Contrasting T and you will OT training, we see that the translation of overall performance often is selective. Studies and this administer OT understand enhanced amygdala activity due to the fact showing concern and you can prevention, whereas T administration education interpret an identical feeling because increased fury and you will approach. When it comes to each other hormones, we need to look at the chance that the effects of exogenous hormones into female and male minds will in all probability disagree. Because of the higher OT receptor thickness throughout the female notice, administration away from OT can result in quite high levels of uptake and you can amount consequences can be nonlinear, once the has been found with other hormones. It is possible that at least some section of T’s neural effects can be found via aromatization to oestradiol during the presynaptic terminals which in women can get enhance sex-typical fear responding to help you issues. T tends to establish completely different consequences into female head and this, in the place of a man brain, wasn’t prenatally planned by T. Gene term regarding the head try sexually dimorphic and subject to sex hormones: a comparable hormone may cause the term of different genetics within the male and female minds [90,91].
Lower-top affective tendencies so you’re able to strategy or avoid stimulus located in the limbic system are part of good ‘reflexive’ behavioural manage system sculpted chiefly by evolutionary forces. Into the human beings, such tendencies are subject to sophisticated ‘reflective’ control. Mental intensity and you will behavioural effect might be modulated of the prefrontal cortex, particularly the orbitofrontal (OFC) area, with head connections to the newest amygdala. Within the neuroimaging education, negative correlations are located ranging from amygdala and you will OFC pastime when you look at the impulsively competitive some body . Into the knowledge in which members is taught to imagine aggressing facing otherwise harming someone else, deactivation of your own OFC has been seen. Women enjoys a much bigger ventromedial PFC and you will best lateral OFC [95,96]. A great meta-analysis off 88 studies said better OFC activity in females so you can facial stimulus portraying negative feelings (, discover plus ). This suggests that women is more beneficial for the in an instant regulating mental answers. This is certainly backed by training regarding hormones together with neurotransmitter serotonin. When you are progesterone develops useful connections between your amygdala and you can PFC , T decreases it, if you are making connectivity for the notice base unaffected [82,98]. OT kvinner Jordanian, a good neuropeptide upregulated by the oestrogen, appears to have opposite consequences to people off T. OT improves amygdala–prefrontal relationships while reducing amygdala coupling toward attention stalk . Serotonin (5-HT) plays a key role in the functional connectivity between the PFC and the amygdala. There is a dense concentration of 5-HT receptors in the limbic system (including the amygdala) with projections to the prefrontal cortex. Dietary tryptophan depletion (which reduces 5-HT levels) reduces connectivity in the prefrontal–amygdala circuitry specifically when viewing angry faces . Women have higher 5-HT transporter availability and, because this regulates 5-HT neurotransmission, baseline serotonin may be higher in women than men. Studies have reported a higher density of 5-HT1A receptors in women in areas including the amygdala and medial and orbital PFC . Receptor density in these areas is significantly negatively correlated with lifetime aggression. In animal research, 5-HT receptor density is also negatively correlated with T. Although this has not been replicated with humans, men (but not women) with high levels of aggression are characterized by a combination of high T and low 5-HT . Reduced serotonin availability or uptake, associated with high T, may explain men’s diminished prefrontal control over emotion-driven behaviour. The central amygdala projects downward to the hypothalamus and brain stem to initiate autonomic and hypothalamic–pituitary–adrenal (HPA) responses to threat. Sex differences in self-reported and behavioural measures of fear are not matched by differences in sympathetic nervous system reactivity. When fear is induced through incremental behavioural approach to spiders , inhalation of CO2-enriched air , affective images , scary movie clips or emotional imagery , sex differences in heart rate and blood pressure are not found. In the HPA system, evidence indicates somewhat higher salivary cortisol measures in men after experimental stress induction .(c) Amygdala–peripheral connections