University of Waterloo, Canada.
University of Waterloo, Canada.
Appetite. 2018 Jul 1;126:73-79. doi: 10.1016/j.appet.2018.03.022. Epub 2018 Mar 27.
The dorsolateral prefrontal cortex (dlPFC) plays a central role in the inhibition of eating, but also the modulation of conscious thought processes that might precede, accompany or follow initial food tasting. The latter might be particularly important to the extent that post-tasting cognitions may drive prolonged eating beyond the satiety point. However, we know very little about the effect of the dlPFC on conation following initial food sampling. This investigation compared the effects of dlPFC attenuation using repetitive transcranial magnetic stimulation (rTMS) on social cognition following (Study 1) and prior to (Study 2) a food consumption opportunity.
In Study 1, participants (N = 21; M = 21 years) were randomized to active or sham continuous theta-burst stimulation (cTBS; an inhibitory variant of rTMS) targeting the left dlPFC followed by an interference task. Participants subsequently completed measures of attitudes, norms and perceived control following a mock taste test. In Study 2, a second sample of right handed participants (N = 37; M = 21 years) were assigned to active or sham cTBS, followed by an interference task and two measures of attitudes (implicit and explicit), both assessed prior to the same taste test paradigm.
In Study 1, findings revealed a reliable effect of cTBS on post-tasting attitudes (t(1,19) = 3.055, p = .007; d = 1.34), such that attitudes towards calorie dense snack foods were significantly more positive following active stimulation than following sham stimulation. Similar effects were found for social norms (t(1,19) = 3.024, p = .007, d = 1.31) and perceived control (t(1,20) = 19.247, p < .001, d = 0.50). In Study 2, no effects of cTBS were observed on pre-consumption attitudes, despite reliable effects on interference scores and subsequent consumption.
The left dlPFC may selectively modulate facilitative social cognition following initial food sampling (but not pre-consumption).
背外侧前额叶皮层（dlPFC）在抑制进食方面起着核心作用，但也调节着可能先于、伴随或紧随初始食物品尝的有意识思维过程。后者可能尤为重要，因为品尝后的认知可能会驱使进食时间延长超过饱腹感点。然而，我们对 dlPFC 对初始食物采样后的意愿的影响知之甚少。本研究比较了使用重复经颅磁刺激（rTMS）对 dlPFC 进行衰减对（研究 1）和在（研究 2）食物摄入机会之前对社会认知的影响。
在研究 1 中，参与者（N=21；M=21 岁）被随机分配到接受左 dlPFC 的活性或假连续 theta 爆发刺激（cTBS；rTMS 的一种抑制变体），然后进行干扰任务。随后，参与者在模拟味觉测试后完成态度、规范和感知控制的测量。在研究 2 中，另一组右利手参与者（N=37；M=21 岁）被分配到活性或假 cTBS，然后进行干扰任务和两项态度测量（内隐和外显），均在相同的味觉测试范式之前进行评估。
在研究 1 中，研究结果显示 cTBS 对品尝后态度有可靠的影响（t(1,19)=3.055，p=.007；d=1.34），即与假刺激相比，积极刺激后对高热量零食的态度明显更为积极。社会规范（t(1,19)=3.024，p=.007，d=1.31）和感知控制（t(1,20)=19.247，p<.001，d=0.50）也有类似的影响。在研究 2 中，尽管对干扰分数和随后的消费有可靠的影响，但 cTBS 对消费前态度没有影响。
左 dlPFC 可能选择性地调节初始食物采样后的促进性社会认知（但不是消费前）。
