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SELF-HYPNOSIS FOR DEPRESSION IN PRIMARY CARE
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Delgado et al. (2008) showed that reappraisal and other cognitive strat-
egies share the same pathway as simple extinction of fear; both utilize
the vmPFC/amygdala suppression circuit, and they postulate that the
human cognitive strategy has made use of a preexisting pathway of
extinction; the relative cortical thickness of the vmPFC across mamma-
lian species predicts the speed of extinction.
Studies that have looked at genetic markers for depression have
explored the vulnerability of dynamic biological processes in the brain.
The 5-HTTLPR (5 Hydroxy-tryptamine transporter-linked polymor-
phic region) polymorphism is associated with depression in adults
(Collier et al., 1996); although the connection is by no means clear
(Mendlewicz et al., 2004). One study looked at carriers with no history
of depression; in response to masked fearful faces, carriers of this gene
showed reduced connectivity in the vmPFC/amygdala circuit com-
pared to noncarriers, and the degree of reduction correlated with mea-
sures of depressive thinking (Pezwas et al., 2005). The DLPFC appears
to suppress the amygdala even in established depression but in a dif-
ferent pattern from controls; depressed subjects paying attention to
fearful faces suppressed amygdalar activity by activation of the
DLPFC (controls did not suppress) but decreased such suppression
when instructed to ignore fearful faces (these used as a distracter to a
main task) when controls successfully suppressed (Fales et al., 2008).
This study, along with Whalen et al. (1998), suggests that depressed
individuals have an increased sensitivity to preconscious, subliminal
signals; such signals are mediated through midbrain structures with
the amygdala “surveying emotionally valenced stimuli without aware-
ness” (Whalen et al., p. 411), probably through thalamo-amygdalar
circuitry (LeDoux, Sakaguchi, Iwata, & Reis, 1986), which bypasses the
cortex, such preattentional subliminal triggers promoting a negative
cognitive bias outside of the conscious awareness. This emphasizes the
need to inhibit preconscious subliminal triggers by recruitment of cog-
nitive strategies at a level outside awareness: we cannot consciously
inhibit the behavioral and neurochemical withdrawal response to a
negative trigger, which never reaches conscious awareness. Implicit
priming can also be effective in a positive way in depression; unscram-
bling a scrambled sentence with decentering concepts (e.g., “Mood
long does any last how?” unscrambles to “How long does any mood
last?”), reduces overgeneralization despite no instruction to do any
more than unscramble (Watkins, Teasdale, & Williams, 2000).
The hippocampus is part of the associative cortex (medial temporal
lobe) where concomitant information about time, place, autonomic
and hormonal internal states, and unfolding sequences of events are
associated, strengthened if deemed relevant, compared with previous
memories, and written off to the cortex in the form of stable long-term
memory. The dentate gyrus (DG) of the hippocampus is at its most
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