Rinberg hopes to carry his research more deeply into the brain to see how other regions of the organ aid in perceiving odors and objects once they receive information from the olfactory bulb.
The film features a world ceded to intelligent computers that relegate humans to a shared simulated reality created in their brains—similar to the way the researchers devised an artificial odor. He graduated from the University of Virginia School of Medicine in Already a subscriber?
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Get smart. Sign up for our email newsletter. Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? The scientists asked the network to assign data representing different odors to categories, and to correctly categorize not just single odors, but also mixtures of odors.
If you combine the scents of two different apples, he explains, the brain still smells apple. In contrast, if two photographs of cats are blended pixel by pixel, the brain no longer sees a cat. It took the artificial network only minutes to organize itself. The structure that emerged was stunningly similar to that found in the fruit fly brain. Each neuron in the compression layer received inputs from a particular type of input neuron and connected, seemingly randomly, to multiple neurons in the expansion layer.
The surprising convergence provides strong support that the brain circuits that interpret olfactory information are optimally organized for their task, he says. Now, researchers can use the model to further explore that structure, exploring how the network evolves under different conditions and manipulating the circuitry in ways that cannot be done experimentally.
Previous item Next item. Massachusetts Institute of Technology. Search MIT. Search websites, locations, and people. Enter keywords to search for news articles: Submit. Browse By. Artificial networks learn to smell like the brain. Publication Date :. Press Inquiries. Identifying the smell as freshly baked bread is a complicated process. But, compared to the other senses, the sense of smell is often underappreciated.
In a survey of 7, young people around the world, about half of those between the age of 16 and 30 said that they would rather lose their sense of smell than give up access to technology like laptops or cell phones. But 5 percent of our DNA is devoted to olfaction, a fact that emphasizes how important our sense of smell is, he said.
Smell begins at the back of nose, where millions of sensory neurons lie in a strip of tissue called the olfactory epithelium. The tips of these cells contain proteins called receptors that bind odor molecules. The receptors are like locks and the keys to open these locks are the odor molecules that float past, explains Leslie Vosshall , a scientist who studies olfaction at Rockefeller University. People have about different types of olfactory receptors.
For comparison, dogs have about two times as many. Each receptor can be activated by many different odor molecules, and each odor molecule can activate several different types of receptors. Two of the keys are a perfect fit and open the door easily.
The complexity of receptors and their interactions with odor molecules are what allow us to detect a wide variety of smells. And what we think of as a single smell is actually a combination of many odor molecules acting on a variety of receptors, creating an intricate neural code that we can identify as the scent of a rose or freshly-cut grass. Once an odor molecule binds to a receptor, it initiates an electrical signal that travels from the sensory neurons to the olfactory bulb , a structure at the base of the forebrain that relays the signal to other brain areas for additional processing.
One of these areas is the piriform cortex, a collection of neurons located just behind the olfactory bulb that works to identify the smell.
Smell information also goes to the thalamus, a structure that serves as a relay station for all of the sensory information coming into the brain.
The thalamus transmits some of this smell information to the orbitofrontal cortex, where it can then be integrated with taste information. What we often attribute to the sense of taste is actually the result of this sensory integration. This coupling of smell and taste explains why foods seem lackluster with a head cold. This happens because the thalamus sends smell information to the hippocampus and amygdala , key brain regions involved in learning and memory.
Although scientists used to think that the human nose could identify about 10, different smells, Vosshall and her colleagues have recently shown that people can identify far more scents.
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