Cerebellum

Question 1

What does heuristic mean?

Answer 1

Simpler, designed for someone to discover something

Question 2

What is the basic function of the cerebellum?

Answer 2

It calibrates reflexes

Question 3

There are two inputs for the cerebellum. What are they and what do they do?

Answer 3

The sensory inputs (such as vestibular, ocular, etc.), which provide the initial reflex, and the inferior olivary nuclei input, which registers unexpected results and sends modulating action potentials.

“The short loop is modulated by the long loop.”

Question 4

The deep cerebellar nuclei are the __________ centers.

Answer 4

output (they receive the processed information from the cerebellar cortex and send axons to the brainstem and elsewhere)

Question 5

The flocculonodular lobe is __________ to the anterior lobe.

Answer 5

caudal

Question 6

Which part of the cerebellum is connected to the vestibular system?

Answer 6

The archicerebellum (aka the flocculonodular lobe); it is also called the vestibulocerebellum

Question 7

The deep cerebellar nuclei are in the same horizontal plane as the ______________.

Answer 7

MCP

Question 8

From outside to inside, what are the layers of the cerebellum?

Answer 8

Molecular layer
Purkinje layer
Granule layer (recall that the granule layer starts out external, but by the time you’re a toddler, the cells have migrated internally)
White matter

Question 9

What fibers cross between the flat, nearly two-dimensional purkinje cells?

Answer 9

Parallel fibers

Question 10

Describe the differences between climbing fibers and parallel fibers in terms of how they interact with purkinje cells.

Answer 10

Parallel fibers only touch a small portion of the purkinje cell –though they synapse with many different cells – whereas climbing fibers wrap around purkinje cells and make many points of contact with an individual cell. As such, climbing cells can more easily generate an action potential in purkinje fibers.

Question 11

Simultaneous input from inferior olivary nucleus axons and mossy fibers leads to _____________.

Answer 11

long-term depression; this leads to plasticity and modulation of the relevant reflex

Question 12

The ______ and ________ carry the main inputs to the cerebellum, while the ________ carries the main output.

Answer 12

ICP; MCP; SCP

Question 13

The _________ lobe of the cerebellum is the most recent and is also called the neocerebellum.

Answer 13

posterior; it is also called the corticocerebellum

Question 14

The paleocerebellum is also called the ____________.

Answer 14

anterior lobe or spinocerebellum

Question 15

In cross sections, one observes that the cerebellum consists of ______________.

Answer 15

a three-layered cortex surrounding two deep nuclei

Question 16

There are four nuclei in the cerebellum: ___________.

Answer 16

dentate; globose; emboliform; and fastigial

Question 17

The corticocerebellum projects to the ________ nuclei.

Answer 17

dentate

Question 18

Efferents from the vermis project to the _________ nuclei.

Answer 18

fastigial

Question 19

The paravermis efferents project to the _________ nuclei.

Answer 19

globose and emboliform (together called the interpositus)

Question 20

Efferents from the flocculo-nodular lobe project to the ______________.

Answer 20

vestibular nuclei (afferents also pass back this way)

Question 21

All of the cerebellar lobes receive innervation from the _______________.

Answer 21

contralateral inferior olivary nucleus

Question 22

The vermal zone controls ___________.

Answer 22

axial movements (like posture) and integration of head and eye movements

Question 23

The paravermal zones control ____________.

Answer 23

fine-tuning of the limbs

Question 24

The lateral lobes control _________________.

Answer 24

higher order movements of limbs such as initiation and planning

Question 25

There is no somatotopic map in the _____________.

Answer 25

lateral lobes

Question 26

There is a somatotopic map for ___________ information.

Answer 26

afferent (upside-down guy in the vermal/paravermal area)

Question 27

Information from the cerebrum synapses on _______ nuclei before crossing.

Answer 27

basal pons

Question 28

The paravermal regions send output to the _____________.

Answer 28

red nuclei (for control of distal limbs)

Question 29

Ultimately, the flocculo-nodular lobe controls ____________.

Answer 29

axial muscles (to coordinate vestibular information with posture) and the vestibular reflex

Question 30

Ultimately, the vermal zones control __________.

Answer 30

axial muscles (locomotion and gaze)

Question 31

Cerebellar deficits are always _______________.

Answer 31

ipsilateral

Question 32

Cerebellar deficits do not affect ______________.

Answer 32

sensation or muscle strength

Question 33

What is dysmetria?

Answer 33

Past-pointing (the inability to put a limb in a desired location)

Question 34

What is the HANDS Tremor mnemonic for cerebellar lesions?

Answer 34

Hypotonia
Ataxia
Nystagmus
Dysarthria
Stance/gait problems 

Tremor (with intention)

Question 35

How many granule cells are there?

Answer 35

10^11!! (more than the entire cerebral cortex)

Question 36

Differentiate climbing fibers and mossy fibers.

Answer 36

Climbing fibers come from the inferior olivary nuclei

Mossy fibers come from everywhere else

Question 37

Explain the pathway by which mossy fibers excite purkinje cells.

Answer 37

Mossy fibers connect to many granule cells and excite them. Granule cells then excite purkinje cells via parallel fibers.

Question 38

Each purkinje is contacted by __________ parallel fibers and ____________ climbing fiber(s).

Answer 38

~200,000; 1

Question 39

How does purkinje cell activation affect the deep nuclei?

Answer 39

It inhibits them. “The cerebellum acts as an inhibitory delay loop, with a presumed action in shaping the timing of descending motor commands.”

Question 40

The only output from the cerebellar cortex is via the ____________ cells.

Answer 40

purkinje

Question 41

Simple spikes in purkinje arise from ____________ fibers.

Answer 41

mossy

Question 42

Complex spikes occur when ______________.

Answer 42

a stimulus does not match the expected outcome (i.e., the firing of inferior olivary nucleus climbing fibers)

Question 43

Climbing fiber input leads to ____________.

Answer 43

calcium entry

Question 44

The combination of mossy fiber and climbing fiber stimulus leads to ______________.

Answer 44

long-term depression

Question 45

What separates the flocculonodular lobe from the rest of the cerebellum?

Answer 45

The posterolateral fissure

Question 46

The cerebrocerebellum receives innervation from the ___________.

Answer 46

pons (but originally from the cerebrum)

Question 47

Axons from the inferior olivary nucleus cross the midline ___________ and proceed through the ___________.

Answer 47

immediately; inferior cerebellar peduncle

Question 48

Clarke’s column relays _______________.

Answer 48

proprioceptive information from the lower extremities

Question 49

Axons from the SCP cross the midline ____________ and then synapse on the _______________.

Answer 49

in the brainstem; red nucleus

Question 50

The pontine nuclei receive innervation from the ___________ cerebral cortex and project to the ______________ cerebellum.

Answer 50

ipsilateral; contralateral

Question 51

In the upper midbrain, what do the SCP look like?

Answer 51

Mickey’s eyes!

Question 52

The VA/VL are ______________.

Answer 52

ventral anterior nucleus of the thalamus; ventral lateral nucleus of the thalamus

Question 53

The subthalamic nuclei are ____________ to the mammillary bodies.

Answer 53

superior and lateral

Question 54

The VA/VL are __________ to the subthalamic nuclei.

Answer 54

superior