Oxytocin modulates semantic integration in speech comprehension
Ye, Z., Stolk, A., Toni, I., & Hagoort, P.
Oxytocin modulates semantic integration in speech comprehension. Journal of Cognitive Neuroscience, 29
, 267-276. doi:10.1162/jocn_a_01044.
Listeners interpret utterances by integrating information from
multiple sources including word level semantics and world knowledge.
When the semantics of an expression is inconsistent with
his or her knowledge about the world, the listener may have to
search through the conceptual space for alternative possible
world scenarios that can make the expression more acceptable.
Such cognitive exploration requires considerable computational
resources and might depend on motivational factors. This study
explores whether and how oxytocin, a neuropeptide known to
influence socialmotivation by reducing social anxiety and enhancing
affiliative tendencies, can modulate the integration of world
knowledge and sentence meanings. The study used a betweenparticipant
double-blind randomized placebo-controlled design.
Semantic integration, indexed with magnetoencephalography
through the N400m marker, was quantified while 45 healthymale
participants listened to sentences that were either congruent or
incongruent with facts of the world, after receiving intranasally
delivered oxytocin or placebo. Compared with congruent sentences,
world knowledge incongruent sentences elicited a stronger
N400m signal from the left inferior frontal and anterior
temporal regions and medial pFC (the N400m effect) in the placebo
group. Oxytocin administration significantly attenuated the
N400meffect at both sensor and cortical source levels throughout
the experiment, in a state-like manner. Additional electrophysiological
markers suggest that the absence of the N400m effect in
the oxytocin group is unlikely due to the lack of early sensory or
semantic processing or a general downregulation of attention.
These findings suggest that oxytocin drives listeners to resolve
challenges of semantic integration, possibly by promoting the
cognitive exploration of alternative possible world scenarios.