Sensory-driven decisions are formed by accumulating information over time. Although parietal cortex activity is thought to represent accumulated evidence for sensory-based decisions, recent perturbation studies in rodents and non-human primates have challenged the hypothesis that these representations actually influence behavior. Here, we asked whether the parietal cortex integrates acoustic features from auditory cortical inputs during a perceptual decision-making task. If so, we predicted that selective inactivation of this projection should impair subjects’ ability to accumulate sensory evidence. We trained gerbils to perform an auditory discrimination task and obtained measures of integration time as a readout of evidence accumulation capability. Minimum integration time was calculated behaviorally as the shortest stimulus duration for which subjects could discriminate the acoustic signals. Direct pharmacological inactivation of parietal cortex increased minimum integration times, suggesting its role in the behavior. To determine the specific impact of sensory evidence, we chemogenetically inactivated the excitatory projections from auditory cortex to parietal cortex and found this was sufficient to increase minimum behavioral integration times. Our signal-detection-theory-based model accurately replicated behavioral outcomes and indicated that the deficits in task performance were plausibly explained by elevated sensory noise. Together, our findings provide causal evidence that parietal cortex plays a role in the network that integrates auditory features for perceptual judgments.

感官驱动的决定是通过随着时间的推移积累信息而形成的。尽管顶叶皮层活动被认为代表了基于感官的决定的累积证据，但最近对啮齿动物和非人类灵长类动物的扰动研究挑战了这些表征实际上影响行为的假设。在这里，我们询问在感知决策任务期间顶叶皮层是否整合了来自听觉皮层输入的声学特征。如果是这样，我们预测这种投射的选择性失活会削弱受试者积累感官证据的能力。我们训练沙鼠执行听觉辨别任务，并获得整合时间的测量值作为证据积累能力的读数。最小积分时间在行为上被计算为受试者可以区分声学信号的最短刺激持续时间。顶叶皮层的直接药理学失活增加了最小整合时间，表明其在行为中的作用。为了确定感官证据的具体影响，我们通过化学遗传学使从听觉皮层到顶叶皮层的兴奋性投射失活，发现这足以增加最小行为整合时间。我们基于信号检测理论的模型准确地复制了行为结果，并表明任务表现的缺陷可以由感觉噪声升高来解释。总之，我们的研究结果提供了因果证据，表明顶叶皮层在整合听觉特征以进行感知判断的网络中发挥作用。