Kuo Austin, Gardner Justin L, Merriam Elisha P
Laboratory of Brain and Cognition, NIMH, NIH, Bethesda, MD.
Neurosciences Interdepartmental Program, Stanford University, Stanford, CA.
bioRxiv. 2025 Apr 11:2025.02.22.639626. doi: 10.1101/2025.02.22.639626.
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 (Ca) 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.
虽然已知小鼠视觉系统与灵长类动物有很大不同，但如果这两个系统共享计算原理，那么跨物种的结果推广仍有可能。一个显著的差异是，在小鼠浅层上丘（SC）中发现了方向选择性，但在灵长类动物的SC中通常未观察到。然而，如果小鼠浅层SC中的方向选择性表现出与灵长类动物初级视觉皮层（V1）相似的特性，例如对其他刺激维度差异的不变性，那么计算原理可能存在保守性。然而，最近的一项钙（Ca）成像研究揭示了小鼠浅层SC中刺激方向的群体图谱，该图谱随刺激特性（如大小、形状和空间频率）而变化，这显然与灵长类动物方向选择性的计算原理相矛盾。为了协调小鼠和灵长类动物方向选择性的机制，我们构建了小鼠浅层SC群体的计算模型，这些模型具有固定的、刺激不变的感受野（RFs），经典地用于描述猴子外侧膝状体核（LGN）和V1中的神经RFs。在偏好的空间频率下，模型RFs在孔径和光栅方向不同时表现出更强的反应，而在非偏好频率下，方向选择性反转，与成像数据匹配。我们通过在空间频率域中可视化刺激-RF相互作用提供了一个直观的解释。本质上定向的RFs对于解释大部分成像数据并非必要，但单个单元的建模表明可能存在一个本质上方向选择性细胞的亚群。总之，我们的群体建模方法为与感觉神经生理学的既定结果一致的刺激依赖性方向选择性提供了一个简洁的解释。更广泛地说，我们提供了一个群体建模框架，用于建立跨物种的共享计算。
