Is evaluation of humorous stimuli associated with frontal cortex morphology? A pilot study using facial micro-movement analysis and MRI.
Humour involves the ability to detect incongruous ideas violating social rules and norms. Accordingly, humour requires a complex array of cognitive skills for which intact frontal lobe functioning is critical. Here, we sought to examine the association of facial expression during an emotion inducing experiment with frontal cortex morphology in healthy subjects. Thirty-one healthy male subjects (mean age: 30.8±8.9 years; all right-handers) watching a humorous movie ("Mr. Bean") were investigated. Markers fixed at certain points of the face emitting high-frequency ultrasonic signals allowed direct measurement of facial movements with high spatial-temporal resolution. Magnetic resonance images of the frontal cortex were obtained with a 1.5-T Magnetom using a coronar T2- and protondensity-weighted Dual-Echo-Sequence and a 3D-magnetization-prepared rapid gradient echo (MPRAGE) sequence. Volumetric analysis was performed using BRAINS. Frontal cortex volume was partly associated with slower speed of "laughing" movements of the eyes ("genuine" or Duchenne smile). Specifically, grey matter volume was associated with longer emotional reaction time ipsilaterally, even when controlled for age and daily alcohol intake. These results lend support to the hypothesis that superior cognitive evaluation of humorous stimuli - mediated by larger prefrontal grey and white matter volume - leads to a measurable reduction of speed of emotional expressivity in normal adults.
Juckel
Georg
G
Department of Psychiatry, Ruhr-University Bochum, Germany. georg.juckel@wkp-lwl.org
Mergl
Roland
R
Brüne
Martin
M
Villeneuve
Isabelle
I
Frodl
Thomas
T
Schmitt
Gisela
G
Zetzsche
Thomas
T
Born
Christine
C
Hahn
Klaus
K
Reiser
Maximilian
M
Möller
Hans-Jürgen
HJ
Bär
Karl-Jürgen
KJ
Hegerl
Ulrich
U
Meisenzahl
Eva Maria
EM
D000328:Adult; D001696:Biomechanical Phenomena; D005145:Face / Q000502:physiology*; D005149:Facial Expression; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007845:Laughter / Q000523:psychology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D010865:Pilot Projects; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000502:physiology*; D012904:Smiling; D014925:Wit and Humor as Topic / Q000523:psychology*; D055815:Young Adult