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Neuroimaging data analysis often requires purpose-built software, which can be challenging to install and may produce different results across computing environments. Beyond being a roadblock to neuroscientists, these issues of accessibility and portability can hamper the reproducibility of neuroimaging data analysis pipelines. Here, we introduce the Neurodesk platform, which harnesses software containers to support a comprehensive and growing suite of neuroimaging software (https://www.neurodesk.org/). Neurodesk includes a browser-accessible virtual desktop environment and a command line interface, mediating access to containerized neuroimaging software libraries on various computing platforms, including personal and high-performance computers, cloud computing and Jupyter Notebooks. This community-oriented, open-source platform enables a paradigm shift for neuroimaging data analysis, allowing for accessible, flexible, fully reproducible, and portable data analysis pipelines.

Previous research has shown that capture of visual attention is influenced by prior learning about reward: signals of high reward value are more likely to capture attention (and gaze) than signals of low reward value. In the current study, we show in two experiments that attentional priority is modulated not only by reward magnitude, but also by the uncertainty associated with that reward. Participants completed a visual search task in which they were required to make a saccade to a target shape to earn monetary reward. The color of a color-singleton distractor in the search array signaled the reward outcome(s) that were available. Different distractor colors were associated with different degrees of variance and expected value in reward outcome. Notably, participants were never required to look at the colored distractor, and doing so would slow their response to the target. Nevertheless participants often made eye-movements towards the distractor, and across both experiments they were more likely to look at distractors associated with high outcome variance versus low outcome variance. This pattern was observed when all distractors had equal expected value (Experiment 1), and when the difference in variance was opposed by a substantial difference in expected value (i.e., the high-variance distractor had low expected value, and vice versa: Experiment 2). Our results suggest that reward variance exerts a critical role in modulating rapid attentional and oculomotor priority. More generally, these findings are consistent with theoretical accounts that propose an information-seeking role for visual attention, and suggest that prioritization in line with “attentional exploration” can operate rapidly and on a learned basis.

Funder: The University of Queensland, Cognitive impairment in psychosis is one of the strongest predictors of functional decline. Problems with decision-making processes, such as goal-directed action and reversal learning, can reflect cortico-striatal dysfunction. The heterogenous symptoms and neurobiology observed in those with psychosis suggests that specific cognitive phenotypes may reflect differing causative mechanisms. As such, decision-making performance could identify subgroups of individuals with more severe cortico-striatal dysfunction and help to predict their functional decline. The present work evaluated the relationship between goal-directed action, reversal learning, and symptom profiles in those with psychosis. We assessed decision-making processes in healthy controls (N = 34) and those with persistent psychosis (N = 45), subclassifying subjects based on intact/impaired goal-directed action. Compared with healthy controls (

Accurate quantification of effect sizes has the power to motivate theory, and reduce misinvestment of scientific resources by informing power calculations during study planning. However, a combination of publication bias and small sample sizes (~$N$ = 25) hampers certainty in current effect size estimates. We sought to determine the extent to which sample sizes may produce error in effect size estimates for four commonly used paradigms assessing attention, executive function and implicit learning (Attentional Blink (AB), Multitasking (MT), Contextual Cueing (CC), Serial Response Task (SRT)). We combined a large data-set with a bootstrapping approach to simulate 1000 experiments across a range of $N$ (13-313). Beyond quantifying the effect size and statistical power that can be anticipated for each study design, we demonstrate that experiments with lower values of N can potentially double or triple information loss. Furthermore, we identify the probability that sampling a similar study will provide a reasonable effect size estimate, and show that using such an approach for power calculations will lead to an imprecise estimate between 40-67% of the time, given commonly used sample sizes. We conclude with practical recommendations for researchers and demonstrate how our simulation approach can yield theoretical insights that are not readily achieved by other methods; such as identifying the information gained from rejecting the null hypothesis, and quantifying the contribution of individual variation to error in effect size estimates.

Sharing of research code would greatly benefit neuroscience, but this practice is hampered by a collective action problem. Since the development of the internet, conditional pledge platforms (e.g., Kickstarter) have increasingly been used to solve globally-dispersed collective action problems (Hallam, 2016). However, this strategy has yet to be implemented within academia. In this brief paper, we introduce a general purpose conditional pledge platform for the research community: Project Free Our Knowledge. We highlight a new conditional pledge campaign that was initiated at Brainhack 2021 and aims to motivate a critical mass of neuroscientists to share their research code. Crucially, this commitment activates only when a user-defined threshold of support is reached. We conclude by sharing our vision for how the research community could use collective action campaigns to create a sustained, evidence-based movement for social change in academia.

Performing two tasks concurrently typically leads to performance costs. Historically, multitasking costs have been assumed to reflect fundamental constraints of cognitive architectures. A new perspective proposes that multitasking costs reflect information sharing between constituent tasks; shared information gains representational efficiency, at the expense of multitasking capability. We test this theory by determining whether increasing cross-task information harms multitasking. 48 participants performed multitasks where they mapped keypresses to four shapes. In a subsequent statistical learning task, these shapes then formed pairs that were predictive or non-predictive of an upcoming target judgement. When participants again responded to these shapes in the multitasking context, performance was poorer when the shape pair had been predictive of target outcomes in the learning phase, relative to non-predictive. Thus, associating common information to shape pairings transferred to negatively impact multitasking performance, providing the first causal evidence for the shared representational account of multitasking performance.

Cognitive impairments in psychosis are one of the strongest predictors of functional decline. Cortico-striatal dysfunction may contribute to both psychosis and cognitive impairment in psychotic illnesses. The decision-making processes underlying goal-directed action and serial reversal learning can be measured and are sensitive to changes reflecting cortico-striatal dysfunction. As such, changes in decision-making performance may assist with predicting functional decline in people with psychosis. We assessed decision-making processes in healthy controls (N=34), and those with early psychosis (N=15) and persistent psychosis (N=45). We subclassified subjects based on intact/impaired goal-directed action. Compared with healthy controls (

As the global health crisis unfolded throughout the world, many academic conferences moved online in 2020. This move has been hailed as a positive step towards inclusivity in its attenuation of economic, physical and legal barriers and effectively enabled many individuals who have traditionally been underrepresented to join and participate. A number of studies have outlined how moving online made it possible to gather a more global community and has increased opportunities for individuals with various constraints, e.g. caregiving responsibilities. Yet, the mere existence of online conferences is unfortunately no guarantee that everyone can attend and participate meaningfully. In fact, many elements of an online conference are still significant barriers to truly diverse participation: the tools used can be inaccessible for some individuals; the scheduling choices can favour some geographical locations; the setup of the conference can provide more visibility to well-established researchers and reduce opportunities for early career researchers. While acknowledging the benefits of an online setting, especially for individuals who have traditionally been underrepresented or excluded, we recognize that fostering social justice requires inclusivity to actively be centered in every aspect of online conference design.Here, we draw from the literature and from our own experiences to identify practices that purposefully encourage a diverse community to: attend, participate in, and lead online conferences. Reflecting on how to design more inclusive online events is especially important as multiple scientific organizations have announced that they will continue offering an online version of their event when in-person conferences can resume.

Humans show striking limitations in information processing when multitasking yet can modify these limits with practice. Such limitations have been linked to a frontal-parietal network, but recent models of decision-making implicate a striatal-cortical network. We adjudicated these accounts by investigating the circuitry underpinning multitasking in 100 human individuals and the plasticity caused by practice. We observed that multitasking costs, and their practice-induced remediation, are best explained by modulations in information transfer between the striatum and the cortical areas that represent stimulus-response mappings. Specifically, our results support the view that multitasking stems at least in part from taxation in information sharing between the putamen and pre-supplementary motor area (pre-SMA). Moreover, we propose that modulations to information transfer between these two regions leads to practice-induced improvements in multitasking.

Available online 30 April 2021. Brainhack is an innovative meeting format that promotes scientific collaboration and education in an open, inclusive environment. This NeuroView describes the myriad benefits for participants and the research community and how Brainhacks complement conventional formats to augment scientific progress. The present manuscript is part of a growing community effort to collate Brainhack-related insights and expertise into a Jupyter Book (http://brainhack.org/brainhack_jupyter_book/) that will serve as a centralized set of resources for the community; we acknowledge all the individuals who contributed and will make ongoing contributions to these resources. A pre-print version of the present manuscript is available as part of the Jupyter Book. Moreover, we would like to acknowledge all Brainhack organizers, supporters, presenters, and participants for their contribution to growing and maintaining this community. The benefits described in this manuscript would not be possible without them. We also thank all institutions, labs, and organizations who have helped this community grow, meet in stimulating environments, and add an excellent educational resource pool and agenda. With an expanding community, Brainhack’s support network keeps growing, and we thank all labs and individual researchers for their dedication and expertise offered to this community (see http://brainhack.org/brainhack_jupyter_book/acknowledgments.html for a full list of individual acknowledgments; an updated list will be maintained in the Jupyter Book). Grants and funding bodies: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 867458 awarded to Julia M. Huntenburg; from ANR-19-DATA-0025 NeuroWebLab for Katja Heuer, Roberto Toro, and Nicholas Traut; and from NIH K00MH122372 for Stephanie Noble. The Brainhack Community member list and contributions of the different authors are detailed at http://brainhack.org/brainhack_jupyter_book/contributors.html. Our crediting system is described here: http://brainhack.org/brainhack_jupyter_book/neuroview_authorship-agreement.html.

Although humans show a remarkable ability to make rapid and accurate decisions in novel situations, it is surprisingly difficult to observe transferable benefits when training decision-making performance. The current study investigated whether 2 properties of decision-making-amodal processing and encoding of abstract relationships-could be leveraged to produce transferable training gains, compared with the performance of an active-control group. Experiment 1 showed that training responses to visually presented stimuli (letters) did not transfer to benefit performance for the same stimuli presented in the auditory modality. Therefore, training exercises the integration of modality-specific information, not a supramodal category. However, Experiment 2 showed that when stimuli share an abstract rule, training transfers to new materials that conform to the same modality and rule, and to analogous rules in a new modality. Therefore, transfer of training benefits requires an abstract code that can be generalized to new stimulus sets. (PsycINFO Database Record

Humans show striking limitations in information processing when multitasking, yet can modify these limits with practice. Such limitations have been linked to a frontal-parietal network, but recent models of decision-making implicate a striatal-cortical network. We adjudicated these accounts by investigating the circuitry underpinning multitasking in 100 individuals and the plasticity caused by practice. We observed that multitasking costs, and their practice induced remediation, are best explained by modulations in information transfer between the striatum and the cortical areas that represent stimulus-response mappings. Specifically, our results support the view that multitasking stems at least in part from taxation in information sharing between the putamen and pre-supplementary motor area (pre-SMA). Moreover, we propose that modulations to information transfer between these two regions leads to practice-induced improvements in multitasking.Significance statementHumans show striking limitations in information processing when multitasking, yet can modify these limits with practice. Such limitations have been linked to a frontal-parietal network, but recent models of decision-making implicate a striatal-cortical network. We adjudicated these accounts by investigating the circuitry underpinning multitasking in 100 individuals and the plasticity caused by practice. Our results support the view that multitasking stems at least in part from taxation in information sharing between the putamen and pre-supplementary motor area (pre-SMA). We therefore show that models of cognitive capacity limits must consider how subcortical and cortical structures interface to produce cognitive behaviours, and we propose a novel neurophysiological substrate of multitasking limitations.

Negotiating the information-rich sensory world often requires the concurrent management of multiple tasks. Despite this requirement, humans are thought to be poor at multitasking because of the processing limitations of frontoparietal and subcortical (FP-SC) brain regions. Although training is known to improve multitasking performance, it is unknown how the FP-SC system functionally changes to support improved multitasking. To address this question, we characterized the FP-SC changes that predict training outcomes using an individual differences approach. Participants (n = 100) performed single and multiple tasks in pre- and posttraining magnetic resonance imaging (fMRI) sessions interspersed by either a multitasking or an active-control training regimen. Multivoxel pattern analyses (MVPA) revealed that training induced multitasking improvements were predicted by divergence in the FP-SC blood oxygen level-dependent (BOLD) response patterns to the trained tasks. Importantly, this finding was only observed for participants who completed training on the component (single) tasks and their combination (multitask) and not for the control group. Therefore, the FP-SC system supports multitasking behavior by segregating constituent task representations.

Humans can show striking capacity limitations in sensorimotor processing. Fortunately, these limitations can be attenuated with training. However, less fortunately, training benefits often remain limited to trained tasks. Recent behavioral observations suggest that the extent to which training transfers may depend on the specific stage of information processing that is being executed. Training benefits for a task that taps the consolidation of sensory information (sensory encoding) transfer to new stimulus–response mappings, whereas benefits for selecting an appropriate action (decision-making/response selection) remain specific to the trained mappings. Therefore, training may have dissociable influences on the neural events underlying subsequent sensorimotor processing stages. Here, we used EEG to investigate this possibility. In a pretraining baseline session, participants completed two four-alternative-choice response time tasks, presented both as a single task and as part of a dual task (with another task). The training group completed a further 3,000 training trials on one of the four-alternative-choice tasks. Hence, one task became trained, whereas the other remained untrained. At test, a negative-going component that is sensitive to sensory-encoding demands (N2) showed increased amplitudes and reduced latencies for trained and untrained mappings relative to a no-train control group. In contrast, the onset of the stimulus-locked lateralized readiness potential, a component that reflects the activation of motor plans, was reduced only for tasks that employed trained stimulus–response mappings, relative to untrained stimulus–response mappings and controls. Collectively, these results show that training benefits are dissociable for the brain events that reflect distinct sensorimotor processing stages.

How does the brain combine information predictive of the value of a visually guided task (incentive value) with information predictive of where task relevant stimuli may occur (spatial certainty)? Human behavioural evidence indicates that these two predictions are combined additively to bias visual selection (additive hypothesis), whereas neuroeconomic studies posit that they may be multiplicatively combined (expected value hypothesis). We sought to arbitrate between these two alternatives, and to test the possibility that both operations are available to visual prioritization mechanisms, but that their use is context dependent (mixed operations hypothesis). Participants viewed two coloured placeholders that specified the potential value of correctly identifying an imminent letter target if it appeared in that placeholder. Then, prior to the targets presentation, an endogenous spatial cue was presented indicating the targets more likely location. Spatial cues were parametrically manipulated with regard to the information gained (in bits). Across two experiments, response time and accuracy were greater for targets appearing in high versus low value placeholders and higher when targets appeared in validly cued locations, even under conditions designed to impinge the optimality of an additive operation. Interestingly, these factors did not interact; Bayesian model selection showed that the additive hypothesis clearly outperformed the expected value and mixed operations hypotheses in accounting for the observed data from both experiments. These findings refute theories that expected value computations are the singular mechanism driving the deployment of endogenous spatial attention. Instead, incentive value and spatial certainty seem to act independently to influence visual selection.

A growing body of research suggests that dual-task interference in sensory consolidation (e.g., the attentional blink, AB) and response selection (e.g., the psychological refractory period, PRP) stems from a common central bottleneck of information processing. With regard to response selection, it is well known that training reduces dual-task interference. We tested whether training that is known to be effective for response selection can also reduce dual-task interference in sensory consolidation. Over two experiments, performance on a PRP paradigm (Exp. 1) and on AB paradigms (differing in their stimuli and task demands, Exps. 1 and 2) was examined after participants had completed a relevant training regimen (T1 practice for both paradigms), an irrelevant training regimen (comparable sensorimotor training, not related to T1 for both tasks), a visual-search training regimen (Exp. 2 only), or after participants had been allocated to a no-training control group. Training that had shown to be effective for reducing dual-task interference in response selection was also found to be effective for reducing interference in sensory consolidation. In addition, we found some evidence that training benefits transferred to the sensory consolidation of untrained stimuli. Collectively, these findings show that training benefits can transfer across cognitive operations that draw on the central bottleneck in information processing. These findings have implications for theories of the AB and for the design of cognitive-training regimens that aim to produce transferable training benefits.

Background: T-cell immunoglobulin mucin-3 (TIM3) has recently been described as an acute myeloid leukemia (AML) stem cell antigen expressed on leukemic myeloblasts, but not on normal hematopoietic stem cells. TIM3 is also expressed by monocytes, natural killer cells, and several T cell subsets; however, normal myeloblasts have not been well-characterized or compared to AML. A specific flow cytometric marker capable of separating leukemic myeloblasts from non-neoplastic myeloblasts would be diagnostically useful, especially in the post-chemotherapy setting. Methods: TIM3 myeloblast expression was assessed in 69 bone marrow and/or peripheral blood specimens, including 27 AML and 42 non-neoplastic cases (20 with a recent history of chemotherapy). TIM3 median fluorescence intensity (MFI) was evaluated within myeloblast, monocyte, T cell, and natural killer cell populations. Results: The median percentage of myeloblasts positive for TIM3 was lower in non-neoplastic specimens without a history of recent chemotherapy (50.3%) as compared to AML (71.4%), but not significantly different as compared to non-leukemic myeloblasts in the post-chemotherapy setting (72.4%). Mean myeloblast TIM3 MFI was higher in AML myeloblasts and non-leukemic myeloblasts in the post-chemotherapy setting as compared to non-neoplastic myeloblasts in cases lacking a history of chemotherapy. Mean monocyte, natural killer cell, and T-cell TIM3 MFI remained relatively constant in varied clinical settings. Conclusions: We confirm that leukemic myeloblasts overexpress TIM3 as compared to non-neoplastic controls; however, high levels of expression may also be seen among non-leukemic myeloblasts in the post-chemotherapy setting. This overlap limits the diagnostic utility of TIM3 as a specific marker of neoplasia. © 2013 International Clinical Cytometry Society

The abilities to select appropriate responses and suppress unwanted actions are key executive functions that enable flexible and goal-directed behavior. However, to date it has been unclear whether these two cognitive operations tap a common action control resource or reflect two distinct processes. In the present study, we used an individual differences approach to examine the underlying relationships across seven paradigms that varied in their response selection and response inhibition requirements: stop-signal, go–no-go, Stroop, flanker, single-response selection, psychological refractory period, and attentional blink tasks. A confirmatory factor analysis suggested that response inhibition and response selection are separable, with stop-signal and go–no-go task performance being related to response inhibition, and performance in the psychological refractory period, Stroop, single-response selection, and attentional blink tasks being related to response selection. These findings provide evidence in support of the hypothesis that response selection and response inhibition reflect two distinct cognitive operations.

Background: Attention bias modification (ABM) procedures have been shown to modify biased attention with important implications for emotional vulnerability and resilience. The use of ABM to reduce potentially toxic biases, for instance, is a newly emerging therapy for anxiety disorders. A separate line of gene-by-environment interaction research proposes that many so-called vulnerability genes or risk alleles are better seen as plasticity genes, as they seem to make individuals more susceptible to environmental influences for better and for worse. Methods: A standard ABM procedure was used with a sample of 116 healthy adults. Participants were randomly assigned to one of two training groups. One received an ABM procedure designed to induce a bias in attention toward negative material, while the other was trained toward positive pictures. Individuals with low- and high-expressing forms of the serotonin transporter gene (5-HTTLPR) were compared. Results: Those with a low-expression form (S/S, S/Lg, or Lg/Lg) of the 5-HTTLPR gene developed stronger biases for both negative and positive affective pictures relative to those with the high-expression (La/La) form of the gene. Conclusions: Here, we report the first evidence that allelic variation in the promotor region of the 5-HTTLPR gene predicts different degrees of sensitivity to ABM. These results suggest a potential cognitive mechanism for the gene-by-environment interactions that have been found in relation to the serotonin transporter gene. Variation on this genotype may therefore determine who will benefit most (and least) from therapeutic interventions, adversity, and supportive environments.

The ability to perform multiple, concurrent tasks efficiently is a much-desired cognitive skill, but one that remains elusive due to the brain's inherent information-processing limitations. Multitasking performance can, however, be greatly improved through cognitive training (Van Selst et al., 1999, Dux et al., 2009). Previous studies have examined how patterns of brain activity change following training (for review, see Kelly and Garavan, 2005). Here, in a large-scale human behavioral and imaging study of 100 healthy adults, we tested whether multitasking training benefits, assessed using a standard dual-task paradigm, are associated with variability in brain structure. We found that the volume of the rostral part of the left dorsolateral prefrontal cortex (DLPFC) predicted an individual's response to training. Critically, this association was observed exclusively in a task-specific training group, and not in an active-training control group. Our findings reveal a link between DLPFC structure and an individual's propensity to gain from training on a task that taps the limits of cognitive control.SIGNIFICANCE STATEMENTCognitive “brain” training is a rapidly growing, multibillion dollar industry (Hayden, 2012) that has been touted as the panacea for a variety of disorders that result in cognitive decline. A key process targeted by such training is “cognitive control.” Here, we combined an established cognitive control measure, multitasking ability, with structural brain imaging in a sample of 100 participants. Our goal was to determine whether individual differences in brain structure predict the extent to which people derive measurable benefits from a cognitive training regime. Ours is the first study to identify a structural brain marker—volume of left hemisphere dorsolateral prefrontal cortex—associated with the magnitude of multitasking performance benefits induced by training at an individual level.

We describe a novel method to detect specific polymerase chain reaction (PCR) target amplicons, involving thermostable ligation of fluorescent and biotinylated oligonucleotides, microparticle bead capture of the ligated products, and flow cytometric analysis. This approach, termed fluorescent ligation detection reaction (f-LDR) is more rapid and cost-effective than oligoprobe Southern blot hybridization (SBH). A standard f-LDR protocol was developed to detect the leukemia-associated chimeric transcripts bcr-abl and promyelocytic leukemia-retinoic acid receptor a (PML-RARalpha) in 2 multiplex and multicolor assays. The f-LDR platform was 100% specific and demonstrated comparable or better sensitivity than standard oligoprobe SBH. The usefulness of f-LDR was evaluated in 94 posttherapy samples from 13 patients with acute promyelocytic leukemia with the PML-RARalpha gene fusion. The f-LDR method was highly concordant (93%) with oligoprobe SBH; essentially all discrepancies were noted to be due to the enhanced sensitivity of f-LDR. We conclude that f-LDR is a highly specific and sensitive post-PCR method with wide potential application.

Synovial sarcomas (SS) are characterized by the t(X;18)(p11;q11) translocation and its resultant fusion gene, SYT-SSX. Two homologues of the SSX gene (ie, SSX1 and SSX2) are involved in the vast majority of SS and the SYT-SSX1 type of fusion has been associated with inferior clinical outcome. Thus, detection of the presence and type of SYT-SSX fusion is critical for diagnosis and prognosis in SS. Identification of SYT-SSX fusion type is typically accomplished by reverse-transcription polymerase chain reaction (RT-PCR) followed by a post-PCR analytic method. As mRNA nucleotide sequences of the SSX1 and SSX2 segments involved in the SYT-SSX fusion are nearly identical, post-PCR methods must be highly discriminatory. We describe a novel method to identify and differentiate these two chimeric transcripts using RT-PCR followed by fluorescent thermostable ligase detection reaction (f-LDR), microparticle bead capture and flow cytometric detection. Evaluation of this unique approach in 11 cases of SS without prior knowledge of SYT-SSX status, six cases of control sarcomas (CS) and three hematopoietic cell lines, revealed that the f-LDR technique was rapid, unambiguous, and highly specific. The f-LDR results were compared to XmnI enzyme digestion patterns and sequencing of PCR products, revealing a 100% concordance for all cases of SS with regards to SYT-SSX transcript type. In addition, there was a strong association of transcript type detected by f-LDR and morphological subclassification of SS, as previously reported. We conclude that this f-LDR method with flow-based detection is a robust approach to post-PCR detection of specific nucleotide sequences in SS and may be more broadly applicable in molecular oncology.

Despite the myriad of tasks that are managed on a daily basis, humans show striking limitations in their capacity to process multiple cognitive operations concurrently. The observation that performance suffers as a consequence of completing two tasks together, relative to in isolation, is arguably one of the most central in psychology and neuroscience. These multitasking performance decrements are observable even under conditions where tasks do not overlap in terms of sensory-input and response-output modalities - motivating the proposal that the human brain contains an amodal, central “bottleneck” of information processing. Although such costs are pervasive, they fortunately are not immutable. Training can overcome multitasking limitations. Given the pervasive nature of these impairments, understanding the behavioural and system-level neural mechanisms that give rise to reduced multitasking costs following training holds the potential to confer transferable performance benefits. The experiments in this thesis investigate the behavioral and neural consequences of training attentional processes involved in multitasking, in terms of the degree to which training benefits transfer to new tasks and information processing stages, and the neural mechanisms that underpin training induced performance improvements. Study 1 investigated whether training that is known to benefit multitasking performance at the level of response-selection (as measured by the psychological refractory period paradigm, PRP) can transfer to benefit performance on other tasks: Both new response-selection tasks, and those that tap sensory-encoding limitations (as measured by the attentional blink, AB), which have also been attributed to the central bottleneck. Over two experiments, performance on a PRP paradigm (Experiment 1) and upon AB paradigms (differing across stimulus- and task-demands, Experiments 1 and 2) was examined after participants completed a relevant training regimen (task 1 sensory-motor (S-R) mappings for the PRP and AB), an irrelevant training regimen (comparable sensorimotor training, not related to task 1), a visual-search training regimen (Experiment 2 only) or after allocation to a no-train control group. Training that was effective for reducing response-selection interference transferred to reduce interference in sensory-encoding, but did not transfer to benefit performance for new stimulus-response (S-R) mappings. In contrast, training transferred to benefit sensory-encoding of untrained stimuli, suggesting that training has dissociable consequences for sensory-encoding and response-selection. As training benefits for a task tapping sensory-encoding transfers to new S-R mappings, whereas benefits for response-selection remain specific to the trained mappings, training may have dissociable influences on the neural events corresponding to these processing stages. Study 2 used EEG to investigate this hypothesis. In a pre-training baseline session, participants completed two 4-alternative choice (4ac) response time (RT) tasks, presented both as a single-task and as part of a dual-task (with another task). The training group completed a further 3000 training trials upon one of the 4ac tasks. Hence one task became trained, while the other remained untrained. At test, a negative going component that is sensitive to sensory-encoding demands (N2) showed increased amplitudes and reduced latencies for trained and untrained mappings relative to a no-train control group. In contrast, both multitasking costs and the onset of the stimulus-locked lateralized readiness potential (s-LRP), a component that reflects the activation of motor plans, was reduced only for tasks that employed trained S-R mappings, relative to untrained S-R mappings and controls. Collectively, these results show that training benefits are dissociable for the brain events that reflect distinct information processing stages. Currently, the systems-level neural mechanisms that give rise to training benefits are unknown, with no work having examined the antecedents of individual differences in multitasking training outcomes with appropriate active-controls and sensitive analysis techniques. Study 3 addressed this issue with a large-scale functional-magnetic-resonance-imaging (fMRI) study. One hundred participants completed a multitasking paradigm in baseline and test sessions while being scanned. Intervening these sessions, 50 participants completed a multitasking training regimen, while the remaining 50 completed an attentional-training active-control regimen. Blood-oxygen-level-dependent Activity (BOLD) activity in frontal, parietal and subcortical regions tracked multitasking costs and training induced improvements. Of primary interest, a multivariate analysis showed that increased task-specific representation in these areas predicted multitasking-training gains. The results demonstrate that training overcomes multitasking costs by functionally segregating task-specific networks within task-relevant areas. The work presented in this thesis provides insights regarding the cognitive and neural mechanisms that enable the brain to improve performance to solve the multitasking problem. Furthermore, these findings have implications for cognitive training regimens that aim to achieve transferable training benefits, and for theoretical understanding of the central limitation in human information processing.

Background Response inhibition is a prototypical executive function of considerable clinical relevance to psychiatry. Nevertheless, our understanding of its pharmacological modulation remains incomplete. Methods We used a randomized, double-blind, placebo-controlled, crossover design to examine the effect of an acute dose of methylphenidate (MPH) (30 mg), atomoxetine (ATM) (60 mg), citalopram (CIT) (30 mg), and placebo (PLAC) (dextrose) on the stop signal inhibition task in 24 healthy, right-handed men 18–35 years of age. Participants performed the task under each of the four drug conditions across four consecutive sessions. Results Methylphenidate led to a reduction in both response time variability and stop-signal reaction time (SSRT), indicating enhanced response inhibition compared with all other drug conditions. Crucially, the enhancement of response inhibition by MPH occurred without concomitant changes in overall response speed, arguing against a simple enhancement of processing speed. We found no significant differences between ATM and PLAC, CIT and PLAC, or ATM and CIT for either response time variability or SSRT. Conclusions An acute dose of MPH but not ATM or CIT was able to improve SSRT and reduce response time variability in nonclinical participants. Improvements in response inhibition and response variability might underlie the reported clinical benefits of MPH in disorders such as attention-deficit/hyperactivity disorder.

Distinction of normal B-lymphoid proliferations including precursors known as hematogones from acute lymphoblastic leukemia (ALL) is critical for disease management. We present a multiparameter assessment of 27 bone marrow samples containing at least 25% hematogones (range, 25%-72%) by morphologic review. We used flow cytometry to evaluate B-cell differentiation antigen and adhesion molecule expression and immunohistochemistry on clot sections to evaluate architectural distribution. Flow cytometry revealed that intermediately differentiated cells (CD19+, CD10+) predominated, followed in frequency by CD20+, surface immunoglobulin-positive cells, with CD34+, terminal deoxynucleotidyl transferase (TdT)-positive cells as the smallest subset. Adhesion molecules (CD44, CD54) were expressed more heterogeneously compared with expression in acute lymphoblastic leukemia. Immunohistochemistry revealed that CD34+, TdT-positive cells were dispersed without significant clustering, while CD20+ cells exceeded CD34/TdT-positive cells in 24 of 25 cases. This multidisciplinary study demonstrates that hematogone-rich lymphoid proliferations exhibit a spectrum of B-lymphoid differentiation antigen expression with predominance of intermediate and mature B-lineage cells, heterogeneity of adhesion molecule expression, and nonclustered bone marrow architectural distribution.

Establishing the diagnosis of myelodysplastic syndrome (MDS) can be difficult and requires a multiparametric approach, with correlation of the clinical, morphologic and genetic features. Although M...

a p o d t d a A woman was referred for a 1-year history of symptomatic persistent anemia requiring repeated blood ransfusion. Her medical history was only remarkable for acuired hypothyroidism. She denied any recent history of weight oss or hematochezia. She previously underwent esophagogasroduodenoscopy and colonoscopy, which revealed no source of leeding. She received a transfusion every 2 months before dmission and again 2 weeks before. A computed tomography can of the abdomen was performed approximately 1 year efore presentation, which was negative. Gynecologic work-up ncluding transvaginal ultrasonography was also unrevealing. n presentation, physical examination was unremarkable exept for pallor. Laboratory data were pertinent for hemoglobin g/dL, iron 10 g/dL, total iron-binding capacity 450 g/dL, and ferritin 40 ng/mL. She was transfused 4 units, but her hemoglobin gradually trended back down from 9.6 g/dL after transfusion to 7.2 g/dL during a period of 4 days. Esophagogastroduodenoscopy was performed with small bowel biopsy to investigate celiac disease. The duodenum mucosa appeared endoscopically normal, and no source of bleeding was identified. Pathology report of the small intestine showed an intact villous architecture with no significant abnormality. Computed tomographic enterography revealed a large cystic lobulated mass in the small intestinal mesentery, and the lesion infiltrated an adjacent segment of small bowel (Figure A). Exploratory laparotomy revealed a hemorrhagic mass (8.5 6 4 cm) at the mesenteric surface of the small bowel (Figure B). Pathologic findings revealed the tumor mass was composed of cystic spaces filled with hemorrhage, and the stroma was composed of a fibrocollagenous tissue (Figure C). Immunohistochemical staining for lymphatic endothelial marker D2-40 antibody was positive in the endothelial lining of the cystic spaces (Figure D) as well as variable staining for CD34 and CD31, which confirmed the diagnosis of lymphangioma. There was no evidence of an epithelial or mesenchymal malignancy identified. Her longstanding refractory iron deficiency anemia was thought to be due to chronic indolent gastrointestinal bleeding from lymphangioma involving the mesentery and wall of overlying small bowel. She fully recovered from iron deficiency anemia and required no more blood transfusion. Lymphangioma of the small bowel mesentery is a rare intraabdominal tumor, and it reportedly represents only 1 per 100,000 hospital admissions.1 Although lymphangiomas are often diagnosed in the head, neck, and axilla in young patients, they also occur sporadically as intra-abdominal lymphangiomas during adulthood. It originates from the mesentery in which most lymphatic channels are included. The etiology of lymphangioma is still unclear. Although it is a benign proliferation of lymph vessels, it could transform into a lymphangiosarcoma especially after irradiation.2 The clinical symptoms range from bdominal pain, anemia from blood loss, and obstruction to erforation. Because of the low incidence and vague symptoms f intra-abdominal lymphangioma, it is often unexpectedly iagnosed as large-size multicystic tumors. This case highlights hat lymphangioma should be considered in the differential iagnosis of iron deficiency anemia and tumors with cystic ppearance in abdominal cavity.

Spatial asymmetries are an intriguing feature of directed attention. Recent observations indicate an influence of temperament upon the direction of these asymmetries. It is unknown whether this influence generalises to visual orienting behaviour. The aim of the current study was therefore to explore the relationship between temperament and measures of spatial orienting as a function of target hemifield. An exogenous cueing task was administered to 92 healthy participants. Temperament was assessed using Carver and White's (1994) Behavioural Inhibition System and Behavioural Activation System (BIS/BAS) scales. Individuals with high sensitivity to punishment and low sensitivity to reward showed a leftward asymmetry of directed attention when there was no informative spatial cue provided. This asymmetry was not present when targets were preceded by spatial cues that were either valid or invalid. The findings support the notion that individual variations in temperament influence spatial asymmetries in visual orienting, but only when lateral targets are preceded by a non-directional (neutral) cue. The results are discussed in terms of hemispheric asymmetries and dopamine activity.

Terrestrial Trunked Radio (TETRA) technology ("Airwave") has led to public concern because of its potential interference with electrical activity in the brain. The present study is the first to examine whether acute exposure to a TETRA base station signal has an impact on cognitive functioning and physiological responses. Participants were exposed to a 420 MHz TETRA signal at a power flux density of 10 mW/m(2) as well as sham (no signal) under double-blind conditions. Fifty-one people who reported a perceived sensitivity to electromagnetic fields as well as 132 controls participated in a double-blind provocation study. Forty-eight sensitive and 132 control participants completed all three sessions. Measures of short-term memory, working memory, and attention were administered while physiological responses (blood volume pulse, heart rate, skin conductance) were monitored. After applying exclusion criteria based on task performance for each aforementioned cognitive measure, data were analyzed for 36, 43, and 48 sensitive participants for these respective tasks and, likewise, 107,125, and 129 controls. We observed no differences in cognitive performance between sham and TETRA exposure in either group; physiological response also did not differ between the exposure conditions. These findings are similar to previous double-blind studies with other mobile phone signals (900-2100 MHz), which could not establish any clear evidence that mobile phone signals affect health or cognitive function.

BACKGROUND: "Airwave" is the new communication system currently being rolled out across the United Kingdom for the police and emergency services, based on the Terrestrial Trunked Radio Telecommunications System (TETRA). Some police officers have complained about skin rashes, nausea, headaches, and depression as a consequence of using their Airwave handsets. In addition, a small subgroup in the population self-report being sensitive to electromagnetic fields (EMFs) in general. OBJECTIVES: We conducted a randomized double-blind provocation study to establish whether short-term exposure to a TETRA base station signal has an impact on the health and well-being of individuals with self-reported "electrosensitivity" and of participants who served as controls. METHODS: Fifty-one individuals with self-reported electrosensitivity and 132 age- and sex-matched controls participated in an open provocation test; 48 sensitive and 132 control participants went on to complete double-blind tests in a fully screened semianechoic chamber. Heart rate, skin conductance, and blood pressure readings provided objective indices of short-term physiological response. Visual analog scales and symptom scales provided subjective indices of well-being. RESULTS: We found no differences on any measure between TETRA and sham (no signal) under double-blind conditions for either controls or electrosensitive participants, and neither group could detect the presence of a TETRA signal at rates greater than chance (50%). When conditions were not double blind, however, the self-reported electrosensitive individuals did report feeling worse and experienced more severe symptoms during TETRA compared with sham. CONCLUSIONS: Our findings suggest that the adverse symptoms experienced by electrosensitive individuals are due to the belief of harm from TETRA base stations rather than to the low-level EMF exposure itself.