Behavior is determined not only by stimuli but also by internal states of those behavior generating networks that function as sensory motor-integrators. An important type of network state is an experience-dependent state that relies on the memory of recent experiences. Consequently, to generate responses, networks integrate both current stimuli and memories of recent experiences that are expressed as network states. We propose to study how experience dependent states are generated, expressed, and integrated with stimuli that impinge on the network. Towards this purpose, we will use a well characterized preparation that generates ingestive and egestive responses. We will use a multidisciplinary approach that combines electrophysiological, biochemical and cell-biological techniques. Repetitive stimulation of an input that elicits egestive responses establishes a network state that is manifested in repetition priming, i.e., a progressive increase of egestiveness of the response. Importantly, in the aftermath of repetitive stimulation of egestive inputs, a task switch cost is observed, i.e., stimulation of an ingestive input now elicits egestive rather than ingestive responses. The fact that the same network state has two different manifestations has made it possible to dissociate the functions of network states and network connectivity. Based on a series of recent findings, we propose that the EN- stimulation dependent network state is not implemented through recruitment of a singular set of specialized neurons but instead emerges as a result of the parallel peptidergic modulation of the excitability of several neurons that play a critical role in expressing various manifestations of network states. However, network states are not the sole determinant of responses. We propose that the specificity of responses that networks generate in different states depends not only on the momentary state of the network but also on the characteristics of neuronal connections within the network. Finally, we suggest that the mnemonic component of network states, i.e., persistent modification of neuronal excitability is mediated by peptidergic activation of specific second messenger systems whose role we propose to test. Various forms of pathology of initiation and repetition of movements are observed in Parkinsons disease, autistic children, and are also induced as a result of brain lesions. Thus, it may be hoped that understanding the mechanisms of the phenomena that we propose to study may a novel perspective on these disorders.

Public Health Relevance

We propose to study the neural basis of behavior switching and stability. These two processes are disrupted in childhood autism and Parkinson's disease. These studies may lead to novel insights into the nature of the behavioral deficits in these diseases.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
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Special Emphasis Panel (ZRG1)
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Gnadt, James W
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Icahn School of Medicine at Mount Sinai
Schools of Medicine
New York
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Perkins, Matthew H; Cropper, Elizabeth C; Weiss, Klaudiusz R (2018) Cellular Effects of Repetition Priming in the Aplysia Feeding Network Are Suppressed during a Task-Switch But Persist and Facilitate a Return to the Primed State. J Neurosci 38:6475-6490
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Yang, Chao-Yu; Yu, Ke; Wang, Ye et al. (2016) Aplysia Locomotion: Network and Behavioral Actions of GdFFD, a D-Amino Acid-Containing Neuropeptide. PLoS One 11:e0147335
Cropper, Elizabeth C; Dacks, Andrew M; Weiss, Klaudiusz R (2016) Consequences of degeneracy in network function. Curr Opin Neurobiol 41:62-67
Svensson, Erik; Evans, Colin G; Cropper, Elizabeth C (2016) Repetition priming-induced changes in sensorimotor transmission. J Neurophysiol 115:1637-43
Siniscalchi, Michael J; Cropper, Elizabeth C; Jing, Jian et al. (2016) Repetition priming of motor activity mediated by a central pattern generator: the importance of extrinsic vs. intrinsic program initiators. J Neurophysiol 116:1821-1830

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