|Psychological Science 2017, 40(6) 1511-1517 DOI: ISSN: 0412-1961 CN: 21-1139/TG|
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Effects of Non-invasive Neurostimulation of Prefrontal Cortex on Eating Control: A Systematic Review Based on rTMS and tDCS
Unhealthy eating habits can lead to overweight, obesity and eating disorder. A study has shown that obesity and disordered eating is a formidable global medical challenge, especially in China. The number of people who are worldwide overweight or obese has augmented dramatically over the past decades. The hedonic-inhibitory model of feeding posits that overconsumption of palatable food results from the disrupted balance between appetitive motivation mediated by the mesolimbic reward system and active inhibitory control mediated by the prefrontal areas, whereby appetitive motivation may override inhibitory control. Recently, data from obesity neuroimaging studies shows that imbalance in the prefrontal and limbic brain circuits that support cognition and reward-related aspects of eating behavior. Indeed, obesity and eating disorder often display abnormal neural activity in the prefrontal control circuitry, a key area for the eating control and processing of food motivation and satiety signaling. In this context, there is a pressing need for novel approach to prevention and treatment of obesity and eating disorder. Non-invasive neuromodulation techniques allow the external manipulation of the human brain in a safe manner, without the requirement of a neurosurgical procedure. Over the past decades there has been rising interest in the use of non-invasive neuromodulation in neurology and psychiatry motivated by the shortage of existing treatments. The most commonly used non-invasive neuromodulation techniques are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current simulation (tDCS). The purpose of this work is to conduct a systematic review of rTMS and tDCS efficacy on improving the eating control among the healthy participants and eating disorder as well as methodological considerations and its potential mechanism. Eating control is a new application for the non-invasive neuromodulation, with the earliest study dating back to 2004. To date, seeing that the vital role of the prefrontal regions on the inhibit the hedonic eating, the most studies published to this day pay attention to the prefrontal cortex, especially in the dorsolateral prefrontal cortex (DLPFC). In the healthy participants, most studies have found that the subjective food craving was reduced and the food-related cognitive function was enhanced after one session stimulation. In the eating disorders, improvement in clinical symptoms and alteration of the neurobiological basis were shown after one or more sessions. Nonetheless, it is necessary to note that a small number of studies did not achieve the desirable intervention effect. Non-invasive neuromodulation stimulating the prefrontal cortex would bring a series of neural physiological and biochemical changes, which boosts the capacity to control the hedonic eating and inhibits the appetitive motivation. This will heighten the strength of the top-down executive function and suppress the bottom-up reward impulsivity, thereby facilitating the eating control among the obesity and eating disorder. To sum, non-invasive neurostimulation technology might effectively enhance the ability to control appetite, which ultimately improves the symptoms of disordered eating by altering the neuropsychological mechanism of the prefrontal cortex to adjust its excitability. Future research should further take the effect of different stimulation parameters and other target sites into account, consider the individual differences and explore the underlying neuralmechanism by integrating with other neurophysiological techniques and combining with the objective behavioral paradigms.
|Keywords： non-invasive neurostimulation technology, tDCS, rTMS, eating control, prefrontal cortex|
|Received 2016-09-18 Revised 2017-04-20 Online: 2017-11-20|
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