Motor imagery, forward models and the cerebellum:a commentary on Rieger et al., 2023

In this commentary on Rieger et al., Psychological Research Psychologische Forschung, 2023, I discuss possible ways to test the hypothesis that action imagery is achieved by simulations of actions through an internal forward model. These include brain imaging, perturbation through TMS, and psychophysical tests of adaptation of intended reach actions.</p

Identifying the causal mechanisms of the quiet eye

Scientists who have examined the gaze strategies employed by athletes have determined that longer quiet eye (QE) durations (QED) are characteristic of skilled compared to less-skilled performers. However, the cognitive mechanisms of the QE and, specifically, how the QED affects performance are not yet fully understood. We review research that has examined the functional mechanism underlying QE and discuss the neural networks that may be involved. We also highlight the limitations surrounding QE measurement and its definition and propose future research directions to address these shortcomings. Investigations into the behavioural and neural mechanisms of QE will aid the understanding of the perceptual and cognitive processes underlying expert performance and the factors that change as expertise develops

Taking a second or a third look at symbolic but not at literal haiku: An eye-tracking study

a bitter rain – two silences beneath the one umbrella Is the connotative meaning of a text readily available or is it accessed only after re-examining a text? Thirtyone English native speakers (10 male, mean age 21) read 24 haiku, 12 in their original/symbolic version and 12 in a version in which the most symbolic word (the keyword "bitter" in the example above) was replaced by a more literal word ("loud"), reducing the text’s symbolic purport. Participants' eye movements were recorded using the eye-tracker EyeLink 1000. The effect of the word substitution was measured globally, by comparing the total reading times for the two haiku types, and locally, by examining first pass duration and dwell time on a word closely connected to the keyword (the referent, "silences") and on the last word ("umbrella"), as this might show wrap-up processes. First pass durations showed no effects of the substitution. However, total reading time and dwell time on both the referent and the last-word regions were significantly longer for haiku with the original keyword than for haiku with the altered keyword. These findings suggest that the texts’ connotative meaning was not available immediately but only through re-reading of the texts

Limits to tDCS effects in language:failures to modulate word production in healthy participants with frontal or temporal tDCS

Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms

Reading between the lines: Inference processes in the online comprehension of symbolic haiku

a bitter rain – two silences beneath the one umbrella Is the connotative meaning of texts readily available or is it gleaned at an extra cognitive cost? The eye-movements of 31 English native speakers (10 male, mean age 21 years) were recorded while reading 24 haiku, 12 in the original/symbolic version, and 12 in a modified version where the most symbolic word (the keyword ‘bitter’ in the example) was replaced by a more literal word (‘loud’) reducing the text’s symbolic purport. The effects of keyword substitutions were measured globally, comparing total reading times for the two haiku types, and locally, examining the first pass gaze durations and dwell times on a word closely connected to the keyword, the referent ‘silences’, and on the last word, ‘umbrella’, to examine wrap-up processes. First pass duration showed no effects of the substitution. However, dwell time on referents and last-word regions, and total reading time were significantly longer for the original than for the altered haiku, suggesting that the connotative meaning of the texts was not available immediately but only through re-reading of the texts. The implications of these findings are discussed in relation to the literature on the processing of inferences in symbolic texts

The Development of the Head of the Imago of Chironomus

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Graph network analysis of immediate motor-learning induced changes in resting state BOLD

Recent studies have demonstrated that following learning tasks, changes in the resting state activity of the brain shape regional connections in functionally specific circuits. Here we expand on these findings by comparing changes induced in the resting state immediately following four motor tasks. Two groups of participants performed a visuo-motor joystick task with one group adapting to a transformed relationship between joystick and cursor. Two other groups were trained in either explicit or implicit procedural sequence learning. Resting state BOLD data were collected immediately before and after the tasks. We then used graph theory-based approaches that include statistical measures of functional integration and segregation to characterise changes in biologically plausible brain connectivity networks within each group. Our results demonstrate that motor learning reorganizes resting brain networks with an increase in local information transfer, as indicated by local efficiency measures that affect the brain's small world network architecture. This was particularly apparent when comparing two distinct forms of explicit motor learning: procedural learning and the joystick learning task. Both groups showed notable increases in local efficiency. However changes in local efficiency in the inferior frontal and cerebellar regions also distinguishes between the two learning tasks. Additional graph analytic measures on the &quot;non-learning&quot; visuo-motor performance task revealed reversed topological patterns in comparison with the three learning tasks. These findings underscore the utility of graph-based network analysis as a novel means to compare both regional and global changes in functional brain connectivity in the resting state following motor learning tasks

Modulation of linguistic prediction by TDCS of the right lateral cerebellum

AbstractIt has been postulated recently that the cerebellum contributes the same prediction and learning functions to linguistic processing as it does towards motor control. For example, repetitive TMS over posterior-lateral cerebellum caused a significant loss in predictive language processing, as assessed by the latency of saccades to target items of spoken sentences, using the Visual World task. We aimed to assess the polarity-specific effects of cerebellar TDCS, hypothesising that cathodal TDCS should impair linguistic prediction, and anodal TDCS facilitate it. Our design also tested whether TDCS modulated associative learning in this task. A between groups (sham, anodal, cathodal) design was used, with concurrent stimulation during performance of a manual variation of the Visual World paradigm, and with assessment of latency reduction over repeated presentations of the spoken sentences. Mixed model ANOVA was used to analyse change in response latency. Cathodal TDCS decreased participants’ response time advantage for the predictable sentence items without change for non-predictable items, consistent with the previous TMS results. Furthermore, anodal stimulation enhanced the response time advantage for the predictable items, again without change in latencies for non-predictive items. We found a clear practice-based effect over 4 blocks. However, this difference was not significantly modulated by either anodal or cathodal stimulation. Our results therefore support the hypothesis that cerebellum contributes to predictive language processing, mirroring its predictive role in motor control, but we do not yet have evidence that the learning process was affected by cerebellar TDCS