Despite accumulating evidence of inter and intraindividual variability in response to theta burst stimulation, it is widely believed that in therapeutic applications, repeated sessions can have a “build-up” effect that increases the response over and above that seen in a single session. However, strong evidence for this is lacking. Therefore, we examined whether daily administration of intermittent theta burst stimulation (iTBS) over the primary motor cortex induces cumulative changes in transcranial magnetic stimulation measures of cortical excitability, above the changes induced by sham stimulation. Over five consecutive days, 20 healthy participants received either active iTBS or sham stimulation. Each day, baseline measures of cortical excitability were assessed before and up to 30 min after the intervention. There was no significant difference in the rate of response between iTBS and sham stimulation on any of the 5 days. There was no iTBS specific cumulative increase of corticospinal excitability. The likelihood that an individual would remain a responder from day-to-day was low in both groups, implying high within-subject variability of both active and sham iTBS after-effects. In contrast, we found a high within-subject repeatability of resting and active motor threshold, and baseline motor-evoked potential amplitude. In summary, sham stimulation has similar effect to active iTBS on corticospinal excitability, even when applied repeatedly for 5 days. Our results might be relevant to research and clinical applications of theta burst stimulation protocols.
COBISS.SI-ID: 5150380
Depression is often a chronic and relapsing mental disorder, characterized by deficits in everyday func-tioning, low quality of life and high disease burden for society. Although we have witnessed an improve-ment in different treatments for depression, there is still a large number of patients who do not respond to treatment or do not achieve satisfactory remis-sion. Definitions of treatment resistant depression are currently not unified, which precludes reliable assesments of its prevalence. We will present a review of current findings about resistence to treatment in depression, risk factors for its development and exist-ing systems for definition of treatment resistant depression in clinical practice. Latest classification systems are more complex and therefore time con-suming, but could represent an important step towards more objective assesment of treatment resistance compared with current clinical practice.
COBISS.SI-ID: 34206169
Objective: Suicidal behavior is a complex phenomenon, an outcome of both environmental and genetic factors. In the present study, we looked for a potential association between suicide and the reelin gene as reelin has been associated previously with several psychiatric disorders, including depression. Materials and methods: We analyzed three single nucleotide polymorphisms (SNPs) in the reelin gene, rs2965087, rs7341475, and rs362691, in a population of 483 suicide victims and 332 healthy controls, all Caucasians. An analysis was carried out according to sex and the method of suicide. In a group of 77 suicide victims with psychological autopsy data, suicide threats, suicide in the family, and number of depression symptoms were also considered. Results: Analysis of all three polymorphisms did not confirm an association with suicide in general. However, for subjects included in psychological autopsy study, association with previous announcement of suicide in the group of subjects with TT genotype for polymorphism rs2965087 was determined. Furthermore, the results pointed to an association with reported suicide in the family of suicide victims in case of the TT genotype. In contrast, the number of depressive symptoms, besides suicidal threats, was lower in the group with the TT genotype. Limitations: Psychological autopsies can be associated with recall bias and the sample was rather small and therefore underpowered. Conclusion: The present investigation, performed on a study sample from a population with one of the highest suicide rates in the world, indicated an association between rs2965087 in the reelin gene and the expression of suicidal threats a month before suicide in contrast to other symptoms of depression.
COBISS.SI-ID: 32798937
Broca's region and adjacent cortex presumably take part in working memory (WM) processes. Electrophysiologically, these processes are reflected in synchronized oscillations. We present the first study exploring the effects of a stroke causing Broca's aphasia on these processes and specifically on syn- chronized functional WM networks. We used high-density EEG and coherence analysis to map WM net- works in ten Broca's patients and ten healthy controls during verbal WM task. Our results demonstrate that a stroke resulting in Broca's aphasia also alters two distinct WM networks. These theta and gamma functional networks likely reflect the executive and the phonological processes, respectively. The striking imbalance between task-related theta synchronization and desynchronization in Broca%s patients might represent a disrupted balance between task-positive and WM-irrelevant functional networks. There is complete disintegration of left fronto-centroparietal gamma network in Broca's patients, which could reflect the damaged phonological loop.
COBISS.SI-ID: 3138220
Understanding complex systems such as the human brain requires characterization of the system's architecture across multiple levels of organization - from neurons, to local circuits, to brain regions, and ultimately large-scale brain networks. Here we focus on characterizing the human brain's large-scale network organization, as it provides an overall framework for the organization of all other levels. We developed a highly principled approach to identify cortical network communities at the level of functional systems, calibrating our community detection algorithm using extremely well-established sensory and motor systems as guides. Building on previous network partitions, we replicated and expanded upon well-known and recently-identified networks, including several higher-order cognitive networks such as a left-lateralized language network. We expanded these cortical networks to subcortex, revealing 358 highly-organized subcortical parcels that take part in forming whole-brain functional networks. Notably, the identified subcortical parcels are similar in number to a recent estimate of the number of cortical parcels (360). This whole-brain network atlas - released as an open resource for the neuroscience community - places all brain structures across both cortex and subcortex into a single large-scale functional framework, with the potential to facilitate a variety of studies investigating large-scale functional networks in health and disease.
COBISS.SI-ID: 66391394