Neural coding of tactile decisions in the human prefrontal cortex.
The neural processes underlying tactile decisions in the human brain remain elusive. We addressed this question in a functional magnetic resonance imaging study using a somatosensory discrimination task, requiring participants to compare the frequency of two successive tactile stimuli. Tactile stimuli per se engaged somatosensory, parietal, and frontal cortical regions. Using a statistical model that accounted for the relative difference in frequencies (i.e., Weber fraction) and discrimination accuracy (i.e., correct or incorrect), we show that trial-by-trial relative frequency difference is represented linearly by activity changes in the left dorsolateral prefrontal cortex (DLPFC), the dorsal anterior cingulate cortex, and bilateral anterior insular cortices. However, a circumscribed region within the left DLPFC showed a different response pattern expressed as activity changes that were monotonically related to relative stimulation difference only for correct but not for incorrect trials. Our findings suggest that activity in the left DLPFC encodes stimulus representations that underlie veridical tactile decisions in humans.
Pleger
Burkhard
B
Wellcome Center of Neuroimaging, University College London, London WC1N 3AR, United Kingdom. b.pleger@fil.ion.ucl.ac.uk
Ruff
Christian C
CC
Blankenburg
Felix
F
Bestmann
Sven
S
Wiech
Katja
K
Stephan
Klaas E
KE
Capilla
Almudena
A
Friston
Karl J
KJ
Dolan
Raymond J
RJ
D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D003657:Decision Making / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009474:Neurons / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D014110:Touch / Q000502:physiology*