In contrast to classical views of working memory (WM) maintenance, recent research investigating activity-silent neural states has demonstrated that persistent neural activity in sensory cortices is not necessary for active maintenance of information in WM. Previous studies in humans have measured putative memory representations indirectly, by decoding memory contents from neural activity evoked by a neutral impulse stimulus. However, it is unclear whether memory contents can also be decoded in different species and attentional conditions. Here, we employ a cross-species approach to test whether auditory memory contents can be decoded from electrophysiological signals recorded in different species. Awake human volunteers (N = 21) were exposed to auditory pure tone and noise burst stimuli during an auditory sensory memory task using electroencephalography. In a closely matching paradigm, anesthetized female rats (N = 5) were exposed to comparable stimuli while neural activity was recorded using electrocorticography from the auditory cortex. In both species, the acoustic frequency could be decoded from neural activity evoked by pure tones as well as neutral frozen noise burst stimuli. This finding demonstrates that memory contents can be decoded in different species and different states using homologous methods, suggesting that the mechanisms of sensory memory encoding are evolutionarily conserved across species.

中文翻译：

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解码跨物种听觉感官记忆的内容

与工作记忆 (WM) 维持的经典观点相反，最近调查活动静默神经状态的研究表明，感觉皮层中的持续神经活动对于 WM 中信息的主动维持不是必需的。先前对人类的研究通过解码由中性脉冲刺激引起的神经活动的记忆内容，间接测量了假定的记忆表征。然而，尚不清楚记忆内容是否也可以在不同的物种和注意力条件下被解码。在这里，我们采用跨物种方法来测试是否可以从不同物种记录的电生理信号中解码听觉记忆内容。在使用脑电图的听觉感觉记忆任务期间，清醒的人类志愿者 (N = 21) 暴露于听觉纯音和噪声爆发刺激。在一个紧密匹配的范例中，麻醉的雌性大鼠 (N = 5) 暴露于类似的刺激，同时使用来自听觉皮层的皮层电图记录神经活动。在这两个物种中，声频都可以从由纯音和中性冷冻噪声爆发刺激引起的神经活动中解码。这一发现表明，可以使用同源方法在不同物种和不同状态下对记忆内容进行解码，这表明感觉记忆编码的机制在物种间是进化上保守的。麻醉雌性大鼠 (N = 5) 暴露于类似的刺激，同时使用来自听觉皮层的皮层电图记录神经活动。在这两个物种中，声频都可以从由纯音和中性冷冻噪声爆发刺激引起的神经活动中解码。这一发现表明，可以使用同源方法在不同物种和不同状态下对记忆内容进行解码，这表明感觉记忆编码的机制在物种间是进化上保守的。麻醉雌性大鼠 (N = 5) 暴露于类似的刺激，同时使用来自听觉皮层的皮层电图记录神经活动。在这两个物种中，声频都可以从由纯音和中性冷冻噪声爆发刺激引起的神经活动中解码。这一发现表明，可以使用同源方法在不同物种和不同状态下对记忆内容进行解码，这表明感觉记忆编码的机制在物种间是进化上保守的。