Science Square

  • Issue 78 / November - December 2010

    Fathers are special, too

    The Fountain

    1- Fathers are special, too

    Original Article: Mak, G.K. & Weiss, S., Nature Neuroscience 13, 753 (2010).
    Motherhood or maternal recognition is well characterized by associated brain plasticity during both early development and adulthood. Unlike motherhood, paternal-offspring recognition and its related brain plasticity is poorly understood. A group from University of Calgary designed a set of experiments to test whether father mice can recognize their own infants once they’ve reached adulthood. They exposed adult males to their own and genetically unrelated infants for 2 days. The fathers were tested for adult offspring recognition six weeks later. Assay compared the time spent by the fathers with their own and unrelated offsprings. Results showed that although the father mice show similar parenting behavior toward both sets of infants (own and adopted), they only recognize their own pups as adults. Paternal recognition is associated with increased prolactin (a hormone primarily associated to lactation), mediated neurogenesis in the olfactory bulb, and hippocampus, a major component of mammalian brain. These newly generated neurons are important for the formation of socially relevant olfactory memories. Authors also found that the fathers must physically interact with the infants in order to recognize them later. This is confirmed by some control experiments in which fathers are only allowed to see, smell or hear infants through a wire mesh barrier which was not sufficient to induce neurogenesis. One of the socially relevant benefits of paternal recognition of the infants as adults is to avoid incest interactions which cause inbreeding depression.

    2- Recently revealed hideous effects of smoking on children
    Original Articles: Brion, M.J. et al., Pediatrics 126, e57 (2010) & Kwok, M.K. et al., Pediatrics 126, e46 (2010).

    Smoking is bad for our health, but apparently it may also have subtle, yet far-reaching consequences on our children according to two recent studies. The first study reports that mothers who smoke during pregnancy are more likely to have children with psychological problems. A related study presents evidence that babies who develop in the presence of second-hand smoke (from their fathers) may develop weight problems. Dr. Mary-Jo Brion of the University of Bristol tells “Babies exposed to smoke (in the womb) may be prone to rule breaking, such as lying, cheating, bullying, and disobedience in later years” and adds “To some extent it is somewhat surprising that … maternal smoking may also directly impact child behaviors from exposing the fetus to tobacco in utero.” The other study suggests that smoking around expecting mothers (even when the mother herself is not smoking) also affects the child: higher childhood weight appears to be clearly correlated with paternal smoking. “To protect their children, fathers should avoid smoking from conception onward,” says Dr. Mary Schooling of the University of Hong Kong. Furthermore, smoking mothers should not be too surprised to see their children “disobey” when they tell them not to smoke.

    3- Exposure to certain wavelengths of light resets the body clock
    Original Article: Gooley, J.J. et al., Science Translational Medicine 2, 31ra33 (2010).

    With the introduction of high-tech gadgets into our lives, our daily functions have changed drastically. As opposed to old-fashioned bed-time reading of an “actual” book made of paper, we fiddle with our iphones or ipads or notebooks or channel surf on our bedside TVs before going to sleep. A recent study revealed that exposure to certain wavelengths of light, such as those from laptops or TVs, would negatively influence our circadian rhythms (daily rhythmic activity cycle) by resetting our body clocks (e.g., keeping us awake when we should be sleeping). The feeling of sleepiness at night time is triggered by the secretion of a hormone called melatonin. It had been known that exposure of blue light to the eye’s photoreceptor system located in the ganglion cells suppresses the melatonin secretion, therefore stimulating alertness. In their recent work, researchers at Brigham and Women’s Hospital showed that green light exposure of a different cell population on the eyes – cone cells – also resets the body clock by suppressing melatonin secretion. The senior author of the paper, Dr. Steven Lockley, said in an interview that “we need to think about the entire spectrum of light when designing light therapy or lightning designs to boost alertness or induce sleepiness.” The moral of the story is to be more vigilant about our interaction with fancy electronic gadgets at night if we want to have a healthy and relaxing sleep.

    4- Poor teachers may impede good students

    Original Articles: Taylor, J. et al., Science 328, 512 (2010).
    Scholars know that educational environment, including both tasks and the social environment of a classroom, affects children’s achievement just as much as genetic factors. But the teacher plays a main role, because the quality of the educational environment depends on teachers’ performances. A new study underlined the importance of qualified teachers and how they can make a difference in education. The researchers examined the influence of teacher quality by studying 280 identical and 526 fraternal twin pairs in the first and second grades in different Florida schools representing a diverse environment. Identical twins share 100 percent of their genes and fraternal twins share half, and some of the twins were taught by the same teacher but some were in different classes. The researchers used an Oral Reading Fluency test which is based on how many words in a paragraph a child can accurately read in a minute in order to assess the reading skills of children. The researchers recorded the reading scores of students in the beginning of the semester and at the end of the semester, and they followed the students’ improvements during the year. To measure teacher quality, they used the scores of twins’ classmates. By studying twins’ groups, researchers were able to eliminate some other factors such as genetics and socio-economic conditions. According to the findings, the teachers played a role in “moderating” students’ achievements, and they helped the students to grow to their full potential. When teacher quality is very low, genetic variance is constricted, whereas, when teacher quality is very high, genetic variance blooms. As the study’s lead author, Jeanette Taylor, said “Better teachers provide an environment that allows children to reach their potential.”


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