Paul Katz, professor of biology and director of neuroscience, and Vincent Lyzinski, a network expert and assistant professor of mathematics and statistics, recently received a three-year, $3.5 million grant from the NIH’s National Institute of Neurological Disorders and Stroke for a new collaboration between researchers at four universities who will explore the neuron-level mechanisms of how the brain makes decisions.
The project is part of President Obama’s 2013 Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative at NIH, which seeks to accelerate the development and application of new technologies leading to “a revolutionary new dynamic picture of the brain that, for the first time, shows how individual cells and complex neural circuits interact in both time and space.”
Katz says, “It’s a new area of exploration; we’re going to get the complete wiring diagram of the brain of a sea slug and use that information to determine how behaviors are produced at the resolution of individual neurons. It represents a concerted effort to understand how the brain is connected and how neurons produce behaviors.” The research plan includes stimulating the mollusks with the smell of food and watching their neurons as they respond.
As he explains, in mammals, it is difficult or impossible to examine the neural mechanisms that translate a decision into an action because of the complexity of the neural computation, the number of neurons involved and the complexity of the physical change produced by the movement of the animal.To reduce these complexities, Katz and colleagues will study foraging decisions in a very simple animal, the nudibranch mollusk Berghia stephanieae. This sea slug has fewer than 4,000neurons and they are identifiable as individuals or as members of particular classes.
Katz says, “Sea slugs have most of the neurotransmitters that we do but fewer neurons. We can learn general principles by studying such simple animals because they do have behaviors and they do have motivation.”
This project, which will involve collaborating researchers at Harvard University, Rosalind Franklin University and the Scripps Institute of Oceanography at the University of California San Diego, will map the synaptic connectivity of the brain, known as the “connectome,” by serially sectioning the brain and reconstructing neurons and synapses from electron microscopic images.
The RNA expressed by each of the neurons in the brain will be sequenced and transcriptomes mapped onto each neuron in the connectome, Katz says. Transgenic animals will be produced, allowing the team to optically record the activity of neurons as the animal produces behavior. The pattern of activity will then be mapped onto the wiring diagram of the brain to determine how signals are passed through the network and how that network changes as the animal matures.