The role of sustained posterior brain activity in the serial chaining of two cognitive operations: A MEG study
 

Zhao Fan (1, 2), Suresh D. Muthukumaraswamy (3), Krish D. Singh (3) and Kimron Shapiro (4)*

(1) Key Laboratory of Adolescent Cyberpsychology and Behavior (CCNU), Ministry of Education, Wuhan, 430079, China
(2) School of Psychology, Central China Normal University, Wuhan, 430079, China
(3) CUBRIC, School of Psychology, Cardiff University, Cardiff, CF10 3AT, UK
(4) School of Psychology, Bangor University, Bangor, Wales, LL57 2AS, UK

* Corresponding Author: Kimron Shapiro, School of Psychology, Bangor University, Bangor, Wales, UK LL57 2AS
Telephone: +44 (0) 01248 383626 Email: k.shapiro@bangor.ac.uk

 

Abstract

A fundamental necessity in human cognition is to link sequential mental operations where appropriate execution of the second task requires input from the first. The present study explores the neural basis of such ¡®chaining¡¯ using a novel PRP task. Participants were required to make speeded responses to two sequential visual tasks that were chained or independent. Magnetoencephalographic (MEG) signals were recorded simultaneously to reveal the brain¡¯s response to these similar but fundamentally different conditions. RTs to Task 1 and 2 were slower in the Chained condition, and their temporal coupling weakened, relative to the Independent condition. MEG analysis of the accompanying event-related fields (ERFs) revealed an increased sustained posterior component (SPC) in the Chained condition beginning approximately 350ms after Task 2 onset and lasting for 450ms. Beamformer localisation of this ERF effect revealed a left hemisphere source near the junction of the temporal, parietal and occipital lobes. These results extend our understanding of the behavioural and corresponding neural mechanisms required by everyday decision making. (Fan, Muthukumaraswamy, Singh & Shapiro, 2012, Psychophysiology).