Mendoza Germán, Fonseca Esmeralda, Merchant Hugo, Gutierrez Ranier
Laboratory of Systems Neurophysiology, Institute of Neurobiology, National Autonomous University of Mexico, Juriquilla Querétaro 76230, Mexico.
Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA.
iScience. 2024 Oct 30;27(12):111287. doi: 10.1016/j.isci.2024.111287. eCollection 2024 Dec 20.
The gustatory system allows us to perceive and distinguish sweetness from water. We studied this phenomenon by recording neural activity in rats' anterior insular (aIC) and orbitofrontal (OFC) cortices while they categorized varying sucrose concentrations against water. Neurons in both aIC and OFC encoded the categorical distinction between sucrose and water rather than specific sucrose concentrations. Notably, aIC encoded this distinction faster than OFC. Conversely, the OFC slightly preceded the aIC in representing choice information, although both cortices encoded the rat's choices in parallel. Further analyses revealed dynamic and sequential encoding of sensory and categorical decisions, forming brief sequences of encoding neurons throughout the trial rather than long-lasting neuronal representations. Our findings, supported by single-cell, population decoding, and principal-component analysis (PCA), demonstrate that gustatory cortices employ neuronal sequences to compute sensorimotor transformations, from taste detection to categorical decisions, and continuously update this process as new taste information emerges using dynamic coding.
味觉系统使我们能够感知并区分甜味和水味。我们通过记录大鼠前脑岛（aIC）和眶额皮质（OFC）的神经活动来研究这一现象，在此过程中，大鼠要对不同浓度的蔗糖溶液与水进行区分。aIC和OFC中的神经元编码的是蔗糖和水之间的类别差异，而非特定的蔗糖浓度。值得注意的是，aIC编码这种差异的速度比OFC快。相反，尽管两个皮质区域并行编码大鼠的选择，但OFC在表示选择信息方面比aIC略早。进一步的分析揭示了感觉和类别决策的动态和顺序编码，在整个试验过程中形成了编码神经元的简短序列，而不是持久的神经元表征。我们的研究结果得到了单细胞、群体解码和主成分分析（PCA）的支持，表明味觉皮质利用神经元序列来计算从味觉检测到类别决策的感觉运动转换，并在新的味觉信息出现时使用动态编码不断更新这一过程。
