Characterization of oscillatory changes in hippocampus and amygdala after deep brain stimulation of the infralimbic prefrontal cortex

Abstract

Deep brain stimulation (DBS) is a new investigational therapy that has generated positive results in refractory depression. Although the neurochemical and behavioral effects of DBS have been examined, less attention has been paid to the influence of DBS on the network dynamics between different brain areas, which could contribute to its therapeutic effects. Herein, we set out to identify the effects of 1 h DBS in the infralimbic cortex (IL) on the oscillatory network dynamics between hippocampus and basolateral amygdala (BLA), two regions implicated in depression and its treatment. Urethane‐anesthetized rats with bilaterally implanted electrodes in the IL were exposed to 1 h constant stimulation of 130 Hz of frequency, 60 μA of constant current intensity and biphasic pulse width of 80 μsec. After a period of baseline recording, local field potentials (LFP) were recorded with formvar‐insulated stainless steel electrodes. DBS of the IL increased the power of slow wave (SW, <1.5 Hz) and theta (3–12 Hz) frequencies in the hippocampus and BLA. Furthermore, IL DBS caused a precise coupling in different frequency bands between both brain structures. The increases in SW band synchronization in hippocampus and BLA after DBS suggest that these changes may be important for the improvement of depressive behavior. In addition, the augmentation in theta synchrony might contribute to improvement in emotional and cognitive processes.

Neural oscillations in the infralimbic cortex after electrical stimulation of the amygdala. Relevance to acute stress processing

“…Hz; Cervera-Ferri et al, 2016). In agreement with these results, clinical studies have shown that diminished SW activity in depression is restored after effective antidepressant treatments (Thase, 1997;Duncan et al, 2013).…”

“…Diminished slow oscillatory activity has been reported in two different animal models of depression (Voget et al ; Zheng & Zhang ), and reduced sleep SW activity (ranging from 1 to 4 Hz), has been postulated to be a biomarker of Major Depression Disease (Duncan & Zarate, ). Recently, this assertion has been extended to lower frequencies (<1.5 Hz; Cervera‐Ferri et al, ). In agreement with these results, clinical studies have shown that diminished SW activity in depression is restored after effective antidepressant treatments (Thase, ; Duncan et al, ).…”

“…Experimental data have also shown that IL deep brain stimulation (DBS), which improves depression symptoms, also increases slow oscillatory activities within the stimulated area (Etiévant et al, ). Besides, during the DBS of the IL, which has anxiolytic‐like effects (Jiménez‐Sánchez et al, ), an increase in SW power (<1.5 Hz) frequencies in both the hippocampus and the basolateral complex of the amygdala (BLA) in urethane‐anesthetized rats is observed (Cervera‐Ferri et al, ).…”

“…Hz) frequencies in both the hippocampus and the basolateral complex of the amygdala (BLA) in urethane-anesthetized rats is observed (Cervera-Ferri et al, 2016).…”

Modulation of Theta-Band Local Field Potential Oscillations Across Brain Networks With Central Thalamic Deep Brain Stimulation to Enhance Spatial Working Memory

“…In rodents, theta oscillations in the hippocampus were restored by stimulating the fornix, and spatial working memory task performance was improved (Bick and Eskandar, 2016). Also, after application of DBS in the infralimbic cortex fin rodents, the cognitive function and memory were improved, and theta oscillations in the hippocampus were restored (Cervera Ferri et al, 2016). An improvement in working memory was found after electrical stimulation of the central thalamus (CT) in object recognition memory tasks in rodents (Mair and Hembrook, 2008).…”