en Clinical Neuroscience Clinical Neuroscience Original Original <strong>Introduction</strong>: Regarding the neurofeedback training process, previous studies indicate that 10%-50% of subjects cannot gain control over their brain activity even after repeated training sessions. This study is conducted to overcome this problem by investigating inter-individual differences in neurofeedback learning to propose some predictors for the trainability of subjects.<br> <strong>Methods</strong>: Eight healthy female students took part in 8 (electroencephalography) EEG neurofeedback training sessions for enhancing EEG gamma power at the Oz channel. We studied participants&rsquo; preexisting fluid intelligence and EEG frequency sub-bands&rsquo; power during 2-min eyes-closed rest and a cognitive task as psychological and neurophysiological factors, concerning neurofeedback learning performance. We also assessed the self-reports of participants about mental strategies used by them during neurofeedback to identify the most effective successful strategies.<br> <strong>Results</strong>: The results revealed that a significant percentage of individuals (25% in this study) cannot learn how to control their brain gamma activity using neurofeedback. Our findings suggest that fluid intelligence, gamma power during a cognitive task, and alpha power at rest can predict gamma-enhancing neurofeedback performance of individuals. Based on our study, neurofeedback learning is a form of implicit learning. We also found that learning without a user&rsquo;s mental efforts to find out successful mental strategies, in other words, unconscious learning, lead to more success in gamma-enhancing neurofeedback.<br> <strong>Conclusion</strong>: Our results may improve gamma neurofeedback efficacy for further clinical usage and studies by giving insight about both non-trainable individuals and effective mental strategies. Neurofeedback, Brain-Computer Interface (BCI)-illiteracy, Performance prediction, Fluid intelligence, Mental strategies 701 714 http://bcn.iums.ac.ir/browse.php?a_code=A-10-1878-1&slc_lang=en&sid=1 Zeynab Khodakarami z.khodakarami@gmail.com 13700319475328460029581 13700319475328460029581 Yes Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran. Mohammad Firoozabadi pourmir@modares.ac.ir 13700319475328460029582 13700319475328460029582 No Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.