How do our eyes stay focused on what we reach for?
Findings offer new insights into how our movements are coordinated

Date:
April 20, 2022
Source:
New York University
Summary:
Keeping our eyes focused on what we reach for, whether it be an
item at the grocery store or a ground ball on the baseball field,
may appear seamless, but, in fact, is due to a complex neurological
process involving intricate timing and coordination. Researchers
now shed additional light on the machinations that ensure we don't
look away from where we are reaching.



FULL STORY ========================================================================== Keeping our eyes focused on what we reach for, whether it be an item
at the grocery store or a ground ball on the baseball field, may appear seamless, but, in fact, is due to a complex neurological process involving intricate timing and coordination. In a newly published study in the
journal Nature, a team of researchers sheds additional light on the machinations that ensure we don't look away from where we are reaching.


==========================================================================
The work centers on a form of coordinated looking and reach called
"gaze anchoring" -- the temporary stoppage of eye movements in order to coordinate reaches.

"Our results show that we anchor our gaze to the target of the reach
movement, thereby looking at that target for longer periods," explains
Bijan Pesaran, a professor at NYU's Center for Neural Science and one
of the paper's authors.

"This is what makes our reaches much more accurate. The big question
has been: How does the brain orchestrate this kind of natural behavior?"
The study, conducted with Maureen Hagan, a neuroscientist at Australia's
Monash University, explores the frequently studied but not well understood process of gaze anchoring -- in particular, how different regions of
the brain communicate with each other.

To examine this phenomenon, the scientists studied brain activity in the
arm and eye movement regions of the brain at the same time as non-human primates performed a sequence of eye and arm movements. The first movement
was a coordinated look-and-reach to a target. Then, as little as 10 milliseconds later, a second target was presented that subjects needed
to look at as quickly as possible. This second eye movement revealed the
gaze anchoring effect. These movements are similar to those made when
changing the radio while driving and attending to a traffic light --
if you quickly look away from the radio to the traffic light, you might
not select the right channel.

Their results showed that, during gaze anchoring, neurons in the part
of the brain -- the parietal reach region -- used for reaching work
to inhibit neuron activity in the part of the brain -- the parietal
saccade region -- used for eye movements. This suppression of neuron
firing serves to inhibit eye movement, keeping our eyes centered on
the target of our reach, which then enhances the accuracy of what we're grasping for. Importantly, the scientists note, the effects were tied
to patterns of brain waves at 15-25 Hz, called beta waves, that organize
neural firing across the different regions of the brain.

"Beta waves have been previously linked to attention and cognition,
and this study reveals how beta activity may control inhibitory brain mechanisms to coordinate our natural behavior," explains Pesaran.

By further illuminating the neurological processes of coordinated looking
and reaching, tying them to inhibitory beta waves, this study offers the potential to better understand afflictions of attention and executive
control that orchestrate natural behaviors like coordinated looking
and reaching.

The research was supported by the National Institutes of Health (T32
EY007136), Australian Research Council (DE180100344), the National Science Foundation (BCS-0955701), the National Eye Institute (R01-EY024067), the
Army Research Office, the Simons Foundation, a McKnight Scholar Award,
and a Sloan Research Fellowship.


========================================================================== Story Source: Materials provided by New_York_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Maureen A. Hagan, Bijan Pesaran. Modulation of inhibitory
communication
coordinates looking and reaching. Nature, 2022; DOI:
10.1038/s41586-022- 04631-2 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220420113001.htm

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