Transcranial Alternating Current Stimulation Increases Risk-Taking Behavior in the Balloon Analog Risk Task

Abstract

The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC). It has been proposed that in conflict and reward situations, theta-band (4–8 Hz) oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere (RH), is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial alternating current stimulation, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation/RH stimulation/Sham stimulation), with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1 mA peak-to-peak). During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

Transcranial Alternating Current Stimulation at Beta Frequency: Lack of Immediate Effects on Excitation and Interhemispheric Inhibition of the Human Motor Cortex

“…The fact that we did not observe tACS-induced neuroplasticity does not preclude that tACS is not sufficient to modulate behavior and or learning. In fact, a huge body of literature reported modulatory effects of tACS on behavior such as alterations in perception (Kanai et al, 2010; Feurra et al, 2011b), motor performance (Pogosyan et al, 2009; Wach et al, 2013) and cognition (Marshall et al, 2006; Sela et al, 2012). …”

Enhancing decision-making and cognitive impulse control with transcranial direct current stimulation (tDCS) applied over the orbitofrontal cortex (OFC): A randomized and sham-controlled exploratory study

“…Moreover, it is possible that some of our nearly significant findings might have resulted from intrinsic task-related "ceiling/floor" or time-dependent effects that limited the detection of post-tDCS changes. Indeed, previous studies have shown that healthy participants performing the BART tend to exhibit a risk-averse response style that often leads to suboptimal results (Bornovalova et al, 2009;Sela et al, 2012), and that tDCS might preferentially improve cognitive skills in subjects who present with lower baseline performance (Tseng et al, 2012). Consequently, we anticipate that tDCS may induce more prominent behavioural effects if administered to individuals who commonly present with baseline deficits in decision-making and impulse control such as those with suicidal behaviour (Richard-Devantoy et al, 2014) or addiction disorders (Bechara, 2005).…”

EEG oscillations: From correlation to causality

“…Thus, this study demonstrates topographical specificity, but leaves frequency-specificity unaddressed. Similarly, Sela et al (2012) restricted their analyses to topographical effects of theta tACS in showing that stimulation of the left dorsolateral prefrontal cortex led to riskier decision-making than stimulation of the right dorsolateral prefrontal cortex.…”