Inberg, Sharon et al. (2017) International Worm Meeting "Mechanosensory experience determines nociceptive and proprioceptive behavioral plasticity."

Podbilewicz, Benjamin, Inberg, Sharon, Iosilevskii , Yael

[International Worm Meeting, 2017]

We are interested in how animals adjust their innate behavioral outputs in response to sensory experience. C. elegans has the ability to undergo molecular, cellular and behavioral plasticity. Our sensory experience paradigm involves comparing isolated worms, to those that were grown in crowded conditions. We found that animals grown in isolation exhibit a change in the arborized dendritic structure of the PVD nociceptor neuron. To test behavioral consequences of mechanosensory isolation we used two assays to measure the response to high threshold mechanosensory stimulation and proprioception. We found that isolation induced a decrease in response to harsh touch that was gentle touch-independent, since mec-4 touch-insensitive worms show the same isolation-induced reduction in response to harsh touch. The reduction in the responsiveness was also demonstrated by optogenetic stimulation of the PVD, where isolated worms exhibit reduced responsiveness. These findings suggest that the presynaptic activities of the PVD are responsible for the experience induced behavioral plasticity. To reveal the mechanisms mediating these behavioral changes we used mutants for a family of voltage independent sodium channels (Degenerins). We tested mutations on different degenerins for isolation-induced behavioral plasticity and three were found to have reproducible effects: asic-1, mec-10, and degt-1. Most of the combinations of these three genes failed to induce the behavioral plasticity for the response to harsh touch following isolation, indicating that degenerins are important for the experience induced plasticity in response to harsh touch. In parallel to the nociceptive changes following isolation, a change in the proprioception of the worms was observed. Specifically, isolation induced an increase in the wavelength and the amplitude of crawling worms, without any effect on the velocity or the total tracking length covered by the worms. As controls, we isolated worms with glass beads in their plates and we observed partial rescue of the proprioceptive phenotype, indicating that the isolation induced change is mediated by mechanosensory signals. Taken together, we propose that nociceptive and propioceptive innate behavioral repertoires that are mediated by the PVD are plastic and dependent on the amount of mechanosensory experience and a combination of the activities of three degenerins.

Inberg, Sharon et al. (2015) International Worm Meeting "Mechanosensory stimulation controls behaviour andPVD dendritic tree menorah structure."

Inberg, Sharon, Podbilewicz, Benjamin

[International Worm Meeting, 2015]

Many discoveries in neurosciences revealed the interconnections between epigenetic, synaptic and circuit modifications to sensory experience and behaviour. In contrast, very little is known about how neuronal activity and sensory experience influence the structure and function of dendritic trees.To study whether mechanosensory stimulation affects behaviour and the dendritic tree architecture, we used natural mechanical stimulation with signals that are generated by physical contacts between worms. We first compared grouped to single isolated embryos to test the influence of mechanosensory experience on behaviour using a paradigm established by the Rankin lab (Rose et al. 2005). We found that worm isolation affected two behaviours: First, it altered the sinusoidal waveforms produced during worm movement. Second, it decreased the number of responses generated by the adult following harsh mechanical stimulation.We then asked whether the morphology of the polymodal mechanosensory PVD is affected by mechanical isolation, focusing on the number and geometry of its repetitive dendritic trees that are similar to "menorahs" (Oren-Suissa et al. 2010). We found that isolation of both larvae and adult worms significantly affected two parameters of PVD structure: First, it increased the number of dendritic branches. Second, it modified the straight geometry of the "candles" of the menorahs (quaternary branches), into wavy structures. Moreover, when we isolated worms with glass beads, that function as static mechanical stimulators in the plate, the reduction in the number of straight quaternary branches following isolation was rescued. In contrast, isolation of worms following chemical stimulation (with plates previously exposed to worms) resulted in similar effect on the PVD, as without chemical stimulation.In conclusion, our observations indicate that mechanical isolation induces changes in dendritic branching architecture of the PVD. We found that the menorahs structural plasticity is accompanied by altered behavioural output in functions that are mediated, at least in part, by the PVD. Thus, we propose that mechanical isolation during development and adulthood affects PVD dendritic arbors and these structural changes influence worm behaviour. The genetic basis of these structural and behavioural modifications is currently being characterized.

Susan Carlson et al. (2008) C.elegans Aging, Stress, Pathogenesis, and Heterochrony Meeting "Iowa State University ADVANCE Program's Collaborative Transformation: Advancing Women Faculty in STEM Fields"

Susan Carlson, Jo Anne Powell-Coffman, Lisa Larson, Diane Debinski, Sharon Bird, Kristen Constant, Jan Thompson, Charles Glatz, Bonnie Bowen, Carla Fehr, Fred Janzen, Sandra Gahn, Florence Hamrick

[C.elegans Aging, Stress, Pathogenesis, and Heterochrony Meeting, 2008]

The goal of the NSF-funded ISU ADVANCE program is to investigate the effectiveness of a multilevel collaborative effort to produce institutional transformation that results in the full participation of women faculty in science, technology, engineering and math fields in the university. Our approach focuses on transforming departmental cultures, practices, and structures, as well as university policies. Here, we summarize the findings of the Collaborative Transformation Project with the 3 departments that participated in the first round (Departments of Genetics, Development, and Cell Biology; Ecology, Evolution, and Organismal Biology; and Material Science and Engineering) (Bird and Hamrick 2008). A 3-step process for departmental transformation includes (1) focus groups to discuss aspects of department culture, practice and structure, (2) needs assessment meetings tailored to meet the needs of individual departments, and (3) collaborative problem solving sessions involving department faculty and ADVANCE program leaders. The findings include 6 major issues common to all 3 departments. Some issues do not specifically address gender or race, but these issues can have a disproportionate effect on underrepresented groups. Each of the 3 focal departments has developed strategies for change that address the issues identified in their departments. Examples of these strategies will be presented. Bird, Sharon R. and Florence A. Hamrick. 2008. ISU ADVANCE Collaborative Transformation Project: First Round Focal Department Synthesis Report. Ames, IA: Iowa State University ADVANCE Program. http://www.advance.iastate.edu