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The motor cortex controls skilled arm movement by sending temporal patterns of activity to lower motor centres 1 . Local cortical dynamics are thought to shape these patterns throughout movement execution 2 – 4 . External inputs have been implicated in setting the initial state of the motor cortex 5 , 6 , but they may also have a pattern-generating role. Here we dissect the contribution of local dynamics and inputs to cortical pattern generation during a prehension task in mice. Perturbing cortex to an aberrant state prevented movement initiation, but after the perturbation was released, cortex either bypassed the normal initial state and immediately generated the pattern that controls reaching or failed to generate this pattern. The difference in these two outcomes was probably a result of external inputs. We directly investigated the role of inputs by inactivating the thalamus; this perturbed cortical activity and disrupted limb kinematics at any stage of the movement. Activation of thalamocortical axon terminals at different frequencies disrupted cortical activity and arm movement in a graded manner. Simultaneous recordings revealed that both thalamic activity and the current state of cortex predicted changes in cortical activity. Thus, the pattern generator for dexterous arm movement is distributed across multiple, strongly interacting brain regions. The complex patterns of activity in motor cortex that control movements such as reach and grasp are dependent on both upstream neuronal activity in the thalamus and the current state of the cortex.

Background Although electromyogram (EMG) pattern recognition (PR) for multifunctional upper limb prosthesis control has been reported for decades, the clinical benefits have rarely been examined. The study purposes were to: 1) compare self-report and performance outcomes of a transradial amputee immediately after training and one week after training of direct myoelectric control and EMG pattern recognition (PR) for a two-degree-of-freedom (DOF) prosthesis, and 2) examine the change in outcomes one week after pattern recognition training and the rate of skill acquisition in two subjects with transradial amputations. Methods In this cross-over study, participants were randomized to receive either PR control or direct control (DC) training of a 2 DOF myoelectric prosthesis first. Participants were 2 persons with traumatic transradial (TR) amputations who were 1 DOF myoelectric users. Outcomes, including measures of dexterity with and without cognitive load, activity performance, self-reported function, and prosthetic satisfaction were administered immediately and 1 week after training. Speed of skill acquisition was assessed hourly. One subject completed training under both PR control and DC conditions. Both subjects completed PR training and testing. Outcomes of test metrics were analyzed descriptively. Results Comparison of the two control strategies in one subject who completed training in both conditions showed better scores in 2 (18%) dexterity measures, 1 (50%) dexterity measure with cognitive load, and 1 (50%) self-report functional measure using DC, as compared to PR. Scores of all other metrics were comparable. Both subjects showed decline in dexterity after training. Findings related to rate of skill acquisition varied considerably by subject. Conclusions Outcomes of PR and DC for operating a 2-DOF prosthesis in a single subject cross-over study were similar for 74% of metrics, and favored DC in 26% of metrics. The two subjects who completed PR training showed decline in dexterity one week after training ended. Findings related to rate of skill acquisition varied considerably by subject. This study, despite its small sample size, highlights a need for additional research quantifying the functional and clinical benefits of PR control for upper limb prostheses.

Detection of repeating patterns within continuous sound streams is crucial for efficient auditory perception. Previous studies demonstrated a remarkable sensitivity of the human auditory system to periodic repetitions in unfamiliar, meaningless sounds. Automatic repetition detection was reflected in different EEG markers, including sustained activity, neural synchronisation, and event-related responses to pattern occurrences. The current study investigated how listeners’ attention and the temporal regularity of a sound modulate repetition perception, and how this influence is reflected in different EEG markers that were previously suggested to subserve dissociable functions. We reanalysed data of a previous study in which listeners were presented with sequences of unfamiliar artificial sounds that either contained repetitions of a certain sound segment or not. Repeating patterns occurred either regularly or with a temporal jitter within the sequences, and participants’ attention was directed either towards the pattern repetitions or away from the auditory stimulation. Across both regular and jittered sequences during both attention and in-attention, pattern repetitions led to increased sustained activity throughout the sequence, evoked a characteristic positivity-negativity complex in the event-related potential, and enhanced inter-trial phase coherence of low-frequency oscillatory activity time-locked to repeating pattern onsets. While regularity only had a minor (if any) influence, attention significantly strengthened pattern repetition perception, which was consistently reflected in all three EEG markers. These findings suggest that the detection of pattern repetitions within continuous sounds relies on a flexible mechanism that is robust against in-attention and temporal irregularity, both of which typically occur in naturalistic listening situations. Yet, attention to the auditory input can enhance processing of repeating patterns and improve repetition detection.

The authors show that rats trained with overlapping complex odorant mixtures have improved behavioral discrimination ability and enhanced cortical ensemble pattern separation. Training to disregard normally detectable differences between overlapping mixtures impairs cortical pattern separation and behavioral discrimination. These results show that the balance between pattern separation and completion is experience dependent. Learning to adapt to a complex and fluctuating environment requires the ability to adjust neural representations of sensory stimuli. Through pattern completion processes, cortical networks can reconstruct familiar patterns from degraded input patterns, whereas pattern separation processes allow discrimination of even highly overlapping inputs. Here we show that the balance between pattern separation and completion is experience dependent. Rats given extensive training with overlapping complex odorant mixtures showed improved behavioral discrimination ability and enhanced piriform cortical ensemble pattern separation. In contrast, behavioral training to disregard normally detectable differences between overlapping mixtures resulted in impaired piriform cortical ensemble pattern separation (enhanced pattern completion) and impaired discrimination. This bidirectional effect was not found in the olfactory bulb; it may be due to plasticity within olfactory cortex itself. Thus pattern recognition, and the balance between pattern separation and completion, is highly malleable on the basis of task demands and occurs in concert with changes in perceptual performance.

Previous work has shown that symmetrical stimuli are judged as lasting longer than asymmetrical ones, even when actual duration is matched. This effect has been replicated with different methods and stimuli types. We aimed to a) replicate the effect of symmetry on subjective duration, and b) assess whether it was further modulated by the number of symmetrical axes. There was no evidence for either effect. This null result cannot be explained by reduced statistical power or enhanced floor or ceiling effects. There is no obvious stimulus-based explanation either. However, we are mindful of the reproducibility crisis and file drawer problems in psychology. Other symmetry and time perception researchers should be aware of this null result. One possibility is that the effect of symmetry on subjective duration is limited to very specific experimental paradigms.

With the increasing use of real-time monitoring procedures in clinical practice, psychological time series become available to researchers and practitioners. An important interest concerns the identification of pattern transitions which are characteristic features of psychotherapeutic change. Change Point Analysis (CPA) is an established method to identify the point where the mean and/or variance of a time series change, but changes of other and more complex features cannot be detected by this method. In this study, an extension of the CPA, the Pattern Transition Detection Algorithm (PTDA), is optimized and validated for psychological time series with complex pattern transitions. The algorithm uses the convergent information of the CPA and other methods like Recurrence Plots, Time Frequency Distributions, and Dynamic Complexity. These second level approaches capture different aspects of the primary time series. The data set for testing the PTDA (300 time series) is created by an instantaneous control parameter shift of a simulation model of psychotherapeutic change during the simulation runs. By comparing the dispersion of random change points with the real change points, the PTDA determines if the transition point is significant. The PTDA reduces the rate of false negative and false positive results of the CPA below 5% and generalizes its application to different types of pattern transitions. RQA quantifiers also can be used for the identification of nonstationary transitions in time series which was illustrated by using Determinism and Entropy. The PTDA can be easily used with Matlab and is freely available at Matlab File Exchange ( https://www.mathworks.com/matlabcentral/fileexchange/80380-pattern-transition-detection-algorithm-ptda ).

Pattern separation is the process of transforming highly similar sensory inputs into distinct, dissimilar representations. It takes place in the hippocampus and is thought to be used in episodic memory. Impaired pattern separation performance has been recognized as a predictor for the development of cognitive impairments such as dementia in humans and as being present in patients with schizophrenia and post-traumatic stress disorder (PTSD). In this protocol, we describe how to implement a simple and robust object pattern separation (OPS) task in mice and rats that we have previously established and validated. This two-trial memory task uses specific object locations so differences in performance can be calibrated with the extent of object movement. Changes in performance are indicative of spatial pattern separation. In contrast to other pattern separation tasks, the OPS task allows detection of spatial pattern separation performance bidirectionally. Furthermore, the OPS task is cheaper and easier to use and interpret than other tasks that use more than two objects or that are touch-screen based. The entire protocol, from vivarium acclimatization to training of the animals, takes ~35–41 d. After successful training, the animals can be tested repeatedly, and three OPS experiments (n = 20–24 per experimental day) can be performed per week. A standard level of expertise in behavioral studies in rodents is sufficient to successfully integrate this paradigm into an existing rodent test battery.

Understanding visual narrative sequences, like those in comics, requires readers to track situational information like the continuity of characters, locations, or events across panels. Yet, some sequences intentionally present incongruities, which may elicit the inference that the narrative presents two separate domains: an established, expected storyworld (primary domain) and an additional context surrounding the incongruous events (auxiliary domain), like a character's imagination, dreams, or memories. This paper describes how these inferences are supported by visual constructional patterns, which emerge across a wide range of narratives, yielding further insight into the fundamental role of graphic and structural cues within visual storytelling. Keywords: incongruity resolution, domains, parallel architecture, visual language, comics.

Insight into early precursors of proportional reasoning is necessary to further our theoretical understanding of mathematical development and to guide early interventions. Although several researchers have suggested patterning as a possible precursor for proportional reasoning, there is little empirical evidence to support this assumption, particularly at a young age. To address this gap, the current study explored if patterning in 4-to 5-year-olds (n = 346) is associated with proportional reasoning one and a half years later. Two measures of patterning ability (repeating and growing patterns) and two measures of proportional reasoning (one with discrete quantities and one with a discrete and a continuous quantity) were administered, together with measures addressing general cognitive and numerical abilities. Regression analyses showed that patterning is a unique predictor of proportional reasoning ability over and above sex and general cognitive and numerical abilities. An interaction effect between pattern types and the nature of the quantities was observed: Performance on repeating patterns was uniquely related to performance on proportional reasoning with two discrete quantities, whereas performance on growing patterns was uniquely related to performance on proportional reasoning with a discrete and a continuous quantity. Theoretical implications and suggestions for future studies are discussed.

Number transcoding, the ability to convert digits to words and vice versa, is a critical skill in mathematical literacy and in everyday life. While transcoding is known to be difficult for children, it is unclear whether it challenges adults too, and if so, what the source of that difficulty is. Here, we analyzed the number reading performance of 172 neurotypical adults. Their mean error rate was 6.5%, considerably higher than that typically observed in word-reading tasks, indicating that transcoding is a relatively challenging task even in adulthood. To investigate the cognitive origin of this difficulty, we examined the error types produced by these participants, as well as by a second group of 51 adults with a number-reading deficit (dysnumeria, mean error rate of 28.7%). In both groups, most errors reflected corruptions of the number’s syntactic structure. Moreover, among adults with dysnumeria, the most common subtype was syntactic dysnumeria. These findings indicate that, as in children, the primary challenge in adult number reading lies in the processing of the number’s syntactic structure.