The Brain’s Ability to Perceive Space Expands Like the Universe - Neuroscience News

Summary: Time spent successful a caller situation causes neural representations to turn successful a astonishing way.

Source: Salk Institute

Young children sometimes judge that the satellite is pursuing them, oregon that they tin scope retired and interaction it. It appears to beryllium overmuch person than is proportional to its existent distance. As we determination astir our regular lives, we thin to deliberation that we navigate abstraction successful a linear way.

But Salk scientists person discovered that clip spent exploring an situation causes neural representations to turn successful astonishing ways.

The findings, published in Nature Neuroscience on December 29, 2022, amusement that neurons successful the hippocampus indispensable for spatial navigation, memory, and readying represent space in a mode that conforms to a nonlinear hyperbolic geometry—a three-dimensional expanse that grows outward exponentially. (In different words, it’s shaped similar the interior of an expanding hourglass.)

The researchers besides recovered that the size of that abstraction grows with time spent successful a place. And the size is expanding successful a logarithmic manner that matches the maximal imaginable summation successful accusation being processed by the brain.

This find provides invaluable methods for analyzing information connected neurocognitive disorders involving learning and memory, specified arsenic Alzheimer’s disease.

“Our survey demonstrates that the encephalon does not ever enactment successful a linear manner. Instead, neural networks relation on an expanding curve, which tin beryllium analyzed and understood utilizing hyperbolic geometry and information theory,” says Salk Professor Tatyana Sharpee, holder of the Edwin K. Hunter Chair, who led the study.

“It is breathtaking to spot that neural responses successful this country of the encephalon formed a representation that expanded with acquisition based connected the magnitude of clip devoted successful a fixed place. The effect adjacent held for miniscule deviations successful clip erstwhile carnal ran much dilatory oregon faster done the environment.”

Sharpee’s laboratory uses precocious computational approaches to amended recognize however the encephalon works. They precocious pioneered the usage of hyperbolic geometry to amended recognize biologic signals similar odor molecules, arsenic good arsenic the cognition of smell.

In the existent study, the scientists recovered that hyperbolic geometry guides neural responses arsenic well. Hyperbolic maps of sensory molecules and events are perceived with hyperbolic neural maps.

New experiences are absorbed into neural representations implicit time, symbolized present by a hyperboloid hourglass. Credit: Salk Institute

The abstraction representations dynamically expanded successful correlation with the magnitude of clip the rat spent exploring each environment. And, erstwhile a rat moved much dilatory done an environment, it gained much accusation astir the space, which caused the neural representations to turn adjacent more.

“The findings supply a caller position connected however neural representations tin beryllium altered with experience,” says Huanqiu Zhang, a postgraduate pupil successful Sharpee’s lab.

“The geometric principles identified successful our survey tin besides usher aboriginal endeavors successful understanding neural activity in assorted encephalon systems.”

“You would deliberation that hyperbolic geometry lone applies connected a cosmic scale, but that is not true,” says Sharpee.

“Our brains enactment overmuch slower than the speed of light, which could beryllium a crushed that hyperbolic effects are observed connected graspable spaces alternatively of astronomical ones. Next, we would similar to larn much astir however these dynamic hyperbolic representations successful the brain grow, interact, and pass with 1 another.”

Other authors see P. Dylan Rich of Princeton University and Albert K. Lee of the Janelia Research Campus astatine the Howard Hughes Medical Institute.

About this spatial cognition probe news

Author: Press Office
Source: Salk Institute
Contact: Press Office – Salk Institute
Image: The representation is credited to Salk Institute

Original Research: Open access.
“Hippocampal spatial representations grounds a hyperbolic geometry that expands with experience” by Huanqiu Zhang et al. Nature Neuroscience

Abstract

Hippocampal spatial representations grounds a hyperbolic geometry that expands with experience

Daily acquisition suggests that we comprehend distances adjacent america linearly. However, the existent geometry of spatial practice successful the encephalon is unknown.

Here we study that neurons successful the CA1 portion of rat hippocampus that mediate spatial cognition correspond abstraction according to a non-linear hyperbolic geometry. This geometry uses an exponential standard and yields greater positional accusation than a linear scale.

We recovered that the size of the practice matches the optimal predictions for the fig of CA1 neurons. The representations besides dynamically expanded proportional to the logarithm of clip that the carnal spent exploring the environment, successful correspondence with the maximal communal accusation that tin beryllium received. The dynamic changes tracked adjacent tiny variations owed to changes successful the moving velocity of the animal.

These results show however neural circuits execute businesslike representations utilizing dynamic hyperbolic geometry.