loss (i.e. paralysis) or decresed (paresis) of funtion

Loss of Excitation: Loss of Function

Exaggerated Fucntion

Loss of Inhibition: Increase in Function

Can unmake functions (Babinski sign)

Reinnervation: restoration or change in function

Pain, temperature, simple touch

Spinothalamic (body)

Trigeminothalamic (face)

Discriminative touch, 2-point discrimination, conscious proprioception

Dorsal columns/Medial Lemniscus (body)

Trigeminothalamic (face)

Unconscious Proprioception

Dorsal Spinocerebellar

Ventral Spinocerebellar

Pain, temperature, simple touch

Body

Neuron 2 crosses out in the spinal cord at or above the level of entry of Neuron 1

"Voluntary Motor"

Corticospinals (body)

Corticobulbar (face)

Other

Cerebello-thalamo-cortical

Cortico-striato-pallidal

Pallido-thalamo-cortical

Pain, temperature, simple touch

Face

Neuron 2 is found in the spinal cord at or above the level of entry of Neuron 1

Discriminative touch, 2-pt discrimination, conscious proprioception, kinesthesia (sense of mvmt), vibration

Discriminative touch, 2-point discrimination, conscious proprioception, kinesthesia (sense of mvmt), vibration

Discriminative touch: "you touched me on the tip of my nose"-specific

Neuron 2 is in the lower medulla (gracile & cuneate) nuclei

Unconscious proprioception

info mostly comes from Golgi tendon organs & muscle

Because info is channeled to the cerebellum & not the cerebral cortex, info is not consciously percieved=unconscious proprioception

Voluntary Motor

influence small groups of motor neurons that innervate a single muscle

Body-small individual movements by muscles

Voluntary motor

can influence small groups of motor neurons that innervate a single muscle

small individual muscle involved in speech production (i.e. facial, jaw mvmts, tongue)

Include all structures leading from a field of peripheral stimulation (e.g. cutaneous, muscle, joint, tendon receptors) to the cerebral cortex (sensory cerebellar pathways expected)

Each pathway consists of 3 neurons-ASCENDING

Neuron 1 (primary afferent nerve cell body) is in the DRG or a CN sensory ganglion cell

Neuron 2 is located in a semgent of spinal gray matter or in the brainstem

The axon of Neuron 2 decussates & travels in a tract on the contralateral side of entry to end in the thalamus

Neuron 3 relays nfo from thalamus to cerebral cortex (sensory regions)

DESCENDING

Consists of an UMN and a LMN

UMN: in cerebral cortex (not just motor cortex)

Influences action of lower motor neurons

Axons of UMN decussate in the medulla (pyramids)

LMN: located in nuclei in the ventral & lateral horns of the spinal cord & in motor nuclei of the brainstem

From LMN out to skeletal muscle

signs & symptoms that relfect Loss of inhibitory influences on LMNs

Weakenss/Paresis

Increased deep tendon reflexes (hyperflexia)

Increased muscle tone/spasticity (hypertonia)-loss of inhibitation of stretch reflex whic normally maintains muscle tone

signs & symptoms that reflect loss of singals to generate muscle contraction

Weakness/paresis/paralysis

Decreased/Abolished deep tendon reflexes

Muscle atrophy & fasciculation

(results from spontaneous cx of muscle fiber bundles that are usu. suppressed by muscle tone)

Hypotonia (Flaccidity)-no way of making muscle cx-occurs b/c efferent segment of stretch reflex is gone)

disrupt axonal communication

(And may cause the death of the neurons of origin)

Lesions of the CNS-

TINNTING

Can results from

Trauma

Ischemia

Neoplasm

Neuro-degenerative disorder

Toxins

Infection

Nutritional deficiences

Genetic

Cerebellum

provides error correction for motor system

cortico-striato-pallidal

And

pallido-thalamo-cortical

basal ganglia

allow for learning of complex motor tasks making them nearly automatic