Do you know that emotions increase activity in the visual cortex, so “colors look more vivid and details stand out when we’re happy, angry, or frightened”? Or that hair cells play a vital function in hearing and that as we get older the “progressive loss of hair cells means less acute hearing, particularly in higher frequencies”? How about that olfactory receptor cells are themselves neurons that are “on one end in direct contact with the external world and the other in direct contact with the brain”? Have you ever wanted to learn more about how our senses function?
Many factors weigh into how we perceive the world, and last night we tapped into two areas: hearing and memory, at a “Pint of Science” gathering at DROM in the East Village. Beer in hand, attendees packed the venue, eager to learn more from hometown scientists James Hudspeth of Rockefeller University and Paula Croxson of Mount Sinai.
Hudspeth, a Dana Alliance member and hearing expert, spoke about how hearing works, and the role of tiny hair cells in the cochlea. As explained on his Howard Hughes Medical Institute page, “Each cochlea normally contains about 16,000 hair cells, which convert mechanical inputs derived from sounds into electrical signals that the brain can interpret.”
It is the loss of these hair cells, which don’t regenerate in humans, that leads to the most common form of hearing loss, said Hudspeth. Lucky for us, other species can regenerate these cells (amphibians and reptiles, for example). Dr. Hudspeth is using zebra fish in his lab to study this ability; he hopes new therapies can be produced for people in the next five to ten years. In the meantime, cochlear implants are being used by more than 300,000 people in the US.
Topics at this year’s annual meeting of American Association for the Advancement of Sciences (AAAS) ranged from genome editing to the gravitational waves of black holes. Many of the neuroscience-related talks and panels focused on the senses and perception: I heard a lot about hearing this year. Here are some highlights:
Kids: “We tend to think of kids as being the source of noise, not the victims of noise,” said Nan Bernstein Ratner of University of Maryland, College Park, who organized a symposium on effects of noise on children. But not only do small children not have access to the volume control when the TV is too loud, they have not yet mastered the ability to sort out important (speech) sounds from other noise.
We traditionally refer to five senses: sight, hearing, taste, smell, and touch. But it’s not that simple. Our new primer, on the senses, delves into the complex systems that enable us to connect to the world.
It’s a dynamic process. The brain is not simply a receiving station for sensory signals, and what we see, hear, and feel are constantly shaped by emotions, memories, moods, and beliefs. Our sense of the world is a creation of the brain, and the same physical sensation may be experienced quite differently at different times of life, and even from day to day.
Read Part I of the primer now; Part II will post on the Dana Foundation homepage on Monday, August 26.
– Ann L. Whitman
Americans are pretty traditional in their Independence Day celebrations, mostly sticking to a day of barbeques and fireworks. So to prepare and improve these activities, check out several science stories related to the holiday experience.
I don’t know about you, but on a hot day, after eating a salty cheeseburger, I go straight for the ice cream. It’s just so good that I eat it too quickly, and, d’oh!, ice cream headache. In a short video, Ferris Jabr of Scientific American explains the science behind this phenomenon, also known as brain freeze, and how to get rid of it or avoid it entirely.