Neuroanat Knowt 3

Describe where the cerebellum is

It is at the caudal base of the brainstem, caudal to the 4th ventricle and the foramen of Magendie, but superior to the Cisterna magna and foramen magnum

The cerebellum has an important role in: _____, but ALSO has a role in: ______.

Important role in: motor control and coordination, but also Important in: cognition and emotion.

Describe the vermis location wise

It is the central column of the cerebellum/midline of the structure extending down several lobes, but stops before the nodulus

The vermis is involved in coordination of:

Vermis is involved in the coordination of axial (trunc) and proximal muscles…. especially important in posture and gait (rhythm of walking/running)

Describe the “cerebellar hemispheres” anatomically

They are locations like the vermis, but they are lateral to the vermis. They are divided into the paravermi and the lateral hemispheres (one on each side of the vermis)

What would the paravermi regions of the cerebellum be most associated with functionally?

Coordination of distal muscles

What would the lateral vermi be most associated with functionally?

They are connected with the cerebral cortex, so planning and timing of movements

Which region(s) of the cerebellum are connected with the cerebral cortex?

The lateral vermis of the cerebellum

Let’s say we know a person has a cerebellar injury, and their symptom is that they are having trouble typing on their keyboard… what part of the cerebellum is likely injured?

The paravermis, since it’s involved with distal muscles

Let’s say we know a person has a cerebellar injury, and their symptom is that they are having deficits in learning/coordination…. what part of the cerebellum is likely injured?

The lateral vermis

The primary fissure of the cerebellum separates what ?

It separates the anterior and posterior lobes, running through the vermi/hemispheres.

The anterior lobe of the cerebellum is also called the: _______ because ________

Anterior lobe aka: spino-cerebellum, bc it regulates body posture and limb movements. With strong connectivity to the spinal chord

The posterior lobe of the cerebellum is also called the: _______ because ________

cerebro-cerebellum, because it is involved in fine-tuning movements, planning, and cognitive functions and has strong connectivity with the cerebral cortex.

The most evolutionarily recent part of the cerebellum is the _________, while the most evolutionarily ancient part of the cerebellum is the ________

Most recent: posterior lobe (cerebro-cerebellum), Most ancient: flocculo-nodular lobe (vestibulo-cerebellum)

We hav ethe anterior lobe and the posterior lobes of the cerebellum.. what is the third and last lobe?

The flocculo-nodular lobe

Say 3 things about the flocculo-nodular lobe of the cerebellum

It is situated inferiorly, it has two parts (flocculus and nodulus), and it is involved in balance/strong connectivity with the vestibular system

What connects the cerebellum with the rest of the CNS?

3 large fiber bundles called the Cerebellar Peduncles

What are the 3 Cerebellar Peduncles?

1) Superior Cerebellar Peduncle

2) Middle Cerebellar Peduncle

3) Inferior Cerebellar Peduncle

The superior cerebellar peduncle is mainly a source of: ________. BUT it also has: __________.

It’s mainly a source of cerebellar output, or efferents to the midbrain/thalamus. But it also has 2 incoming tracts: the ventral spino-cerebellar tract, and the tecto-spino cerebellar tract (from superior/inferior colliculi of midbrain).

The middle cerebellar peduncle connects the: __________. Part of the : ______________________. Overall function:

Middle cereb peduncle connects the pontine nuclei to the cerebellum. It is part of the larger cortico-ponto-cerebellar system, which receives sensory information from cortical sources. Overall function: is that it likely associates movements with auditory and visual inputs.

4 important types of fibers enter the cerebellum through the inferior cerebellar peduncle… what are those 4 fibers?

1) Dorsal spino-cerebellar: proprioceptive input

2) Olivo-cerebellar : From inferior olivary nucleus of medulla (movement, info from spinal chord)

3) Reticulo-cerebellar: from Reticular formation to the vermis (reticulo-cerebellar tracts)

4) Vestibulo-cerebellar: from Vestibular nuclei

What are the 3 cellular layers with how the Cerebellum is organized?

The molecular layer first, then the purkinje cell layer, then the granular layer

What are the two ways in which ALL inputs are organized in the cerebellum?

1) Climbing fibers - arise from the superior olive, and ascend through the white matter, past the granule cells, and spiral around purkinje cells where they make numerous strong synapses

2) Mossy fibers - originate in the pons, and synapse onto the granule cells, and project into deep cerebellar nuclei

What is the one way in which all outputs are organized in the cerebellum?

Purkinje cell axons converge onto and inhibit cerebellar / vestibular nuclei

Where are the vestibular nuclei?

In the flocculo-nodular lobe

What are the 3 deep cerebellar nuclei?

1) Fastigial @ vermis - receives input from flocculo-nodular

2) Interposed nuclei - receives input from paravermis

3) Dentate - largest, and receives input from lateral cerebellar hemispheres

In the fastigial nucleus, its output runs through the : ___________ to influence:

inferior cerebellar peduncle to influence vestigial nuclei, RF, and trigeminal motor, oculomotor, abudcens, and facial nerve.

Interposed nuclei receive input from the ______ , and projects through the _______ to:

paravermis, superior cerebellar to the red nucleus, ventrolateral nucleus of the thalamus.

The dentate nucleus is a source of massive ______ relay to the _____, ________, and ____________.

motor relay tot eh midbrain, red nucleus, ventrolateral (VL) nucleus of the thalamus

What nucleus of the cerebellum is likely the largest source of influence on motor output?

dentate nucleus

What is Ataxia?

Ataxia is a lack of voluntary muscle coordination. It results in gait abnormality and clumsiness, in both truncal and appendicular muscles. Truncal ataxia: lack of coordination of central body parts (sitting upright) —> lesions in vermis. Appendicular ataxia: lack of coordination of limbs, problem with fine movements, and reaching —→ lesions in paravermis

What is the difference between spino-cerebellar ataxia (SCA) and ataxia telangieltasia (AT)

SCA is caused by genetic mutations leading to a loss of cells in cerebellum, while AT is neurodegenerative condition affecting nervous/immune system.