Cross-language morphological transfer in similar-script bilinguals.

The current study explored cross-language morphological transfer mechanisms using a similar-script morphological translation priming paradigm in highly proficient unbalanced Turkish (first language; L1)-English (second language; L2) bilinguals. Using noncognate English and Turkish stimuli that shared a similar meaning with no form overlap (e.g., ice [Eng.] - buz [Tur.]), in Experiment 1, L2 English stem targets (e.g., ICE) were primed by affixed L1 nonwords (e.g., buzca [iceish]), nonaffixed L1 nonwords (e.g., buznak [iceald]), and unrelated L1 nonwords (e.g., tusku [keyment]). The results revealed priming effects in both the affixed and nonaffixed nonword conditions relative to the unrelated control, and significantly larger priming in the affixed than the nonaffixed condition. In addition, enhanced cross-language morphological transfer effects were evidenced in bilinguals with an earlier age of L2 acquisition. In Experiment 2, English stem targets (e.g., ICE) were primed by nonaffixed L1 nonwords including translated stems (e.g., buznak [iceald]), semantically related stems (e.g., suzur [waterew]), and unrelated L1 nonwords (e.g., tuszur [keyew]). The results showed significantly larger priming effects in the translated condition compared with the semantic and unrelated control conditions, with no priming in the semantic condition relative to the unrelated condition, suggesting that cross-language morphological priming effects were specifically due to the lexico-semantic relationship between the embedded word and its translation equivalent.

Can music enhance awareness in unresponsive people with severe dementia? An exploratory case series using behavioral, physiological and neurophysiological measures.

In five people with severe dementia, we measured their behavioral and physiological responses to familiar/unfamiliar music and speech, and measured ERP responses to subject's own name (SON) after exposure to familiar/unfamiliar music or noise. We observed more frequent behavioral responses to personally-significant stimuli than non-personally-significant stumuli, and higher skin temperatures for music than non-music conditions. The control group showed typical ERPs to SON, regardless of auditory exposure. ERP measures were unavailable for the dementia group given challenges of measuring EEG in this population. The study highlights the potential for personally-significant auditory stimuli in enhancing responsiveness of people with severe dementia.

Rates of false positive outcomes on the A-WPTAS picture items in a sample of non-concussed athletes.

Accurate diagnosis of sports related concussion ensures that athletes are removed from play if concussed and prevents incorrect removal when a concussion has not occurred. Although various screening tools are currently in use, there is no gold standard measure with which to diagnose sports related concussion.Objective: The current study aimed to investigate the diagnostic accuracy of the Abbreviated Westmead Post Traumatic Amnesia Scale (A-WPTAS) picture task, a neurocognitive measure used to assess mild traumatic brain injury. The incidence of false positive classifications and the potential confounding effect of exercise on scores on the A-WPTAS picture items were examined.Methods: The study included an athlete group comprising 33 players and a control group comprising 37 subjects. The A-WPTAS picture task was completed on three testing occasions, separated by three week intervals.Results: Results revealed that the A-WPTAS picture task was highly accurate (>95%) in correctly classifying participants with no concussion across all three testing occasions. There was no significant difference between the two groups in relation to false positive outcomes on any testing occasion, suggesting that exercise was not a confounding factor.Conclusions: Findings provide preliminary evidence to support the use of the A-WPTAS picture task in a sporting context.

A validation of Emotiv EPOC Flex saline for EEG and ERP research.

BACKGROUND: Previous work has validated consumer-grade electroencephalography (EEG) systems for use in research. Systems in this class are cost-effective and easy to set up and can facilitate neuroscience outside of the laboratory. The aim of the current study was to determine if a new consumer-grade system, the Emotiv EPOC Saline Flex, was capable of capturing research-quality data. METHOD: The Emotiv system was used simultaneously with a research-grade EEG system, Neuroscan Synamps2, to collect EEG data across 16 channels during five well-established paradigms: (1) a mismatch negativity (MMN) paradigm that involved a passive listening task in which rare deviant (1,500 Hz) tones were interspersed amongst frequent standard tones (1,000 Hz), with instructions to ignore the tones while watching a silent movie; (2) a P300 paradigm that involved an active listening task in which participants were asked to count rare deviant tones presented amongst frequent standard tones; (3) an N170 paradigm in which participants were shown images of faces and watches and asked to indicate whether the images were upright or inverted; (4) a steady-state visual evoked potential (SSVEP) paradigm in which participants passively viewed a flickering screen (15 Hz) for 2 min; and (5) a resting state paradigm in which participants sat quietly with their eyes open and then closed for 3 min each. RESULTS: The MMN components and P300 peaks were equivalent between the two systems (BF10 = 0.25 and BF10 = 0.26, respectively), with high intraclass correlations (ICCs) between the ERP waveforms (>0.81). Although the N170 peak values recorded by the two systems were different (BF10 = 35.88), ICCs demonstrated that the N170 ERP waveforms were strongly correlated over the right hemisphere (P8; 0.87-0.97), and moderately-to-strongly correlated over the left hemisphere (P7; 0.52-0.84). For the SSVEP, the signal-to-noise ratio (SNR) was larger for Neuroscan than Emotiv EPOC Flex (19.94 vs. 8.98, BF10 = 51,764), but SNR z-scores indicated a significant brain response at the stimulus frequency for both Neuroscan (z = 12.47) and Flex (z = 11.22). In the resting state task, both systems measured similar alpha power (BF10 = 0.28) and higher alpha power when the eyes were closed than open (BF10 = 32.27). CONCLUSIONS: The saline version of the Emotiv EPOC Flex captures data similar to that of a research-grade EEG system. It can be used to measure reliable auditory and visual research-quality ERPs. In addition, it can index SSVEP signatures and is sensitive to changes in alpha oscillations.

Neurogaming Technology Meets Neuroscience Education: A Cost-Effective, Scalable, and Highly Portable Undergraduate Teaching Laboratory for Neuroscience.

Active research-driven approaches that successfully incorporate new technology are known to catalyze student learning. Yet achieving these objectives in neuroscience education is especially challenging due to the prohibitive costs and technical demands of research-grade equipment. Here we describe a method that circumvents these factors by leveraging consumer EEG-based neurogaming technology to create an affordable, scalable, and highly portable teaching laboratory for undergraduate courses in neuroscience. This laboratory is designed to give students hands-on research experience, consolidate their understanding of key neuroscience concepts, and provide a unique real-time window into the working brain. Survey results demonstrate that students found the lab sessions engaging. Students also reported the labs enhanced their knowledge about EEG, their course material, and neuroscience research in general.

Evidence accumulation in the integrated and primed Stroop tasks.

We report distributional analyses of response times (RT) in two variants of the color-word Stroop task using manual keypress responses. In the classic Stroop task, in which the color and word dimensions are integrated into a single stimulus, the Stroop congruence effect increased across the quantiles. In contrast, in the primed Stroop task, in which the distractor word is presented ahead of colored symbols, the Stroop congruence effect was manifested solely as a distributional shift, remaining constant across the quantiles. The distributional-shift pattern mirrors the semantic-priming effect that has been reported in semantic categorization tasks. The results are interpreted within the framework of evidence accumulation, and implications for the roles of task conflict and informational conflict are discussed.

The magic of words reconsidered: Investigating the automaticity of reading color-neutral words in the Stroop task.

In 2 variants of the color-word Stroop task, we compared 5 types of color-neutral distractors-real words (e.g., HAT), pseudowords (e.g., HIX), consonant strings (e.g., HDK), symbol strings (e.g., #$%), and a row of Xs (e.g., XXX)-as well as incongruent color words (e.g., GREEN displayed in red). When participants named the color, relative to a row of Xs, words and pseudowords interfered equally and more than the consonant strings, which in turn interfered more than the symbols. In contrast, when participants identified the color by manual key-press responses, all 5 types of neutral strings produced equal color response latencies. In both tasks, the incongruent color words produced robust interference relative to the color-neutral words. Reaction time (RT) distribution analyses showed that all interference effects (relative to the row of Xs) increased across the quantiles. We interpret these results in terms of an evidence accumulation process in which the interfering distractor reduces the effective rate of evidence accumulation for the color target. We take the results to argue that the task of reading, even when triggered unintentionally, is not an invariant process driven solely by the stimulus properties, and is instead guided by the task goal. (PsycINFO Database Record

Validation of the Emotiv EPOC EEG system for research quality auditory event-related potentials in children.

Background. Previous work has demonstrated that a commercial gaming electroencephalography (EEG) system, Emotiv EPOC, can be adjusted to provide valid auditory event-related potentials (ERPs) in adults that are comparable to ERPs recorded by a research-grade EEG system, Neuroscan. The aim of the current study was to determine if the same was true for children. Method. An adapted Emotiv EPOC system and Neuroscan system were used to make simultaneous EEG recordings in nineteen 6- to 12-year-old children under "passive" and "active" listening conditions. In the passive condition, children were instructed to watch a silent DVD and ignore 566 standard (1,000 Hz) and 100 deviant (1,200 Hz) tones. In the active condition, they listened to the same stimuli, and were asked to count the number of 'high' (i.e., deviant) tones. Results. Intraclass correlations (ICCs) indicated that the ERP morphology recorded with the two systems was very similar for the P1, N1, P2, N2, and P3 ERP peaks (r = .82 to .95) in both passive and active conditions, and less so, though still strong, for mismatch negativity ERP component (MMN; r = .67 to .74). There were few differences between peak amplitude and latency estimates for the two systems. Conclusions. An adapted EPOC EEG system can be used to index children's late auditory ERP peaks (i.e., P1, N1, P2, N2, P3) and their MMN ERP component.

An RT distribution analysis of relatedness proportion effects in lexical decision and semantic categorization reveals different mechanisms.

The magnitude of the semantic priming effect is known to increase as the proportion of related prime-target pairs in an experiment increases. This relatedness proportion (RP) effect was studied in a lexical decision task at a short prime-target stimulus onset asynchrony (240 ms), which is widely assumed to preclude strategic prospective usage of the prime. The analysis of the reaction time (RT) distribution suggested that the observed RP effect reflected a modulation of a retrospective semantic matching process. The pattern of the RP effect on the RT distribution found here is contrasted to that reported in De Wit and Kinoshita's (2014) semantic categorization study, and it is concluded that the RP effect is driven by different underlying mechanisms in lexical decision and semantic categorization.

The masked semantic priming effect is task dependent: Reconsidering the automatic spreading activation process.

Semantic priming effects are popularly explained in terms of an automatic spreading activation process, according to which the activation of a node in a semantic network spreads automatically to interconnected nodes, preactivating a semantically related word. It is expected from this account that semantic priming effects should be routinely observed when the prime identity is veiled from conscious awareness, but the extant literature on masked semantic priming effects is notoriously mixed. The authors use the same prime-target pairs in the lexical decision task and the semantic categorization task and show that although masking the prime eliminates the semantic priming effect in lexical decision, reliable semantic priming effects are observed with both masked and unmasked primes in the semantic categorization task. The authors explain this task dependence in terms of their account of semantic priming effects based on notions of evidence accumulation and source confusion and support their account by means of reaction time distribution analyses.

Relatedness proportion effects in semantic categorization: reconsidering the automatic spreading activation process.

Semantic priming effects at a short prime-target stimulus onset asynchrony are commonly explained in terms of an automatic spreading activation process. According to this view, the proportion of related trials should have no impact on the size of the semantic priming effect. Using a semantic categorization task ("Is this a living thing?"), we show that on the contrary, there is a robust effect of relatedness proportion on the size of the semantic priming effect. This effect is not due to the participants using the prime to predict the target category/response, as manipulating the proportion of category/response-congruent trials produces a very different pattern. Taken together with response time distribution analysis, we argue that the semantic priming effect observed here is best explained in terms of an evidence accumulation process and source confusion between the prime and target.