Today I read a short news item in New Scientist that relayed something about
research relevant to Sudden Infant Death Syndrome done by Jan-Marino Ramirez
of University of Chicago (originally reported in The Journal of Neuroscience
vol 26 page 2623). It stated that his and his collaborators' reseach had
confirmed that serotonin activates "pacemaker" neurons in the medulla -
cells that promote the gasping/anti-suffocation reflex.
The short article also mentioned that other studies have found that victims
of SIDS have fewer serotonin receptors in the same brain region.
An environment that chronically compromises infants' innate need for optimal
stimulation and relaxing reassurance tend to cause "specific/synaptic
hibernation" and a depression/depletion of serotonergic activity (and of
course also a corresponding increase of opioidergic activity).
Not that this scenario cannot crucially combine with the ordinarily
considered contributory factors, such as smoke-polluted air, a face-down
sleeping position, and overheating.
By "love deprivation" I refer to a basically detrimental conditioning of
brain-chemistry and neural functions caused by relatively fixed sources of
adversely influential environmental features;
Slightly less generally put: I refer to the negation or absence of the need
for comforting and stimulating touch, and close physical proximity and a
sufficient daily dose of healthy emotional interactivity provided
(preferably) by parents;
And, for something really specific and of particular relevance to SIDS:
a lack of a comforting physical closeness caused by the common idea and
insistence that babies should sleep and learn to go to sleep in a separate
room away from their parents.