UMass Neurosciences Director, Paul Katz received a $3.5 Million grant from the NIH Brain Initiative to lead a team of researchers from four universities to study the brain of a nudibranch. The grant is entitled “A 5-dimensional connectomics approach to the neural basis of behavior” because it examines the brain 3 dimensions of space and 2 dimensions of time: real time and developmental time. The researchers seek to build a complete wiring diagram of the brain of the nudibranch, Berghia stephanieae, which only has about 4000 neurons. This is much less complex than mammalian brains and even less complex than the brain of a fruit fly. However it is more complex that the only nervous system for which there is a complete wiring diagram, the nematode, C. elegans, which has only 300 neurons. Katz is collaborating with Jeff Lichtman at Harvard University reconstruct all of the neurons and synapses from electron microscopic images. In addition, UMass post-doctoral fellow Desmond Ramirez is building a light level atlas of the Berghia brain with fluorescence images. Ramirez is also using high-throughput RNA sequencing to map the genes that are expressed in each neuron back onto that brain atlas.
The combination of the EM, light, and single neuron RNAseq approaches will provide a wealth of network data. UMass Mathematics professor, Vincent Lyzinski, who is a co-PI on the grant, is an expert on network analysis and will probe the resulting data to look for structure. The team will also examine how the network develops as the sea slugs grow from having about 1000 neurons to their adult size. Collaborator, Deirdre Lyons at the Scripps Institution of Oceanography at the University of California San Diego is sequencing the genome of Berghia and attempting to express exogenous genes in neurons. The goal is to create transgenic sea slugs that express genetically-encoded activity sensors in their neurons, allowing brain activity to be monitored while the animals behave. William Frost at Rosalind Franklin University will record neuronal activity while the animals are producing behaviors, which the Katz lab is characterizing. The researchers hope to develop new ways of analyzing and interpreting large ensembles of neurons and how they produce behaviors.