Effects of theta transcranial alternating current stimulation (tACS) on exploration and exploitation during uncertain decision-making

Miles Wischnewski, Boukje Compen

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Exploring ones surroundings may yield unexpected rewards, but is associated with uncertainty and risk. Alternatively, exploitation of certain outcomes is related to low risk, yet potentially better outcomes remain unexamined. As such, risk-taking behavior depends on perceived uncertainty and a trade-off between exploration-exploitation. Previously, it has been suggested that risk-taking may relate to theta activity in the prefrontal cortex. Furthermore, previous studies hinted at a relationship between a right-hemispheric bias in frontal theta asymmetry and risky behavior. In the present double-blind sham-controlled within-subject study, we applied bifrontal transcranial alternating current stimulation (tACS) at the theta frequency (5 Hz) on eighteen healthy volunteers during a gambling task. Two tACS montages with either left-right or posterior-anterior current flow were employed at an intensity of 1 mA. Results showed that, compared to sham, theta tACS increased perceived uncertainty irrespective of current flow direction. Despite this observation, no direct effect of tACS on exploration behavior and general risk-taking was observed. Furthermore, frontal theta asymmetry was more right-hemispherically biased after posterior-anterior tACS, compared to sham. Finally, we used electric field simulation to identify which regions were targeted by the tACS montages as an overlap in regions may explain why the two montages resulted in comparable outcomes. Our findings provide a first step towards understanding the relationship between frontal theta oscillations and different features of risk-taking.

Original languageEnglish
Article number113840
Pages (from-to)113840
Number of pages11
JournalBehavioural Brain Research
Volume426
DOIs
Publication statusPublished - 24 May 2022

Keywords

  • Double-Blind Method
  • Electroencephalography
  • Humans
  • Prefrontal Cortex
  • Reward
  • Transcranial Direct Current Stimulation/methods
  • Uncertainty
  • RISK-TAKING
  • Decision making
  • PERFORMANCE
  • INFORMATION
  • SENSITIVITY
  • Risk taking
  • REWARD
  • PREFRONTAL CORTEX
  • Exploration and exploitation
  • Theta oscillations
  • FRONTAL MIDLINE THETA
  • Frontal asymmetry
  • NONINVASIVE BRAIN-STIMULATION
  • DYNAMICS
  • Transcranial alternating current stimulation
  • WORKING-MEMORY

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