Cervical spondylotic myelopathy: Changes of fractional anisotropy in the spinal cord and magnetic resonance spectroscopy of the primary motor cortex in relation to clinical symptoms and their duration.

OBJECTIVE: To determine the changes in fractional anisotropy (FA) at the proximal spinal cord and in magnetic resonance spectroscopy (MRS) of the precentral gyrus in patients with cervical spondylotic myelopathy (CSM) with respect to clinical symptoms and their duration. MATERIAL AND METHODS: 20 patients with CSM (7 female; mean age 64.6 ± 10.5 years) and 18 age/sex matched healthy controls (9 female; mean age 63.5 ± 6.6 years) were prospectively included. Clinical data (modified Japanese Orthopaedic Association Score (mJOA) and Neck Disability Index (NDI)) and 3T MR measurements including DTI at the spinal cord (level C2/3) with FA and MRS of the left and right precentral gyrus were taken. Clinical correlations and regression analyses were performed. RESULTS: Mean clinical scores of patients were significantly different to controls (mJOA; CSM: 10.2 ± 2.9; controls: 18.0 ± 0.0, p < 0.001; NDI; CSM: 41.4±23.5; controls: 4.4±6.6, p<0.001); FA was significantly lower in patients (CSM: 0.645 ± 0.067; controls: 0.699 ± 0.037, p = 0.005). MRS showed significantly lower metabolite concentrations between both groups: creatine (Cr) (CSM: 46.46±7.64; controls: 51.36±5.76, p = 0.03) and N-acetylaspartate (NAA) (CSM: 93.94±19.22; controls: 107.24±20.20, p = 0.05). Duration of symptoms ≤6 months was associated with increased myo-inositol (Ins) (61.58±17.76; 44.44±10.79; p = 0.02) and Ins/Cr ratio (1.36±0.47; 0.96±0.18; p = 0.014) compared to symptoms >6 months. CONCLUSION: Metabolic profiles of the precentral gyrus and FA in the uppermost spinal cord differ significantly between patients and healthy controls. Ins, thought to be a marker of endogenous neuroinflammatory response, is high in the early course of CSM and normalizes over time.

Violence-related content in video game may lead to functional connectivity changes in brain networks as revealed by fMRI-ICA in young men.

In violent video games, players engage in virtual aggressive behaviors. Exposure to virtual aggressive behavior induces short-term changes in players' behavior. In a previous study, a violence-related version of the racing game "Carmageddon TDR2000" increased aggressive affects, cognitions, and behaviors compared to its non-violence-related version. This study investigates the differences in neural network activity during the playing of both versions of the video game. Functional magnetic resonance imaging (fMRI) recorded ongoing brain activity of 18 young men playing the violence-related and the non-violence-related version of the video game Carmageddon. Image time series were decomposed into functional connectivity (FC) patterns using independent component analysis (ICA) and template-matching yielded a mapping to established functional brain networks. The FC patterns revealed a decrease in connectivity within 6 brain networks during the violence-related compared to the non-violence-related condition: three sensory-motor networks, the reward network, the default mode network (DMN), and the right-lateralized frontoparietal network. Playing violent racing games may change functional brain connectivity, in particular and even after controlling for event frequency, in the reward network and the DMN. These changes may underlie the short-term increase of aggressive affects, cognitions, and behaviors as observed after playing violent video games.

Serotonergic modulation of resting state default mode network connectivity in healthy women.

The default mode network (DMN) plays a central role in intrinsic thought processes. Altered DMN connectivity has been linked to diminished cerebral serotonin synthesis. Diminished brain serotonin synthesis is further associated with a lack of impulse control and various psychiatric disorders. Here, we investigated the serotonergic modulation of intrinsic functional connectivity (FC) within the DMN in healthy adult females, controlling for the menstrual cycle phase. Eighteen healthy women in the follicular phase (aged 20-31 years) participated in a double-blind controlled cross-over study of serotonin depletion. Acute tryptophan depletion (ATD) and a balanced amino acid load (BAL), used as the control condition, were applied on two separate days of assessment. Neural resting state data using functional magnetic resonance imaging (fMRI) and individual trait impulsivity scores were obtained. ATD compared with BAL significantly reduced FC with the DMN in the precuneus (associated with self-referential thinking) and enhanced FC with the DMN in the frontal cortex (associated with cognitive reasoning). Connectivity differences with the DMN between BAL and ATD in the precentral gyrus were significantly correlated with the magnitude of serotonin depletion. Right medial frontal gyrus and left superior frontal gyrus connectivity differences with the DMN were inversely correlated with trait impulsivity. These findings partially deviate from previous findings obtained in males and underline the importance of gender-specific studies and controlling for menstrual cycle to further elucidate the mechanism of ATD-induced changes within intrinsic thought processes.

Effects of serotonin depletion on punishment processing in the orbitofrontal and anterior cingulate cortices of healthy women.

Diminished synthesis of the neurotransmitter serotonin (5-HT) has been linked to disrupted impulse control in aversive contexts. However, the neural correlates underlying a serotonergic modulation of female impulsivity remain unclear. The present study investigated punishment-induced inhibition in healthy young women. Eighteen healthy female subjects (aged 20-31) participated in a double-blinded, counterbalanced, placebo-controlled, within subjects, repeated measures study. They were assessed on two randomly assigned occasions that were controlled for menstrual cycle phase. In a randomized order, one day, acute tryptophan depletion (ATD) was used to reduce 5-HT synthesis in the brain. On the other day, participants received a tryptophan-balanced amino acid load (BAL) as a control condition. Three hours after administration of ATD/BAL, neural activity was recorded during a modified Go/No-Go task implementing reward or punishment processes using functional magnetic resonance imaging (fMRI). Neural activation during No-Go trials in punishment conditions after BAL versus ATD administration correlated positively with the magnitude of central 5-HT depletion in the ventral and subgenual anterior cingulate cortices (ACC). Furthermore, neural activation in the medial orbitofrontal cortex (mOFC) and the dorsal ACC correlated positively with trait impulsivity. The results indicate reduced neural sensitivity to punishment after short-term depletion of 5-HT in brain areas related to emotion regulation (subgenual ACC) increasing with depletion magnitude and in brain areas related to appraisal and expression of emotions (mOFC and dorsal ACC), increasing with trait impulsivity. This suggests a serotonergic modulation of neural circuits related to emotion regulation, impulsive behavior, and punishment processing in females.

Optimized mismatch negativity paradigm reflects deficits in schizophrenia patients. A combined EEG and MEG study.

Mismatch negativity (MMN) and its neuromagnetic analog (MMNm) are event-related brain responses elicited by changes in a sequence of auditory events and indexes early cognitive processing. It consistently detects neural processing deficits in schizophrenia. So far MMN is assessed with different methods (electroencephalography, EEG; magnetoencephalography, MEG) and with different paradigms: the "traditional" oddball design with rare deviants (20%) or the "optimum" design with 50% deviants varying in one of five parameters each. These MMN measures may not reflect one unitary mechanism which is equally affected in schizophrenia. We compared both designs in 12 patients with schizophrenia and controls using MEG and EEG. Automated, observer-independent data analysis rendered the procedures suitable for clinical applications. The optimum design was fastest to detect MMN and MEG had the best signal-to-noise ratio. In addition MMN was mostly reduced in schizophrenia if measured with MEG in the optimum paradigm. Optimized paradigms improve sensitivity and speed for the detection of schizophrenia endophenotypes. Dysfunctions in this disorder may lie primarily in the fast and automatic encoding of stimulus features at the auditory cortex.