Sensory Acquisition

Question 1

Where does the cerebellum arise from? Animal Example

Answer 1

Sensory columns of the neural tube. Cyclostomes

Question 2

Paulin: Fish

Answer 2

CBM lesion experiments contradictory evidence for role in movement control. Lesion disrupts ability to locate sound.

Question 3

Paulin: Amphibians

Answer 3

CBM is small and simple. Inconsistent with increased motor demands when transitioning to land locomotion.

Question 4

Paulin: Reptiles

Answer 4

In turtles, medial CBM is reduced and lack of sensory innervation. In Japanese turtle, medial CBM is enhanced and associated with sensory requirements.

Question 5

Paulin: Rodents vs Mammals

Answer 5

Motor argument. Enlargement of lobule VI associated with complex motor system. Whiskers stimulate lobule VI of CBM.

Mammals also have large lobule VI but little motor control of their beak, but the beak is very sensitive to tactile sensation.

Lobule VI more sensory than motor.

Question 6

Paulin: Bats vs Cetaceans

Answer 6

Vermal lobule VIII expanded in whales with echolocation.

Vermal lobule VIII also expanded in bats with echolocation.

Same CBM region of expansion related to sensory perception rather than motor requirements.

Question 7

Paulin’s conclusion about cerebellum function

Answer 7

More likely involved in tracking movements than making them.

Question 8

Paulin: Cats

Answer 8

Cerebellum very responsive to auditory stimuli and sensitive to direction of movement of stimuli.

Question 9

Rebuttal: Correlation between relative size and complexity of CBM and animal’s agility

Answer 9

Motor complexity complemented with other sensory systems.

Question 10

Rebuttal: particular lobules expanded in relation to fine motor control systems.

Answer 10

Motor systems are also sensory. Echolocation between cetaceans and bats with same lobule expansion but different motor requirements.

Question 11

Rebuttal: CBM damage produces deficits in motor control and coordination, but not perceptual deficits.

Answer 11

Perceptual deficits not attributed to motor deficits have been reported. Haith’s lecture showing CBM patients deficits during simple limb movement.

Active movement vs passive movement. Knowledge of perception does not affect the proprioception in cbl patients

Question 12

Rebuttal: neuronal activity in CBM related to movements

Answer 12

Sensory inputs correlated with motor outputs. Does it control movements or analyze sensory data during movements?
Timing not informative because would need movement and CBM input.

Question 13

Rebuttal: CBM outputs go to premotor and motor regions.

Answer 13

Doesn’t imply that CBM output is restricted to motor control. Could be that CBM output helps influence motor control.

Question 14

Bower: Control of Sensory Data Acquisition

What is the function of the cerebellum?

Answer 14

CBM projects to motor cortex so that it acquires better sensory data. Projections to other areas (DLPFC) show that CBM computation also may be useful for non-motor behavior.

Fractured somatotopy

Question 15

Bower’s observations of Purkinje Cells

Answer 15

Purkinje Cells respond to tactile stimulation. Ascending axons have more powerful synapse than parallel fibers. “Dendritic state” of PCs reflects sensory information from tactile surfaces.

Interpretation: parallel fibers provide modulatory role within context of powerfully driven inputs.

Question 16

Bower: what is CBM controlling? What does the CBM do?

Answer 16

Acquisition of sensory data. CBM receives input from sensory systems and influences motor cortex to adapt and adjust.

Question 17

Implications of Bower’s CBM hypothesis

Answer 17

CBM must receive high quality sensory information.

Motor coordination often recovers after lesion. Other structures develop compensatory measures to cover poor sensory data.

Most common clinical effect of CBM lesion is slowing down. Takes more time to adjust and organize movements with bad sensory data that CBM cannot process.

Question 18

Gao et al. Experiment. Hypothesized order of activation

Methods.

Answer 18

fMRI experiment with different tactile stimulations on the hand. Some just sensory, some just motor some combo. See which one triggered most activation in CBM.

GOD>CD>CS>GO.
Motor+Sensory > just motor.

Sensory > just motor.

Question 19

Results of Gao et al. Experiment. Tactile sensations and looking at activation.

Answer 19

GOD>CD>CS>GO.

Sensory information more activation that just motor. CBM cortex and dentate had more activation.

Question 20

Cerebellum and Auditory Function Meta-Analysis Results (ALE) What were investigators worried about and what did they do?

Answer 20

Cerebellum, frontal, temporal lobe activations.
They were worried about attention tasks, so they removed active tasks. This resulted in disappearance of frontal, parietal and insular regions but cerebellar activation REMAINED!

Question 21

Baumann & Mattingley 2010 Experiment: Auditory and Visual Sensory Discrimination

1. Methods
2. Results
3. fMRI results.

Answer 21

1. Finding direction of auditory or visual signal in noise. Cerebellar patients wouldn’t extract signal in noise.
2. CBL patients less able to detect direction of coherent motion.
3. Cerebellar involvement greater when finer level of sensory data acquisition is needed. So, more CBM activation when the signal was low and difficult to ascertain. Results showed negative correlation in regions of Crus I. Consistent with sensory acquisition role of cerebellum!