Nathaniel Sawtell, PhD
- Associate Professor of Neuroscience
Unraveling the functions of neural circuits is a fundamental challenge for neuroscience. Research in my laboratory focuses on understanding the functions of cerebellum-like sensory structures and the cerebellum in fish and mammals. We are also interested in understanding the neural mechanisms through which past experience and sensorimotor context affect early stages of sensory processing. Cerebellum-like structures associated with electrosensory systems in fish offer a number of advantages for linking synaptic, cellular, and circuit properties with systems level functions. First, the functional circuitry of cerebellum-like structures is relatively simple and well characterized. Second, a plausible systems level function for cerebellum-like structures has been identified.
In vivo studies conducted in several phylogenetically distinct groups of fish have shown that cerebellum-like circuits act as an adaptive filter—learning and removing predictable features of the sensory input, for example those due to the animal's own behavior. Adaptive filtering allows unpredictable and thus behaviorally relevant features of the sensory input to be processed more easily. A combination of experimental and modeling studies have led to a hypothesis regarding how this adaptive filtering is implemented in cerebellum-like circuits. Key ingredients include: (1) principal neurons that integrate peripheral electrosensory input with a diverse array of sensory and motor information conveyed by parallel fibers and (2) anti-Hebbian spike timing-dependent plasticity at parallel fiber synapses onto principal cells. One goal of research in the lab is to deepen and extend our understanding of the cellular and circuit mechanisms underlying the generation and use of sensory predictions in the electrosensory lobe of weakly electric mormyrid fish.
Predicting sensory events is of general importance both for sensory processing and motor control. Intriguingly, several lines of evidence suggest that the mammalian cerebellum itself is involved in generating such predictions. A second focus of our research is to extend studies of sensory predictions in fish to other cerebellum-like structures and to the cerebellum itself. Initial studies will include tests of the adaptive filter hypothesis in the mammalian dorsal cochlear nucleus and investigations of regions of the mormyrid cerebellum closely associated with electrosensory processing.
- Synapses and Circuits
- Sensory Physiology
- Neurobiology of Learning and Memory
- Cognitive/Systems Neuroscience
- Systems and Circuits
CEREBELLAR CIRCUITRY IN THE PATHOPHYSIOLOGY OF TREMOR (Federal Gov)
Sep 5 2018 - Jun 30 2023
MECHANISMS FOR INTERNAL MODELS IN A CEREBELLUM-LIKE CIRCUIT (Federal Gov)
Jul 1 2016 - May 31 2021
MECHANISMS FOR CANCELLING SELF-GENERATED SOUNDS IN THE MOUSE DORSAL COCHLEAR NUCLEUS (Federal Gov)
Jun 1 2016 - May 31 2021
CIRCUIT MECHANISMS FOR THE CANCELLATION OF SELF-GENERATED SOUNDS IN THE DORSAL COCHLEAR NUCLEUS (Federal Gov)
Sep 1 2017 - Aug 31 2020
IOS EDGE: TAKING ELECTRIC FISH RESEARCH TO THE EDGE WITH GENEMANIPULATION TECHNOLOGIES (Federal Gov)
Jun 1 2017 - May 31 2020
MIDBRAIN ELECTROSENSORY PROCESSING IN MORMYRID FISH: MULTIMODALINTEGRATION, RECURRENT FEEDBACK, AND CEREBELLAR INFLUENCE (Federal Gov)
Jul 1 2017 - Apr 30 2020
FROM SENSATION TO PERCEPTION: CELLULAR AND CIRCUIT MECHANISMS UNDERLYING PREY DETECTION IN AN ELECTRIC FISH (Federal Gov)
Sep 1 2014 - Aug 31 2017
ADAPTIVE SENSORY PROCESSING IN THE DORSAL COCHLEAR NUCLEUS OF THE MOUSE (Federal Gov)
Sep 1 2014 - Aug 31 2017
NEURAL MECHANISMS FOR PREDICTING THE SENSORY CONSEQUENCES OF BEHAVIOR (Private)
Jan 1 2016 - Dec 31 2016
NEURAL MECHANISMS FOR SENSORY PREDICTION IN A CEREBELLUM-LIKE STRUCTURE (Federal Gov)
Aug 1 2011 - Jul 31 2014
MECHANISMS FOR SENSORY PREDICTION IN A CEREBELLUM-LIKE CIRCUIT (Federal Gov)
Aug 15 2010 - Jul 31 2014
MECHANISMS FOR SENSORY PREDICTION IN CEREBELLAR CIRCUITS (Private)
Jul 1 2011 - Jun 30 2014
MECHANISMS FOR ADAPTIVE SENSORY PROCESSING IN CEREBELLUM-LIKE CIRCUITS (Private)
Sep 15 2011 - Sep 15 2013
LEARNING AND PROCESSING OF ELECTROSENSORY PATTERNS IN MORMYRID ELECTRIC FISH (Federal Gov)
Sep 1 2011 - Aug 31 2012
Requarth, T. Kaifosh, P. and Sawtell N.B. (2014) A role for mixed corollary discharge and proprioceptive signals in predicting the sensory consequences of movements. J Neurosci. 34:16103-16.
Requarth, T. and Sawtell N.B. (2014) Plastic corollary discharge predicts sensory consequences of movements in a cerebellum-like circuit. Neuron 82:896-907.
Alvina K., Sawtell N.B. (2014) Sensory processing and corollary discharge effects in posterior caudal lobe Purkinje cells in a weakly electric mormyrid fish. J Neurophysiol. 112:328-39.
Kennedy, A., Wayne, G., Kaifosh, P., Alvina, A., Abbott, L.F., and Sawtell, N.B. (2014) A temporal basis for predicting the sensory consequences of motor commands in an electric fish. Nat. Neurosci. 17:416-422.
Requarth, T. and Sawtell, N.B. (2011) Neural mechanisms for filtering self-generated sensory signals in cerebellum-like circuits. Curr. Opin. Neurobiol.21(4):602-8.
Sawtell, N.B. (2010) Multimodal integration in granule cells as a basis for associative plasticity and sensory prediction in a cerebellum-like circuit. Neuron 66:573-584.