Humans perceive numerous categories of objects and actions, but where are these categories represented spatially in the brain? Researchers reporting in the December 20 issue of the Cell Press journal Neuron present their study that undertook the remarkable task of determining how the brain maps over a thousand object and action categories when subjects watched natural movie clips. The results demonstrate that the brain efficiently represents the diversity of categories in a compact space. Instead of having a distinct brain area devoted to each category, as previous work had identified, for some but not all types of stimuli, the researchers uncovered that brain activity is organized by the relationship between categories.
"Humans can recognize thousands of categories. Given the limited size of the human brain, it seems unreasonable to expect that every category is represented in a distinct brain area," says first author Alex Huth, a graduate student working in Dr. Jack Gallant's laboratory at the University of California, Berkeley.
The authors proposed that perhaps a more efficient way for the brain to represent object and action categories would be to organize them into a continuous space that reflects the similarity between categories.
To test this hypothesis, they used blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) to measure human brain activity evoked by natural movies in five people. They then mapped out how 1,705 distinct object and action categories are represented across the surface of the cortex of the brain. Their results show that categories are organized as smooth gradients that cover much of the surface of the visual as well as nonvisual cortex, such that similar categories are located next to each other, and notably, this organization was shared across the individuals imaged.
"Discovering the feature space that the brain uses to represent information helps us to recover functional maps across the cortical surface. The brain probably uses similar mechanisms to map other kinds of information across the cortical surface, so our approach should be widely applicable to other areas of cognitive neuroscience," says Dr. Gallant.
Cell Press: http://www.cellpress.com
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Algorithms developed by Google designed to encode thoughts, could lead to computers with ‘common sense’ within a decade, says leading AI scientist
New fossil evidence suggests dogs emerged as a separate species from wolves far earlier than scientists previously believed
Researchers discover the 425-million-year-old remains of a new species of parasite - still clamped to the host animal it invaded.
It should be raptor egg blue instead of robin egg blue. Some modern birds lay colourful eggs, but now we know it's a trick their dinosaur ancestors used too
WASHINGTON (Reuters) - Scientists on Thursday unveiled the most comprehensive analysis ever undertaken of the world's ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.
Scientists on Thursday unveiled the most comprehensive analysis ever undertaken of the world's ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.
Researchers say they're excited about a new brain implant that allowed a paralyzed patient to control a robotic arm with his mind. Erik Sorto is the first in the world to have this new neural prosthetic device. Elaine Quijano reports.
Genetically, at least, not that much has changed in the billion years since you two last shared a relative. Roughly half the 500 genes yeast need for life are interchangeable with the human versions.
What controls aging? Biochemist Cynthia Kenyon has found a genetic mutation that can more than double the lifespan of a tiny worm, which points to how we might one day significantly extend human life.
Java sparrows amp up their tunes with acoustic beak taps synchronized with chirps