Lawrence Baruch Cohen PhD
Professor of Cellular and Molecular Physiology
Brain; Central Nervous System; Neurons; Vertebrate Physiology; Olfaction; Olfactory Bulb; Protein Sensors of Voltage and Calcium
Current ProjectsOne active area is development of protein sensors of membrane potential. At present the voltage signals are either to slow or too small. We hope to fine a sensor that is both fast and has a large signal.
A second area is understanding the role of the mammalian olfactory bulb in olfactory processing. We want to know what the interneurons do and we want to compare the input (now well known) with the output (now a black hole).
One reason the brain is difficult to study is that many individual neurons or brain areas are active at once; conventional techniques allow one to monitor only one or a few neurons or locations at a time. We have worked on two variations of an optical method for measuring brain activity; both utilize voltage-sensitive or Calcium-sensitive dyes and a fast camera with frame rates of 1 kHz or a 2-photon microscope. In the first variation, we use the dyes and a 2-photon microscope to follow the spike activity of individual neurons, and in favorable preparations about 500 individual neurons can be monitored simultaneously. We hope that monitoring many neurons simultaneously will improve our understanding about how nervous systems are organized to generate behaviors. In the second variation, each pixel in the recording receives light from a large number of neurons and processes (e.g. from an area of cortex 20 um x 20 um) and thus each signal represents the average of a population of neurons. There are several interesting aspects of vertebrate brain function where populations are involved.