Austin Kuo

All Publications

• Orientation maps in mouse superior colliculus explained by population model of non-orientation selective neurons. The Journal of neuroscience : the official journal of the Society for Neuroscience Kuo, A., Gardner, J. L., Merriam, E. P. 2025

  Abstract

  Mouse superficial superior colliculus (sSC) has been found to have orientation selective maps, suggesting a fundamentally different selectivity than in primate SC. Moreover, orientation selectivity in mouse sSC appears to change with stimulus properties such as size, shape and spatial frequency, in contradistinction to the computational principle of invariance in primates. To reconcile mouse and primate mechanisms for orientation selectivity, we constructed a computational model of mouse sSC populations with circular-symmetric, center-surround (i.e., not intrinsically orientation selective), stimulus-invariant receptive fields (RFs), classically used to describe monkey lateral geniculate nucleus (LGN) neurons. This model produced population maps similar to those found in mouse sSC, which show strong radial orientation preferences at retinotopic locations along stimulus edges. We show how this selectivity depended critically on spatial frequency tuning of the model units. The model predicted a shift from radial to anti-radial orientation preferences from the same simulated units at high stimulus spatial frequencies, also consistent with measurements from mouse sSC. We found intrinsically oriented RFs were largely unnecessary to explain the imaging data, but could explain a possible small subpopulation of intrinsically orientation selective neurons. We conclude that to study orientation selectivity in mouse sSC and other systems, the problem is not the choice of stimulus. Rather than endless tweaks to find the perfect, unbiased stimulus, image-computable population modeling is the solution. Regardless of the stimulus presented, comparing how well models of intrinsically or non-intrinsically orientation selective units account for empirical data provides definitive evidence for underlying neural selectivity.Significance Statement Measurements of neural population activity from mouse superior colliculus (SC) show patterns of orientation selectivity differing markedly from those observed in primates. Do such measurements necessarily imply different neural mechanisms across species? We developed a modeling framework that explicitly predicts population activity using well-established mechanisms from classic primate single-unit neurophysiology. Notably, this framework was sufficient to explain a diverse array of population measurements in mouse SC. Our results reconcile seemingly contradictory neural phenomena across species and visual areas through a principled approach for making inferences across measurement scales (i.e., single neurons to neural populations), providing a unifying framework for determining shared computational mechanisms broadly throughout the brain.

  View details for DOI 10.1523/JNEUROSCI.1133-25.2025

  View details for PubMedID 41193256

• Shared computational principles for mouse superior colliculus and primate population orientation selectivity. bioRxiv : the preprint server for biology Kuo, A., Gardner, J. L., Merriam, E. P. 2025

  Abstract

  While the mouse visual system is known to differ substantially from the primate, if the two systems share computational principles, then generalization of results across species may still be possible. One prominent difference is that orientation selectivity is found in mouse superficial superior colliculus (SC), but is not commonly observed in primate SC. Nevertheless, there may be conservation of computational principles if orientation selectivity in mouse superficial SC displays similar properties to primate primary visual cortex (V1), such as invariance to differences in other stimulus dimensions. However, a recent calcium (Ca2+) imaging study revealed a population map for stimulus orientation in mouse superficial SC that changed with stimulus properties such as size, shape and spatial frequency, in apparent contradistinction to computational principles for orientation selectivity in primates. To reconcile mouse and primate mechanisms for orientation selectivity, we constructed computational models of mouse superficial SC populations with fixed, stimulus-invariant receptive fields (RFs) classically used to describe neural RFs in monkey lateral geniculate nucleus (LGN) and V1. At preferred spatial frequencies, model RFs exhibited stronger responses where the aperture and gratings were differently oriented, while at non-preferred frequencies, orientation selectivity reversed, matching the imaging data. We provide an intuitive explanation by visualizing stimulus-RF interactions in the spatial frequency domain. Intrinsically oriented RFs were unnecessary to explain much of the imaging data, but modeling of single units suggests a possible subpopulation of intrinsically orientation-selective cells. In summary, our population modeling approach provides a parsimonious explanation for stimulus-dependent orientation selectivity consistent with well-established results from sensory neurophysiology. More broadly, we provide a population modeling framework for establishing shared computations across species.

  View details for DOI 10.1101/2025.02.22.639626

  View details for PubMedID 40568074

  View details for PubMedCentralID PMC12190478