Continuous Theta Burst Stimulation Over the Dorsolateral Prefrontal Cortex and the Pre-SMA Alter Drift Rate and Response Thresholds Respectively During Perceptual Decision-Making

Dejan Georgiev; Lorenzo Rocchi; Pierluigi Tocco; Maarten Speekenbrink; John C Rothwell; Marjan Jahanshahi

doi:10.1016/j.brs.2016.04.004

Continuous Theta Burst Stimulation Over the Dorsolateral Prefrontal Cortex and the Pre-SMA Alter Drift Rate and Response Thresholds Respectively During Perceptual Decision-Making

Brain Stimul. 2016 Jul-Aug;9(4):601-8. doi: 10.1016/j.brs.2016.04.004. Epub 2016 Apr 12.

Authors

Dejan Georgiev¹, Lorenzo Rocchi², Pierluigi Tocco³, Maarten Speekenbrink⁴, John C Rothwell³, Marjan Jahanshahi⁵

Affiliations

¹ Cognitive Motor Neuroscience Group, Institute of Neurology, University College London, 33 Queen Square, London, WC1N 3BG, UK; Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK; Department of Neurology, University of Ljubljana, Zaloška cesta 2, 1000 Ljubljana, Slovenia.
² Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK; Department of Neurology and Psychiatry, Università di Roma "Sapienza", Viale dell'Università 30, 00185 Rome, Italy.
³ Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK.
⁴ Division of Psychology and Language Sciences, UCL Cognitive, Perceptual and Brain Sciences, London WC1E 6BT, UK.
⁵ Cognitive Motor Neuroscience Group, Institute of Neurology, University College London, 33 Queen Square, London, WC1N 3BG, UK; Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK. Electronic address: m.jahanshahi@ucl.ac.uk.

PMID: 27157058
DOI: 10.1016/j.brs.2016.04.004

Abstract

Background: The speed-accuracy trade-off (SAT) refers to the balancing of speed versus accuracy during decision-making. SAT is very commonly investigated with perceptual decision-making tasks such as the moving dots task (MDT). The dorsolateral prefrontal cortex (DLPFC) and the pre-supplementary motor area (pre-SMA) are two brain regions considered to be involved in the control of SAT.

Objectives/hypotheses: The study tested whether the DLPFC and the pre-SMA play an essential role in the control of SAT. We hypothesized that continuous theta burst stimulation (cTBS) over the right DLPFC would primarily alter the rate of accumulation of evidence, whereas stimulation of the pre-SMA would influence the threshold for reaching a decision.

Methods: Fifteen (5 females; mean age = 30, SD =5.40) healthy volunteers participated in the study. We used two versions of the MDT and cTBS over the right DLPFC, pre-SMA and sham stimulation. The drift diffusion model was fit to the behavioural data (reaction time and error rate) in order to calculate the drift rate, boundary separation (threshold) and non-decision time.

Results: cTBS over the right DLPFC decreased the rate of accumulation of evidence (i.e. the drift rate from the diffusion model) in high (0.35 and 0.5) but not in low coherence trials. cTBS over the pre-SMA changed the boundary separation/threshold required to reach a decision on accuracy, but not on speed trials.

Conclusions: The results suggest for the first time that both the DLPFC and the pre-SMA make essential but distinct contributions to the modulation of SAT.

Keywords: Continuous theta burst stimulation; DLPFC; Perceptual decision-making; Pre-SMA; Speed–accuracy trade off.

MeSH terms

Adult
Decision Making / physiology*
Female
Humans
Male
Prefrontal Cortex / physiology*
Psychomotor Performance / physiology*
Theta Rhythm / physiology*
Transcranial Magnetic Stimulation / methods
Young Adult