2014 — 2015 |
Miller, Cory T (co-PI) [⬀] Mitchell, Jude F |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Optogenetic Tools to Distinguish Neuronal Class in Behaving Non-Human Primates @ Salk Institute For Biological Studies
DESCRIPTION (provided by applicant): A major obstacle to understanding the neural mechanisms underlying behavior is our inability to distinguish between neuronal classes in recordings from behaving animals. Mouse transgenic lines, including CRE lines, have made it possible to use optogenetic techniques to selectively activate different classes to determine their role in behavior. However, it remains a challenge to determine the neuronal identity based on optogenetic stimulation, as the latency of response to direct stimulation can overlap with strong but indirect disynaptic excitation. The proposed research will introduce novel methods for distinguishing direct from indirect stimulation in order to label neuronal identity. It will furthe develop these methods for extracellular recordings made with linear array electrodes and using current source density (CSD) analysis to identify laminar location. These methods will be validated in CRE mice, and then applied to the marmoset (Callithrix jacchus). The marmoset is a particularly interesting primate model because it offers opportunities for dissecting neural circuitry that are comparable to the mouse. It matures quickly and breeds well in captivity, so it is amenable to the kinds of genetic manipulation used in mice and has produced the first primate transgenic lines. It also has a lissencephalic (flat) cortex which aids in laminar recordings. Preliminary data show marmosets can perform visual tasks under head-restraint, making them suitable to awake neurophysiology. Establishing these methods will create opportunities to study cortical circuits at a mechanistic level, enabling the field to understand how aberrations in the cortical circuitry give rise to devastating disorders such as schizophrenia and autism.
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1 |
2020 — 2021 |
Rucci, Michele [⬀] Poletti, Martina (co-PI) [⬀] Mitchell, Jude |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Center For Vision Science Symposium: Active Vision; Rochester, Ny; June 2020 @ University of Rochester
This award will support travel and attendance costs for students, postdoctoral fellows, and faculty speakers at the 31st Center for Vision Science (CVS) Symposium on Active Vision. The Symposium will be held at the University of Rochester June 11-14, 2020. Active vision, the study of vision in the context of natural motor behavior, has grown and expanded greatly in recent years, in part due to advances in computational power, display technology, and ability to track body movements.
A rapidly growing body of evidence indicates that motor activity plays a critical role in the computational strategies used for establishing neural representations and achieving task demands. By bringing together a diverse array of viewpoints and creative methodological approaches to the study of the visual system in action, this symposium aims to uncover common principles of visuomotor computation, identify promising new research directions, disseminate knowledge of recent advances in the field, and attract and help form a new generation of researchers.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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0.915 |
2020 — 2021 |
Mitchell, Jude F |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Neural Basis of Trans-Saccadic Perception @ University of Rochester
Project Summary Human vision relies on rapid eye movements called saccades that occur a few times every second. These saccades bring peripherally identified objects to the fovea for high resolution inspection. This split-second sampling of the world defines the perception-action cycle of natural vision and profoundly impacts perception. While much is known about the neural mechanisms involved in the onset of this cycle, how targets are selected before saccades, virtually nothing is known about how pre-saccadic representations would impact processing of post-saccadic information about targets that now appear at the fovea. The proposed research addresses fundamental questions about how pre- and post-saccadic visual information are combined across saccades to maximize information for attended targets. Experiments will be performed in the common marmoset, a New World primate whose smooth cortex affords advantages for recording with high-density silicon arrays across cortical representations and in the longer term for imaging and optogenetic manipulation of large scale neural circuits. In Aim 1, we will test if pre-saccadic information is enhanced in early visual cortex to favor higher acuity information that is most relevant to the fovea and thus could provide a ?foveal preview? to prime post- saccadic processing. In Aim 2 we test if pre-saccadic enhancement is target specific and involves a selection of target features, such as orientation or motion. In Aim 3 we record from foveal populations in early visual cortex to determine how pre-saccadic selection alters post- saccadic processing, and specifically, if pre-saccadic feature selection of the target biases processing to favor the continued selection of the target at the fovea based on increasing gain for its features. This research will provide the first evaluation at the level of single neurons and neural codes of post-saccadic foveal enhancement and the role of pre-saccadic target selection. This has broader impacts for understanding attention under natural viewing conditions where the eyes parse visual scenes, and more generally, for how sensory-motor predictions influence visual perception.
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