Neural correlates of non-specific skin conductance responses during resting state fMRI

• Published in: NeuroImage (Orlando, Fla.) Vol. 214; p. 116721
• Main Authors: Gertler, Joshua, Novotny, Stephanie, Poppe, Andrew, Chung, Yu Sun, Gross, James J., Pearlson, Godfrey, Stevens, Michael C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2020; Elsevier Limited; Elsevier
• Subjects: Adolescent; Brain; Brain - physiology; Brain Mapping; Child; Conductance; Cortex (cingulate); Cortex (insular); Cortex (parietal); Electrodermal; Emotions; Female; fMRI; Functional magnetic resonance imaging; Galvanic Skin Response - physiology; Humans; Image Processing, Computer-Assisted; Information processing; Magnetic Resonance Imaging; Male; Nervous system; Operculum; Parietal lobe; Rest; Resting state; Sensory integration; Skin; Skin conductance; Somatosensory cortex; Spontaneous fluctuations; fMRI; Skin conductance; Electrodermal; Resting state; Spontaneous fluctuations
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2020.116721

Skin conductance responses (SCRs) reliably occur in the absence of external stimulation. However, the neural correlates of these non-specific SCRs have been less explored than brain activity associated with stimulus-elicited SCRs. This study modeled spontaneous skin conductance responses observed during an unstructured resting state fMRI scan in 58 adolescents. A Finite Impulse Response (FIR) fMRI model was used to detect any type of hemodynamic response shape time-locked to non-specific SCRs; the shape of these responses was then carefully characterized. The strongest evidence for signal change was found in several sub-regions of sensorimotor cortex. There also was evidence for engagement of discrete areas within the lateral surfaces of the parietal lobe, cingulate cortex, fronto-insular operculum, and both visual and auditory primary processing areas. The hemodynamic profile measured by FIR modeling clearly resembled an event-related response. However, it was a complex response, best explained by two quickly successive, but opposing neuronal impulses across all brain regions – a brief positive response that begins several seconds prior to the SCR with a much longer negative neuronal impulse beginning shortly after the SCR onset. Post hoc exploratory analyses linked these two hemodynamic response phases to different emotion-related individual differences. In conclusion, this study shows the neural correlates of non-specific SCRs are a widespread, cortical network of brain regions engaged in a complex, seemingly biphasic fashion. This bimodal response profile should be considered in replication studies that attempt to directly link brain activity to possible homeostatic mechanisms or seek evidence for alternative mechanisms. •Neural correlates of spontaneous nonspecific SCRs is a widespread cortical network.•This network displayed a seemingly biphasic event related hemodynamic response.•Both phases of the hemodynamic response correlated with behavioral measures.•Studies are needed to replicate this response and explore neural mechanisms.