Lecture 11 Flashcards
What structure is being described here?
Plays major roles in the timing of motor activities and in rapid, smooth progression from one muscle movement to the next
It is nonessential to locomotion (although locomotion without the cerebellum is highly abnormal) but it helps to sequence motor activities
It helps by making corrective adjustments to motor activities while they are being executed
Compares actual movements with intended movements
Aids cortex in planning the next sequential movement
Learns from it’s mistakes
The Cerebellum
Identify the three lobes of the cerebellum.
Anterior Lobe
Posterior Lobe
Flocculonodular Lobe (which is associated with the vestibular system)
What and where is the vermis; with what functions is it associated?
The vermis is located in the medial portion of the cerebellum
It is associated with control functions for muscle movements of the axial body/Neck/Shoulders/Hips
List the four pairs of deep cerebellar nuclei and relate lesions to their normal function.
Dentate, Emboliform, and Globose nuclei (all have the same functions that are related to limb musculature and fine manipulative movement)
Lesions in these nuclei result in extremity ataxia
Fastigial Nuclei functions are related to postural activity and limb movements via reticulospinal and vestibulospinal tracts
Lesions in these nuclei will result in trunk ataxia
List the 4 cell types that make up the cerebellar cortex and describe their circuitry. (project from where and end where?)
Granular Cells: axons form parallel fibers in the cortex (+)
Golgi Cells: project from parallel fibers to granular cell bodies (-)
Basket Cells: project from parallel fibers to Purkinje axon hillock (-)
Stellate Cells: project form parallel fibers to Purkinje dendrites (-)
Describe the functional unit of the cerebellum in terms of what each unit is centered around, what it corresponds to and where it’s output is.
Each functional unit is centered on a purkinje cell and a corresponding deep nuclear cell
The output of a functional unit is from a deep nuclear cell and it’s afferent inputs to the cerebellum are mainly from the climbing and mossy fibers
How does removal of the cerebellum affect movements of the body?
They become abnormal due to the lack of cerebellar modulation
Which afferent tracts of the cerebellum form the mossy fibers? (3 of them)
Mossy Fibers: originate from multiple centers in the brainstem and spinal cord
including vestibulocerebellar, spinocerebellar, and pontocerebellar tracts
The following describes which clinical abnormality?
When the brain overcompensates in the opposite direction for the succeeding compensatory movement
Dysmetria
The following describes which clinical abnormality?
Uncoordinated movements
Ataxia
The following describes which clinical abnormality?
When a person, attempting to point in one location, overshoots (or goes “past”) the intended location
Past pointing
The following describes which clinical abnormality?
Rapidly losing all perception of the instantaneous position of the hand during the attempt to “flip from palmar to dorsal” on alternating hands”. This results in a serious of stalled but attempted jumbled movements.
Dysdiadochokinesia
The following describes which clinical abnormality?
Jumbled vocalization with syllables held for too long, too short, too loud, or too weak. Caused from lack of control of the individual muscle movements int he larynx that are required to speak normally.
Dysarthria
The following describes which clinical abnormality?
The tremor of the eyeballs that occurs usually when one attempts to fixate the yes on a scene to one side of the head.
Cerebellar Nystagmus
The following describes which clinical abnormality?
Decreased tone of musculature
Hypotonia
