Divergent thinking tests have been used extensively in neuroscientific studies of creativity. However, output from tests of divergent thinking can be scored in different ways, and those scores can ...influence assessments of divergent thinking performance and its relationship with brain activation. Here we sought to investigate the relationship between various methods of scoring the Alternate Uses Task (AUT)—a well-known test of divergent thinking—and regional grey matter volume (GMV) using voxel-based morphometry (VBM). We assessed AUT performance based on (a) traditional approaches that involve scoring participants’ output on fluency, flexibility, originality, and elaboration, (b) a subjective approach that involves scoring output directly on “snapshot” creativity, and (c) the definitional approach that involves scoring output separately on novelty and usefulness—the two criteria deemed necessary and jointly sufficient to categorize an idea as creative. Correcting for age, sex, intracranial volume, verbal IQ and working memory capacity, we found negative correlations between regional GMV in the left inferior temporal gyrus (ITG) and novelty and usefulness scores, but no correlation involving other scoring approaches. As part of the brain's core semantic system, this region is involved in concept retrieval and integration. We discuss the implications of these findings for our understanding of the neural bases of divergent thinking, and how ITG could be related to the generation of novel and useful responses.
Traditionally, it has been assumed that logical thinking requires deliberation. However, people can also make logical responses quickly, exhibiting logical intuitions. We examined the neural ...correlates of logical intuitions by administering base rate problems during fMRI scanning using a two-response paradigm where participants first responded quickly and then reflectively to problems that did or did not pit a normative response against an intuitively-cued stereotypical response (i.e., conflict vs. non-conflict problems). As predicted, participants were less likely to make judgments in accordance with base rates on conflict problems. Critically, in only 4% of cases did longer deliberation change an initially biased response to a normatively correct response. The fMRI data revealed that intuitively-made initial biased judgments nevertheless activate regions typically involved in cognitive control, executive functions and attention, including anterior, inferior, middle and superior frontal cortex, suggesting that even when errors are made, there might be very early awareness of conflict.
We present a theoretical overview and experimental demonstration of a continuous-wave, cavity-enhanced optical absorption spectrometry method to detect molecular gas. This technique utilizes the two ...non-degenerate polarization modes of a birefringent cavity to obtain a zero background readout of the intra-cavity absorption. We use a double-pass equilateral triangle optical cavity design with additional feed-forward frequency noise correction to measure the R14e absorption line in the 30012←00001 band of CO 2 at 1572.655 nm. We demonstrate a shot noise equivalent absorption of 3 × 10 −13 cm −1 Hz −1/2 .
Targeting a future Gravity Recovery and Climate Experiment (GRACE) mission, we present a new laser interferometry architecture that can be used to recover the displacement between two spacecraft from ...multiple interspacecraft measurements. We show it is possible to recover the displacement between the spacecraft centers of mass in post-processing by forming linear combinations of multiple, spatially offset, interspacecraft measurements. By canceling measurement error due to angular misalignment of the spacecraft, we remove the need for precise placement or alignment of the interferometer, potentially simplifying spacecraft integration. To realize this multi-link architecture, we propose an all-fiber interferometer, removing the need for any ultrastable optical components such as the GRACE Follow-On mission’s triple mirror assembly. Using digitally enhanced heterodyne interferometry, the number of links is readily scalable, adding redundancy to our measurement. We present the concept, an example multi-link implementation and the signal processing required to recover the center of mass displacement from multiple link measurements. Finally, in a simulation, we analyze the limiting noise sources in a 9 link interferometer and ultimately show we can recover the
80
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displacement sensitivity required by the GRACE Follow-On laser ranging interferometer.
Embodied cognition holds that abstract concepts are grounded in perceptual-motor simulations. If a given embodied metaphor maps onto a spatial representation, then thinking of that concept should ...bias the allocation of attention. In this study, we used positive and negative self-esteem words to examine two properties of conceptual cueing. First, we tested the orientation-specificity hypothesis, which predicts that conceptual cues should selectively activate certain spatial axes (in this case, valenced self-esteem concepts should activate vertical space), instead of any spatial continuum. Second, we tested whether conceptual cueing requires semantic processing, or if it can be achieved with shallow visual processing of the cue words. Participants viewed centrally presented words consisting of high or low self-esteem traits (e.g., brave, timid) before detecting a target above or below the cue in the vertical condition, or on the left or right of the word in the horizontal condition. Participants were faster to detect targets when their location was compatible with the valence of the word cues, but only in the vertical condition. Moreover, this effect was observed when participants processed the semantics of the word, but not when processing its orthography. The results show that conceptual cueing by spatial metaphors is orientation-specific, and that an explicit consideration of the word cues' semantics is required for conceptual cueing to occur.
•Corticospinal tract involvement with a stroke lesion is a biomarker of motor outcome.•Four approaches quantifying corticospinal tract involvement were compared.•All approaches explained 20–30% of ...variance in chronic stroke motor impairment.•Maximum overlap and percent subsections injured approaches explained most variance.
Susceptibility weighted imaging (SWI) is a relatively new imaging technique. Its high sensitivity to hemorrhagic components and ability to depict microvasculature by means of susceptibility effects ...within the veins allow for the accurate detection, grading, and monitoring of brain tumors. This imaging modality can also detect changes in blood flow to monitor stroke recovery and reveal specific subtypes of vascular malformations. In addition, small punctate lesions can be demonstrated with SWI, suggesting diffuse axonal injury, and the location of these lesions can help predict neurological outcome in patients. This imaging technique is also beneficial for applications in functional neurosurgery given its ability to clearly depict and differentiate deep midbrain nuclei and close submillimeter veins, both of which are necessary for presurgical planning of deep brain stimulation. By exploiting the magnetic susceptibilities of substances within the body, such as deoxyhemoglobin, calcium, and iron, SWI can clearly visualize the vasculature and hemorrhagic components even without the use of contrast agents. The high sensitivity of SWI relative to other imaging techniques in showing tumor vasculature and microhemorrhages suggests that it is an effective imaging modality that provides additional information not shown using conventional MRI. Despite SWI's clinical advantages, its implementation in MRI protocols is still far from consistent in clinical usage. To develop a deeper appreciation for SWI, the authors here review the clinical applications in 4 major fields of neurosurgery: neurooncology, vascular neurosurgery, neurotraumatology, and functional neurosurgery. Finally, they address the limitations of and future perspectives on SWI in neurosurgery.
Background
Several measures of upper limb (UL) motor tasks have been developed to characterize recovery. However, UL performance and movement quality measures in isolation may not provide a true ...profile of functional recovery.
Objective
To investigate the measurement properties of a new trunk-based Index of Performance (IPt) of the UL combining endpoint performance (accuracy and speed) and movement quality (trunk displacement) in stroke.
Methods
Participants with stroke (n = 25, mean time since stroke: 18.7 ± 17.2 months) performed a reaching task over 3 evaluation sessions. The IPt was computed based on Fitts’ Law that incorporated endpoint accuracy and speed corrected by the amount of trunk displacement. Test–retest reliability was analyzed using intraclass correlation coefficient (ICC) and Bland–Altman plots. Standard error of measurement (SEM) and Minimal Detectable Change (MDC) were determined. Validity was investigated through the relationship between IPt, Fugl–Meyer Assessment (FMA-UE), and Action Research Arm Test (ARAT), as well as the ability of IPt to distinguish between levels of UL motor impairment severity.
Results
Test–retest reliability was excellent (ICC = .908, 95% CI: 0.807-0.96). Bland–Altman did not show systematic differences. SEM and MDC95 were 14% and 39%, respectively. Construct validity was satisfactory. The IPt showed low-to-moderate relationships with FMA-UE (R2 ranged from .236 to .428) and ARAT (R2 ranged from .277 to .306). IPt scores distinguished between different levels of UL severity.
Conclusions
The IPt showed evidence of good reliability, and initial validity. The IPt may be a promising tool for research and clinical settings. Further research is warranted to investigate its validity with additional comparator instruments.
We demonstrate for the first time the use of digital range-gating in OFDR to allow for orders of magnitude reduction in the required sampling rates. This allows for sensing over long lengths of fiber ...with fast sweeps of the optical source frequency, without requiring impractical sampling rates. The range-gating is achieved using digitally enhanced interferometry (DI), which isolates individual sections of OFDR signal bandwidth. The reductions in sampling rates permitted by the bandwidth-division are demonstrated both numerically and experimentally.
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