Erin Gutilla Profile Page
|Biochemistry & Molecular Biology major, Mathematics & Psychology double minor|
|Neuroscience, Cell Biology, Molecular Biology|
|E.A. Gutilla; T.O. Sharpee; J.C. Horton; L.C. Sincich. Diversity of interspike interval distributions in macaque retinal ganglion cells and thalamic relay neurons. Society for Neuroscience Conference, 2010.|
|MSTP Retreat 2012 Poster Abstract-
Previous projects focused on spinal cord injury (SCI) models have identified phosphatase and tensin homolog (PTEN) as a key modulator of the neuronal regenerative process. Specifically, AAV-Cre-mediated genetic deletion of PTEN and resultant increases in mammalian target of rapamycin (mTOR) activity optimize the amount of axon regeneration observed following SCI (Park et al., 2012, Exp. Neurol. 223, 45-40). Our preliminary studies show that an immunohistochemically comparable PTEN expression profile can be achieved following electrical stimulation of the rodent motor cortex. By conducting parametric experiments to elucidate optimal surgical technique, stimulation paradigm, and duration of observed post-stimulation expression changes, we have begun to establish the design of a promising and potentially therapeutic SCI intervention.
Society for Neuroscience 2010 Poster Abstract-
In single neurons, the variation in time intervals between spikes is both the carrier of information about incoming signals and the source of noise that limits the information transmission. Prior experiments have largely focused on variations in interspike interval (ISI) distributions as a source of noise in neural transmission, analyzing distributions generated in the absence of changing stimuli. For example, Kuffler et al. (1957) found that cat retinal ganglion cells (RGCs), when presented with steady illumination, have an ISI distribution that fits a gamma probability density function. We wondered if similar fits could be found under conditions that more closely resemble natural stimulation, and whether the ISI distributions of neurons in the lateral geniculate nucleus (LGN) were similar to those produced by RGCs. We recorded extracellularly from 20 optic tract fibers and 36 LGN neurons in four anesthetized macaques undergoing neuromuscular blockade to prevent eye movements. Nine of the LGN neurons included large enough excitatory postsynaptic potentials from the retina that RGC spike trains could also be reconstructed. The stimulus was a spot of light of the preferred color limited to the receptive field center, which varied in luminance with a naturalistic temporal frequency power spectrum. We also included periods of steady illumination and a suite of standard luminance modulations for comparison. ISI distributions from cells recorded during the sustained stimulus were fit best with a gamma probability density function, indicating that such stimulus responses follow a renewal process model as previously suggested. ISI distributions generated during naturalistic stimulus conditions differed from sustained stimulus responses and were not well fit by gamma functions. These ISI distributions varied widely in shape, indicating that a simple noise model does not capture the range of spike intervals employed by neurons under more normal conditions. We used principle component analysis to determine if the ISI distributions were correlated with different RGC and LGN cell classes. Two classes stood out: parasol RGCs and parvocellular LGN neurons appeared to have distinct ISI distributions, when compared to the remaining cell types. For connected RGC-LGN cell pairs, the ISI distributions were similar, though not identical because synaptic efficacy diminishes with longer ISIs. The diversity of ISI distributions during naturalistic stimulation points to differences in neural codes used by different classes of cells to transmit information.
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