Langlois Thomas, Charlton Julie A, Goris Robbe L T
Center for Perceptual Systems, The University of Texas at Austin, Austin, TX USA.
Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA.
bioRxiv. 2024 Oct 10:2024.09.23.614567. doi: 10.1101/2024.09.23.614567.
Perceptual judgements of the environment emerge from the concerted activity of neural populations in decision-making areas downstream of sensory cortex [1, 2, 3]. When the sensory input is ambiguous, perceptual judgements can be biased by prior expectations shaped by environmental regularities [4, 5, 6, 7, 8, 9,10,11]. These effects are examples of Bayesian inference, a reasoning method in which prior knowledge is leveraged to optimize uncertain decisions [12, 13]. However, it is not known how decision-making circuits combine sensory signals and prior expectations to form a perceptual decision. Here, we study neural population activity in the prefrontal cortex of macaque monkeys trained to report perceptual judgments of ambiguous visual stimuli under two different stimulus distributions. We analyze the component of the neural population response that represents the formation of the perceptual decision (the decision variable, DV), and find that its dynamical evolution reflects the integration of sensory signals and prior expectations. Prior expectations impact the DV's trajectory both before and during stimulus presentation such that DV trajectories with a smaller dynamic range result in more biased and less sensitive perceptual decisions. These results reveal a mechanism by which prefrontal circuits can execute Bayesian inference.
对环境的感知判断源自感觉皮层下游决策区域中神经群体的协同活动[1,2,3]。当感觉输入模糊不清时，感知判断可能会受到由环境规律塑造的先验期望的影响[4,5,6,7,8,9,10,11]。这些效应是贝叶斯推理的实例，贝叶斯推理是一种利用先验知识优化不确定决策的推理方法[12,13]。然而，目前尚不清楚决策回路如何将感觉信号和先验期望结合起来以形成感知决策。在此，我们研究了猕猴前额叶皮层中的神经群体活动，这些猕猴经过训练，要在两种不同的刺激分布下报告对模糊视觉刺激的感知判断。我们分析了神经群体反应中代表感知决策形成的成分（决策变量，DV），发现其动态演变反映了感觉信号和先验期望的整合。先验期望在刺激呈现之前和期间都会影响DV的轨迹，使得动态范围较小的DV轨迹会导致更有偏差且敏感性更低的感知决策。这些结果揭示了前额叶回路执行贝叶斯推理的一种机制。
