Real-time NIRS Neurofeedback Regulating Brain Cognitive Function in Obese Individuals

Real-time Neurofeedback Regulating Brain Cognitive Function in Obese Individuals: a Near-infrared Spectroscopy-based Study.

To determine the efficacy of real-time fNIRS neurofeedback for regulating the brain cognitive function in obese individuals.

In the current study, 60 obese subjects will be recruited, and they were randomly classified into the group who will receive real neurofeedback and the group who will receive sham neurofeedback. Participants will receive the real-time neurofeedback for 12 times, 3 to 4 times a week, each time the real-time neurofeedback consists of 12 sessions of liftstone as the index reflecting the brain activity. Sham group will receive the identical neurofeedback. All of the subjects will undergo magnetic resonance imaging scan, during which T1, diffusion tensor imaging, resting-state, and task fMRI data will be collected. For task Fmri scan, the participants will be asked to finish four cognitive task, including 2-Back working memory, Go/No-Go task, Willingness to Pay for Food, and Delay Discounting tasks. Clinical measurements including BMI, eating behavior, psychiatric status will be assessed. Those aforementioned examinations will be performed at before the neurofeedback, 6th times and the end of the treatment.

Neurofeedback as a treatment for people which can be interpreted as a way to increase behavioral inhibition. A method to assess brain activity is functional near-infrared spectroscopy (NIRS), measuring hemodynamic correlates of neural activity.

The Willingness to Pay for Food (WTP) task is designed to evaluate obese subjects' cognitive decision ability regarding food. Participants are provided with four response options (i.e. 5¥，30¥，70¥，100¥) that can be selected to purchase a series of visually presented food items (HC, High-calorie food and LC, Low-calorie food).The task will record subjects' response time (RT) and money values selected for each presented food items. Mean response time and mean money values selected for HC food and LC food will be calculated and reported respectively. Shorter RT and bigger more money values selected for LC food represents better outcome. Shorter RT and bigger more money values selected for HC food represents worse outcome.

The Go/No-Go task is designed to evaluate subjects' inhibitory control capacity. Participants were instructed to press a button as quickly and accurately as possible in response to go trials and to refrain from responding to no-go trials. The current task involved two conditions (Go-condition and NoGo-condition). The task will record subjects' response time (RT) and whether correct for each trial response. Task response accuracy, response time, omission error rate (OE, %) and commission error rate (CE, %) will be calculated and reported. Omission error rate (OE, %) was calculated by dividing the total number of non-responses to go-items by the total number of go-trials. Commission error rate (CE, %) was calculated by dividing the total number of incorrect responses to no-go trials by the total number of no-go trials. Higher accuracy, lower RT, lower OE and lower CE represent better treatment outcome.

The Working Memory task (WM) is designed to evaluate obese subjects' short-term memory. Subjects performed food pictures variant version of working memory (n-back) tasks, which were block designed. In 0-back blocks (including 0-back block for HC (High-calorie food), LC (Low-calorie food) and Neutral pictures respectively), subjects were required to identify a single prespecified picture. Briefly, subjects were asked to press a button as quickly to indicate whether a picture presented on a screen matched the picture previously presented.The task will record subjects' response time (RT) and accuracy for each n-back block. Subjects' 2-back response time and accuracy for HC and LC will be calculated and reported. Shorter RT and higher accuracy of 2-back for HC and LC represents better outcome. Longer RT and lower accuracy of 2-back for HC and LC represents worse outcome.

Inclusion Criteria: Body mass index (BMI) ≥ 25 18 to 65 years old No severe mental disorders(depression; schizophrenia; bipolar disorder; etc.). Exclusion Criteria: Severe dysfunction of heart, liver, kidney and hematopoietic system Substance addiction Patients who cannot be treated with fMRI or fNRIS neurofeedback Those who take other weight loss drugs.

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