Basal Ganglia, Cerebellum, Cortical Control

Front 1

Basal ganglia: function (general)

Back 1

involved in orchestrating automated patterns of movement (“remembered movements”) such as walking, riding a bicycle.

Front 2

Basal ganglia structures:

Back 2

Caudate, putamen, globus pallidus, STN, substantia nigra

Front 3

Striatum consists of:

Back 3

Caudate, putamen

Front 4

T/F histologically, caudate and putamen are part of same structure

Back 4

T

Front 5

lentiform nucleus=

Back 5

putamen + globus pallidus

Front 6

Thru what outputs does the basal ganglia affect movement?

Back 6

Through output connections to the motor thalamus (VA/VL) relayed to motor cortex

Front 7

What is the major output of the basal ganglia?

Back 7

flows from the internal segment of the globus pallidus (GPi) and substantia nigra, pars reticulata (SNr) to the motor thalamus (VA).

Then the info is conveyed to the supplementary motor cortex. (m2)

Front 8

Subsections of striatum

Back 8

1) Striosomes
2) Matrix

Front 9

D1 dopaminergic receptors predominate in the ________ while D2 receptors predominate in the ________ of striatum.

Back 9

Striosomes; Matrix

Front 10

Direct pathway associated with _________; indirect pathway associated with__________.

Back 10

GPi (Striosomes); GPe (Matrix)

Front 11

____________ are the principal cell type, are GABA-ergic (inhibitory), and give rise to all striatal efferents (striatopallidals & striatonigrals).

Back 11

Spiny neurons

Front 12

_________are cholinergic, short-axon neurons which have intrinsic striatal circuitry (short axons which do not leave the striatum).

Back 12

Aspiny neurons

Front 13

Spiny neurons use ______ as an NT; Aspiny use ___________

Back 13

GABA (inhibitory); ACh (Excitatory)

Front 14

The principal source of input (afferents) to the striatum are ________ and ________.

Back 14

corticostriates and nigrostriates

Front 15

What are corticostriates?

Back 15

Principal source of input from broad areas of cerebral cortex (glutamate, excitatory); Sensorimotor cortex to putamen; associational cortex to caudate

Front 16

Corticostriates from association cortex go to the _______

Back 16

caudate nucleus.

Front 17

Corticostriates from sensorimotor cortex (e.g., pre and post central gyri) go to the _______

Back 17

putamen

Front 18

Corticostriates use ______ as NT

Back 18

Glu

Front 19

Where are the nigrostriates from?

Back 19

Substantia nigra pars compacta (DA) to caudate and putamen. Probably neuromodulatory via 2nd messengers; neither excitatory or inhibitory

Front 20

Thalamostriates use _____ as NT

Back 20

Glu

Front 21

Striatal afferents

Back 21

Corticostriates (GLUT); Nigrostriates (DA)

Front 22

Striatal efferents

Back 22

All GABA.

Striatopallidals (striosomes->Gpi and matrix-->GPe)

Striatonigrals (striosomes->SNc and matrix-->SNr)

Front 23

The ____ pathway facilitates movement, while the ____ pathway inhibits movement.

Back 23

direct ; indirect

Front 24

Which pathway goes thru the subthalamic nucleus?

Back 24

Indirect

Front 25

Huntington's disease is associated with atrophy of _____

Back 25

striatum

Front 26

In HD, loss of major inhibition of the _____ results in increased inhibition of the _____.

Back 26

GP; STN

Front 27

Less tonic inhibition of the motor thalamus results in increased excitation of _______

Back 27

motor cortex

Front 28

Segments of globus pallidus

Back 28

Internal (GPi) and External (GPe)

Front 29

Pallidal afferents

A) GPi
B) GPe

Back 29

Striatopallidals (GABA) from striatum.

A) direct loop
B) indirect loops (thru STN)

Subthalamo-pallidals (Glu) from STN to GPi as part of indirect loop

Front 30

Pallidal efferents
A) GPi
B) GPe

Back 30

ALL are inhibitory (GABA).
A) Directly to motor thalamus (mostly VA)
B) To STN (indirect loop)

Front 31

Why is the GP frequently a target of neurosurgery to relieve tremors?

Back 31

It's one of 2 principal origins of outflow from basal ganglia to motor thalamus and cortex

Front 32

Subthalamic afferents and efferents.

Back 32

Receives principal input from GPe and projects to GPi via indirect loop

Front 33

A lesion of the subthalamic nucleus results in___________

Back 33

contralateral hemiballism.

These are large amplitude, ballistic proximal limb movements.

Front 34

What type of neurons are those of the STN? WHat's special about this?

Back 34

ONLY excitatory (glutamatergic) neurons in the basal ganglia

Front 35

Two parts of the substantia nigra and how they differ

Back 35

Pars compacta (DA); Pars reticulata (GABA)

Front 36

Part of substantia nigra that provides tonic inhibition to the motor thalamus (VA/VL) and superior colliculus (where a pause in activity allows eye movement to occur)

Back 36

SN Pars reticulata

Front 37

Substantia nigra afferents

Back 37

From striatum (GABA).
Striosomes --> pars compacta (SNc)

Matrix --> pars reticulata, SNr

Front 38

Substantia nigra efferents

Back 38

1) Nigrostriatals (DA): SNc -->striatum (DA)

2) Nigrothalamics: SNr --> motor thalamus (GABA)

2) Nigrotectals - SNr --> sup colliculus (GABA)

Front 39

Actions of substantia nigra efferents

Back 39

Tonically inhibit motor thalamus and superior colliculus

Front 40

Sx of PD

Back 40

Resting tremor
Bradykinesia
Festinating Gait- baby steps
“Freezing”(inertia)- difficulty initiating movements
Rigidity
Masked face

Front 41

Where are neurons lost in PD?

Back 41

Substantia Nigra Pars Compacta (DA-producing)

Front 42

Increased inhibition of the motor thalamus results in decreased thalamocortical excitation of the ______

Back 42

motor cortex. Leads to less movement (happens in PD)

Front 43

The principal outflow from the basal ganglia to the motor thalamus (VA/VL) is from the:

Back 43

Globus pallidus, internal segment (GPi)
Substantia nigra, pars reticulata (SNr)

Front 44

If basal ganglia are lesioned, the dysfunction affects the ______ motor cortex, and deficits (thru the pyramidal system) are expressed on the _______ side of the body.

Back 44

ipsilateral; contralateral

Front 45

Corticostriates from motor cortex project to the ______.

Back 45

putamen

Front 46

T/F Outflow from the globus pallidus targets the motor thalamus (VA/VL), which projects in turn back to motor cortex (esp. supplementary motor cortex).

Back 46

T

Front 47

why are certain oculomotor deficits associated with basal ganglia disease?

Back 47

Corticostriates from frontal eye field project to caudate nucleus. FEF is located in posterior part of middle frontal gyrus, and initiates voluntary saccadic eye movements.

Some of the outflow from the globus pallidus targets the mediodorsal (MD) nucleus of the thalamus, which projects in turn back to the frontal eye field.

Front 48

why are certain cognitive deficits associated with basal ganglia disease.

Back 48

Corticostriates from PFC project to caudate. Some of the outflow from GP targets mediodorsal nucleus of thalamus, which projects in turn back to PFC.

Front 49

Primary function of cerebellum

Back 49

To detect "motor error" - the difference between intended/planned and actual movement.

Front 50

vestibulocerebellum: main job

Back 50

phylogenetically oldest part of cerebellum; receives input from vestibular system and is primarily concered with regulation of movements underlying posture and equilibrium/position in space.

Front 51

vestibulocerebellum: inputs

Back 51

vestibular system

Front 52

vestibulocerebellum: components

Back 52

flocculus and nodulus

Front 53

cerebrocerebellum: main purpose

Back 53

regulation of highly skilled movements, including speech. Especially concerned with planning and execution of complex spatial and temporal sequences of movement.

Front 54

cerebrocerebellum: located

Back 54

mostly lateral cerebellum

Front 55

spinocerebellum: location

Back 55

medial cerebellum

Front 56

connections between cerebellum and other parts of CNS occur by what?

Back 56

cerebellar peduncles

Front 57

Superior cerebellar peduncle: what is pathway?

Back 57

Almost entirely efferent from deep cerebellar to upper motor neurons.

Think efferent to motor cortex.

Front 58

Middle cerebellar peduncle: what is pathway?

Back 58

Afferent pathway to cerebellum. Most cell bodies here are in base of pons where they form pontine nuclei.

Think brainstem.

Front 59

Inferior cerebellar peduncle: what is pathway?

Back 59

Multiple afferent and efferent. Think spinal cord

Front 60

Input - cerebrocerebellum
Output - premotor cortex (motor planning)

Back 60

Dentate nucleus

Front 61

Input - spinocerebellum
Output – motor cortex and brainstem

Back 61

Interposed and fastigial

Front 62

Input - vestibulocerebellum
Output – ocular motor and spinal cord

Back 62

vestibular (not actually in cerebellum)

Front 63

Largest source of inputs to cerebellum, with major destination being cerebrocerebellum

Back 63

Cerebral cortex

Front 64

Vestibular axons from vestibular nuclei in medulla project to what?

Back 64

Vestibulocerebellum

Front 65

What is the functional organization of the outputs from the cerebellum to cerebral cortex?

Back 65

Cerebellar cortex --> Deep cerebellar nuclei --> (thru superior cerebellar peduncle) --> VL complex of thalamus --> Primary motor and premotor cortex

Front 66

Vestibulocerebellum: principal destination

Back 66

Medial systems: axial motor neurons

Front 67

Spinocerebellum Vermis: principal destination

Back 67

Medial systems: vestibular nucleus, reticular formation, motor cortex

Front 68

Spinocerebellum Intermediate part of hemisphere: principal destination

Back 68

Lateral systems: red nucleus, distal regions of motor cortex

Front 69

Cerebrocerebellum: principal destination

Back 69

Integration areas: red nucleus and premotor cortex

Front 70

Vestibulocerebellum: deep nucleus

Back 70

lateral vestibular

Front 71

Spinocerebellum Vermis: deep nucleus

Back 71

Fastigial

Front 72

Spinocerebellum Intermediate Part: deep nucleus

Back 72

Interposed

Front 73

Cerebrocerebellum: deep nucleus

Back 73

Dentate

Front 74

Most input signals for cerebellum come from _____ and _______

Back 74

motor and parietal cortex

Front 75

Modulatory signals from the _______ contribute to cerebellar learning and memory.

Back 75

inferior olive

Front 76

T/F Sensory information from vestibular, spinal and trigeminal inputs monitor position and motion of the body.

Back 76

T

Front 77

T/F Deep cerebellar nuclei cross in the midbrain and project to the contralateral thalamus and then primary and premotor cortex.

Back 77

T

Front 78

3 layers of cerebellar cortex from outer-->innermost

Back 78

Molecular, purkinje, granular

Front 79

Characteristics of what cell layer:
input from mossy fibers
synapses form glomeruli
granule cells have parallel fibers
golgi II cells

Back 79

Granule cell layer

Front 80

Characteristics of what cell layer:
input from inferior olive
climbing fibers contact Purkinje cells
Purkinje axons, output of cortex

Back 80

Purkinje cell layer

Front 81

Where do climbing fibers originate?

Back 81

inferior olive

Front 82

What's the purpose of climbing fibers?

Back 82

Direct modulatory input onto purkinje cells

Front 83

What is the only output cell of cerebellar cortex?

Back 83

purkinje

Front 84

What NT do purkinje cells use?

Back 84

GABA. This means entire output of cerebellum is inhibitory

Front 85

Basket and stellate cells found in what layer?

Back 85

Molecular

Front 86

What are basket cells?

Back 86

Inhibitory cells in molecular layer. Forms inhibitory complexes of synapses around purkinje cell bodies

Front 87

What are stellate cells?

Back 87

Receives input from parallel fibers and provide inhibitory input to purkinje cell dendrites

Front 88

Golgi cells: where found?

Back 88

Cell bodies in granular layer, apical dendrites in molecular layer

Front 89

What are granule cells?

Back 89

Give rise to specialized axons called parallel fibers that ascend to molecular layer. They bifurcate to form T-shaped branches that synapse (+) onto purkinje dendrites

Front 90

Two excitatory inputs to Purkinje cells

Back 90

1) Parallel fibers of granule cells

2) Climbing fibers (from inf olive)

Front 91

Provide lateral inhibition: cell type

Back 91

Basket and stellate

Front 92

Mossy fibers synapse on what?

Back 92

Granule cells

Front 93

Where do mosssy fibers come from?

Back 93

Pontine nuclei (cerebral cortex), spinal cord, vestibular system

Front 94

give rise to parallel fibers that contact multiple Purkinje cells
form parallel beams of excitation throughout cerebellar cortex

Back 94

granular cell

Front 95

Significance of complex spikes

Back 95

Generate by the climbing fibers on the Purkinje cell.

may modify parallel fibers inputs

Front 96

excitatory onto cerebellar nuclei and granule cells

Back 96

mossy fibers

Front 97

excitatory onto Purkinje cells

Back 97

Climbing fibers

Front 98

Inhibitory onto cerebellar nuclei

Back 98

Purkinje cells

Front 99

are inhibitory interneurons
lateral inhibition to adjacent Purkinje cells
sharpen the beam of excitation

Back 99

Basket cells

Front 100

Hallmark of patients with cerebellar damage

Back 100

Difficulty producing smooth, well-coordinated movements. Movements are jerky and imprecise (cerebellar ataxia)

Front 101

How do Purkinje cells and deep cerebellar nuclear cells recognize potential movement errors?

Back 101

They compare patterns of convergent activity that are concurrently available to both cell types.

Front 102

What is the deep excitatory loop?

Back 102

The mossy fiber synapses on the deep cerebellar nuclei cell directly (excitatory). It provides background flow of activity through the cerebellum.

Front 103

What is the cortical inhibitory loop?

Back 103

circuits in the cerebellar “cortex” provide inhibitory modulation by way of the Purkinje cells.
Purkinje cells are synapsing on the deep cerebellar nuclei cells

Front 104

T/F Changes in dischage rates from Purkinje and deep nuclear cells are observed during movement “error correction signals”.

Back 104

T

Front 105

Dysdiadochokinesia: defn

Back 105

Inability to perform rapid, alternating movement (involving antagonist muscles)

Front 106

T/F Action/intention tremors may occur due to cerebellar damage

Back 106

t

Front 107

What are the cortical centers that control voluntary movement?

Back 107

Primary motor cortex (area 4), premotor cortex and supplementary motor area (6)

Front 108

responsible for execution of movement

Back 108

primary motor cortex

Front 109

excitation of cell in motor cortex is transferred via what tracts?

Back 109

corticobulbar, corticospinal

Front 110

T/F Sensory and motor homunculus are the same

Back 110

F

Front 111

What is the Jacksonian March?

Back 111

Refers to the fact that epileptic events that are spreading that start in motor cortex result in progressive spread of contractions begining with fingers and then moved up.

Observation of this was influential in figuring out the homunculus.

Front 112

concerned with generation of patterns or programs for movement

Back 112

Premotor cortex and supplementary motor area

Front 113

T/F Centers involved in movement are Located in the frontal lobe (anterior to the central sulcus)

Back 113

T

Front 114

Concerned with motivation and strategies for movement

Back 114

Prefrontal cortex

Front 115

Inability to execute learned sequences despite intact pathways is called

Back 115

Apraxia

Front 116

Provides motor regions with info about environmental surroundings and external space thru multimodal sensory integration

Back 116

posterior parietal cortex

Front 117

Stroke in motor cortex: Sx

Back 117

Initially flaccid paralysis on contralateral side, then spastic paralysis. Loss of fine motor control.

Front 118

Lesion of STN results in

Back 118

Hemiballism

Front 119

Modulates flow of activity from thalamus to motor cortex

Back 119

Basal ganglia

Front 120

Direct projection pathwy thru basal ganglia.

Back 120

Ultimately excitatory.

SN (D1)-->(+) striatum --> (-) GPi ---> (-) VA/VL thalamus

Front 121

indirect projection pathwy thru basal ganglia.

Back 121

Ultimately inhibitory

SN (D2) --> (-) striatum --> (-)GPe ---> (-) STN --> (+) GPi --> (-) VL/VA of thalamus

Front 122

What structures help assemble a program or motor plan?

Back 122

Basal ganglia and pontocerebellum

Front 123

Removal of central inhibitory influences on postural muscles results in what?

Back 123

Spasticity. Due to increased gamma activity

Front 124

What does positive babinski sign indicate?

Back 124

Impairment of central control over lower motor neurons