`Degeneracy' in network function has been observed in a number of species. In these situations one particular pattern of motor activity is encoded by more than one set of cellular and synaptic properties. A question of general interest is: how does this impact network function? Experiments proposed in this application will study degeneracy in a multi-tasking network in the context of `task' switching, i.e., the cessation of one type of motor program and the initiation of another. We will test a novel hypothesis that postulates that the ability to `task' switch is determined by the nature of the mechanisms that are used to pattern activity. In particular, we suggest that this is likely to be the case in a commonly observed situation, i.e., in the situation where modulatory neurotransmitters play an important role in configuring neural activity. Effects of modulatory transmitters generally persist, which creates a form of implicit memory. We suggest that this implicit memory can either impede or promote task switching. In more specific terms, our experiments are conducted in an experimentally advantageous network that mediates feeding related behaviors. Our experiments take advantage of considerable preliminary data that indicate that egestive patterns of motor activity can be induced in this network in at least two ways, i.e., they are encoded as two distinct sets of cellular and synaptic properties. Proposed experiments will determine whether this is the case, and will contrast transitions to ingestive activity from the two types of egestive configurations. We suggest that in one situation the network will be able to change the nature of the motor program relatively quickly, whereas in the other situation it will not. We will determine why this is the case in experiments that will analyze underlying mechanisms at both the circuit and cellular/molecular level. Switches in network activity are important for the survival of most species. In humans, costs associated with task switching can significantly impact performance. Nevertheless cellular and molecular mechanisms that facilitate or impede task switching have not been described. To our knowledge we are the only group working in a tractable model system that is studying this phenomenon at a cellular/molecular level.

Public Health Relevance

Research addresses a fundamental question in basic Neuroscience and will test a hypothesis that postulates that the ability of a network to `task' switch is determined by the nature of the cellular/molecular mechanisms that are used to pattern activity. Task switching is important for the survival of most species and when it does not occur efficiently task switch costs are observed. In humans task switch costs significantly impact productivity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS070583-07
Application #
9355473
Study Section
Neurobiology of Learning and Memory Study Section (LAM)
Program Officer
Gnadt, James W
Project Start
2010-02-01
Project End
2021-07-31
Budget Start
2017-08-01
Budget End
2018-07-31
Support Year
7
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Icahn School of Medicine at Mount Sinai
Department
Neurosciences
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
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Jing, Jian; Alexeeva, Vera; Chen, Song-An et al. (2015) Functional Characterization of a Vesicular Glutamate Transporter in an Interneuron That Makes Excitatory and Inhibitory Synaptic Connections in a Molluscan Neural Circuit. J Neurosci 35:9137-49

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