Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology & The National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK.
Neuroimage. 2013 Jan 1;64:284-9. doi: 10.1016/j.neuroimage.2012.08.068. Epub 2012 Aug 30.
In paced random number generation (RNG) participants are asked to generate numbers between 1 and 9 in a random fashion, in synchrony with a pacing stimulus. Successful task performance can be achieved through control of the main biases known to exist in human RNG compared to a computer generated series: seriation, cycling through a set of available numbers, and repetition avoidance. A role in response inhibition and switching from automatic to controlled processing has previously been ascribed to the subthalamic nucleus (STN). We sought evidence of frequency-specific changes in STN oscillatory activity which could be directly related to use of such strategies during RNG. Local field potentials (LFPs) were recorded from depth electrodes implanted in the STN of 7 patients (14 sides) with Parkinson's disease (PD), when patients were on dopaminergic medication. Patients were instructed to (1) generate a series of 100 numbers between 1 and 9 in a random fashion, and (2) undertake a control serial counting task, both in synchrony with a 0.5 Hz pacing stimulus. Significant increases in LFP power (p ≤ 0.05) across a narrow gamma frequency band (45-60 Hz) during RNG, compared to the control counting task, were observed. Further, the number of 'repeated pairs' (a decline in which reflects repetition avoidance bias in human RNG) was positively correlated with these gamma increases. We therefore suggest that STN gamma activity is relevant for controlled processing, in particular the active selection and repetition of the same number on successive trials. These results are consistent with a frequency-specific role of the STN in executive processes such as suppression of habitual responses and 'switching-on' of more controlled processing strategies.
在 paced random number generation (RNG) 中，参与者被要求以随机的方式在同步的 pacing 刺激下生成 1 到 9 之间的数字。通过控制人类 RNG 中存在的主要偏差，可以成功完成任务，这些偏差包括序列化、在一组可用数字中循环以及避免重复。先前认为，丘脑底核（STN）在反应抑制和从自动处理到受控处理的转换中起作用。我们寻求 STN 振荡活动的频率特异性变化的证据，这些变化可能与在 RNG 期间使用这些策略直接相关。我们从 7 名患有帕金森病（PD）的患者（14 侧）的深部电极中记录了局部场电位（LFPs），当患者服用多巴胺能药物时。患者被指示（1）以随机方式生成 100 个 1 到 9 之间的数字序列，（2）在 0.5 Hz 的 pacing 刺激同步下进行控制序列计数任务。与对照计数任务相比，在 RNG 期间观察到 LFPs 功率（p ≤ 0.05）在一个狭窄的伽马频带（45-60 Hz）中显著增加。此外，“重复对”的数量（反映了人类 RNG 中重复避免偏差的下降）与这些伽马增加呈正相关。因此，我们认为 STN 伽马活动与受控处理有关，特别是在连续试验中主动选择和重复相同数字。这些结果与 STN 在抑制习惯性反应和“开启”更受控处理策略等执行过程中的频率特异性作用一致。
