Auricular transcutaneous vagus nerve stimulation acutely modulates brain connectivity in mice

Background: Brain electrical stimulation techniques take advantage of the intrinsic plasticity of the nervous system, opening a wide range of therapeutic applications. Vagus nerve stimulation (VNS) is an approved adjuvant for drug-resistant epilepsy and depression. Its non-invasive form, auricular transcutaneous VNS (atVNS), is under investigation for applications, including cognitive improvement. Objective: We aimed to study the effects of atVNS on brain connectivity, under conditions that improved memory persistence in CD-1 male mice. Methods: Acute atVNS in the cymba conchae of the left ear was performed using a standard stimulation protocol under light isoflurane anesthesia, immediately or 3 h after the training/familiarization phase of the novel object-recognition memory test (NORT). Another cohort of mice was used for bilateral c-Fos analysis after atVNS administration. Spearman correlation of c-Fos density between each pair of the thirty brain regions analyzed allowed obtaining the network of significant functional connections in stimulated and non-stimulated control brains. Results: NORT performance was enhanced when atVNS was delivered just after, but not 3 h after, the familiarization phase of the task. No alterations in c-Fos density were associated to electrostimulation, but a significant effect of atVNS was observed on c-Fos- based functional connectivity. atVNS induced a clear reorganization of the network, increasing the inter-hemisphere connections and the connectivity of locus coeruleus. Conclusion: Our results provide new insights in the effects of atVNS on memory performance and brain connectivity extending our knowledge of the biological mechanisms of bioelectronics in medicine.

Two-Year-Old Children Expect Native, but Not Foreign Speakers to Use the Same Tool for the Same Purpose

Previous research has already demonstrated that even very young children are sensitive to language cues and learn differently from native and foreign speaker models. A possible explanation for this phenomenon suggests that spoken language is a sign of someone's cultural background and in this sense demonstrates the person's culture specific knowledge. The aim of the present study was to investigate what children think about native and foreign speakers' behavior in a domain that is typically regulated by cultural norms (tool usage), specifically whether they expect group members to act alike or not. In a violation of expectation paradigm, two-year-old toddlers first watched a video on which a native and a foreign speaker person used different tools for achieving the same goal. In the test phase a new native speaker model appeared and selected one of the previously seen tools for the same goal as it was used before. Results indicated that toddlers were surprised if the native speaker model had chosen the tool that had previously been used by the foreign speaker. In Experiment 2, the familiarization phase was exactly the same as in Experiment 1, but during the test phase, the model spoke a foreign language. Results, in this case, showed no significant differences between looking times. These experiments suggest that two-year-olds expect native (but not foreign) speakers to use the same tool for the same goals. As tool usage is a fundamental element of cultural knowledge, we propose that this pattern of results suggest that children expect native speakers to possess shared cultural knowledge at least in the domain of artifacts.

Generalized Learning of Dysarthric Speech Between Male and Female Talkers

Purpose Perceptual training is a listener-targeted means for improving intelligibility of dysarthric speech. Recent work has shown that training with one talker generalizes to a novel talker of the same sex and that the magnitude of benefit is maximized when the talkers are perceptually similar. The current study expands previous findings by investigating whether perceptual training effects generalize between talkers of different sex. Method Forty new listeners were recruited for this study and completed a pretest, familiarization, and posttest perceptual training paradigm. Historical data collected using the same three-phase protocol were included in the data analysis. All listeners were exposed to the same talker with dysarthria during the pretest and posttest phases. For the familiarization phase, listeners were exposed to one of four talkers with dysarthria, differing in sex and level of perceptual similarity to the test talker or a control talker. During the testing phases, listener transcribed phrases produced by the test talker with dysarthria. Listener transcriptions were then used to calculate a percent words correct intelligibility score. Results Multiple linear regression analysis revealed that intelligibility at posttest was not predicted by sex of the training talker. Consistent with earlier work, the magnitude of intelligibility gain was greater when the familiarization and test talkers were perceptually similar. Additional analyses revealed greater between-listeners variability in the dissimilar conditions as compared to the similar conditions. Conclusions Learning as a result of perceptual training with one talker with dysarthria generalized to another talker regardless of sex. In addition, listeners trained with perceptually similar talkers had greater and more consistent intelligibility improvement. Together, these results add to previous evidence demonstrating that learning generalizes to novel talkers with dysarthria and that perceptual training is suitable for many listeners.

A STATISTICAL APPROACH FOR RELIABLE MEASUREMENT WITH FAMILIARIZATION TRIALS

An accurate and reliable measurement is important in exercise science. The measurement tends to be less reliable when subjects are not professional athletes or are unfamiliar with a given task. These subjects need familiarization trials, but determination of the number of familiarization trials is challenging because it may be individual-specific and task-specific. Some participants may be eliminated because their results deviate from arbitrary ad hoc rules. We treat these challenges as a statistical problem, and we propose model-averaging to measure a subject’s familiarized performance without fixing the number of familiarization trials in advance. The method of model-averaging accounts for the uncertainty associated with the number of familiarization trials that a subject needs. Simulations show that model-averaging is useful when the familiarization phase is long or when the familiarization occurs at a fast rate relative to the amount of noise in the data. An applet is provided on the internet with a very brief User’s Guide included in the appendix to this article. Keywords: Familiarization; reliability; accuracy; model-averaging; Akaike Information Criterion

Autistic Traits Differently Account for Context-Based Predictions of Physical and Social Events

Autism is associated with difficulties in making predictions based on contextual cues. Here, we investigated whether the distribution of autistic traits in the general population, as measured through the Autistic Quotient (AQ), is associated with alterations of context-based predictions of social and non-social stimuli. Seventy-eight healthy participants performed a social task, requiring the prediction of the unfolding of an action as interpersonal (e.g., to give) or individual (e.g., to eat), and a non-social task, requiring the prediction of the appearance of a moving shape as a short (e.g., square) or a long (e.g., rectangle) figure. Both tasks consisted of (i) a familiarization phase, in which the association between each stimulus type and a contextual cue was manipulated with different probabilities of co-occurrence, and (ii) a testing phase, in which visual information was impoverished by early occlusion of video display, thus forcing participants to rely on previously learned context-based associations. Findings showed that the prediction of both social and non-social stimuli was facilitated when embedded in high-probability contexts. However, only the contextual modulation of non-social predictions was reduced in individuals with lower ‘Attention switching’ abilities. The results provide evidence for an association between weaker context-based expectations of non-social events and higher autistic traits.

A precursor of reading ability? 3-month-old infants easily learn to pair a phoneme with a visual shape

Being aware of the phonemes that compose syllables is difficult without having learned to read an alphabetic script, a skill generally acquired around 5 to 7 years of age. Nevertheless, preverbal infants are particularly good at discriminating syllables that differ by a single phoneme. Do they perceive syllables as a whole unit or can they become aware of the underlying phonemes if their attention is attracted to the relevant level of analysis? We trained 3-month-old infants to pair two consonants, co-articulated with different vowels, with two visual shapes. Using event-related potentials, we show that infants generalize the learned associations to new syllables with respect to a familiarization phase. The systematic pairing of a visual label with a phonetic category is thus easy to learn, suggesting that the main process underlying reading (i.e., grapheme-phoneme pairing) is grounded in the early faculties of the human linguistic system.

The robustness and generalizability of findings on spontaneous false belief sensitivity: a replication attempt

Influential studies showed that 25-month-olds and neurotypical adults take an agent's false belief into account in their anticipatory looking patterns (Southgate et al. 2007 Psychol. Sci. 18 , 587–592 ( doi:10.1111/j.1467-9280.2007.01944.x ); Senju et al. 2009 Science 325 , 883–885 ( doi:10.1126/science.1176170 )). These findings constitute central pillars of current accounts distinguishing between implicit and explicit Theory of Mind. In our first experiment, which initially included a replication as well as two manipulations, we failed to replicate the original finding in 2- to 3-year-olds ( N = 48). Therefore, we ran a second experiment with the sole purpose of seeing whether the effect can be found in an independent, tightly controlled, sufficiently powered and preregistered replication study. This replication attempt failed again in a sample of 25-month-olds ( N = 78), but was successful in a sample of adults ( N = 115). In all samples, a surprisingly high number of participants did not correctly anticipate the agent's action during the familiarization phase. This led to massive exclusion rates when adhering to the criteria of the original studies and strongly limits the interpretability of findings from the test phase. We discuss both the reliability of our replication attempts as well as the replicability of non-verbal anticipatory looking paradigms of implicit false belief sensitivity, in general.

The use of periodized exercise prescription in rehabilitation: a systematic scoping review of literature

Objective: To describe the use of periodized exercise prescription with patients in the context of rehabilitation. Data source: The following databases were searched: The Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, CINAHL, ScienceDirect, PEDro, Web of Science, SPORTDiscus, SAGE and Google Scholar. Databases were searched from inception to March 2018. Results: The literature search yielded 1772 articles with 1755 being excluded leaving 17 articles in total for the full review. Methodological quality and internal validity of the included papers were lacking. The included studies failed to indicate in which phase rehabilitation had occurred. Programme structure relating to the use of a familiarization phase, sequencing of exercises and structuring of specific phases (i.e. macrocycle, mesocycle and microcycle) was not present and lacked consistency across the board. Conclusion: Periodization models of exercise prescription are being used within a variety of population groups in the rehabilitation setting. Integration of periodization principles into a rehabilitation programme still however remains a challenge. Although there is a lack of consistency with regard to the structure and implementation of a periodized model of exercise prescription in the rehabilitation context, it seems to be an alternative way in which to prescribe exercise within the rehabilitation setting.

The traces that novel morphologically complex words leave in memory are abstract in nature

Previous work has shown that novel morphologically complex words (henceforth neologisms) leave traces in memory after just one encounter. This study addressed the question whether these traces are abstract in nature or exemplars. In three experiments, neologisms were either primed by themselves or by their stems. The primes occurred in the visual modality whereas the targets were presented in the auditory modality (Experiment 1) or vice versa (Experiments 2 and 3). The primes were presented in sentences in a selfpaced reading task (Experiment 1) or in stories in a listening comprehension task (Experiments 2 and 3). The targets were incorporated in lexical decision tasks, auditory or visual (Experiment 1 and Experiment 2, respectively), or in stories in a self-paced reading task (Experiment 3). The experimental part containing the targets immediately followed the familiarization phase with the primes (Experiment 1), or after a one week delay (Experiments 2 and 3). In all experiments, participants recognized neologisms faster if they had encountered them before (identity priming) than if the familiarization phase only contained the neologisms’ stems (stem priming). These results show that the priming effects are robust despite substantial differences between the primes and the targets. This suggests that the traces novel morphologically complex words leave in memory after just one encounter are abstract in nature.