Axon Guidance Autonomy and Tensional Requirement for Synaptic Function: Is Learning a Forced Response?

Individual neurons extend multiple processes whose growth cones exhibit different responses to their environment. In culture, detached growth cones display guidance autonomy, contain mRNA for cytoskeletal and other axonal components, and are capable of synthesizing protein locally. However, the extent to which growth cone\u27s autonomy contributes to its pathfinding function within the complex in vivo environment is unknown. Here, we show that detached axonal growth cones from identified Drosophila motoneurons maintain balanced filopodial activities as they extend, navigate and target postsynaptic partner cells normally. After detachment, the growth cones continue to synthesize the synaptic vesicle protein Synaptotagmin but, upon contacting targets, fail to concentrate it at the presynaptic site normally. However, if held by a micropipette that resupplies mechanical tension, the growth cones\u27 ability to localize synaptic vesicles is restored. Our results demonstrate functional autonomy of axonal growth cones as they navigate and initiate synaptogenesis, while implicating intercellular tension as a novel retrograde mechanism to adjust synaptic function

Natural Sciences at Parkland College -- Spring 2017

This issue of the Natural Sciences Newsletter features an article on the SciCommons, an open tutoring center for Natural Sciences students at Parkland, a report on the seventh annual Illinois Science Olympiad Regional Tournament, submissions from the Astronomy Club and Science Club, a summary of the Laboratory Skills Assessment Survey, an article on internationalizing curriculum, and an article on the local March for Science (April 22, 2017)

Natural Sciences at Parkland College - Fall 2017

The Parkland College Natural Sciences Department Newsletter for Fall 2017 -- this issue features an article on IR cameras, use of display case, engaging students outside the classroom with the Astronomy Club and the Parkland Science Club, the solar eclipse, updates from the professional development subcommittee for faculty, summaries from events and meetings, a report on Phenotypic Pasticity Research Experience for Community College Students (PRECS) first summer, and a special feature from former professor Rich Blazier, with a special feature on the history of the Natural Sciences Department

Natural Sciences at Parkland College

The Parkland College Natural Sciences Department Newsletter for Spring 2018 -- this issue features a review of ZipGrade, a summary of efforts to provide Green Infrastructure Certification at Parkland, a report on the Illinois Science Olympiad (Parkland has hosted the Regional Tournament for eight years), news from Phi Theta Kappa and the Natural Sciences Club, and on the Planetarium\u27s upcoming upgrade, as well as what what to expect with the new D2L/Cobra upgrade, a celebration of Parkland Teaching Excellence Award winner Chris Warren, and the second part in a series on the history of Natural Sciences at Parkland by former Parkland instructor and Department Chair, Rich Blazier

Axon Guidance Autonomy and Tensional Requirement for Synaptic Function: Is Learning a Forced Response

45 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.Individual neurons extend multiple processes whose growth cones exhibit different responses to their environment. In culture, detached growth cones display guidance autonomy, contain mRNA for cytoskeletal and other axonal components, and are capable of synthesizing protein locally. However, the extent to which growth cone's autonomy contributes to its pathfinding function within the complex in vivo environment is unknown. Here, we show that detached axonal growth cones from identified Drosophila motoneurons maintain balanced filopodial activities as they extend, navigate and target postsynaptic partner cells normally. After detachment, the growth cones continue to synthesize the synaptic vesicle protein Synaptotagmin but, upon contacting targets, fail to concentrate it at the presynaptic site normally. However, if held by a micropipette that resupplies mechanical tension, the growth cones' ability to localize synaptic vesicles is restored. Our results demonstrate functional autonomy of axonal growth cones as they navigate and initiate synaptogenesis, while implicating intercellular tension as a novel "retrograde" mechanism to adjust synaptic function.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Learning by Tension

Memory and learning in animals is mediated by neurotransmission at the synaptic junctions (end point of axons). Neurotransmitters are carried by synaptic vesicles which cluster at the junctions, ready to be dispatched for transmission. The more a synapse is used, higher is the clustering, and higher is the neurotransmission efficiency (plasticity), i.e., the junction “remembers” its use in the near past, and modifies accordingly. This usage dependent plasticity offers the basic mechanism of memory and learning. A central dogma in neuroscience is that, clustering is the result of a complex biochemical signaling process. We show, using MEMS sensors and fruit fly (Drosophila) embryo nervous system, that mechanical tension in axons is essential for clustering. Without tension, clustering disappears, but reappears with application of tension. Nature maintains a rest tension of 1nN in axons of Drosophila for learning and memory