Structural Connectivity Variances Underlie Functional and Behavioral Changes During Pain Relief Induced by Neuromodulation.
An increased understanding of the relationship between structural connections and functional and behavioral outcomes is an essential but under-explored topic in neuroscience. During transcranial direct current stimulation (tDCS)-induced analgesia, neuromodulation occurs through a top-down process that depends on inter-regional connections. To investigate whether variation in anatomical connectivity explains functional and behavorial outcomes during neuromodulation, we first combined tDCS and a tonic pain model with concurrent arterial spin labelling that measures cerebral perfusion related to ongoing neural activity. Left dorsolateral prefrontal cortex (L-DLPFC) tDCS induced an analgesic effect, which was explained by reduced perfusion to posterior insula and thalamus. Second, we used diffusion imaging to assess white matter structural integrity between L-DLPFC and thalamus, two key components of the neuromodulatory network. Fractional anisotropy of this tract correlated positively with functional and behavioral modulations. This suggests structural dependence by the neuromodulatory process to induce analgesia with potential relevance for patient stratification.
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.|Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom.
Richard L
RL
Lin
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.
Gwenaëlle
G
Douaud
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.|Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom.
Nicola
N
Filippini
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.
Thomas W
TW
Okell
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.|Oxford Centre for Human Brain Activity, Department of Psychiatry, University of Oxford, Oxford OX1 3UH, United Kingdom.
Charlotte J
CJ
Stagg
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom.|Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom.
Irene
I
Tracey
D001519:Behavior; D001921:Brain / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways; D010146:Pain / Q000175:diagnosis / Q000523:psychology*; D010147:Pain Measurement; D017397:Prefrontal Cortex / Q000502:physiology; D013788:Thalamus / Q000502:physiology; D065908:Transcranial Direct Current Stimulation