Contrasting T and you can OT education, we see the translation off performance often is choosy. Knowledge and therefore give OT translate improved amygdala pastime due to the fact showing anxiety and you can avoidance, whereas T administration training understand an equivalent impression as the enhanced anger and you will approach. In terms of each other hormone, we should think about the chance that results of exogenous hormonal to the male and female heads will in all probability disagree. Because of the higher OT receptor thickness regarding the female mind, government away from OT can result in extremely high quantities of use and you may serving outcomes is nonlinear, since the is known together with other hormonal. It will be easy you to at the least some part of T's neural consequences are present through aromatization to oestradiol in the presynaptic terminals which in female could possibly get promote sex-typical worry in reaction in order to hazard. T tends to write completely alkuperäinen sivusto different consequences towards feminine brain and that, instead of a man brain, hasn't been prenatally prepared of the T. Gene term regarding the mind try sexually dimorphic and you will controlled by sex hormones: the same hormones may cause the phrase of various family genes within the male and female minds [ninety,91].
(b) Amygdala–frontal associations
Lower-peak affective inclinations so you're able to approach or avoid stimuli located in the limbic system are included in good ‘reflexive' behavioural control system toned mainly by evolutionary pushes. In the human beings, these inclinations was susceptible to expert ‘reflective' handle. Mental strength and you can behavioral reaction is modulated by the prefrontal cortex, especially the orbitofrontal (OFC) part, which has head involvement with the brand new amygdala. From inside the neuroimaging degree, negative correlations are located anywhere between amygdala and you can OFC craft from inside the impulsively aggressive anybody . Within the knowledge in which users is actually instructed to assume aggressing against otherwise damaging someone, deactivation of your own OFC is known. Female has actually a more impressive ventromedial PFC and best horizontal OFC [95,96]. Good meta-analysis of 88 degree claimed greater OFC craft in females to face stimuli portraying bad emotion (, find and additionally ). This suggests that women tends to be more efficient into the in an instant regulating mental responses.
This is exactly backed by studies off hormonal in addition to neurotransmitter serotonin. While you are progesterone grows useful relationships within amygdala and you may PFC , T decrease they, if you find yourself leaving associations to your head stalk unchanged [82,98]. OT, an excellent neuropeptide upregulated from the oestrogen, seemingly have opposite consequences to those out-of T. OT improves amygdala–prefrontal relationships if you find yourself cutting amygdala coupling with the mind 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.
(c) Amygdala–peripheral relationships
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 .