Medial cerebellar peduncle : No efferent fibers

Inferior cerebellar peduncle :

Through juxtarestiform bodyFastigiobulbar tract (fastigial nuclei to

vestibular and reticular nuclei


10/14

Physiology

Normal cerebellar function

Responsible for muscle synergy (coordination) throughout thebody

Coordinates the action od muscles and times their contraction

movement smoothly and accurately

As a monitor of other center of the brain (not the iniator!)

The modulator (regulator) of motor activities; integrated with :

Vestibular system (maintain muscle tone and equilibrium)

General proprioceptive and exteroceptive receptors

Auditory and visual system

Basically a somatic afferent organ !!


11/14

Cerebellar Disorder

Neocerebellum Dysmetriainability to stop the movement at the desired point

(overshoots or stops before it is reached)

Intention tremorevident during purposeful movement, butabsent/diminished with rest. Titubation : rhytmic tremor iof the head,

3-4x/minute- lesion in the midline of cerebellum Postural disturbance

A/dysdiadochokinesis - inability to stop a movement and follow itimmediately by directly opposite action

Hypotoniaipsilateral to the lesion site; loss of cerebellar facilitation

to the stretch reflex Eye disturbance : skew deviation and nystagmus (also occurred in

vestibular lesion and its connections)

Disturbance of articulation and phonation : scanning speech/stacatto

Gait disturbance : cerebellar ataxia (tend to fall to the lesion site)


12/14

Cerebellar Disorder

Paleocerebellum

Symptoms and signs of postural and muscle tone

disrturbance

Archicerebellum Truncal ataxia (swaying while sitting)

Vertigo


13/14

Examination of coordination

Equilibratory coordination - maintanance of balance andthe coordination of the body as a whole; examination ofstation and gait

Truncal ataxia, titubation

Romberg sign, Walk tandem

Non-equilibratory coordinationability to carry outdiscrete, relatively fine, intentional movement withextremities.

Dysmetria, Dysdiadochokinesia

Nose-to-finger test, finger-to-finger test, heel-to-knee-to-toetest

Rebound test, test pointing and past pointing

Functional test : button-unbuttoning, writing, picking coin atdesk


14/14

Documents

Coordination.br