Developing Our Sense of Smell

When our noses pick up a scent, whether the aroma of a sweet rose or the sweat of a stranger at the gym, two types of sensory neurons are at work in sensing that odor or pheromone. These sensory neurons are particularly interesting because they are the only neurons in our bodies that regenerate throughout adult life—as some of our olfactory neurons die, they are soon replaced by newborns. Just where those neurons come from in the first place has long perplexed developmental biologists. Previous hypotheses about the origin of these olfactory nerve cells have given credit to embryonic cells that develop into skin or into the central nervous system, where ear and eye sensory neurons, respectively, are known to originate. But biologists at the California Institute of Technology (Caltech) have now found that neural-crest stem cells—multipotent, migratory cells unique to vertebrates that give rise to many structures in the body such as facial bones and smooth muscle—also play a key role in building olfactory sensory neurons in the nose.

The First Genetic-Linkage Map

A hand-drawn map published 100 years ago held the first proof that chromosomes carry our genetic material.

Mayo Appointed to National Science Board

President Barack Obama has appointed Stephen Mayo, Caltech's William K. Bowes Jr. Foundation Chair of the Division of Biology and Bren Professor of Biology and Chemistry, to the National Science Board, the governing body of the National Science Foundation.

Sorting Out Stroking Sensations

The skin is a human being's largest sensory organ, helping to distinguish between a pleasant contact, like a caress, and a negative sensation, like a pinch or a burn. Previous studies have shown that these sensations are carried to the brain by different types of sensory neurons that have nerve endings in the skin. Only a few of those neuron types have been identified, however, and most of those detect painful stimuli. Now biologists at the California Institute of Technology (Caltech) have identified in mice a specific class of skin sensory neurons that reacts to an apparently pleasurable stimulus.

Research Update: Wordy Worms and Their Eavesdropping Predators

For over 25 years, Paul Sternberg has been studying worms—how they develop, why they sleep, and, more recently, how they communicate. Now, he has flipped the script a bit by taking a closer look at how predatory fungi may be tapping into worm conversations to gain clues about their whereabouts.

Social Synchronicity

Humans have a tendency to spontaneously synchronize their movements. For example, the footsteps of two friends walking together may synchronize, although neither individual is consciously aware that it is happening. Similarly, the clapping hands of an audience will naturally fall into synch. Although this type of synchronous body movement has been observed widely, its neurological mechanism and its role in social interactions remain obscure. A new study, led by cognitive neuroscientists at the California Institute of Technology (Caltech), has found that body-movement synchronization between two participants increases following a short session of cooperative training, suggesting that our ability to synchronize body movements is a measurable indicator of social interaction.

Brain Control with Light

Viviana Gradinaru (BS '05) might one day be getting inside your head—but in a good way. An assistant professor of biology at Caltech, Gradinaru is trying to map out the brain's wiring diagrams. Gradinaru will discuss her work at 8:00 p.m. on Wednesday, December 5 in Caltech's Beckman Auditorium. Admission is free.

An Eye for Science: In the Lab of Markus Meister

Take one look around Markus Meister's new lab and office space on the top floor of the Beckman Behavioral Biology building, and you can tell that he has an eye for detail. Curving, luminescent walls change color every few seconds, wrapping around lab space and giving a warm glow to the open, airy offices that line the east wall. A giant picture of neurons serves as wallpaper, and a column is wrapped in an image from the inside of a retina. And while he may have picked up some tips from his architect wife to help direct the design of his lab, Meister is the true visionary—a biologist studying the details of the eye.

A Fresh Look at Psychiatric Drugs

Drugs for psychiatric disorders such as depression and schizophrenia often require weeks to take full effect. "What takes so long?" has formed one of psychiatry's most stubborn mysteries. Now a fresh look at previous research on quite a different drug—nicotine—is providing answers. The new ideas may point the way toward new generations of psychiatric drugs that work faster and better.

Developmental Bait and Switch

During the early developmental stages of vertebrates—animals that have a backbone and spinal column, including humans—cells undergo extensive rearrangements, and some cells migrate over large distances to populate particular areas and assume novel roles as differentiated cell types. Understanding how and when such cells switch their purpose in an embryo is an important and complex goal for developmental biologists. A recent study, led by researchers at the California Institute of Technology (Caltech), provides new clues about this process—at least in the case of neural crest cells, which give rise to most of the peripheral nervous system, to pigment cells, and to large portions of the facial skeleton.


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