Neuronal correlates of entry of spontaneous thought into the stream of consciousness: Don't think about the white bear [NeuronÁlnÍ korelÁty spontÁnnÍho vstupu informace do proudu vÌDomÍ: Nemyslete na bÍlÉho medvÌda]
Abstract
Most studies of neuronal correlates of consciousness focus on the domain of visual perception and mechanisms of the entry of external stimuli into the stream of consciousness. This study focused on alternative and much less explored topic - neuronal correlates of entry of internally generated mental content into the stream of consciousness and its rivalry with other intrinsically generated mental contents.
Eleven participants (4 males, mean age 28,4 years) underwent a study using functional magnetic resonance. Their task was to imagine six different scenarios of social situations with an additional instruction not think about a white bear and when such a thought occurs, report it immediately with a button press.
Using these instructions, we created a rivalry between two endogenous mental states, where one is goal-directed thought (various scenarios) and the other is a spontaneously occurring/intruding thought (white bear). The timing of target events (i.e. spontaneous thoughts) was used for the fMRI analysis.
On the individual subject level, statistical parametric maps of a contrast corresponding to the relative change of signal at the time of reporting spontaneous thoughts compared to the rest of the task were obtained. On the group level, one sample t-test on the contrast images was conducted with the hypothesis of null mean value.
Intruding thoughts induced neuronal activation in the left inferior parietal lobe, left insular cortex, anterior cingulate cortex, and in the right fronto-parietal network. These areas have been often found active in paradigms during detection of external salient events or awareness of visual stimuli.
Our study demonstrates that the salience network is active also during awareness of internally generated spontaneous thoughts and not only in the case of external stimulation that is used most frequently in consciousness studies. Thus, the paradigm used in our study might be, due to its corresponding results to the studies using external stimuli, regarded as a competent tool for studying the rather neglected domain of conscious experience called mind-wandering. (C) 2018 Pacini Editore S.p.A.
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