say may indicate evidence of a mood
problem. The researchers then examined
the hippocampus of the hamsters’
brains and found that those that spent
the night in dim blue or white light
had a significantly reduced density of
dendritic spines, a condition that has
been linked to depression (The Journal
of Neuroscience, Aug. 7).
n Personality may affect a new
mother’s decision to breastfeed, finds
research out of Swansea University
in the United Kingdom. Scientists
surveyed 602 mothers with infants age 6
months to 12 months, asking about the
mothers’ personalities, how long they
breastfed and about their breastfeeding
attitudes and experiences. Moms who
indicated that they were extroverted and
emotionally stable were significantly
more likely to initiate breastfeeding
and continue it longer. Those who
were introverted or anxious were more
likely to use formula or only breastfeed
for a short while (Journal of Advanced
Nursing, online Aug. 6).
n Regular marijuana use in
adolescence — but not adulthood
— may permanently impair brain
function and cognition and increase
the risk of developing psychiatric
disorders such as schizophrenia, finds
a study with mice at the University
of Maryland School of Medicine.
The scientists first examined cortical
oscillations — patterns of the activity
of neurons in the brain that underlie
the brain’s various functions — in
young mice, and then exposed the
rodents to very low doses of the active
ingredient in marijuana for 20 days.
They found that after the mice were
exposed to the ingredient, their cortical
oscillations were grossly altered and
they exhibited impaired cognitive
abilities that persisted into adulthood.
In a repeat of the experiment with
adult mice, cortical oscillations and
cognitive function remained normal
(Neuropsychopharmacology, July 4).
n After a conflict, spouses want to
see a willingness of their partner to
relinquish power, not an apology,
suggest the results of a study led
by Baylor University psychologists.
The researchers asked 455 married
participants ages 18 to 77 to
independently list desired resolutions
to a conflict — anything from a minor
disagreement to a big argument. They
found that the No. 1 desired resolution
was shared control, which can come
in the form of giving a partner more
independence, admitting faults,
showing respect and being willing to
compromise (Journal of Social and
Clinical Psychology, June).
Adolescent mice exposed to the active ingredient in marijuana had impaired cognitive
abilities that persisted into adulthood, research finds.