Neuro Cerebellum Ssom Keifer 4/23/10

Front 1

Cerebellum
(overview)

Back 1

neuroanatomy and synaptic transmission well understood
function in motor control and sensorimotor integration
exact function unknown
one of best understood in terms structure, but
function active area of research

Front 2

Cerebellum
surface features
(3 lobes)

Back 2

Anterior lobe
Posterior lobe
Flocculonodular lobe:
--nodule
--flocculus

Front 3

Cerebellum
surface features
(2 fissures and what they separate)

Back 3

Primary fissure b/w Anterior and Posterior lobes
Posterolateral fissure b/w Posterior and flocculonodular lobes

Front 4

Cerebellum
Other surface landmarks
(name)

Back 4

folia
vermis
tonsils

Front 5

Cerebellum
surface landmarks
folia

Back 5

transverse folds that comprise the cerebellar cortex

Front 6

Cerebellum
surface landmarks
vermis

Back 6

("wormlike")
region along midline

Front 7

Cerebellum
surface landmarks
tonsils

Back 7

protrusions on the inferior surface of cerebellum

Front 8

Cerebellum
(cerebellum made up of)

Back 8

cortex

deep cerebellar nuclei:
located in white matter (4/side)

cerebellar peduncles:
provide input/output pathways
(3/side)

Front 9

Cerebellar Cortex
(name the cortical layers)

Back 9

Molecular layer
Purkinje cell layer
Granule cell layer

Front 10

Cerebellar Cortex
Molecular layer

Back 10

most superficial
mainly axons and synapses

Front 11

Cerebellar Cortex
Purkinje cell layer

Back 11

made up of single row Purkinje cells,
the principal cells of cerebellar cortex

Front 12

Cerebellar Cortex
Granule cell layer

Back 12

contains interneurons such as:
Golgi cells
granule cells and
stellate cells

numerous synapses

Front 13

Cerebellar Cortex
Afferent INPUTS
(2 types)

Back 13

Climbing fibers
Mossy fibers

Front 14

Cerebellar Cortex
Afferent INPUTS
Climbing fibers
(originate from, wrap around, each Purkinje cell receives how many climbing fiber(s)

Back 14

originate from contralateral IOC
wrap around dendrites of Purkinje cell
**ONE** climbing fiber input per Purkinje cell

Front 15

Cerebellar Cortex
Afferent INPUTS
Mossy fibers
(originate from)

Back 15

originate from many different areas of the brain (pontine nuclei, SC, vestibular nuclei)

Front 16

Cerebellar Cortex
Afferent INPUTS
Mossy fibers
(synapse onto _,
which then send their axons into _ layer and bifurcate into _ branches that run parallel to _,
these fibers are called _)

Back 16

inputs synapse onto granule cells
granule cells send axons into molecular layer
bifurcate into 2 branches that
run parallel to folia
*parallel fibers*

Front 17

Cerebellar Cortex
Afferent INPUTS
Mossy fibers
(Each Purkinje cell receives _ mossy fiber input)

Back 17

**THOUSANDS**

Front 18

Cerebellar Cortex
Afferent INPUTS
Climbing fibers
(Each Purkinje cell receives _ climbing fiber input)

Back 18

**ONE**

Front 19

Cerebellar **Cortex**
OUTPUT
(from, excite/inhib?, projects to)

Back 19

from Purkinje cell
*exclusively inhibitory (GABA)*
projects to deep cerebellar nuclei (still in cerebellum!)

Front 20

Deep Cerebellar Nuclei
(comprise the _ of cerebellum)

Back 20

OUTPUT

Front 21

Deep Cerebellar Nuclei
(name them from medial to lateral)

Back 21

medial to lateral:
Fastigial nucleus
Globose nucleus
Emboliform nucleus
Dentate nucleus

Front 22

Deep Cerebellar Nuclei
Globose and Emboliform = ?

Back 22

interpositus (interposed nucleus)

Front 23

Deep Cerebellar Nuclei
(biggest in humans)

Back 23

Dentate nucleus

Front 24

Cerebellar Peduncles
(name)

Back 24

Interior cerebellar peduncle (restiform body)
Middle cerebellar peduncle (brachium pontis)
Superior cerebellar peduncle (brachium conjunctivum)

Front 25

INPUT and OUTPUT of cerebellum made through _

Back 25

3 cerebellar peduncles

Front 26

Cerebellar Peduncles
Restiform body
(fibers from, fibers form, also contains fibers of _ tract)

Back 26

fibers from contralat IOC of medulla
they form climbing fibers

dorsal spinocerebellar tract fibers

Front 27

Cerebellar Peduncles
Brachium pontis
(contains _ fibers from _, these form _ fibers)

Back 27

pontocerebellar fibers from
contralat pontine nuclei
they form mossy fibers

Front 28

Cerebellar Peduncles
Brachium Conjunctivum
(form _ of the cerebellum, from the _ and _ nuclei, project to _ and _)

Back 28

from OUTPUT
interposed and dentate nuclei
project to red nucleus and thalamus

Front 29

Functional Subdivisions of Cerebellum
(name)

Back 29

Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum

Front 30

Functional Subdiv
Vestibulocerebellum
(corresponds to _ lobe,
main input from _ and _,
output to _)

Back 30

*flocculonodular lobe*

input from:
primary vestibular afferents (semicircular canals, otolith)
vestibular nuclei

output:
vestibular nuclei (esp. to lateral or Deiter's nucleus)

Front 31

Vestibulocerebellum (archicerebellum)
(functions in _ _ _)

Back 31

balance
eye movements
coordination of eye and head movements

Front 32

Functional Subdiv
Spinocerebellum (paleocerebellum)
(location, inputs)

Back 32

extends along midline in two sagittally oriented regions:
along vermis and
in intermediate cerebellum next to vermis

main inputs:
from somatosensory fibers from:
SC
spinocerebellar tracts
vestibular inputs

Front 33

Functional Subdiv
Spinocerebellum
(2 output pathways)

Back 33

vermis > fastigial nucleus > lateral vestibular nucleus which forms vestibulospinal tract or fastigial nucleus > reticular formation which forms reticulospinal tract

intermediate cerebellum > interpositus > contralat red nucleus and thalamus via superior cerebellar peduncle;
this info then relayed to motor cortex

Front 34

Spinocerebellum
(functions)

Back 34

general function is **execution** of movements:
vermis to fastigial pw functions in:
vestibular control of body movement (balance, posture)

intermediate cerebellum to interposed nuclei are involved in:
control of limb movement, especially reaching movements

Front 35

Cerebrocerebellum
(location, inputs, outputs)

Back 35

occupies lateral region of cerebellar hemispheres
best dev't in humans

inputs from:
pontine nuclei that relay info from motor cortex

output:
to dentate nucleus
dentate projects via SCbP to contralateral thalamus
which then relays to cortex

Front 36

Cerebrocerebellum
(function)

Back 36

motor planning

Front 37

Cerebellum in Sensorimotor integration

Back 37

remarkable sensory to motor transformation occurs over few synapses
MF and CF convey detailed sensory info into Cb
But signals in deep cerebellar nuclei related to movements with no relation to sensory events

Apparently, sensory to motor transformation so that adaptive movement that interfaces with environmental constraints can be performed

Front 38

CFs appear to act as _

They fire _

Back 38

somatic event detectors or error signals that respond to unexpected stimuli

They only fire a complex spike once every few seconds, like when you bump arm when reaching for something

Front 39

MFs arise from various origins that is reflected in sensitivity to many kinds of stimuli such as _ _ _ _ _

They fire spikes as _ that can accurately signal _

Back 39

auditory
visual
somatosensory
vestibular stimuli
movement

continuous bursts
signal sensory input

Front 40

Example of CF spikes

Back 40

Front 41

Are burst discharges, or motor commands modulated by sensory feedback?

Back 41

NO
findings suggest the burst discharges or motor commands are pre-programmed in the cerebellum and are not modulated by on-going sensory feedback

Front 42

What causes fights at neuroscience conferences?

Back 42

role of cerebellum in motor learning

Very difficult to separate the *learned* aspects of motor behavior from the *performance* of motor acts
(how can you tell if behavior was learned vs. something interfering with execution)

Front 43

experiments suggest that motor commands are driven by _

Back 43

"cerebellar loops" involving:
red nucleus, thalamus, and cortex and return to cerebellum

activity thought to be selected by pattern of Purkinje cell inhibition set up by sensory input from CFs and MFs

errors corrected by new pattern of Purkinje cell activity

Front 44

Cerebellum role in motor learning?
(read the controversial studies)

Back 44

because they cause fights

Front 45

Dysfunction of Cerebellum
(name 2 main types)

Back 45

Midline lesions
Neocerebellar syndrome

Front 46

Dysfunction of Cerebellum
Midline lesions
(affect _ and _,
patient demonstrates _ and _)

Back 46

affect vermis and flocculonodular lobe (the vestibulo- and spinocerebellum)

ataxic gait (unsteady staggering walking and difficulty maintaining equilibrium)
nystagmus (oscillation of eyes)

Front 47

Dysfunction of Cerebellum
Neocerebellar Syndrome
(results from damage to _ _ or _,
deficits are _ on voluntary movements that are essentially intact)

Back 47

classical cerebellar syndrome
damage to:
hemispheres, dentate nucleus, or SCbP
superimposed

Front 48

Dysfunction of Cerebellum
Neocerebellar Syndrome
(name the signs)

Back 48

signs, in varying degree of severity depending on damage:
ataxia
dysmetria
intention tremor
hypotonia
disdiadochokinesis
dysarthria

Front 49

Dysfunction of Cerebellum
ataxia

Back 49

movements are jerky due to loss of coordination of movement
(muscles not working right)

Front 50

Dysfunction of Cerebellum
dysmetria

Back 50

errors in magnitude or range of movement
sometimes called "past-pointing" because the hand overshoots its mark during reaching

Front 51

Dysfunction of Cerebellum
***intention tremor***

Back 51

classical sign of cerebellar damage
tremor occurs during voluntary movements of the ipsilateral limb such as past pointing, but does NOT occur during rest

Front 52

Dysfunction of Cerebellum
disdiadochokinesis

Back 52

impairment in performing rapid alternating movements such as pronation and supination of the hands
these movements are clumsy and irregular

Front 53

Dysfunction of Cerebellum
dysarthria

Back 53

ataxic, slowed speech

Front 54

Cerebellum means _

Back 54

little brain