Prevention Neuroscience Lab, School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Department of Kinesiology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Neuroimage. 2018 Aug 15;177:45-58. doi: 10.1016/j.neuroimage.2018.05.013. Epub 2018 May 6.
Regulation of food cravings is thought to be critical for modulating eating behavior, yet we do not fully understand the mechanisms by which cognitive control operates in the eating context. The current study combined rTMS and EEG paradigms to examine the causal role of the left dorsolateral prefrontal cortex (dlPFC) in modulating visceral and behavioral responses to high calorie foods, and the mediational mechanisms underlying this relation. 28 right-handed female participants received both active and sham continuous theta burst stimulation (cTBS; a rTMS variant used to decrease cortical activity) targeting the left dlPFC in a counterbalanced order. Prior to and following each stimulation session participants completed a flanker and food-cue presentation (high and low calorie food) task. Following cTBS participants had the opportunity to consume both high and low calorie foods during a taste test. Findings revealed a reliable effect of cTBS on food consumption, such that participants selectively ingested significantly more calories from appetitive calorie dense snack foods following active relative to sham cTBS; this effect did not translate to control (low calorie) food consumption. In addition, attenuation of dlPFC activity resulted in the significant increase in N2 amplitude and P3b latency to incongruent flanker trials, and the selective significant increase in the P3a amplitude to and P3a amplitude bias for high calorie food stimuli. Results from the parallel mediation analysis revealed that only the indirect effect of flanker task performance was significant; the indirect effects of stimulation induced changes in the P3 bias for high calorie foods, the urge to consume high calorie foods, and the general liking ratings for high calorie foods were not significant. These findings confirm the causal role of the left dlPFC in the modulation of calorie dense food consumption via inhibitory control capacity.
调节食物渴望被认为是调节进食行为的关键,但我们并不完全了解认知控制在进食环境中运作的机制。本研究结合 rTMS 和 EEG 范式,考察了左背外侧前额叶皮层(dlPFC)在调节对高热量食物的内脏和行为反应中的因果作用,以及这种关系的中介机制。28 名右利手女性参与者以平衡的顺序接受针对左 dlPFC 的活性和假连续 theta 爆发刺激(cTBS;一种用于降低皮质活动的 rTMS 变体)。在每次刺激后,参与者都要完成一个侧抑制和食物线索呈现(高卡路里和低卡路里食物)任务。在 cTBS 之后,参与者有机会在味觉测试中同时食用高卡路里和低卡路里的食物。研究结果显示,cTBS 对食物摄入有可靠的影响,即与假刺激相比,参与者在活性刺激后选择性地摄入了更多高热量的零食;但这种影响并没有转化为对低热量食物的摄入。此外,dlPFC 活动的减弱导致对不一致的侧抑制试验的 N2 振幅和 P3b 潜伏期显著增加,以及对高热量食物刺激的 P3a 振幅和 P3a 振幅偏差的选择性显著增加。平行中介分析的结果表明,只有侧抑制任务表现的间接效应是显著的;刺激引起的对高热量食物的 P3 偏差、对高热量食物的消费欲望以及对高热量食物的总体喜好评分的间接效应不显著。这些发现证实了左 dlPFC 在通过抑制控制能力调节高热量食物消费方面的因果作用。