Artur Marchewka

The Nencki Affective Picture System (NAPS): Introduction to a novel, standardized, wide-range, high-quality, realistic picture database

Selecting appropriate stimuli to induce emotional states is essential in affective research. Only a few standardized affective stimulus databases have been created for auditory, language, and visual materials. Numerous studies have extensively employed these databases using both behavioral and neuroimaging methods. However, some limitations of the existing databases have recently been reported, including limited numbers of stimuli in specific categories or poor picture quality of the visual stimuli. In the present article, we introduce the Nencki Affective Picture System (NAPS), which consists of 1,356 realistic, high-quality photographs that are divided into five categories (people, faces, animals, objects, and landscapes). Affective ratings were collected from 204 mostly European participants. The pictures were rated according to the valence, arousal, and approach–avoidance dimensions using computerized bipolar semantic slider scales. Normative ratings for the categories are presented for each dimension. Validation of the ratings was obtained by comparing them to ratings generated using the Self-Assessment Manikin and the International Affective Picture System. In addition, the physical properties of the photographs are reported, including luminance, contrast, and entropy. The new database, with accompanying ratings and image parameters, allows researchers to select a variety of visual stimulus materials specific to their experimental questions of interest. The NAPS system is freely accessible to the scientific community for noncommercial use by request at http://naps.nencki.gov.pl.

Reversed old/new effect for intentionally forgotten words: an ERP study of directed forgetting.

The present study investigated, using the item-method directed forgetting paradigm, whether successful intentional forgetting is reflected in brain activity, as measured by ERP. We sorted the EEG data into 4 experimental conditions based on the combination of memory instruction and behavioral outcome: TBF_F (to-be-forgotten and forgotten), TBF_R (to-be-forgotten but remembered), TBR_R (to-be-remembered and remembered, i.e. hits) and correct rejections (CR). TBR_R trials elicited a typical old/new effect (approximately 500-750 ms poststimulus) over central and parietal regions. The TBF_F condition, however, elicited ERP that were more negative-going than ERP for CR (the reversed old/new effect). The latter may reflect the very effective inhibition of encoding and retrieval processes. This indicates that intentional processes leading to successful forgetting significantly influence brain activity.

How reliable are gray matter disruptions in specific reading disability across multiple countries and languages? insights from a large‐scale voxel‐based morphometry study

The neural basis of specific reading disability (SRD) remains only partly understood. A dozen studies have used voxel‐based morphometry (VBM) to investigate gray matter volume (GMV) differences between SRD and control children, however, recent meta‐analyses suggest that few regions are consistent across studies. We used data collected across three countries (France, Poland, and Germany) with the aim of both increasing sample size (236 SRD and controls) to obtain a clearer picture of group differences, and of further assessing the consistency of the findings across languages. VBM analysis reveals a significant group difference in a single cluster in the left thalamus. Furthermore, we observe correlations between reading accuracy and GMV in the left supramarginal gyrus and in the left cerebellum, in controls only. Most strikingly, we fail to replicate all the group differences in GMV reported in previous studies, despite the superior statistical power. The main limitation of this study is the heterogeneity of the sample drawn from different countries (i.e., speaking languages with varying orthographic transparencies) and selected based on different assessment batteries. Nevertheless, analyses within each country support the conclusions of the cross‐linguistic analysis. Explanations for the discrepancy between the present and previous studies may include: (1) the limited suitability of VBM to reveal the subtle brain disruptions underlying SRD; (2) insufficient correction for multiple statistical tests and flexibility in data analysis, and (3) publication bias in favor of positive results. Thus the study echoes widespread concerns about the risk of false‐positive results inherent to small‐scale VBM studies. Hum Brain Mapp 36:1741–1754, 2015.

Massive cortical reorganization in sighted Braille readers

The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI: http://dx.doi.org/10.7554/eLife.10762.001

Nencki Affective Word List (NAWL): the cultural adaptation of the Berlin Affective Word List–Reloaded (BAWL-R) for Polish

In the present article, we introduce the Nencki Affective Word List (NAWL), created in order to provide researchers with a database of 2,902 Polish words, including nouns, verbs, and adjectives, with ratings of emotional valence, arousal, and imageability. Measures of several objective psycholinguistic features of the words (frequency, grammatical class, and number of letters) are also controlled. The database is a Polish adaptation of the Berlin Affective Word List–Reloaded (BAWL-R; Võ et al., Behavior Research Methods 41:534–538, 2009), commonly used to investigate the affective properties of German words. Affective normative ratings were collected from 266 Polish participants (136 women and 130 men). The emotional ratings and psycholinguistic indexes provided by NAWL can be used by researchers to better control the verbal materials they apply and to adjust them to specific experimental questions or issues of interest. The NAWL is freely accessible to the scientific community for noncommercial use as supplementary material to this article.

Can Pornography be Addictive? An fMRI Study of Men Seeking Treatment for Problematic Pornography Use

Pornography consumption is highly prevalent, particularly among young adult males. For some individuals, problematic pornography use (PPU) is a reason for seeking treatment. Despite the pervasiveness of pornography, PPU appears under-investigated, including with respect to the underlying neural mechanisms. Using functional magnetic resonance imaging (fMRI), we examined ventral striatal responses to erotic and monetary stimuli, disentangling cue-related ‘wanting’ from reward-related ‘liking’ among 28 heterosexual males seeking treatment for PPU and 24 heterosexual males without PPU. Subjects engaged in an incentive delay task in the scanner, in which they received erotic or monetary rewards preceded by predictive cues. Blood-oxygen-level-dependent responses to erotic and monetary cues were analyzed and examined with respect to self-reported data on sexual activity collected over the 2 preceding months. Men with and without PPU differed in their striatal responses to cues predicting erotic pictures but not in their responses to erotic pictures. PPU subjects when compared with control subjects showed increased activation of ventral striatum specifically for cues predicting erotic pictures but not for cues predicting monetary gains. Relative sensitivity to cues predicting erotic pictures vs monetary gains was significantly related to the increased behavioral motivation to view erotic images (suggestive of higher ‘wanting’), severity of PPU, amount of pornography use per week, and number of weekly masturbations. Our findings suggest that, similar to what is observed in substance and gambling addictions, the neural and behavioral mechanisms associated with the anticipatory processing of cues specifically predicting erotic rewards relate importantly to clinically relevant features of PPU. These findings suggest that PPU may represent a behavioral addiction and that interventions helpful in targeting behavioral and substance addictions warrant consideration for adaptation and use in helping men with PPU.

Task-specific reorganization of the auditory cortex in deaf humans

Significance What principles govern large-scale reorganization of the brain? In the blind, several visual regions preserve their task specificity but switch to tactile or auditory input. It remains open whether this type of reorganization is unique to the visual cortex or is a general mechanism in the brain. Here we asked deaf and hearing adults to discriminate between temporally complex sequences of stimuli during an fMRI experiment. We show that the same auditory regions were activated when deaf subjects performed the visual version of the task and when hearing subjects performed the auditory version of the task. Thus, switching sensory input while preserving the task specificity of recruited areas might be a general principle that guides cortical reorganization in the brain. The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior–lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

Influence of magnetic field strength and image registration strategy on voxel‐based morphometry in a study of Alzheimer's disease

Multi‐centre data repositories like the Alzheimers Disease Neuroimaging Initiative (ADNI) offer a unique research platform, but pose questions concerning comparability of results when using a range of imaging protocols and data processing algorithms. The variability is mainly due to the non‐quantitative character of the widely used structural T1‐weighted magnetic resonance (MR) images. Although the stability of the main effect of Alzheimers disease (AD) on brain structure across platforms and field strength has been addressed in previous studies using multi‐site MR images, there are only sparse empirically‐based recommendations for processing and analysis of pooled multi‐centre structural MR data acquired at different magnetic field strengths (MFS). Aiming to minimise potential systematic bias when using ADNI data we investigate the specific contributions of spatial registration strategies and the impact of MFS on voxel‐based morphometry in AD. We perform a whole‐brain analysis within the framework of Statistical Parametric Mapping, testing for main effects of various diffeomorphic spatial registration strategies, of MFS and their interaction with disease status. Beyond the confirmation of medial temporal lobe volume loss in AD, we detect a significant impact of spatial registration strategy on estimation of AD related atrophy. Additionally, we report a significant effect of MFS on the assessment of brain anatomy (i) in the cerebellum, (ii) the precentral gyrus and (iii) the thalamus bilaterally, showing no interaction with the disease status. We provide empirical evidence in support of pooling data in multi‐centre VBM studies irrespective of disease status or MFS. Hum Brain Mapp 35:1865–1874, 2014.

Dissociable contributions of the left and right posterior medial orbitofrontal cortex in motivational control of goal-directed behavior

Several findings from both human neuroimaging and nonhuman primate studies suggest that the posterior medial orbitofrontal cortex (OFC) may be critical for the motivational control of goal-directed behavior. The present study was conducted to clarify the role of the left and right posterior medial OFC in that function by examining the effects of focal unilateral lesions to this region on the performance on an incentive working memory task. The study covered patients who had undergone surgery for an ACoA aneurysm and normal control subjects (C). The patients were subdivided into three groups: those with resection of the left (LGR+) or right (RGR+) posterior part of the gyrus rectus, and without such a resection (GR-). Participants performed a 2-back working memory task under three motivational conditions (penalty, reward, and no-incentive). The C group performed worse in the penalty condition and better in the reward condition as compared to the no-incentive condition. Similar results were obtained for the GR- group. Performance of the LGR+ group did not depend on incentive manipulations, whereas the RGR+ group performed better in both the penalty and reward conditions than in the no-incentive condition. The results show that the posterior medial OFC is involved in the motivational modulation of working memory performance. Our findings also suggest that the left posterior medial OFC plays a crucial role in this function, whereas the right posterior medial OFC is particularly involved in the processing of the punishing aspect of salient events and it probably mediates in guiding behavior on the basis of negative outcomes of action.

Implicit phonological and semantic processing in children with developmental dyslexia: Evidence from event-related potentials

Dyslexia is characterized by a core phonological deficit, although recent studies indicate that semantic impairment also contributes to this condition. In this study, event-related potentials (ERP) were used to examine whether the N400 wave in dyslexic children is modulated by phonological or semantic priming, similarly to age-matched controls. ERPs were recorded while children listened to word lists in which the semantic and phonological congruency of the terminal words were manipulated. No overt judgments were made by participants. In control children the N400 amplitude to both semantically and phonologically incongruent words was enlarged relative to congruent words. Dyslexic children exhibited a dissociation of priming effects depending on whether semantic or phonological primes were used. Semantic priming elicited an N400 effect comparable to controls, though delayed. In phonological priming, the dyslexics differed from controls in both the phonologically incongruent and congruent conditions showing reduced N400 amplitude in the former and enhanced N400 in the latter. This pattern suggests that when faced with phonological priming, dyslexics show abnormal neural responses related to both integration of similarities between the consecutive stimuli and the ability to detect incongruent stimuli. Semantic priming seems relatively intact in dyslexics, however neural responses to contextual incongruency are delayed.