Resting-state functional connectivity of antero-medial prefrontal cortex sub-regions in major depression and relationship to emotional intelligence.

BACKGROUND: Major depressive disorder has been associated with abnormal resting-state functional connectivity (FC), especially in cognitive processing and emotional regulation networks. Although studies have found abnormal FC in regions of the default mode network (DMN), no study has investigated the FC of specific regions within the anterior DMN based on cytoarchitectonic subdivisions of the antero-medial pre-frontal cortex (PFC). Studies from different areas in the field have shown regions within the anterior DMN to be involved in emotional intelligence. Although abnormalities in this region have been observed in depression, the relationship between the ventromedial PFC (vmPFC) function and emotional intelligence has yet to be investigated in depressed individuals. METHODS: Twenty-one medication-free, non-treatment resistant, depressed patients and 21 healthy controls underwent a resting state functional magnetic resonance imaging session. The participants also completed an ability-based measure of emotional intelligence: the Mayer-Salovey-Caruso Emotional Intelligence Test. FC maps of Brodmann areas (BA) 25, 10 m, 10r, and 10p were created and compared between the two groups. RESULTS: Mixed-effects analyses showed that the more anterior seeds encompassed larger areas of the DMN. Compared to healthy controls, depressed patients had significantly lower connectivity between BA10p and the right insula and between BA25 and the perigenual anterior cingulate cortex. Exploratory analyses showed an association between vmPFC connectivity and emotional intelligence. CONCLUSIONS: These results suggest that individuals with depression have reduced FC between antero-medial PFC regions and regions involved in emotional regulation compared to control subjects. Moreover, vmPFC functional connectivity appears linked to emotional intelligence.

Safety, tolerability, and effectiveness of high doses of adjunctive daily left prefrontal repetitive transcranial magnetic stimulation for treatment-resistant depression in a clinical setting.

OBJECTIVE: Daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) recently received Food and Drug Administration (FDA) approval for the treatment of depression and offers an alternative to traditional approaches. This approval was based on a study using 3000 stimuli per day (15,000 stimuli per week) in adults with unipolar depression not taking antidepressant medications. Several meta-analyses suggest a dose-response relationship with TMS. This study was carried out before US FDA approval to test the safety, tolerability, and effectiveness of adjunctive high-dose left prefrontal rTMS in a clinical setting with particular attention to safety of higher doses and potential interactions with antidepressant medications, speed of response, and effects on suicidality. METHOD: We enrolled 19 patients who were in a current major depressive episode with treatment-resistant unipolar or bipolar depression and treated them in their acute episode and in a maintenance fashion for 18 months. The patients received daily left prefrontal rTMS at 120% resting motor threshold, 10 Hz, 5 seconds on, and 10 seconds off and for a mean of 6800 stimuli per session (34,000 stimuli per week), more than twice the dose delivered in the pivotal FDA trial. All patients continued antidepressant medication throughout the rTMS treatment; thus rTMS was an adjunctive treatment. We measured adverse effects, depression, quality of life, suicidal ideation, and social and physical functioning. RESULTS: These higher rTMS doses were well tolerated without significant adverse effects or adverse events. All measured dimensions showed improvement, with many showing improvement in 1 to 2 weeks. Of perhaps most importance, suicidal ideation diminished in 67% of the patients after just 1 week. CONCLUSIONS: These uncontrolled data suggest that higher doses of daily left prefrontal rTMS may safely be used in outpatients with major depressive episode even as an adjunctive treatment.

Inverse effects of oxytocin on attributing mental activity to others in depressed and healthy subjects: a double-blind placebo controlled FMRI study.

BACKGROUND: Oxytocin is a stress-attenuating and pro-social neuropeptide. To date, no study has looked at the effects of oxytocin in modulating brain activity in depressed individuals nor attempted to correlate this activity with attribution of mental activity in others. METHOD: We enrolled 10 unmedicated depressed adults and 10 matched healthy controls in a crossover, double blind placebo controlled fMRI 40 i.u. intra-nasal oxytocin study (20 i.u. per nostril). Each subject performed reading the mind in the eyes task (RMET) before and after inhalation of oxytocin or placebo control for a total of 80 scans. RESULTS: Before oxytocin administration, RMET engaged the medial and lateral prefrontal cortex, amygdala, insula and associative areas. Depressed subjects showed increased anterior ventral activation for the RMET minus gender identification contrast whereas matched controls showed increased dorsal and frontal activity. Compared to placebo, oxytocin in depressed subjects showed increased activity in the superior middle frontal gyrus and insula, while controls exhibited more activity in ventral regions. Oxytocin also led to inverse effects in reaction times on attribution task between groups, with controls getting faster and depressed individuals slower to respond. CONCLUSION: Depression is associated with increased paralimbic activity during emotional mental attribution of others, appearing to be distinctly modulated by oxytocin when compared to healthy controls. Further studies are needed to explore long-term exposure to pro-social neuropeptides on mood in depressed populations and assess their clinical relevance.

Bilateral epidural prefrontal cortical stimulation for treatment-resistant depression.

BACKGROUND: Treatment-resistant depression presents a serious challenge to both patients and clinicians. The anterior and midlateral prefrontal cortices play complementary roles in integrating emotional and cognitive experiences and in modulating subcortical regions. Both regions offer a distinct opportunity for targeted antidepressant treatments. We chose to pilot the safety and therapeutic benefits of chronic and intermittent epidural prefrontal cortical stimulation (EpCS) in patients with treatment-resistant depression. METHODS: We enrolled five adults with an average of 5.8 failed antidepressant treatments in their current depressive episode. All subjects underwent comprehensive clinical assessments, detailed neuropsychological testing, and presurgical magnetic resonance imaging. Four cortical stimulation paddle leads were stereotactically placed bilaterally over the anterior frontal poles and midlateral prefrontal cortex. We also acquired a postsurgical computed tomography scan and repeatedly assessed clinical outcomes over time of EpCS as an adjunctive treatment to constant medications. RESULTS: All patients tolerated the therapy. At 7-month follow-up, the average improvement from preimplant baseline on the Hamilton Rating Scale for Depression and the Inventory of Depressive Symptoms-Self-Report were 54.9% (+/- 37.7) and 60.1% (+/- 34.1), respectively. Three implanted subjects reached remission. One patient's left hemisphere leads were explanted 12 weeks postsurgery because of a scalp infection. CONCLUSIONS: Bilateral EpCS over anterior and midlateral frontal cortex is a promising new technology for treatment-resistant depression. Future double-blind studies are warranted.

Focal electrically administered therapy: device parameter effects on stimulus perception in humans.

BACKGROUND: Focal electrically administered therapy is a new method of transcranial electrical stimulation capable of focal modulation of cerebral activity. Other than invasive studies in animals and examination of motor output in humans, there are limited possibilities for establishing basic principles about how variation in stimulus parameters impact on patterns of intracortical stimulation. This study used a simpler paradigm and evaluated the effects of different stimulation parameters on subjective perception of the quality and location of scalp pain. METHODS: In 2 studies, 19 subjects were randomly stimulated over the left forehead, varying the anode-cathode arrangement, the intensity of stimulation, the electrode size and placement, and whether the current flow was unidirectional or bidirectional. Subjects rated the location of the sensation and its quality. RESULTS: The perceived center of stimulation moved toward the cathode, regardless of placement. This shift in subjective sensation was more prominent when the electricity was unidirectional. In addition, more intense stimulation, as well as stimulation with a smaller electrode, caused greater perceived pain. Unidirectional stimulation was rated more painful when traveling from a large anode to a small cathode and less painful when traveling from a small anode to a large cathode. Finally, participants were more likely to perceive the electrical stimulation as moving toward a specific direction when the intensity was high than when it was low. CONCLUSIONS: The intensity and location of sensations can be manipulated by varying the intensity, current direction, or geometry of electrodes.

Focal electrical stimulation as a sham control for repetitive transcranial magnetic stimulation: Does it truly mimic the cutaneous sensation and pain of active prefrontal repetitive transcranial magnetic stimulation?

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is a novel, noninvasive method of stimulating selected regions of the brain that has both research applications and potential clinical utility, particularly for depression. To conduct high-quality clinical studies of rTMS, it is necessary to have a convincing placebo (or sham) treatment. Prefrontal rTMS causes cutaneous discomfort and muscle twitching; therefore, an optimal control condition, ie, sham condition, would mimic the cutaneous sensation and muscular discomfort of rTMS without stimulating the brain. Ideally, the quality and intensity of the sham condition would feel identical to the quality and intensity of the rTMS condition, except that the sham would have no effect on cortical activity. We designed and built a focal electrical stimulation system as a sham rTMS condition. Although this electrical sham system is superior to methods used in previous studies, little is known about how the new electrical sham system compares with active rTMS in terms of the level of discomfort and type of sensation it produces. METHODS: We hypothesized that the electrical sham system may not mirror the experimental condition sufficiently. We studied this hypothesis under single-blind conditions in 15 healthy adults by administering either the real or sham rTMS at high and low intensities while subjects, who were unaware of condition, rated subjective qualities of the stimulation (such as tingling, pinching, and piercing), the scalp location of the perception, and the painfulness of the stimuli. RESULTS: At low-intensity stimulation, the two techniques (active and sham) differ with respect to the subjective quality of the sensation. The differences between real and sham rTMS were less dramatic at higher intensities. The best sham condition that most closely mimics real prefrontal rTMS requires individual titration of the intensity of electrical stimulation across a broad range. Performing this titration without unblinding patients is likely possible, but technically challenging. We propose a new approach to do this. CONCLUSION: We conclude that it is possible to create a truly indistinguishable sham condition (with appropriate acoustic masking as well), but more work is needed beyond these initial attempts.