Last night, I headed down to the beautiful Bell House, in the Gowanus section of Brooklyn, for this month's Secret Science Club lecture featuring neurologist Dr Bianca Jones Marlin of Columbia University’s Zuckerman Institute. Dr Jones Marlin was lecturing on the hormone oxytocin and its effects on child-rearing.
Dr Jones Marlin began the lecture by 'setting the mood', playing a bit of Marvin Gaye, and stating that oxytocin changes a subject's internal state, dictating the subject's behavior. Oxytocin sets the mood, effecting how parents and babies interact, how parenthood biologically occurs. Babies have a limited repertoire of responses to stimuli- their laughter or crying elicits responses from adults. To illustrate this, she showed a video of two babies laughing, then showed a video of a crying baby, commenting 'somebody let that baby cry while videotaping it', then admitted that it was her daughter (who was in the audience with the good doctor's husband).
Dr Jones Marlin studies the effects of oxytocin on mice in her laboratory. Baby mice make ultrasonic vocalizations when they are cold, or uncomfortable. These cries alert adult mice- a mother mouse will retrieve a pup and place it in the nest while virgin female mice tend to ignore or even cannibalize crying pups. Motherhood changes the response of a mouse to a pup's vocalizations, and oxytocin is the trigger.
Oxytocin is produced in the paraventricular nucleus of the brain's hypothalamus and is released by the posterior lobe of the pituitary gland. Oxytocin is released during sex (especially during orgasms), birth (uterine contractions cause the release), breast feeding, touch, and eye contact. Among prairie voles, oxytocin plays a role in monogamy- remove oxytocin and the voles sleep around. Oxytocin has also been implicated in human ethnocentrism, leading to newspaper headlines such as 'The Dark Side of Oxytocin' and 'Oxytocin/Schmoxytocin'.
Dr Jones Marlin wanted to study the hard science of oxytocin... Where does it act? When does it act? How does it change behavior? She specifically wanted to study the auditory factors, the sound cues which trigger pup retrieval in mothers and cannibalism in virgin mice. There are receptors in the auditory cortex of a mouse's brain which react to oxytocin. The left-side hearing area (corresponding to Broca's area and Wernicke's area) has double the amount of oxytocin receptors as the right-side does. This finding was an early discovery of lateralization in a non-human brain. Hormones such as oxytocin can play excitatory or inhibitory functions in cells. Dr Jones Marlin made a funny school bus analogy- excitatory hormones are the mischievous kids on the bus, riling things up, while inhibatory hormones are the quiet kids on the bus. Oxytocin is found in inhibitory neurons which regulate maternal roles. Introducing Muscimol to the left auditory cortex prevents pup retrieval by experienced mice- it makes mice into bad moms by interfering with distress messages.
After locating the region of the brain effected by oxytocin, Dr Jones Marlin wanted to find the time scale on which it operated. Oxytocin can be injected into mice, but the production of endogenous oxytocin can be induced through optogenetics- specifically, blue light can activate the release of oxytocin in transgenic mice with added DNA from marine algae. In Dr Jones Marlin's research, she stimulated oxytocin release every three hours for three days straight- she quipped that it was "a long PhD". Inducing oxytocin production in virgin mice can make them into successful 'nannies'- they will retrieve pups which make distress cries and return them to their nest.
The 'language' of the brain is electrical- the neurons speak through spikes of electrical activity. To measure this, a craniotomy is performed on a subject and a glass 'straw' is inserted- a metal probe in the straw can 'listen in' on the spiking electrical output of the neurons. Among subject mice, the neurons of the auditory cortex would spike when a recording of a pup's cries could be heard. Among mother mice, the neurons would fire at the same time when a cry was played, forming a coherent code. A naive virgin mouse has neurons that fire, but there is no encoding of a message. An experienced virgin mouse, exposed to oxytocin, learns the coherent code. Bad nannies can be made into good nannies. Neurons in the hearing area of the brains of transgenic mice can be exposed to blue light, which floods the brain with oxytocin- paired with a pup's cry, a coherent response emerges, and a subject mouse goes from a 'virgin' response to a 'mom' response. The brain knows to release oxytocin during birth- release is triggered by the uterine contractions.
Dr Jones Marlin then went on to discuss her personal reasons for studying oxytocin... In the United States, four to seven children die each day from abuse or neglect. The brains of neglected children have less white matter than the brains of well-treated children, and individuals who suffered child neglect have a life expectancy twenty years shorter than that of their well-treated peers. Dr Jones Marlin took time to thank her great parents, who cared for foster children. She was motivated by the lack of agency that her foster siblings expressed. She wanted to study how parents can be better, by studying transgenerational epigenetic inheritance.
Dr Jones Marlin's lecture was followed by a Q&A session. The first question regarded the role of oxytocin in relationships- it is released through interaction and strengthens bonds. Another question regarded post-partum depression, specifically if oxytocin could help alleviate it- more research is needed in humans. Some bastard in the audience asked if injections of oxytocin could make male mice into good nannies. The gestation period of a mouse is twenty-one days. Males will often eat pups, but twenty-one days after copulation, they will cease this behavior, but pup retrieval is exclusive to female mice. After five days of oxytocin injection with no change in behavior, the injections were stopped. At one point in her talk, Dr Jones Marlin's daughter cried out, and the good doctor joked about leaving the stage to retrieve her, but her husband soon had matters well taken care of.
Another question regarded the interaction between oxytocin and cortisol- oytocin tends to calm individuals, while cortisol is a stress hormone, but their interaction is largely unknown. Yet another question regarded the stimulation of oxytocin production, and Dr Jones Marlin stated that the best answer is "SEX!" She joked that using blue light was impractical, then wondered aloud about why red lights are used to denote the vice district (I would suspect that it's because red light tends to interfere less with night vision). Dr Jones Marlin dismissed the idea of oxytocin supplements: "I would not buy them off of Amazon." She noted that studies on autistic persons suggested that oxytocin improves eye contact, then reiterated that the best way to promote oxytocin production was to make eye contact, to look at people, to kiss, to touch, to have sex. Now, that's not only good advice, but it's good SCIENCE!
Dr Jones Marlin ended the Q&A session by noting that, as a basic biological scientist, she would be at a disadvantage listing the prosocial effects of oxytocin. She studies the biological underpinnings of behavior. She studies the mechanisms so that others can use her research to study the effects of oxytocin in autistic persons or the possible role of oxytocin in countering child abuse.
Here's a 2014 video of Dr Jones Marlin talking about her inspiration for becoming a neuroscientist, and explaining her methodology for measuring neuron activity:
Here's a cute recent video of the good doctor on a local news broadcast taking questions from laypersons on the street:
As you can tell, she is a good sport as well as being a great neuroscientist. Kudos to Dr Jones Marlin for a fantastic lecture. Thanks to Dorian and Margaret and the staff of the beautiful Bell House for presenting another great Secret Science Club event, and high fives to Dr Jones Marlin's nice husband and gorgeous baby girl for their good fortune in having such a wonderful lady in their lives.
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1 comment:
Another fine summary. I really enjoy these. Thank you.
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