LIND Seminar (Leuven research Institute for Neuroscience & Disease) edition:3 location:Mechelen, Belgium date:05 December 2014
With a life-time prevalence of 16 %, anxiety disorders are among the most common psychiatric disorders. Despite their high economical and personal burden, they remain poorly understood and current treatment options are often not adequate. Electrical brain stimulation may be a last-resort option for these severely affected patients. Over the years, the bed nucleus of the stria terminalis (BST) has emerged as a promising new target for treating anxiety disorders. In patients suffering from severe, treatment-refractory obsessive-compulsive disorder (OCD), high-frequency stimulation (HFS) in the BST area has clear anxiolytic effects. In addition, we showed that the BST is hypermetabolic in anxious rats and that BST lesions decrease the expression of anxious behavior, as measured by the startle response and amount of freezing. Since lesions and HFS are known to exert similar effects, we hypothesized that HFS of the BST can reduce the expression of anxiety.
In this study, rats were bilaterally implanted with monopolar electrodes in the BST and assigned to a stimulation (STIM, n = 10) or sham (CTRL, n = 8) group. All animals were subjected to a conditioning paradigm, which results in expression of anxiety on the final test day. At this stage, rats in the STIM group received HFS, whereas CTRL rats received no stimulation. Stimulation parameters were fixed at 100 Hz, 40 µs and 300 µA.
Our study revealed no significant effect of HFS on startle or freezing measurements. Despite the success of HFS in the clinic, determining the optimal stimulation parameters is known to be a cumbersome process, resulting in individual sets of parameters for each patient. For this reason, our results do not necessarily exclude an anxiolytic effect of HFS in the BST, but indicate that further research is necessary to determine the optimal method of stimulation.