Sensation seeking and error processing

Sensation seeking is defined by a strong need for varied, novel, complex, and intense stimulation, and a willingness to take risks for such experience. Several theories propose that the insensitivity to negative consequences incurred by risks is one of the hallmarks of sensation‐seeking behaviors. In this study, we investigated the time course of error processing in sensation seeking by recording event‐related potentials (ERPs) while high and low sensation seekers performed an Eriksen flanker task. Whereas there were no group differences in ERPs to correct trials, sensation seeking was associated with a blunted error‐related negativity (ERN), which was female‐specific. Further, different subdimensions of sensation seeking were related to ERN amplitude differently. These findings indicate that the relationship between sensation seeking and error processing is sex‐specific.     

采用流式细胞微珠法检测肾移植受者体内供者特异性抗体39例

目的 应用流式细胞微珠法检测肾移植受者供者特异性抗体(DSA),并探讨DSA阳性受者的HLA配型及移植物排斥反应发生情况.方法 检测39例亲属肾移植受者移植前、后的DSA,检测供、受者HLA错配情况,记录受者移植后排斥反应的发生情况.分析DSA阳性及阴性受者的HLA错配及排斥反应的发生情况.结果 39例共检测DSA 313次,其中移植前78次,移植后235次,移植前出现DSA阳性的均暂缓手术.5例HLA无错配的受者移植后DSA均为阴性,34例HLA错配的受者移植后12例出现DSA阳性(35.3％,P＜0.05).12例DSA阳性受者中,5例发生排斥反应(41.7％),其排斥反应发生率显著高于DSA阴性的移植受者(7.4％,P＜0.05).发生排斥反应且DSA阳性受者的单抗原微珠免疫荧光强度均值为5723.9±1030.5,高于未发生排斥反应的DSA阳性者的2355.2±609.7(P＜0.05).DSA阳性的受者治疗后,DSA免疫荧光强度有所下降.结论 采用流式细胞微珠法动态监测DSA效果较好,有利于预测和及时防治肾移植后排斥反应.     

Literature Review of Passenger Lymphocyte Syndrome Following Renal Transplantation and Two Case Reports

Passenger lymphocyte syndrome (PLS) is an immune‐mediated hemolysis. It occurs following ABO blood group mismatched solid organ and/or bone marrow transplantation between donor and recipient. We report two cases of PLS occurring after renal transplantation. Both recipients received live related kidney transplants; one from his mother and the other from his brother. The direction of blood group transfer, from donor to recipient, was O Rh D+ to A Rh D+ in both cases. Approximately 12 days after transplantation, both recipients showed a rapid fall in their hemoglobin levels with no identifiable bleeding source. DAT positive hemolysis was confirmed and anti‐A antibodies were detected in recipient sera, confirming a diagnosis of PLS. Both cases required blood transfusion support to maintain their hemoglobin and both had good renal outcomes. We have identified 99 PLS cases following renal transplant in the English literature. Previous ABO sensitization, donor blood group O to recipient blood group A or B transfer, and ciclosporin treatment have been identified as risk factors for PLS. Clinical outcomes in general are good; nonetheless, cases of graft failure and deaths have been reported. Early diagnosis and appropriate treatment are important in at risk individuals.     

Schizophrenia-like neurophysiological abnormalities in 22q11.2 deletion syndrome and their association to COMT and PRODH genotypes

22q11.2 deletion syndrome (22q11.2DS) is a common genetic risk factor for the development of schizophrenia. We investigated two neurophysiological endophenotypes of schizophrenia – P50 sensory gating and mismatch negativity in 22q11.2DS subject and evaluated their association with catechol O-methyltransferase (COMT) and proline dehydrogenase (PRODH) genetic variants. We also assessed the association of neurophysiological measures with schizophrenia-like symptomatology in 22q11.2DS. Fifty-nine subjects, 41 with 22q11.2DS and 18 typically developing controls, participated in the study. The participants with 22q11.2DS were genotyped for the COMT Val¹⁵⁸Met (rs4680) and PRODH Gln¹⁹Pro (rs2008720) and Arg¹⁸⁵Trp (rs4819756) polymorphisms. Following psychiatric evaluation, all the participants underwent neurophysiological recordings and executive function assessment. The 22q11.2DS group showed poorer sensory gating of the P50 response than the controls. Within the 22q11.2DS group, the COMT Met allele was associated with poorer sensory gating, while both the COMT Met allele and the PRODH Pro-Arg haplotype were associated with smaller mismatch negativity amplitudes. Smaller mismatch negativity amplitudes predicted greater impairment of executive functions and greater severity of schizophrenia-like negative symptoms in 22q11.2DS. The current study demonstrates that sensory gating impairments that are typical of schizophrenia are found in 22q11.2DS subjects. Our results further suggest that COMT and PRODH genetic variations contribute to sensory gating and mismatch negativity schizophrenia-like impairments in 22q11.2DS, possibly via dopaminergic/glutamatergic networks. The associations of mismatch negativity impairments with increased severity of schizophrenia-like negative symptoms and poorer executive functions performance in our 22q11.2DS sample suggest that mismatch negativity is a potential endophenotype for schizophrenia in 22q11.2DS.     

Even a rich man can afford that expensive house: ERP responses to construction-based pragmatic constraints during sentence comprehension

A linguistic construction is typically viewed as encoding the pairing of syntactic form and semantic information that is independent of the meaning of constituent words. Here with the event-related potentials (ERPs) we demonstrate that such a construction can also encode pragmatic constraints (event likelihood) that immediately influence online sentence comprehension and the associated neural activity. The lian…dou…construction in Chinese (similar to even in English) normally describes an event of low expectedness (a semantic constraint); it also introduces a pragmatic scale implying that any event with a higher likelihood than the event described must occur (pragmatic inference). By embedding a highly likely event (a rich man buying a house) or an underspecified event (a man buying a house) in the construction, we created an incongruent condition and an underspecified condition and compared both with a control condition in which an event of low expectedness (a poor man buying a house) was described. ERPs on the main verb phrases showed an N400 with a maximum in the right hemisphere followed by a late negativity with an anterior maximum for both the incongruent and underspecified conditions, with a larger N400 effect for the former than for the latter. ERPs on the sentence-final phrases showed a sustained negativity for the incongruent, but not for the underspecified condition. The N400 effect may reflect the increased difficulty in unifying the current event into the lian…dou… construction. The late negativity may reflect a second-pass revision according to the likelihood scale to satisfy the pragmatic constraints of the construction.     

Electrophysiological correlates of the retention of tones differing in timbre in auditory short-term memory

We examined the electrophysiological correlates of retention in auditory short-term memory (ASTM) for sequences of one, two, or three tones differing in timbre but having the same pitch. We focused on event-related potentials (ERPs) during the retention interval and revealed a sustained fronto-central ERP component (most likely a sustained anterior negativity; SAN) that became more negative as memory load increased. Our results are consistent with recent ERP studies on the retention of pitch and suggest that the SAN reflects brain activity mediating the low-level retention of basic acoustic features in ASTM. The present work shows that the retention of timbre shares common features with the retention of pitch, hence supporting the notion that the retention of basic sensory features is an active process that recruits modality-specific brain areas.