What is PPRF lesion?
Unilateral lesions of the PPRF produce characteristic findings: Loss of horizontal saccades directed towards the side of the lesion, no matter the current position of gaze. Contralateral gaze deviation (acute lesions, such as early stroke, only) Gaze-evoked lateral nystagmus on looking away from the side of the lesion.
Where is the PPRF located?
pontine tegmentum
The PPRF is the last supranuclear relay involved in conjugate horizontal eye movement (27). The PPRF is located in the pontine tegmentum near the abducens nucleus and is provided with neural inputs from the cortex (13).
What happens if the abducens nerve is damaged?
Sixth nerve palsy occurs when the sixth cranial nerve is damaged or doesn’t work right. It’s also known as the abducens nerve. This condition causes problems with eye movement. The sixth cranial nerve sends signals to your lateral rectus muscle.
What does abducens nucleus do?
The abducens nucleus is the center for conjugate horizontal movements of the eye. About 70% of the abducens nucleus are motor neurons that control the ipsilateral lateral rectus muscle.
Where is interstitial nucleus of Cajal?
The interstitial nucleus of Cajal is a prominent group of cells within the medial longitudinal fasciculus of the brainstem that is responsible for maintaining oculomotor control, head posture, and vertical eye movement.
What is the function of Pprf?
Eye movement findings with lesions involving the pons
| Structure | Main ocular motor function |
|---|---|
| PPRF* | Horizontal saccade generation |
| MLF | Conjugate gaze and VOR |
| CTT | Conveys information from cerebellum to inferior olive |
| Vestibular nucleus (rostral part) | VOR |
What are the symptoms of abducens nerve lesion?
What are the signs and symptoms of abducens nerve palsy (sixth cranial nerve palsy)?
- Binocular diplopia (worse at distance or lateral gaze)
- Esotropia.
- Head-turn.
- Vision loss.
- Headache, vomiting, pain, or facial numbness.
- Trauma.
- Symptoms of vasculitis, particularly giant cell arteritis.
- Hearing loss.
What is special about the abducens nerve?
The abducens nerve controls the movement of a single muscle, the lateral rectus muscle of the eye. In most other mammals it also innervates the musculus retractor bulbi, which can retract the eye for protection.
What is Pprf?
The PPRF is the premotor structure of all ipsilateral saccades (including quick phases of nystagmus) and the generator of horizontal saccadic pulse. From: Handbook of Clinical Neurology, 2011.
What causes damage to the abducens nerve?
Damage to the abducens nerve can be caused by anything that compresses or stretches the nerve, such as tumors, aneurysms, fractures, or increased intracranial pressure (ICP).