In the experiment, stimulating BNST
neurons with light-which consequently shut down the activity of neurons in the lateral hypothalamus--led to the overeating behavior, the team found.
The BNST gaba neurons have a cell body and a long strand with branched synapses that transmit electrical signals into the lateral hypothalamus.
Stuber and his team wanted to stimulate those synapses by using an optogenetic technique, an involved process that would let him stimulate BNST cells simply by shining light on their synapses.
Those proteins then get expressed only in the BNST cells, including in the synapses that connect to the hypothalamus.
His team then implanted fiber optic cables in the brains of these specially-bred mice, and this allowed the researchers to shine light through the cables and onto BNST synapses.
The BNST also is positioned to integrate information on chronic stress.
For example, considerable data support a role for the CeA, BNST, and noradrenergic systems in the maintenance of alcohol dependence (see Koob 2009), suggesting that the process of addiction is linked to activation of stress (and HPA axis) excitatory pathways.
The mPFC projects to both the CeA and BNST and, at least in the case of the prelimbic region, plays a prominent role in HPA inhibition.
We have hypothesized that an interaction between CRF and NE systems within the BNST and/or CeA mediates stress-induced relapse.
Consistent with the effects of CRF receptor manipulations in the BNST, it was recently shown that blockade of NE receptors in the BNST also interferes in stress-induced relapse (18), a result that indirectly supports the idea that an interaction between NE and CRF systems in the BNST may mediate the effects of stress on relapse.
Pharmacological stimulation or blockade of CRF receptors in the BNST could mimic or block, respectively, the effects of CRF released either from cells intrinsic to this structure, or from CRF cells projecting from the CeA (see Figure 1).
We do not yet known on which efferent neurons of the BNST CRF, and possibly NE (see Fig.