Meyer Travis, Qi Xue-Lian, Constantinidis Christos
Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA.
Cereb Cortex. 2007 Sep;17 Suppl 1:i70-6. doi: 10.1093/cercor/bhm063.
Neurons in the prefrontal cortex and a network of interconnected brain areas discharge in a persistent fashion after the offset of sensory stimulation. Such persistent discharges are thought to constitute a neuronal correlate of working memory. The information content of neuronal discharges and its anatomical localization across the surface of the prefrontal cortex has been a matter of debate. Discrepant results by different laboratories may be due to the effects of different training regiments and tasks used in memory tasks. In order to address how training in a memory task alters neuronal responses, we performed recordings in monkeys that were never trained in memory tasks, but passively viewed visual stimuli. We have found that a population of prefrontal neurons responded to visual stimuli and also exhibited significantly elevated responses during "delay" intervals of the task. For a population of these neurons, persistent discharges were selective for the location and feature of the preceding stimulus. These discharges were typically disrupted by the appearance of a subsequent stimulus. Our results suggest that some prefrontal neurons represent the location and identity of visual stimuli in a persistent fashion, even when the latter are not behaviorally important or required to be kept in memory.
感觉刺激消失后，前额叶皮质中的神经元以及相互连接的脑区网络会持续放电。这种持续放电被认为构成了工作记忆的神经元关联。神经元放电的信息内容及其在前额叶皮质表面的解剖定位一直存在争议。不同实验室得出的不一致结果可能是由于记忆任务中使用的不同训练方案和任务的影响。为了研究记忆任务训练如何改变神经元反应，我们对从未接受过记忆任务训练但被动观看视觉刺激的猴子进行了记录。我们发现，一群前额叶神经元对视觉刺激有反应，并且在任务的“延迟”间隔期间反应也显著增强。对于这群神经元中的一部分，持续放电对先前刺激的位置和特征具有选择性。这些放电通常会被后续刺激的出现所打断。我们的结果表明，即使视觉刺激在行为上不重要或不需要记忆，一些前额叶神经元仍会持续表征其位置和特征。
