Understanding How The Brain Distinguishes Between Stuff And Things

Imagine a shot bouncing down a formation of stairs. Now deliberation astir a cascade of h2o flowing down those aforesaid stairs. The shot and nan h2o behave very differently, and it turns retired that your encephalon has different regions for processing ocular accusation astir each type of beingness matter.

In a caller study, MIT neuroscientists person identified parts of nan brain's ocular cortex that respond preferentially erstwhile you look astatine "things" - that is, rigid aliases deformable objects for illustration a bouncing ball. Other encephalon regions are much activated erstwhile looking astatine "stuff" - liquids aliases granular substances specified arsenic sand.

This distinction, which has ne'er been seen successful nan encephalon before, whitethorn thief nan encephalon scheme really to interact pinch different kinds of beingness materials, nan researchers say. 

When you're looking astatine immoderate fluid aliases gooey stuff, you prosecute pinch it successful different measurement than you do pinch a rigid object. With a rigid object, you mightiness prime it up aliases grasp it, whereas pinch fluid aliases gooey stuff, you astir apt are going to person to usage a instrumentality to woody pinch it."

Nancy Kanwisher, nan Walter A. Rosenblith Professor of Cognitive Neuroscience; a personnel of nan McGovern Institute for Brain Research and MIT's Center for Brains, Minds, and Machines; and nan elder writer of nan study

MIT postdoc Vivian Paulun, who is joining nan module of nan University of Wisconsin astatine Madison this fall, is nan lead writer of nan paper, which appears coming successful nan journal Current Biology. RT Pramod, an MIT postdoc, and Josh Tenenbaum, an MIT professor of encephalon and cognitive sciences, are besides authors of nan study.

Stuff vs. things

Decades of encephalon imaging studies, including early activity by Kanwisher, person revealed regions successful nan brain's ventral ocular pathway that are progressive successful recognizing nan shapes of 3D objects, including an area called nan lateral occipital analyzable (LOC). A region successful nan brain's dorsal ocular pathway, known arsenic nan frontoparietal physics web (FPN), analyzes nan beingness properties of materials, specified arsenic wide aliases stability.

Although scientists person learned a awesome woody astir really these pathways respond to different features of objects, nan immense mostly of these studies person been done pinch coagulated objects, aliases "things." 

"Nobody has asked really we comprehend what we telephone 'stuff' - that is, liquids aliases sand, honey, water, each sorts of gooey things. And truthful we decided to study that," Paulun says.

These gooey materials behave very otherwise from solids. They travel alternatively than bounce, and interacting pinch them usually requires containers and devices specified as spoons. The researchers wondered if these beingness features mightiness require nan encephalon to give specialized regions to interpreting them.

To research really nan encephalon processes these materials, Paulun utilized a software programme designed for ocular effects artists to create much than 100 video clips showing different types of things aliases worldly interacting pinch nan beingness environment. In these videos, nan materials could beryllium seen sloshing aliases tumbling wrong a transparent box, being dropped onto different object, aliases bouncing aliases flowing down a group of stairs. 

The researchers utilized functional magnetic resonance imaging (fMRI) to scan nan ocular cortex of group arsenic they watched nan videos. They recovered that some nan LOC and nan FPN respond to "things" and "stuff," but that each pathway has unique subregions that respond much powerfully to 1 aliases nan other.

"Both nan ventral and nan dorsal ocular pathway look to person this subdivision, pinch 1 portion responding much powerfully to 'things,' and nan different responding much powerfully to 'stuff,'" Paulun says. "We haven't seen this earlier because cipher has asked that before."

Physical interactions

The findings propose that nan encephalon whitethorn person different ways of representing these 2 categories of material, akin to nan artificial physics engines that are utilized to create video crippled graphics. These engines usually correspond a 3D entity arsenic a mesh, while fluids are represented arsenic sets of particles that tin beryllium rearranged. 

"The absorbing presumption that we tin tie from this is that possibly nan brain, akin to artificial crippled engines, has abstracted computations for representing and simulating 'stuff' and 'things.' And that would beryllium thing to trial successful nan future," Paulun says.

The researchers besides hypothesize that these regions whitethorn person developed to thief nan encephalon understand important distinctions that let it to scheme really to interact pinch nan beingness world. To further research this possibility, nan researchers scheme to study whether nan areas progressive successful processing rigid objects are besides progressive erstwhile a encephalon circuit progressive successful readying to grasp objects is active. 

They besides dream to look astatine whether immoderate of nan areas wrong nan FPN correlate pinch nan processing of much circumstantial features of materials, specified arsenic nan viscosity of liquids aliases nan bounciness of objects. And successful nan LOC, they scheme to study really nan encephalon represents changes successful nan style of fluids and deformable substances.

The investigation was funded by nan German Research Foundation, nan U.S. National Institutes of Health, and a U.S. National Science Foundation assistance to nan Center for Brains, Minds, and Machines.