Within the realm of consciousness research, different methods of measuring the content of visual awareness are used: On the one hand, subjective measures require a report of sensory experiences related to a stimulus. On the other hand, objective measures rely on the observer's performance to accurately detect or discriminate the stimulus. The most appropriate measure of awareness is currently debated.
View Article and Find Full Text PDFInteroception, the processing of internal bodily signals, is proposed as the fundamental mechanism underlying emotional experiences. Interoceptive and emotional processing appear distorted in psychiatric disorders. However, our understanding of the neural structures involved in both processes remains limited.
View Article and Find Full Text PDFTranscranial direct current stimulation (tDCS) of the prefrontal cortex might beneficially influence neurocognitive dysfunctions associated with major depressive disorder (MDD). However, previous studies of neurocognitive effects of tDCS have been inconclusive. In the current study, we analyzed longitudinal, neurocognitive data from 101 participants of a randomized controlled multicenter trial (DepressionDC), investigating the efficacy of bifrontal tDCS (2 mA, 30 min/d, for 6 weeks) in patients with MDD and insufficient response to selective serotonin reuptake inhibitors (SSRI).
View Article and Find Full Text PDFWithin consciousness research, the most appropriate assessment of visual awareness is matter of a controversial debate: Subjective measures rely on introspections of the observer related to perceptual experiences, whereas objective measures are based on performance of the observer to accurately detect or discriminate the stimulus in question across a series of trials. In the present study, we compared subjective and objective awareness measurements across different stimulus feature and contrast levels using a temporal two-alternative forced choice task. This task has the advantage to provide an objective psychophysical performance measurement, while minimizing biases from unconscious processing.
View Article and Find Full Text PDFBackground: Transcranial direct current stimulation (tDCS) has been proposed as a feasible treatment for major depressive disorder (MDD). However, meta-analytic evidence is heterogenous and data from multicentre trials are scarce. We aimed to assess the efficacy of tDCS versus sham stimulation as an additional treatment to a stable dose of selective serotonin reuptake inhibitors (SSRIs) in adults with MDD.
View Article and Find Full Text PDFWe assessed the structure-function relationship of the human cholinergic system and hypothesized that structural measures are associated with short-latency sensory afferent inhibition (SAI), an electrophysiological measure of central cholinergic signal transmission. Healthy volunteers (n = 36) and patients with mild cognitive impairment (MCI, n = 20) underwent median nerve SAI and 3T structural MRI to determine the volume of the basal forebrain and the thalamus. Patients with MCI had smaller basal forebrain (p < 0.
View Article and Find Full Text PDFEur Arch Psychiatry Clin Neurosci
October 2021
Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (dlPFC) is currently evolving as an effective and safe therapeutic tool in the treatment of major depressive disorder (MDD). However, already established rTMS treatment paradigms are rather time-consuming. With theta burst stimulation (TBS), a patterned form of rTMS, treatment time can be substantially reduced.
View Article and Find Full Text PDFRecently, modulatory effects of static magnetic field stimulation (tSMS) on excitability of the motor cortex have been reported. In our previous study we failed to replicate these results. It was suggested that the lack of modulatory effects was due to the use of an auditory oddball task in our study.
View Article and Find Full Text PDFImaging studies showed that the structure of the corpus callosum (CC) is affected in amyotrophic lateral sclerosis (ALS). Some clinical studies also suggest that interhemispheric connectivity is altered, since mirror movements seem to occur in ALS. Finally, reduced interhemispheric inhibition (IHI), studied by transcranial magnetic stimulation (TMS), has been reported.
View Article and Find Full Text PDFQuantifying morphological evolution is key to determining the patterns and processes underlying the origin of phyla. We constructed a hierarchical morphological character matrix to characterize the radiation and establishment of echinoderm body plans during the early Paleozoic. This showed that subphylum-level clades diverged gradually through the Cambrian, and the distinctiveness of the resulting body plans was amplified by the extinction of transitional forms and obscured by convergent evolution during the Ordovician.
View Article and Find Full Text PDFThe visual system has one of the most complex structures of all sensory systems and is perhaps the most important sense for everyday life. Its functional organization was extensively studied for decades in animal and humans, for example by correlating circumscribed anatomical lesions in patients with the resulting visual dysfunction. During the past two decades, significant achievements were accomplished in characterizing and modulating visual information processing using non-invasive stimulation techniques of the normal and damaged human eye and brain.
View Article and Find Full Text PDFOxytocin (OT) is a neuropeptide associated with trauma, sociality, and depression. Despite the widely accepted assumption of OT playing a role in the etiology of mood and anxiety disorders, associations between stressful life events, depression, and epigenetic regulation of the gene coding for OT (OXT) have not yet been investigated. We therefore aimed to examine the interrelations of stressful life events, depression severity, and methylation of the promoter region of OXT in a sample of N = 146 inpatients suffering from major depression.
View Article and Find Full Text PDFTheories of emotion suggest a close relation of interoception and emotion. However, knowledge of underlying neuronal networks is still sparse. Repetitive transcranial magnetic stimulation (rTMS) is one neurostimulation method allowing causal conclusions between functions and brain regions via stimulation or inhibition of underlying brain structures.
View Article and Find Full Text PDFThe experience of flow ensues when humans engage in a demanding task while task demands are balanced with the individual's level of skill or ability. Here, we further tested the hypothesis that the medial prefrontal cortex (MPFC) plays a causal role in mediating flow experience using transcranial direct current stimulation (tDCS) to interfere with MPFC's deactivation evoked by a flow paradigm and measured by magnetic resonance (MR)-based perfusion imaging. In a balanced, within-subjects repeated measure design, three treatments of tDCS (sham, anodal, cathodal) were applied in a sample of 22 healthy male participants.
View Article and Find Full Text PDFIn the context of hedonic (over-)eating the ventral tegmental area (VTA) as a core part of the dopaminergic reward system plays a central role in coding incentive salience of high-caloric food. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate whether transcranial magnetic theta-burst stimulation (TBS) over the right mid-ventrolateral prefrontal cortex (mid-VLPFC) can induce modulation of calorie-sensitive brain activation in the VTA. The prefrontal location for TBS had been predetermined by seed-based resting-state fMRI with a functionally defined portion of the VTA serving as seed region obtained from an independent second fMRI experiment.
View Article and Find Full Text PDFBackground: Chronic tinnitus is a frequent, difficult to treat disease with high morbidity.
Objective: This multicenter randomized, sham-controlled trial investigated the efficacy and safety of 1-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left temporal cortex in patients with chronic tinnitus.
Methods: Tinnitus patients were randomized to receive 10 sessions of either real or sham 1-Hz-rTMS (2000 stimuli, 110% motor threshold) to the left temporal cortex.
One aspect of consciousness phenomena, the temporal emergence of visual awareness, has been subject of a controversial debate. How can visual awareness, that is the experiential quality of visual stimuli, be characterized best? Is there a sharp discontinuous or dichotomous transition between unaware and fully aware states, or does awareness emerge gradually encompassing intermediate states? Previous studies yielded conflicting results and supported both dichotomous and gradual views. It is well conceivable that these conflicting results are more than noise, but reflect the dynamic nature of the temporal emergence of visual awareness.
View Article and Find Full Text PDFBackground: Recently, it was reported that the application of a static magnetic field by placing a strong permanent magnet over the scalp for 10 min led to an inhibition of motor cortex excitability for at least 6 min after removing the magnet. When placing the magnet over the somatosensory cortex, a similar inhibitory after effect could be observed as well.
Objective: Our aim was to replicate the inhibitory effects of transcranial static magnetic field stimulation in the motor and somatosensory system.
Structural and functional changes attributable to the neurodegenerative process in Huntington's disease (HD) may be evident in HTT CAG repeat expansion carriers before the clinical manifestations of HD. It remains unclear, though, how far from motor onset a consistent signature of the neurodegenerative process in HD can be detected. Twelve far from onset preHD and 22 age-matched healthy control participants underwent volumetric structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and resting-state functional MRI (11 preHD, 22 controls) as well as electrophysiological measurements (12 preHD, 13 controls).
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
November 2016
The processing and perception of individual internal bodily signals (interoception) has been differentiated to comprise different levels and processes involved. The so-called heartbeat-evoked potential (HEP) offers an additional possibility to examine automatic processing of cardiac signals. Knowledge on neural structures potentially supporting different facets of interoception is still sparse.
View Article and Find Full Text PDFTranscranial direct current stimulation (tDCS) is a common method to modulate cortical activity. Anodal tDCS is usually associated with an enhancement of the stimulated brain area, whereas cathodal tDCS is often described as inhibitory brain stimulation method. Our aim was to investigate whether this canonical assumption derived from the motor system could be transferred to the semantic system.
View Article and Find Full Text PDF