Oxytocin facilitates protective responses to aversive social stimuli in males

There is mounting evidence that oxytocin has anxiogenic and fear-enhancing effects.

“However, against the background of mounting evidence for anxiogenic and fearenhancing OXT effects (33,43,44), it is necessary that the mechanisms determining the outcome of an OXT treatment are completely identified.”

Exogenous OXT can have anxiogenic effects in humans exposed to social stimuli.

“Likewise, exogenous OXT can have anxiogenic effects in humans exposed to social stimuli (Bartz et al., 2010; Striepens et al., 2012; Grillon et al., 2013; MacDonald et al., 2013).”

Oxytocin changes activity in the insular cortex and ventromedial prefrontal cortex and reduces neural responses to stress-related and painful stimuli in the amygdala.

“Furthermore, it has been shown that OXT not only modulates activity in the insular cortex (Striepens et al., 2012;Wigton et al., 2015) and VMPFC (Aoki et al., 2015;Labuschagne et al., 2012) but also reduces the neural response to stress-associated signals (Maier et al., 2018) and painful stimuli in the amygdala (AMY) (Paloyelis et al., 2016).”

Other studies have reported that oxytocin effects on amygdala responses often occur with concurrent changes in its connections with, and activation of, the insula.

“Indeed, other studies have also reported that OXT effects on amygdala responses often occur with concurrent changes in its connections with, and activation of, the insula (27 -29).”

In the absence of social support, oxytocin may increase the sensation of social stress, augment the impact of aversive information on defensive responses, and induce a privileged recall of negative information by increasing neural responses in insular cortex.

“On the other hand, in the absence of social support, OXT may increase the sensation of social stress, augment the impact of aversive information on defensive responses (i.e., the startle reflex), and induce a privileged recall of negative information by increasing neural responses in insular cortex (106,107).”

Social touch in general and the oxytocin effect on hedonic value and neural response to human touch in particular are context dependent.

“Our results strongly corroborate the notion that social touch in general and the OXT effect on hedonic value and neural response to human touch in particular are context dependent (Scheele et al, 2012; Striepens et al, 2014; Striepens et al, 2012).”

IN-OT increases functional coupling between amygdala, anterior insula, and inferior frontal gyrus in response to remembered emotional items.

“IN-OT increases the functional coupling between amygdala, anterior insula, and inferior frontal gyrus in response to remembered emotional items (Striepens et al. 2012).”

Intranasal oxytocin may increase startle responses to stressful stimuli in humans.

“intranasal oxytocin may increase startle responses to stressful stimuli in humans (Grillon et al., 2013; Striepens et al., 2012)”

Intranasal oxytocin facilitates bodily reactions to and episodic memory for aversive events.

“further research showing that OXT IN facilitates bodily reactions to and episodic memory for aversive events (Striepens et al, 2012)”

A single-dose administration of OXT potentiates episodic encoding of aversive events.

“a single-dose administration of OXT potentiates episodic encoding of aversive events (Striepens et al, 2012)”

Oxytocin facilitates Pavlovian fear conditioning by potentiating neural responses to fear-associated stimuli in regions other than the amygdala.

“This specific profile suggests that OXT facilitates Pavlovian fear conditioning by potentiating neural responses to fearassociated stimuli in regions other than the amygdala, highlighting their importance in the acquisition of fear (Eckstein et al, 2014a;Striepens et al, 2012).”