1. Control of facial expressions
Domina Petric, MD

2. Facial nerve, facial cortex
Facial nerve motor nucleus in the pons.
Facial colliculus around the abducens nucleus.
Inferior segment of the lateral part of precentral gyrus is governing the movements of the contralateral lower part of facial musculature.
Control for the upper part of the facial musculature is governed by a region along the mid-sagittal surface of the brain: in the cingulate sulcus, the cingulate motor area.

3. Middle cerebral artery lesion
Causes contralateral facial weakness which is limited to the lower part of the face.

4. Cingulate motor area is supplied by anterior cerebral artery.
Cingulate motor area provides bilateral innervation from upper motor neurons to the facial motor nucleus.

5. Contralateral lower facial musculature weakness
Infarcion in the middle cerebral artery region: inferior and lateral part of the precentral gyrus
Even if one anterior cerebral artery is infarcted, upper parts of the facial musculature will be spared.
Contralateral lower facial musculature weakness

6. Lesion of facial nerve (lower motor neuron lesion), for example, Bell´s palsy causes ipsilateral facial musculature weakness, both upper and lower parts of the face.

7. Motor neuron pools in facial nucleus Activation of facial muscles
Volitional movement: descending pyramidal and extrapyramidal projections from motor cortex and brainstem
Neural systems for emotional expression: descending extrapyramidal projections from medial forebrain and hypothalamus
Emotional facial paresis
Voluntary facial paresis
Duchenne smile
Pyramidal smile
Motor neuron pools in facial nucleus
Activation of facial muscles

8. Pyramidal smile: smile is more symmetrical when there is emotional smile. Duchenne smile: smile is asymmetrical when there is emotional component.
Duchenne smile
Pyramidal smile

9. trigeminal motor nucleus (V)
Cranial nerves motor nuclei with significant contralateral bias in upper motor neuron innervation are:
trigeminal motor nucleus (V)
facial motor nucleus (VII)
spinal accessory nucleus (XI)
hypoglossal nucleus (XII)

10. Upper motor neuron syndrome
II.
Upper motor neuron syndrome

11. Upper motor neuron syndrome
In the early fase of the upper motor neuron damage patient may present with signs and symptoms that look like lower motor neuron injury.
It is a spinal shock.
Spinal shock: patients are weak, muscles appear to be flaccid, muscle tone and reflexes are reduced.

12. Upper motor neuron syndrome
Second fase is typical for upper motor neuron syndrome (up to after one week from injury):
spastic muscles
pathological muscle tone
hyperreflexia

13. Upper vs. lower motor neuron sy.
Upper motor neuron syndrome
Lower motor neuron syndrome
weakness
spasticity
increased muscle tone
hyperactive deep reflexes
clonus
Babinski sign
loss of fine voluntary movements
weakness or paralysis
decreased superficial reflexes
hypoactive deep reflexes
decreased tone
fasciculations and fibrillations (early fase)
severe muscle atrophy
Upper vs. lower motor neuron sy.

14. http://images.clipartpanda.com http://elisasylee.blogspot.hr
Literature
neuroscience/lecture: Leonard E. White, PhD, Duke University