Alterations in Brain Activity Induced by Transcranial Magnetic Stimulation and Their Relation to Decision Making

SIMPLE SUMMARY: In this study, we investigated how inhibiting the motor cortex via Transcranial Magnetic Stimulation (TMS) affects decision-making and awareness of such choices. We employed low-frequency TMS to temporarily inhibit brain activity. During inhibition, participants were asked to select a preference between side-by-side images of everyday items. We discovered that stimulation affected which side people favored when choosing between pictures. The time to make a decision remained the same, as did their explanation for their choices. That is, explanations as to preferred choice almost always had a ‘reason’ behind them. This indicated that choices can be unconsciously influenced below the level of awareness. This study helps us understand the degree to which the unconscious influences our eventual conscious rationalizations. ABSTRACT: Understanding the intricate dynamics between conscious choice and neural processes is crucial for unraveling the complexity of human decision-making. This study investigates the effects of inhibitory Transcranial Magnetic Stimulation (TMS) on choice bias, shedding light on the malleability of cognitive-motor functions involved in decisions. While reaction times remained unaffected, inhibitory TMS to either the left or right motor cortex led to a significant bias in screen side preference during a choice task. These findings suggest that our cognitive-motor processes underlying decision-making can be unconsciously influenced by TMS. Furthermore, analysis of choice attribution categories revealed individual variability, emphasizing the complex nature of the decision-making process. These insights contribute to the ongoing exploration of the neural mechanisms governing human choice. As the neural basis of free will continues to captivate scientific inquiry, this research advances our understanding of the intricate relationship between neural circuits and conscious intention.