Nathan H. Heller

I am a graduate student at the University of California, Santa Cruz (UCSC) in the Scientific Computing and Applied Mathematics (SciCAM) Masters Program, and I recently completed a B.Sc. in Cognitive Science at UCSC, with a minor in Applied Mathematics. I am currently applying to Phd programs in cognitive and computational psychology that have an emphasis in modeling sensory systems.

Research Interests

SciCAM: I am developing a master’s thesis project with Professor Daniele Venturi exploring a system identification method, called Sparse Identification of Nonlinear Dynamics (SINDy), which uses sparse symbolic regression to identify the governing equations of a system. Using simulated data generated by noisy networks of classic neuron models, such as the Hindmarsh-Rose neuron, I am applying SINDy in order to identify the network topology, and recover both the dynamical and functional properties of the network. Over the next year I intend to extend SINDy so it can identify the structure of the noise in the network, as well as fit network models to data obtained with multi-electrode arrays.

CogSci: I am working on several psychophysical studies, focused on motion perception, in Professor Nicolas Davidenko’s High Level Perception Lab. In a recently completed study, we employ maximally ambiguous stimuli to probe the higher and lower order components of our motion processing system, which are tuned to different temporal properties of motion stimuli, and produce distinct motion aftereffects depending on which component dominates. We found that percepts driven by the higher order component, which is known to be subject to attentional manipulation, are uniquely susceptible to cognitive effects. These findings, and the focus of ongoing work in the High Level Perception Lab, reflect general aspects of how the brain functions; for example, the way stimulus feature selection and attentional functions are segregated in the visual hierarchy, but modulate each other through excitatory and inhibitory feedback relations, and the fact that it is possible to infer these feedback relations from reported percepts.

Publications

Heller, N. H., & Davidenko, N. (2017). Dissociating Higher and Lower Order Visual Motion Systems by Priming Illusory Apparent Motion. Perception, 0301006617731007. [Link_Perception]

Davidenko, N., Heller, N. H., Cheong, Y., & Smith, J. (2017). Persistent illusory apparent motion in sequences of uncorrelated random dots. Journal of Vision, 17(3), 19-19. [Link_JOV]

Davidenko, N., Vu, C. Q., Heller, N. H., & Collins, J. M. (2016). Attending to Race (or Gender) Does Not Increase Race (or Gender) Aftereffects. Frontiers in Psychology, 7, 909. [Link_Frontiers]

For list of posters, download my CV

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