The main aim of the study is to investigate whether orally administered oxytocin (24IU) can modulate neural and behavioral responses to positive and negative valence stimuli during basal (emotional scenes) and higher order (facial stimuli) emotional processing.
A number of previous studies have reported both neural and social cognition effects of intranasally administered oxytocin, although it is unclear whether functional effects are mediated by the peptide directly entering the brain or indirectly via raising peripheral concentrations. The investigators hypothesize that one method of producing a similar pattern of increased peripheral oxytocin concentrations but without the possibility of direct entry into the brain would be to administer the peptide lingually. In the current double-blind, between-subject, placebo controlled study 80 healthy male subjects will be recruited and receive either oxytocin (24IU) or placebo control administered orally (lingual). 45 minutes after treatment subjects will be required to complete both face emotion and emotional scene processing tasks during fMRI scanning. After the tasks, subjects will be required to rate their valence, intensity and arousal response to the same emotional face and scene stimuli which were presented during MRI acquisition. Blood samples will be taken before and 30 min after the oral treatment interventions to assess oxytocin blood concentrations. All subjects will be asked to complete a range of questionnaires before treatment to control for possible pre-treatment confounders in terms of personality traits and mood: Beck Depression Inventory II (BDI), Autism Spectrum Quotient (ASQ), Liebowitz Social Anxiety Scale (LSAS), State-Trait Anxiety Inventory (STAI), Childhood Trauma Questionnaire (CTQ), the Second Version of Social Responsiveness Scale(SRS-2), and Interpersonal Reactivity Index (IRI).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
80
Administration of oxytocin (24 international units) orally
Administration of placebo orally
school of life science and technology, University of Electronic Science and Technology of China
Chengdu, Sichuan, China
RECRUITINGEffect of oral oxytocin administration of oxytocin on neural responses to positive and negative valence emotional faces, as assessed by task fMRI
Comparison of neural activation as assessed by functional MRI on the whole brain level between oral administration of oxytocin and placebo by means of treatment (oxytocin, placebo) x emotion (happy, neutral, angry, fear) ANOVAs and emotion-specific comparisons between the treatment groups. We hypothesized that if the effects of oxytocin administration reported following intranasal administration are primarily produced via an increase in peripheral concentrations then oral administration should produce similar effects on neural systems involved in emotional and brain reward processing. If on the other hand some, or all, of the effects of intranasal oxytocin are mediated via a direct action on the brain then oral administration should result in either no effect or alternatively a different pattern of functional effects.
Time frame: 45-90 minutes after treatment
Effect of oral oxytocin administration on neural responses to positive and negative valence scenes, as assessed by fMRI
Comparison of neural activation as assessed by functional MRI on whole brain level between oral administration of oxytocin and placebo by means of treatment (oxytocin, placebo) x emotion (neutral, positive, negative) ANOVAs and emotion-specific post hoc comparisons between the treatment groups. We hypothesize that if the effects of oxytocin administration reported following intranasal administration are primarily produced via an increase in peripheral concentrations then oral administration should produce similar effects on neural systems involved in emotional and brain reward processing. If on the other hand some, or all, of the effects of intranasal oxytocin are mediated via a direct action on the brain then oral administration should result in either no effect or alternatively a different pattern of functional effects.
Time frame: 45-90 minutes after treatment
Effect of oral oxytocin administration on behavioral ratings of face emotion and scene stimuli
Comparison of behavioral ratings of valence, arousal and intensity (9-point Likert scale) for emotional face and social scene stimuli presented again post-scan will be performed in oxytocin versus placebo control groups. We hypothesize that if the effects of oxytocin administration reported following intranasal administration are primarily produced via an increase in peripheral concentrations then oral administration should produce similar effects on behavioral ratings of positive and negative valence emotional stimuli. If on the other hand some, or all, of the effects of intranasal oxytocin are mediated via a direct action on the brain then oral administration should result in either no effect or alternatively in a different pattern of functional effects.
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Time frame: 45-115 minutes after treatment
Change in blood oxytocin concentrations following oral administration of oxytocin
Changes in blood concentrations of oxytocin from baseline after oral oxytocin treatment will be assessed by comparison with the placebo group. We hypothesize that oral oxytocin should produce a significant increase in blood oxytocin concentrations after 30 minutes.
Time frame: 30 minutes before treatment and 30 minutes after treatment
Correlations between neural responses/functional connectivity changes and post-scan behavioral ratings
Correlations between neural responses changes and post-scan behavioral ratings of positive and negative valence stimuli will be performed using Pearson correlation in both oxytocin and placebo groups. We hypothesize that neural responses and behavioral ratings will be correlated.
Time frame: 45-115 minutes after treatment
Correlations between neural responses/functional connectivity in response to positive and negative valence stimuli and basal and oral administration evoked changes in blood concentrations of oxytocin
Correlations between neural responses in response to positive and negative valence stimuli and basal and oral administration evoked changes in blood concentrations of oxytocin will be performed using Pearson correlation in both oxytocin and placebo groups. We hypothesize that neural responses to emotional stimuli will correlate with basal and/or oral administration evoked oxytocin concentrations.
Time frame: 30 minutes before treatment to 90 minutes after treatment
Correlations between behavioral ratings of positive and negative valence stimuli and basal and oral administration evoked changes in blood oxytocin concentrations
Correlations between behavioral ratings of positive and negative valence stimuli and basal and oral administration evoked changes in blood oxytocin concentrations will be performed using Pearson correlation in both oxytocin and placebo groups. We hypothesize that behavioral ratings to emotional stimuli will correlate with basal and/or oral administration evoked oxytocin concentrations.
Time frame: 30 minutes before treatment to 115 minutes after treatment