Pylabianca: comprehensive and user­friendly Python package for single­neuron data analysis.

In the area of electrophysiology, the availability of comprehensive and user­friendly tools for single-neuron data processing, statistical analysis, and fast, intuitive data visualization is limited. To address this gap, we introduce pylabianca, a Python library tailored for robust single and multi­unit data processing. Pylabianca leverages the power of standard Python packages and adopts the application programming interface of MNE­Python, one of the most widely used electrophysiology packages. One of pylabianca's primary objectives is to provide a low entry threshold for scientists, requiring only basic Python programming skills. Pylabianca was designed to streamline most common analyses of single neuron data, and provide convenient data structures to serve as a foundation for building custom analysis pipelines. We believe that pylabianca will contribute to enhancing researchers' capabilities and efficiency in the field of single-neuron electrophysiology.

No relationship between frontal alpha asymmetry and depressive disorders in a multiverse analysis of five studies.

For decades, the frontal alpha asymmetry (FAA) - a disproportion in EEG alpha oscillations power between right and left frontal channels - has been one of the most popular measures of depressive disorders (DD) in electrophysiology studies. Patients with DD often manifest a left-sided FAA: relatively higher alpha power in the left versus right frontal lobe. Recently, however, multiple studies failed to confirm this effect, questioning its reproducibility. Our purpose is to thoroughly test the validity of FAA in depression by conducting a multiverse analysis - running many related analyses and testing the sensitivity of the effect to changes in the analytical approach - on data from five independent studies. Only 13 of the 270 analyses revealed significant results. We conclude the paper by discussing theoretical assumptions underlying the FAA and suggest a list of guidelines for improving and expanding the EEG data analysis in future FAA studies.

Ambiguous at the second sight: Mixed facial expressions trigger late electrophysiological responses linked to lower social impressions.

Social interactions require quick perception, interpretation, and categorization of faces, with facial features offering cues to emotions, intentions, and traits. Importantly, reactions to faces depend not only on their features but also on their processing fluency, with disfluent faces suffering social devaluation. The current research used electrophysiological (EEG) and behavioral measures to explore at what processing stage and under what conditions emotional ambiguity is detected in the brain and how it influences trustworthiness judgments. Participants viewed male and female faces ranging from pure anger, through mixed expressions, to pure happiness. They categorized each face along the experimental dimension (happy vs. angry) or a control dimension (gender). In the emotion-categorization condition, mixed (ambiguous) expressions were classified relatively slower, and their trustworthiness was rated relatively lower. EEG analyses revealed that early brain responses are independent of the categorization condition, with pure faces evoking larger P1/N1 responses than mixed expressions. Some late (728- 880 ms) brain responses from central-parietal sites also were independent of the categorization condition and presumably reflect familiarity of the emotion categories, with pure expressions evoking larger central-parietal LPP amplitude than mixed expressions. Interestingly, other late responses were sensitive to both expressive features and categorization task, with ambiguous faces evoking a larger LPP amplitude in frontal-medial sites around 560-660 ms but only in the emotion categorization task. Critically, these late responses from the frontal-medial cluster correlated with the reduction in trustworthiness judgments. Overall, the results suggest that ambiguity detection involves late, top-down processes and that it influences important social impressions.

Real-time strategy video game experience and structural connectivity - A diffusion tensor imaging study.

Experienced video game players exhibit superior performance in visuospatial cognition when compared to non-players. However, very little is known about the relation between video game experience and structural brain plasticity. To address this issue, a direct comparison of the white matter brain structure in RTS (real time strategy) video game players (VGPs) and non-players (NVGPs) was performed. We hypothesized that RTS experience can enhance connectivity within and between occipital and parietal regions, as these regions are likely to be involved in the spatial and visual abilities that are trained while playing RTS games. The possible influence of long-term RTS game play experience on brain structural connections was investigated using diffusion tensor imaging (DTI) and a region of interest (ROI) approach in order to describe the experience-related plasticity of white matter. Our results revealed significantly more total white matter connections between occipital and parietal areas and within occipital areas in RTS players compared to NVGPs. Additionally, the RTS group had an altered topological organization of their structural network, expressed in local efficiency within the occipito-parietal subnetwork. Furthermore, the positive association between network metrics and time spent playing RTS games suggests a close relationship between extensive, long-term RTS game play and neuroplastic changes. These results indicate that long-term and extensive RTS game experience induces alterations along axons that link structures of the occipito-parietal loop involved in spatial and visual processing.

Age-related within-task adaptations in sequential decision making: Considering cognitive and motivational factors.

Many decisions require sequentially searching through the available alternatives. In these tasks, older adults have been shown to perform worse than younger adults, but the reasons why age differences occur are still unclear. In the present research, we tackle this question by investigating which strategies older and younger adults adopt and how these strategies relate to individual differences in cognitive (mental speed, working memory capacity) and motivational (need for cognitive closure) variables. To achieve this goal, we conducted two studies in which older and younger adults performed a computerized sequential choice task. Study 1 indicated that older adults changed their decision-making strategies throughout the task by reducing the number of options they considered. This change in strategy did not decrease performance because searching less allowed older adults to choose more promising options. In the second study we manipulated whether a long or short search was optimal. In the beginning older adults performed worse than younger adults independent of whether short or long search was adaptive. However, in the second half of the task we found age differences in performance when long search was required, but not when short search was required. In both studies whether or not older adults changed their strategy depended on their need for cognitive closure, suggesting that avoiding cognitive closure facilitates adaptive flexibility. Together, the two studies provide evidence for compensatory strategy adaptations among older adults completing sequential choice tasks. (PsycINFO Database Record

Neural Signatures of Rational and Heuristic Choice Strategies: A Single Trial ERP Analysis.

In multi-attribute choice, people use heuristics to simplify decision problems. We studied the use of heuristic and rational strategies and their electrophysiological correlates. Since previous work linked the P3 ERP component to attention and decision making, we were interested whether the amplitude of this component is associated with decision strategy use. To this end, we recorded EEG when participants performed a two-alternative choice task, where they could acquire decision cues in a sequential manner and use them to make choices. We classified participants' choices as consistent with a rational Weighted Additive rule (WADD) or a simple heuristic Take The Best (TTB). Participants differed in their preference for WADD and TTB. Using a permutation-based single trial approach, we analyzed EEG responses to consecutive decision cues and their relation to the individual strategy preference. The preference for WADD over TTB was associated with overall higher signal amplitudes to decision cues in the P3 time window. Moreover, the preference for WADD was associated with similar P3 amplitudes to consecutive cues, whereas the preference for TTB was associated with substantial decreases in P3 amplitudes to consecutive cues. We also found that the preference for TTB was associated with enhanced N1 component to cues that discriminated decision alternatives, suggesting very early attention allocation to such cues by TTB users. Our results suggest that preference for either WADD or TTB has an early neural signature reflecting differences in attentional weighting of decision cues. In light of recent findings and hypotheses regarding P3, we interpret these results as indicating the involvement of catecholamine arousal systems in shaping predecisional information processing and strategy selection.

It's not only in the eyes: nonlinear relationship between face orientation and N170 amplitude irrespective of eye presence.

We have investigated the interplay between face orientation, eye presence, and N170 amplitude by recording Event Related Potentials. To clarify previous reports of nonlinearity in N170 amplitude changes along rotation angle changes, we adopted Itier et al.'s model (Itier et al., 2007) which links N170 face inversion effects with the presence of eyes. Comparison of N170 amplitude and latency for five stimulus categories (Faces-with-eyes, Faces-without-eyes, Eyes, Cars-with-lights, Cars-without-lights) in five different rotations (0, 45, 90, 135, 180) resulted in mixed conclusions. The main findings of this study are as follows: (1) a strong nonlinear relationship between N170 and angle of rotation that is specific to faces, distinguishing face from car category even when no significant differences were observed between these categories for upright and inverted orientations; and (2) the nonlinear relationship between N170 and angle of rotation does not depend on eye presence. We also propose an alternative model according to which N170 amplitude consists of two related aspects of face processing: (A) incompatibility (relative distance of the stimulus pattern from experience-based hypothetical prototype) and (B) integration (degree to which stimulus is integrated into holistic representation), with the former affecting the latter. Moreover, we suggest two possible neural events underlying these two aspects of face processing: neural population size activated by the stimulus, and synchronization within this population.

EEG beta band activity is related to attention and attentional deficits in the visual performance of elderly subjects.

We have previously shown that beta-band EEG activity is related to attentional modulation in the visual system of cats and humans. In a separate experiment we also observed that some elderly subjects expressed beta-band power decreases during a simple visual attention task, an effect which was accompanied by low behavioral accuracy in this subgroup. Here, we conducted a detailed examination of beta power deficits in elderly subjects in comparison to young controls. In order to do so, we equalized the subjective level of task difficulty by adjusting visual stimuli presentation duration in such a way that elderly and young subjects achieved similar behavioral results. We found that: (1) beta-band power of EEG signals recorded over occipital regions in elderly and young groups is related to visual attention, as judged from increases in beta power preceding correct responses and lack of beta activity change before erroneous responses; (2) despite forming a homogeneous group when screened for dementia (MMSE), age, education level, visual correction, and speed-accuracy trade-off strategy, elderly subjects could be assigned into one of the two subgroups: high performers, who did not differ from young performers in terms of beta-band power increases, and low performers, whose beta power decreased during the most difficult attentional conditions (shortest - 3s and longest - 11s cue-target delays). These findings posit that the beta-band activity decrease recorded in low performing elderly subjects reflects difficulty in activation and deficits in sustaining attentional processes.