Vapor Detection and Discrimination with a Panel of Odorant Receptors

Model diagram to show that the authors measured the amount of luminescence (glow) over time in the cells, and then they used the area under the curve (AUC) as the number they reported to determine response to the odorants.

Today I learned: that scientists have been trying to create artificial “noses”. Traditionally, dogs and other animals have been trained to identify specific smells like cancer, drugs, toxins, etc. But recent research is trying to design these artificial systems that could act as a way to screen for many odors at once. This groups of scientists used cells grown in the lab that have an olfactory receptor (OR) and proteins inside the cell that cause the cell to light up when an odorant (chemical that has a smell) is recognized by the OR. This works because in mammals, when an OR recognizes an odorant, that OR then becomes “activated” and transmits a signal into the cell. The cell then passes that message along to another cell, which passes it onto the area of the brain that processes these signals and tells us what we are smelling. They used seven odorants — ranging from those that smell like cloves to those that smell like banana — and tested them with many different ORs to see how much the cells lit up. With this they were able to identify specifically which ORs responded to which smells and how sensitively they could respond. This system can be used to help create systems that can discriminate between odorants, even if they look very similar in structure.

Reference: Kida, Hitoshi, et al. “Vapor Detection and Discrimination with a Panel of Odorant Receptors.” Nature Communications, vol. 9, no. 1, 2018, doi:10.1038/s41467-018-06806-w.

Musicophilia by Oliver Sacks

If you’re someone who loves music, is a musician, and/or just really likes to learn about the brain, then I highly recommend that you read Musicophilia by Oliver Sacks. I originally chose this book because I love music to the point where I probably spend about 75% of my day with music playing in the background, and I wanted to learn more about how the brain processes music. That being said, I learned far more than I expected, and I was consistently blown away by how complex the brain is and the idiosyncratic ways it manages to function in spite of damage or deterioration. For a scientific field that didn’t really take hold until the 1980s, the amount of information that the neuroscience of music has uncovered is already impressive. Oliver Sacks is probably one of the more well-known science writers, and for good reason. He continually brings a poetic writing style to his books that grabs the imagination of the reader. Once he reels you in with that, he keeps your attention with how he writes about his patients and other medical anecdotes; always blending traditional observation with touches of personal experiences and empathy.

Continue reading…

Distinct Patterns of Brain Activity Mediate Perceptual and Motor and Autonomic Responses to Noxious Stimuli

experimental set-up showing that the scientists randomized the time between laser pulses and how strong the pulses were. Perception (how it felt), motor (reaction time), and autonomic (skin conductance) responses were measured after laser pulses.

Experimental design from Tiemann et al.

Today I learned: a group of scientists figured out that distinct brain responses are involved in mediating our response to pain (noxious stimulus) via motor (movement), perceptual (feeling), and autonomic (unconscious body reactions like signal conducting) responses. To figure out this stimulus-brain-outcome relationship they measured motor (reaction times), perceptual (pain rating 0-100), autonomic (skin conductance), and brain (brain waves) responses to a series of random laser pulses (varied in both the time between pulses and the intensity of the pulses). As expected, more intense laser pulses caused the participants to have a faster reaction time, a higher pain rating, and stronger skin conductance measurements. But what was really interesting about this study was that they found that of the four brain waves they measured, not all were responsible for every response. Rather, each brain wave was involved in mediating either only one or two of the responses to the laser pulses. And contrary to what most people would expect, the earliest brain waves were not involved in the perception response, which means that you don’t need to consciously perceive the painful stimulus in order to have a motor or autonomic response.

Reference: Tiemann, Laura, et al. “Distinct Patterns of Brain Activity Mediate Perceptual and Motor and Autonomic Responses to Noxious Stimuli.” Nature Communications, vol. 9, no. 1, 2018, doi:10.1038/s41467-018-06875-x.