Research has shown that Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security.[21] Many studies have shown a correlation of oxytocin with human bonding, increases in trust, and decreases in fear. One study confirmed a positive correlation between oxytocin plasma levels and an anxiety scale measuring the adult romantic attachment.[22] This suggests oxytocin may be important for the inhibition of the brain regions associated with behavioral control, fear, and anxiety, which may be part of the reason that increased Oxytoicn levels increase orgasms in men and women. Oxytocin also appears to play an important role in autism and may be an effective treatment for autism's repetitive and affiliative behaviors.[26] Oxytocin treatments result in improved eye contact an increased retention of affective speech in individuals with autism.[27]
Oxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in reproduction, in particular during and after childbirth. It is released in large amounts after distension of the cervix and uterus during labor, facilitating birth, and after stimulation of the nipples, facilitating breastfeeding.
Recent studies have begun to investigate oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, and maternal behaviors.[1] For this reason, it is sometimes referred to as the "love hormone". The deficiency of oxytocin is thought to be associated with a lack of empathy. [2]
Oxytocin is a neurotransmitter often called the "bonding" or "love" hormone. Mutual gaze triggers this bonding hormone in both individuals, increasing trust and lowering cortisol. Research shows that maintaining eye contact for 30–60 seconds can initiate this calming, connected state.
- Oxytocin acts in a positive feedback loop; eye contact increases oxytocin, which in turn encourages more eye contact, improving social bonding and engagement
- Impact on Attention: Studies show that increased oxytocin makes individuals more likely to focus on the eye region of faces, promoting better, more direct communication.
- Stress Reduction: The increase in oxytocin prompted by eye contact helps reduce cortisol, thereby reducing stress levels.
- Role in Relationships: Frequent eye contact, sometimes paired with touch, stimulates oxytocin production that enhances connection in romantic relationships, and also plays a role in human-animal bonding.
- Attachment Avoidance: A single dose of oxytocin can increase the likelihood of individuals with higher attachment avoidance engaging in eye contact.
The Effects of Oxytocin in Love Making
Oxytocin encourages desires to be kissed and cuddled by one's lover. In fact being touched anywhere on the body leads to a rise in Oxytocin levels. This causes a chain reaction within the body, including the release of endorphins and testosterone, which results in both biological and psychological arousal.
Erogenous zones including earlobes, neck, mouth and genitals become sensitized to the effect of Oxytocin and become more responsisve from more frequent Oxytocin stimulation. It not only arouses blood and the senses, but also promotes a bond of intimacy and closeness. The cycle continues to fire these pleasure giving endorphins and hormones and we naturally produce more Oxytocin and feel more pleasure as a reward.
By stimulating genital areas and causing the nerves to fire spontaneously, orgasm is reached far easier and more powerfully. In orgasm, male Oxytocin levels quintuple, while women need higher levels if they are to reach orgasm. And during peak sexual arousal, the Oxytocin levels become very high indeed. At this point multiple orgasms can occur.
Breast Feeding and Childbirth
In lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be 'let down' into subareolar sinuses, from where it can be excreted via the nipple.[12] Suckling by the infant at the nipple is relayed by spinal nerves to the hypothalamus. The stimulation causes neurons that make oxytocin to fire action potentials in intermittent bursts; these bursts result in the secretion of pulses of oxytocin from the neurosecretory nerve terminals of the pituitary gland.
Important for cervical dilation before birth, oxytocin causes contractions during the second and third stages of labor. Oxytocin release during breastfeeding causes mild but often painful contractions during the first few weeks of lactation. This also serves to assist the uterus in clotting the placental attachment point postpartum. However, in knockout mice lacking the oxytocin receptor, reproductive behavior and parturition are normal.[13]
Social behavior
Oxytocin is also thought to modulate and reduce inflammation by decreasing certain cytokines. Thus, the increased release in oxytocin following positive social interactions has the potential to improve wound healing. A study by Marazziti and colleagues used heterosexual couples to address this possibility. They found increases in plasma oxytocin following a social interaction were correlated with faster wound healing. They hypothesized this was due to oxytocin reducing inflammation, thus allowing the wound to heal faster. This study provides preliminary evidence that positive social interactions may directly impact aspects of health.[14]
Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security around the mate.[21] Many studies have already shown a correlation of oxytocin with human bonding, increases in trust, and decreases in fear. One study confirmed a positive correlation between oxytocin plasma levels and an anxiety scale measuring the adult romantic attachment.[22] This suggests oxytocin may be important for the inhibition of the brain regions associated with behavioral control, fear, and anxiety, thus allowing orgasm to occur.
Autism
Oxytocin may play a role in autism and may be an effective treatment for autism's repetitive and affiliative behaviors.[26] Oxytocin treatments result in an increased retention of affective speech in adults with autism.[27] Two related studies in adults, in 2003 and 2007, found oxytocin decreased repetitive behaviors and improved interpretation of emotions. More recently, intranasal administration of oxytocin was found to increase emotion recognition in children as young as 12 who are diagnosed with autism spectrum disorders [28] Oxytocin has also been implicated in the etiology of autism, with one report suggesting autism is correlated with genomic deletion of the gene containing the oxytocin receptor gene (OXTR).
Autism may also be associated with an aberrant methylation of OXTR.[27] After treatment with inhaled oxytocin, autistic patients exhibit more appropriate social behavior.[30] While this research suggests some promise, further clinical trials of oxytocin are required to demonstrate potential benefit and side effects in the treatment of autism.
Increasing trust and reducing fear
In a risky investment game, experimental subjects given nasally administered oxytocin displayed "the highest level of trust" twice as often as the control group. Subjects who were told they were interacting with a computer showed no such reaction, leading to the conclusion that oxytocin was not merely affecting risk-aversion.[31] Nasally administered oxytocin has also been reported to reduce fear, possibly by inhibiting the amygdala (which is thought to be responsible for fear responses).[32] Indeed, studies in rodents have shown oxytocin can efficiently inhibit fear responses by activating an inhibitory circuit within the amygdala. Some researchers have argued oxytocin has a general enhancing effect on all social emotions, since intranasal administration of oxytocin also increases envy and Schadenfreude.[33]
Affecting generosity by increasing empathy during perspective taking: In a neuroeconomics experiment, intranasal oxytocin increased generosity in the Ultimatum Game by 80%, but has no effect in the Dictator Game that measures altruism. Perspective-taking is not required in the Dictator Game, but the researchers in this experiment explicitly induced perspective-taking in the Ultimatum Game by not identifying to participants into which role they would be placed.[34] Serious methodological questions have arisen, however, with regard to the role of oxytocin in trust and generosity.[35]
Cognitive function
Certain learning and memory functions are impaired by centrally administered oxytocin.[36] Also, systemic oxytocin administration can impair memory retrieval in certain aversive memory tasks.[37] Interestingly, oxytocin does seem to facilitate learning and memory specifically for social information. Healthy males administered intranasal oxytocin show improved memory for human faces, in particular happy faces.[38][39] They also show improved recognition for positive social cues over threatening social cues [40][41] and improved recognition of fear.[42]
Empathy in healthy males has been shown to be increased after intranasal oxytocin[43][44] This is most likely due to the effect of oxytocin in enhancing eye gaze.[45] There is some discussion about which aspect of empathy oxytocin might alter - for example, cognitive vs. emotional empathy.[46]
[edit]Actions within the brain
Oxytocin secreted from the pituitary gland cannot re-enter the brain because of the blood–brain barrier. Instead, the behavioral effects of oxytocin are thought to reflect release from centrally projecting oxytocin neurons, different from those that project to the pituitary gland, or that are collaterals from them.[47] Oxytocin receptors are expressed by neurons in many parts of the brain and spinal cord, including the amygdala, ventromedial hypothalamus, septum, nucleus accumbens, and brainstem.
Bonding
In the prairie vole, oxytocin released into the brain of the female during sexual activity is important for forming a monogamous pair bond with her sexual partner. Vasopressin, which is similar to Oxytocin in molecular structure and location of production in the brain, appears to have a similar effect in males.[49] Oxytocin has a role in social behaviors in many species, so it likely also does in humans. In a 2003 study, both humans and dog oxytocin levels in the blood rose after five to 24 minutes of a petting session. This possibly plays a role in the emotional bonding between humans and dogs.[50]
Maternal behavior
Female rats given oxytocin antagonists after giving birth do not exhibit typical maternal behavior.[51] By contrast, virgin female sheep show maternal behavior toward foreign lambs upon cerebrospinal fluid infusion of oxytocin, which they would not do otherwise.[52] Oxytocin is involved in the initiation of maternal behavior, not its maintenance; for example, it is higher in mothers after they interact with unfamiliar children rather than their own.[53]
Preparing fetal neurons for delivery
Crossing the placenta, maternal oxytocin reaches the fetal brain and induces a switch in the action of neurotransmitter GABA from excitatory to inhibitory on fetal cortical neurons. This silences the fetal brain for the period of delivery and reduces its vulnerability to hypoxic damage.[58]
Romantic attachment
In some studies, high levels of plasma oxytocin have been correlated with romantic attachment. For example, if a couple is separated for a long period of time, anxiety can increase due to the lack of physical affection. Oxytocin may aid romantically attached couples by decreasing their feelings of anxiety when they are separated.[59]
Virtually all vertebrates have an oxytocin-like nonapeptide hormone that supports reproductive functions and a vasopressin-like nonapeptide hormone involved in water regulation. The two genes are usually located close to each other (less than 15,000 bases apart) on the same chromosome.
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