What Part of the Brain Controls Eye Movements?

How Did One Patient's Shoulder Pain Track Her Gaze?

A 30-year-old woman in the video at the top came in with dizziness, a racing heart, heat intolerance, brain fog and left shoulder pain, after 8 to 10 weeks of physical therapy for the shoulder. Her eye exam showed square wave jerks, the back-and-forth eye movements that appear when the eyes should be holding steady on a target. After our team worked on her neck motion and then on keeping her gaze stable, her head tilt and posture improved as the exam went on, and her standing balance path length dropped from 145 cm to 57 cm. She said her shoulder didn't bother her while her gaze stayed smooth and hurt again when her gaze turned choppy. She held her gaze steadier over time as she did her exercises. Some of her restricted head positions also caused drops in blood flow, and those blood flow changes resolved as well. She's one patient, so read her story as an example of what the exam can show.

What Do Eye Movement Tests Show?

Saccades are the rapid eye movements that change where you're looking, and smooth pursuit keeps a moving target centered on the fovea, the center of vision (Terao, 2017). Shemesh and Zee tie saccade accuracy mainly to the dorsal vermis and posterior fastigial nucleus, and pursuit and steady gaze holding mainly to the flocculus and paraflocculus (Shemesh, 2019):

Saccades that keep missing the target, whether short or long, are one clue our team weighs toward the cerebellar circuits, together with the rest of the exam. Overshooting saccades aren't specific to cerebellar ataxia (Terao, 2017).

Why Do My Eyes Jump When Tracking Something?

In 36 Division I athletes, some concussed and some not, researchers tracked their eyes during a soccer-heading video game 24 to 48 hours after a sport concussion and found slower smooth pursuit in the concussed group. The concussed athletes used larger, faster saccades to keep the target in central vision (Murray, 2020). That study covers the first 2 days after injury, so it says little about symptoms that last. Those are covered in solving lingering post-concussion symptoms.

The flocculus is mainly tied to pursuit maintenance (Shemesh, 2019), so our team treats lagging pursuit as one clue that can point toward that circuit, along with the rest of the exam.

Steady tracking Jumpy tracking

Steady tracking: the eye trace stays on the target, and the flocculus circuit helps maintain the pursuit.

Jumpy tracking: the eye falls behind the target, then jumps to catch up. Each jump is a saccade, and the vermis and fastigial circuit helps keep its size accurate.

Replay

Sudden double vision, a drooping eyelid, new weakness or numbness, trouble speaking, or a sudden severe headache with eye changes needs urgent medical care.

How Does Our Team Use Eye Movement Testing?

Our team records eye movements with video oculography or bedside testing, reads the pattern as a clue to which circuits are underperforming, and checks it against balance, the neck and brain blood flow. It's one part of the exam, and our team retests it after treatment. Bedside versions of these tests are described in the dysautonomia bedside neurological tests.

In our team's view, square wave jerks, the back-and-forth eye movements that appear when the eyes should be holding steady on a target, are one of the most underrated tools for locating and measuring dysfunction in the brain. Video oculography or bedside testing can capture them.

Can Eye Movement Problems Be Retrained?

Neural plasticity is believed to be the basis for both learning in the intact brain and relearning in the damaged brain that occurs through physical rehabilitation (Kleim, 2008). Once the pattern points to a circuit, our team chooses exercises to match it. A patient with hypometric saccades and poor smooth pursuit may benefit from cerebellar-targeted exercises involving timing, coordination and predictive tracking, and a patient with asymmetric vestibulo-ocular reflex gain needs vestibular rehabilitation focused on the underperforming side. Generic balance exercises or vision therapy won't address a specific cerebellar timing issue the way a targeted protocol will. Recovery after a concussion is covered in post-concussion treatment.

Which Brain Areas Run Eye Movements?

Commands to start voluntary saccades arise in the cortex and go to the brainstem, which contains the saccade generators, and the frontal eye field and parietal cortex are especially important for initiating them (Terao, 2017). The frontal eye field sits near the precentral sulcus and/or deep in the back of the superior frontal sulcus (Paus, 1996). The cerebellum is a network hub that optimizes eye movements through its connections with the brainstem (Shemesh, 2019). That same circuitry links to the autonomic system, as covered in proof that the brain controls the autonomic system, and how the cerebellum ties into dysautonomia is covered in the little brain causing your dysautonomia.

Eye Movements and the Brain: FAQ

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