When planning fails: Individual differences and error-related brain activity in problem solving.

The neuronal processes underlying correct and erroneous problem solving were studied in strong and weak problem-solvers using functional magnetic resonance imaging (fMRI). During planning, the right dorsolateral prefrontal cortex was activated, and showed a linear relationship with the participants' performance level. A similar pattern emerged in right inferior parietal regions for all trials, and in anterior cingulate cortex for erroneously solved trials only. In the performance phase, when the pre-planned moves had to be executed by means of an fMRI-compatible computer mouse, the right dorsolateral prefrontal cortex was again activated jointly with right parahippocampal cortex, and displayed a similar positive relationship with the participants' performance level. Incorrectly solved problems elicited stronger bilateral prefrontal and left inferior parietal activations than correctly solved trials. For both individual ability and trial-specific performance, our results thus demonstrate the crucial involvement of right prefrontal cortex in efficient visuospatial planning

18F-FDG PET during stereotactic body radiotherapy for stage I lung tumours cannot predict outcome: a pilot study

(18)F-Fluorodeoxyglucose positron emission tomography (FDG PET) has been used to assess metabolic response several months after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer. However, whether a metabolic response can be observed already during treatment and thus can be used to predict treatment outcome is undetermined. Ten medically inoperable patients with FDG PET-positive lung tumours were included. SBRT consisted of three fractions of 20 Gy delivered at the 80% isodose at days 1, 6 and 11. FDG PET was performed before, on day 6 immediately prior to administration of the second fraction of SBRT and 12 weeks after completion of SBRT. Tumour metabolism was assessed semi-quantitatively using the maximum standardized uptake value (SUV(max)) and SUV(70%). After the first fraction, median SUV(max) increased from 6.7 to 8.1 (p = 0.07) and median SUV(70%) increased from 5.7 to 7.1 (p = 0.05). At 12 weeks, both median SUV(max) and median SUV(70%) decreased by 63% to 3.1 (p = 0.008) and to 2.5 (p = 0.008), respectively. SUV increased during treatment, possibly due to radiation-induced inflammation. Therefore, it is unlikely that (18)F-FDG PET during SBRT will predict treatment success

The right-hemisphere and valence hypotheses: could they both be right (and sometimes left)?

The two halves of the brain are believed to play different roles in emotional processing, but the specific contribution of each hemisphere continues to be debated. The right-hemisphere hypothesis suggests that the right cerebrum is dominant for processing all emotions regardless of affective valence, whereas the valence specific hypothesis posits that the left hemisphere is specialized for processing positive affect while the right hemisphere is specialized for negative affect. Here, healthy participants viewed two split visual-field facial affect perception tasks during functional magnetic resonance imaging, one presenting chimeric happy faces (i.e. half happy/half neutral) and the other presenting identical sad chimera (i.e. half sad/half neutral), each masked immediately by a neutral face. Results suggest that the posterior right hemisphere is generically activated during non-conscious emotional face perception regardless of affective valence, although greater activation is produced by negative facial cues. The posterior left hemisphere was generally less activated by emotional faces, but also appeared to recruit bilateral anterior brain regions in a valence-specific manner. Findings suggest simultaneous operation of aspects of both hypotheses, suggesting that these two rival theories may not actually be in opposition, but may instead reflect different facets of a complex distributed emotion processing system

Observation of Static Pictures of Dynamic Actions Enhances the Activity of Movement-Related Brain Areas

Physiological studies of perfectly still observers have shown interesting correlations between increasing effortfulness of observed actions and increases in heart and respiration rates. Not much is known about the cortical response induced by observing effortful actions. The aim of this study was to investigate the time course and neural correlates of perception of implied motion, by presenting 260 pictures of human actions differing in degrees of dynamism and muscular exertion. ERPs were recorded from 128 sites in young male and female adults engaged in a secondary perceptual task.Our results indicate that even when the stimulus shows no explicit motion, observation of static photographs of human actions with implied motion produces a clear increase in cortical activation, manifest in a long-lasting positivity (LP) between 350–600 ms that is much greater to dynamic than less dynamic actions, especially in men. A swLORETA linear inverse solution computed on the dynamic-minus-static difference wave in the time window 380–430 ms showed that a series of regions was activated, including the right V5/MT, left EBA, left STS (BA38), left premotor (BA6) and motor (BA4) areas, cingulate and IF cortex.Overall, the data suggest that corresponding mirror neurons respond more strongly to implied dynamic than to less dynamic actions. The sex difference might be partially cultural and reflect a preference of young adult males for highly dynamic actions depicting intense muscular activity, or a sporty context

Treating a GAD65 Antibody-Associated Limbic Encephalitis with Basiliximab: A Case Study

Background: Antibodies (ABs) against the 65-kDa isoform of the intracellular enzymeglutamate decarboxylase (GAD65) have been found in limbic encephalitis (LE) andother neurological conditions. The direct significance of anti-GAD65-ABs for epilepsyis unclear. However, in histological preparations from biopsies of resective epilepsysurgeries, predominantly cytotoxic T-lymphocytes were detected making close contactsto neurons. Activated T-lymphocytes can, in turn, be selectively controlled by therapeuticinterleukin-2 receptor Abs, such as basiliximab.Case presentation: We report of a 25-year-old male patient with epilepsy since theage of 18 and displaying clinical signs of LE and a high titer of GAD65 ABs in cerebro-spinal fluid (CSF) and serum. Monthly, repetitive, intravenous cortisone pulse therapiesthat were initially administered for 6 months failed to improve his condition. Subsequentflow-cytometry analysis of CSF showed especially an increased fraction of activatedHLA-DR+CD8+T-lymphocytes (fCD8+TL) when compared to controls. Thus, a second,intravenous cortisone pulse therapy with an additional basiliximab dose of 20 mg/monthwas started. After 3 months, the fCD8+TL in the CSF normalized; after 6 months, thepsychological impulse-control deficits normalized; and after 11 months the patientwas seizure free. However, 7 weeks later, seizures and, later on, psychological deficitsrecurred and fCD8+TL was once again present in the CSF. Flumazenil PET, magneticresonance imaging-volumetry, and neuropsychological changes during therapy aredescribed.Conclusion: The correlation of the fCD8+TL in the CSF with clinical and paraclinical measures of disease activity combined with the unambiguous response to basiliximabstrongly argues in favor of the putative pathogenic role fCD8+TL in anti-GAD65 LE. The clinical relapse at the end of the observation period might be due to the formation ofhuman anti-drug ABs, a well-known complication of therapy with chimeric ABs

True but not false memories are associated with the HTR2A gene

Previous research reported that serotonin receptor 2A gene (HTR2A) polymorphisms were associated with memory. However, it is unknown whether these genetic variants were associated with both true and false memories. The current study of 336 Han Chinese subjects tested 30 single nucleotide polymorphisms (SNPs) within the HTR2A gene for potential associations with true and false memories. False memories were assessed using the Deese-Roediger-McDermott (DRM) paradigm, in which people falsely remember semantically related (but unpresented) words. We found that 11 SNPs within the HTR2A gene were associated with true memory (p=0.000076-0.043). The associations between true memory and seven adjacent SNPs (i.e., rs1923888, rs1745837, rs9567739, rs3742279, rs655888, rs655854, and rs2296972) were still significant after multiple testing corrections. Haplotype-based association analysis revealed that, true memory was positively associated with haplotype A-C-C-G-C-T-A for these seven adjacent SNPs (p=0.000075), which was still significant after multiple testing correction. Only one SNP rs655854 was associated with false memory (p=0.023), and it was not significant after multiple testing correction. This study replicates, in an Asian population, that genetic variation in HTR2A is associated with episodic memory, and also suggests that this association is restricted to true memory