Neural correlates of executive functions

Executive functions involve not only choosing from a range of possible actions but also the inhibition of responses as circumstances demand. Recent studies have demonstrated that many clinical populations, such as people with attention-deficit hyperactivity disorder, major depression disorder, exhibit difficulties in inhibitory control. Several critical brain regions in the frontal area involved in the control/inhibitory processes. To uncover the underlying neural mechanisms of the executive functions, high temporal resoultion EEG and non-invasive transcranial direct current stimulation (tDCS) were applied to investigate when and where control/inhibitory proceses involved.Our main findings suggested that Pre-SMA is a critical brain region involved in inhibitory control when tDCS selectively excite or suppress the neural activity of Pre-SMA, corresponding behavioral peformance was altered either improved/impaired efficiency of inhibitory control. Meanwhile, to our knowledge, this is the first demonstration of non-invasive intervention tDCS altering subjects' inhibitory control. These results further our understanding of the neural bases of inhibitory control and suggest a possible therapeutic intervention method for clinical populations. 

References:

Hsu, T.Y., Tzeng, LY., Yu, J.X., Liang, W.K., Hung, D.L., Tzeng, O.J.L., Walsh V., Muggleton N.G., & Juan, C.H. (2011) Modulating inhibitory control with direct current stimulation of the superior medial frontal cortex. Neuroimage, 56(4), 2249-57.

Lee, H.W., Lu, M.S., Chen, C.Y., Muggleton, N.G., Hsu, T.Y., Juan, C.H. (2016) Roles of the pre-SMA and rIFG in conditional stopping revealed by transcranial magnetic stimulation. Behavioural Brain Research, 296, 459-67. 

Chang, C.F., Hsu, T.Y., Tseng, P., Liang, W.K., Tzeng, O.J.L., Hung, D.L., Juan, C.H. (2013) Right temporo-parietal junction and attentional reorienting. Human Brain Mapping, 34(4), 869-77.

Huang, I.W., Tseng, L.Y., Hsu, T.Y. Sustained or transient control process in congruency sequence effect: An EEG study (in preparation)