The prefrontal cortex (PFC) maintains goal information for action planning, but how recurrent circuits preserve it in an action-usable form over behavioral timescales remains unclear. Here we ask whether short-term synaptic plasticity (STP) can stabilize goal information as action-usable, goal-conditioned dynamics. We incorporated STP into a PFC-inspired reservoir computing model with basal-ganglia-inspired temporal-difference readout learning, and evaluated paired models with and without STP across 100 independently generated networks in a multistep goal-directed action-selection task with delayed execution. Goal identity was highly decodable during the delay even without STP, so STP was not required to form a linearly readable goal representation. Under state noise, however, success without STP fell from 75.8% to 49.5%, whereas the model with STP remained essentially unchanged (91.8% without noise versus 89.2% under noise; paired Cohen's dz=1.31). Time-resolved decoding, state-space separability, and action-value-difference analyses showed that STP preserved goal information as action-relevant goal-conditioned dynamics available at later action opportunities. Gain-matched and STP-state perturbation controls argued against a simple fixed recurrent-scaling explanation and supported online, history-dependent synaptic modulation. Effective-connectivity analyses showed delay-period goal-specific patterning that increased toward the later part of the trial with STP, where it should be read as goal- and task-state-conditioned patterning; effective connectivity without STP was time-invariant. A grid search identified a facilitation-dominant range of STP time constants associated with high success rates. These results suggest that STP supports robust goal-conditioned dynamics through dynamic modulation of goal-dependent effective recurrent connectivity.

翻译：前额叶皮层维持着用于行为规划的目标信息，但循环回路如何以行为可用的形式在行为时间尺度上保留这些信息仍不清楚。本研究探究短期突触可塑性能否将目标信息稳定为行为可用、目标条件化的动力学。我们将短期突触可塑性引入基于前额叶皮层启发的蓄水池计算模型（该模型采用基底节启发的时序差分学习读出机制），并通过有无短期突触可塑性的配对模型，在100个独立生成的网络中评估其在延迟执行的多步目标导向行动选择任务中的表现。尽管无短期突触可塑性时，延迟期内目标身份仍具有高度可解码性，即短期突触可塑性并非形成线性可读目标表征的必要条件，但当引入状态噪声后，无短期突触可塑性模型的成功率从75.8%降至49.5%，而含短期突触可塑性模型则基本保持不变（无噪声时为91.8%，有噪声时为89.2%；配对Cohen’s dz=1.31）。时间分辨解码、状态空间可分性及行动价值差异分析表明，短期突触可塑性以行动相关目标条件化动力学形式保留目标信息，使其在后续行动机会中仍可被利用。增益匹配与短期突触可塑性状态扰动控制实验否定了简单固定循环缩放的解释，支持在线、历史依赖的突触调制。有效连接分析显示，含短期突触可塑性的模型中，延迟期目标特异性模式随试验进程增强——该模式需要在目标与任务状态条件化框架下解读；而无短期突触可塑性的有效连接呈时间不变性。网格搜索确定了与高成功率相关的易化主导型短期突触可塑性时间常数范围。这些结果表明，短期突触可塑性通过动态调制目标依赖的有效循环连接，支撑稳健的目标条件化动力学。