Fine-scale dynamics of calcite precipitation in a large hardwater lake.

In hardwater lakes, calcite precipitation is an important yet poorly understood process in the lacustrine carbon cycle, in which catchment-derived alkalinity (Alk) is both transformed and translocated. While the physico-chemical conditions supporting the supersaturation of water with respect to calcite are theoretically well described, the magnitude and conditions underlying calcite precipitation at fine temporal and spatial scales are poorly constrained. In this study, we used high frequency, depth-resolved (0-30 m) data collected over 18 months (June 2019 - November 2020) in the deeper basin of Lake Geneva to describe the dynamics of calcite precipitation fluxes at a fine temporal resolution (day to season) and to scale them to carbon fixation by primary production. Calcite precipitation occurred during the warm stratified periods when surface water CO2 concentrations were below atmospheric equilibrium. Seasonally, the extent of Alk loss due to calcite precipitation (i.e., [30-42] g C m-2) depended upon the level of Alk in surface waters. Moreover, interannual variability in seasonal calcite precipitation depended on the duration of stratification, which determined the volume of the water layer susceptible to calcite precipitation. At finer timescales, calcite precipitation was characterized by marked daily variability with dynamics strongly related to that of planktonic autotrophic metabolism. Increasing daily calcite precipitation rates (i.e., maximum values 9 mmol C m-3 d-1) coincided with increasing net ecosystem production (NEP) during periods of enhanced water column stability. In these conditions, calcite precipitation could remove as much inorganic carbon from the productive layers as NEP. This study provides mechanistic insights into the conditions driving pelagic calcite precipitation, and quantifies its essential contribution to the coupling of organic and inorganic carbon cycling in lakes.

Therapeutic Garden With Contemplative Features Induces Desirable Changes in Mood and Brain Activity in Depressed Adults.

The therapeutic values of contact with nature have been increasingly recognized. A growing body of evidence suggests that a unique subcategory of "contemplative landscapes" is particularly therapeutic. Previous studies predominantly focused on observational designs in non-clinical populations. It is not known if these effects can be extrapolated to populations suffering from depression, and experimental designs need to be utilized to establish causality. We examined the effects of in-situ passive exposure to three urban spaces on brain activity, namely a Therapeutic Garden with high Contemplative Landscape scores (TG), Residential Green (RG) and Busy Downtown (BD), and self-reported momentary mood in adults aged 21-74 (n = 92), including 24 clinically depressed and 68 healthy participants. Portable, multimodal electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) systems were used to record brain activity, and a Profile of Mood States (POMS) questionnaire was used to record mood before and after exposure. We tested the interactions between the site, time and group for the mood, and between site and group for the neuroelectric oscillations and brain hemodynamics. Self-reported pre- post-mood was significant only at the TG (p = 0.032) in both groups. The lowest Total Mood Disturbance (TMD) was reported at TG and the highest in BD (p = 0.026). Results from fNIRS indicated marginally significant lower oxy-Hb in the frontal region at TG as compared to BD (p = 0.054) across both groups. The marginally significant effect of site and group was also observed (p = 0.062), with the Clinical group showing much lower oxy-Hb at TG than Healthy. The opposite pattern was observed at BD. EEG results showed differences between Healthy and Clinical groups in the Frontal Alpha Asymmetry (FAA) pattern across the sites (p = 0.04), with more frontal alpha right in the Clinical sample and more left lateralization in the Healthy sample at TG. Temporal Beta Asymmetry (TBA) analyses suggested that patients displayed lower bottom-up attention than Healthy participants across all sites (p = 0.039). The results suggest that both healthy and depressed adults benefitted from exposure to TG, with possibly different pathways of mood improvement. Visiting therapeutic nature with contemplative features may provide valuable support for the treatment of depression in clinical populations and a self-care intervention in non-clinical populations.

Effects of COVID-19-related stay-at-home order on neuropsychophysiological response to urban spaces: Beneficial role of exposure to nature?

Background: The COVID-19 pandemic has had severe negative effects on populations worldwide. The seriousness of the pandemic necessitated local and even national lockdowns. In Singapore a national lockdown with aStay-at-Home Order (SHO) lasted for over 7 weeks. The impact of the pandemic and of the long SHO period on neuropsychophysiological functioning remains unknown. Studies prior to the pandemic highlighted the beneficial role of nature exposure on mental health and well-being, although this has not yet been explored in the post-pandemic world. This is the first study to investigate the longitudinal changes in (1) brain frontal alpha asymmetry (FAA; neuroelectric marker of approach-related motivation), (2) depressive mood and (3) symptoms, and (4) emotional response to videos of various urban spaces from before COVID-19 to immediately after the SHO in Singapore was over. Finally, we examined whether higher vs lower exposure to nature during the SHO moderated changes over time. Methods: The sample included 25 healthy adult Singaporeans (56% female, Mage = 40.4 y, SD = 17.8), who attended two electroencephalography (EEG) lab sessions, within a year before the COVID-19 pandemic (T1) and immediately following the SHO (T2). The participants viewed 9 fixed-frame videos, filmed before the pandemic, from 3 urban public spaces (Busy Downtown, Residential Green, Lush Garden) on the roll-up screen. They rated their emotional response (arousal, valence) after each video and completed Becks Depression Inventory-II (BDI-II) as a measure of depressive symptoms, Profile of Mood Scale (POMS), as a measure of momentary mood, and self-reported the frequency and duration of their nature visits during the SHO. Results: Linear mixed models were fitted to examine changes over time, and effect moderation by amount of nature exposure during the SHO. The results showed decrease in FAA (p < 0.001), increase in depressive symptoms (p = 0.046), and a trend for marginal increase in momentary mood disturbance (p = 0.097) after the SHO. Importantly, people with high nature exposure during SHO had greater decrease in FAA over time (p = 0.005) than those with low nature exposure, FAA scores decreased the most for Residential Green. Valence and Arousal did not change over time, but Arousal towards Busy Downtown decreased among high nature exposure individuals (p = 0.002). Conclusions: Post SHO, brain activity and responsiveness to landscapes changed, and showed a general reduction in positive emotions and increased depressive symptoms among participants. The higher nature exposure during the SHO did not help mitigate this depressive symptoms, as previous research would suggest. This can be due to the modified quality of nature exposure during lockdown, which highlights the importance of high quality nature experience in cities and the provision of diversified visual exposures. Potential neuropsychophysiological consequences of SHO should be considered by policy makers in the post-COVID-19 world.

Rhythmic timing in aging adults: On the role of cognitive functioning and structural brain integrity.

Here we asked whether impaired timing in older adults results from an aging clock or a more general brain and cognitive decline. Healthy aging adults (N = 70, aged 62-83 years) tapped to the beat of a periodic and a syncopated rhythm. Analyses focused on performance differences between rhythms (periodic-syncopated), which reduced the impact of timing unrelated processes. Apart from tapping, participants completed a cognitive assessment and neuroimaging of gray matter volume (GMV) and fractional anisotropy (FA) globally as well as regionally (cortical: auditory, premotor, paracentral; subcortical: putamen, caudate, cerebellum). The rhythm difference showed no significant age effects for tapping asynchrony and an age-related decrease for tapping consistency. Additionally, age reduced cognitive functioning, global GMV/FA, and, beyond this, auditory GMV. Irrespective of age, the rhythm difference in tapping asynchrony was linked, not to GMV, but to caudal, premotor, and paracentral FA after controlling for global FA. Tapping consistency was associated with global rather than regional brain integrity. Additionally, age differences in tapping consistency were mediated by a decline in global brain integrity as well as cognitive functioning. Together these results agree with previous proposals differentiating between timing accuracy and reliability and suggest that aging largely preserves the former but not the latter. Whereas timing accuracy may depend on an internal clock supported by robust striatocortical circuitry, timing reliability may depend on global brain and cognitive functioning, which show a pronounced age-related decline. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Beyond physical entrainment: competitive and cooperative mental stances during identical joint-action tasks differently affect inter-subjective neural synchrony and judgments of agency.

Little work has examined how mental stance alone, apart from physical entrainment, affects between-participant neural synchrony during joint social interaction. We report the first findings on how cooperative and competitive mental stances, even during identical visuomotor joint-action tasks, result in distinct neural oscillatory signatures in low beta and theta band between-participant phase synchrony. Two participants jointly controlled a cursor and were instructed to either compete or cooperate to move it to one of three targets. The visuomotor output was identical for both the compete and cooperate conditions because participants were privately given the same target for experimental trials. Cooperation enhanced theta band between-participant phase-locking value (PLV) midtrial at 1-2 seconds, reflecting activation of systems for social coordination to move the cursor in a shared direction. Competition enhanced low beta between-participant PLV, shifting from temporal to frontal regions, indicating that participants focused only on their target and later evaluated self-agency as winner or loser. This interpretation of the neural signature was corroborated by participants' greater post-trial ratings of the degree of control over the cursor during competition. Top-down cooperative and competitive mental stances shape perceptions of social context and affect interpersonal neural synchrony important for representation of self and others' actions.

Groups and Emotional Arousal Mediate Neural Synchrony and Perceived Ritual Efficacy.

We present the first neurophysiological signatures showing distinctive effects of group social context and emotional arousal on cultural perceptions, such as the efficacy of religious rituals. Using a novel protocol, EEG data were simultaneously recorded from ethnic Chinese religious believers in group and individual settings as they rated the perceived efficacy of low, medium, and high arousal spirit-medium rituals presented as video clips. Neural oscillatory patterns were then analyzed for these perceptual judgements, categorized as low, medium, and high efficacy. The results revealed distinct neural signatures and behavioral patterns between the experimental conditions. Arousal levels predicted ratings of ritual efficacy. Increased efficacy was marked by suppressed alpha and beta power, regardless of group or individual setting. In groups, efficacy ratings converged. Individual setting showed increased within-participant phase synchronization in alpha and beta bands, while group setting enhanced between-participant theta phase synchronization. This reflected group participants' orientation toward a common perspective and social coordination. These findings suggest that co-presence in groups leads to a social-tuning effect supported by between-participant theta phase synchrony. Together these neural synchrony patterns reveal how collective rituals have both individual and communal dimensions. The emotionality of spirit-medium rituals drives individual perceptions of efficacy, while co-presence in groups signals the significance of an event and socially tunes enhanced agreement in perceptual ratings. In other words, mass gatherings may foster social cohesion without necessarily requiring group-size scaling limitations of direct face-to-face interaction. This could have implications for the scaling computability of synchrony in large groups as well as for humanistic studies in areas such as symbolic interactionism.

Window View and the Brain: Effects of Floor Level and Green Cover on the Alpha and Beta Rhythms in a Passive Exposure EEG Experiment.

With the growing interest among researchers, practitioners, and urban decision makers in the influence of the built environment on peoples' health, there is increasing emphasis on using scientific knowledge to inform urban design, including methods of neuroscience. As window views are the most immediate medium of visual connection with one's neighbourhood, we surmised that the quality of this view would have an impact on the mental health and well-being of urban dwellers. Accordingly, we investigated how window views taken from different floors of a high-rise block with varying extents of green cover affected 29 healthy residents in an exploratory electroencephalography (EEG) experiment. The results showed that the amount of green cover within the view captured at different floor levels can cause an important interaction effect on the frontal alpha and temporal beta brain oscillations while participants view photographs. These results suggest that the brainwave patterns commonly associated with positive emotional states, motivation, and visual attention mechanisms may be increased by the extent of green cover within the view. This phenomenon seems more pronounced on the higher than lower floors. The observed findings at this stage cannot confirm major effects between floor level, green cover, and brainwaves, however, they emphasize the importance of considering the quality of window views in the planning and design of urban high-rise neighbourhoods. Having a green window view can potentially contribute to the mental health and well-being of urban dwellers.

Estimation of the water quality of a large urbanized river as defined by the European WFD: what is the optimal sampling frequency?

Assessment of the quality of freshwater bodies is essential to determine the impact of human activities on water resources. The water quality status is estimated by comparing indicators with standard thresholds. Indicators are usually statistical criteria that are calculated on discrete measurements of water quality variables. If the time step of the measured time series is not sufficient to fully capture the variable's variability, the deduced indicator may not reflect the system's functioning. The goal of the present work is to assess, through a hydro-biogeochemical modeling approach, the optimal sampling frequency for an accurate estimation of 6 water quality indicators defined by the European Water Framework Directive (WFD) in a large human-impacted river, which receives large urban effluents (the Seine River across the Paris urban area). The optimal frequency depends on the sampling location and on the monitored variable. For fast varying compounds that originate from urban effluents, such as PO[Formula: see text], NH[Formula: see text] and NO[Formula: see text], a sampling time step of one week or less is necessary. To be able to reflect the highly transient character of bloom events, chl a concentrations also require a short monitoring time step. On the contrary, for variables that exert high seasonal variability, as NO[Formula: see text] and O 2, monthly sampling can be sufficient for an accurate estimation of WFD indicators in locations far enough from major effluents. Integrative water quality variables, such as O 2, can be highly sensitive to hydrological conditions. It would therefore be relevant to assess the quality of water bodies at a seasonal scale rather than at annual or pluri-annual scales. This study points out the possibility to develop smarter monitoring systems by coupling both time adaptative automated monitoring networks and modeling tools used as spatio-temporal interpolators.

Evaluating the Training Effects of Two Swallowing Rehabilitation Therapies Using Surface Electromyography--Chin Tuck Against Resistance (CTAR) Exercise and the Shaker Exercise.

In this study, the efficacy of two dysphagia interventions, the Chin Tuck against Resistance (CTAR) and Shaker exercises, were evaluated based on two principles in exercise science-muscle-specificity and training intensity. Both exercises were developed to strengthen the suprahyoid muscles, whose contractions facilitate the opening of the upper esophageal sphincter, thereby improving bolus transfer. Thirty-nine healthy adults performed two trials of both exercises in counter-balanced order. Surface electromyography (sEMG) recordings were simultaneously collected from suprahyoid muscle group and sternocleidomastoid muscle during the exercises. Converging results using sEMG amplitude analyses suggested that the CTAR was more specific in targeting the suprahyoid muscles than the Shaker exercise. Fatigue analyses on sEMG signals further indicated that the suprahyoid muscle group were equally or significantly fatigued (depending on metric), when participants carried out CTAR compared to the Shaker exercise. Importantly, unlike during Shaker exercise, the sternocleidomastoid muscles were significantly less activated and fatigued during CTAR. Lowering the chin against resistance is therefore sufficiently specific and intense to fatigue the suprahyoid muscles.

Auditory rhythms entrain visual processes in the human brain: evidence from evoked oscillations and event-related potentials.

Temporal regularities in the environment are thought to guide the allocation of attention in time. Here, we explored whether entrainment of neuronal oscillations underpins this phenomenon. Participants viewed a regular stream of images in silence, or in-synchrony or out-of-synchrony with an unmarked beat position of a slow (1.3 Hz) auditory rhythm. Focusing on occipital recordings, we analyzed evoked oscillations shortly before and event-related potentials (ERPs) shortly after image onset. The phase of beta-band oscillations in the in-synchrony condition differed from that in the out-of-synchrony and silence conditions. Additionally, ERPs revealed rhythm effects for a stimulus onset potential (SOP) and the N1. Both were more negative for the in-synchrony as compared to the out-of-synchrony and silence conditions and their amplitudes positively correlated with the beta phase effects. Taken together, these findings indicate that rhythmic expectations are supported by a reorganization of neural oscillations that seems to benefit stimulus processing at expected time points. Importantly, this reorganization emerges from global rhythmic cues, across modalities, and for frequencies significantly higher than the external rhythm. As such, our findings support the idea that entrainment of neuronal oscillations represents a general mechanism through which the brain uses predictive elements in the environment to optimize attention and stimulus perception.

Detecting Temporal Change in Dynamic Sounds: On the Role of Stimulus Duration, Speed, and Emotion.

For dynamic sounds, such as vocal expressions, duration often varies alongside speed. Compared to longer sounds, shorter sounds unfold more quickly. Here, we asked whether listeners implicitly use this confound when representing temporal regularities in their environment. In addition, we explored the role of emotions in this process. Using a mismatch negativity (MMN) paradigm, we asked participants to watch a silent movie while passively listening to a stream of task-irrelevant sounds. In Experiment 1, one surprised and one neutral vocalization were compressed and stretched to create stimuli of 378 and 600 ms duration. Stimuli were presented in four blocks, two of which used surprised and two of which used neutral expressions. In one surprised and one neutral block, short and long stimuli served as standards and deviants, respectively. In the other two blocks, the assignment of standards and deviants was reversed. We observed a climbing MMN-like negativity shortly after deviant onset, which suggests that listeners implicitly track sound speed and detect speed changes. Additionally, this MMN-like effect emerged earlier and was larger for long than short deviants, suggesting greater sensitivity to duration increments or slowing down than to decrements or speeding up. Last, deviance detection was facilitated in surprised relative to neutral blocks, indicating that emotion enhances temporal processing. Experiment 2 was comparable to Experiment 1 with the exception that sounds were spectrally rotated to remove vocal emotional content. This abolished the emotional processing benefit, but preserved the other effects. Together, these results provide insights into listener sensitivity to sound speed and raise the possibility that speed biases duration judgements implicitly in a feed-forward manner. Moreover, this bias may be amplified for duration increments relative to decrements and within an emotional relative to a neutral stimulus context.

Emotional expressions in voice and music: same code, same effect?

Scholars have documented similarities in the way voice and music convey emotions. By using functional magnetic resonance imaging (fMRI) we explored whether these similarities imply overlapping processing substrates. We asked participants to trace changes in either the emotion or pitch of vocalizations and music using a joystick. Compared to music, vocalizations more strongly activated superior and middle temporal cortex, cuneus, and precuneus. However, despite these differences, overlapping rather than differing regions emerged when comparing emotion with pitch tracing for music and vocalizations, respectively. Relative to pitch tracing, emotion tracing activated medial superior frontal and anterior cingulate cortex regardless of stimulus type. Additionally, we observed emotion specific effects in primary and secondary auditory cortex as well as in medial frontal cortex that were comparable for voice and music. Together these results indicate that similar mechanisms support emotional inferences from vocalizations and music and that these mechanisms tap on a general system involved in social cognition.

Squeeze me, but don't tease me: human and mechanical touch enhance visual attention and emotion discrimination.

Being touched by another person influences our readiness to empathize with and support that person. We asked whether this influence arises from somatosensory experience, the proximity to the person and/or an attribution of the somatosensory experience to the person. Moreover, we were interested in whether and how touch affects the processing of ensuing events. To this end, we presented neutral and negative pictures with or without gentle pressure to the participants' forearm. In Experiment 1, pressure was applied by a friend, applied by a tactile device and attributed to the friend, or applied by a tactile device and attributed to a computer. Across these conditions, touch enhanced event-related potential (ERP) correlates of picture processing. Pictures elicited a larger posterior N100 and a late positivity discriminated more strongly between pictures of neutral and negative content when participants were touched. Experiment 2 replicated these findings while controlling for the predictive quality of touch. Experiment 3 replaced tactile contact with a tone, which failed to enhance N100 amplitude and emotion discrimination reflected by the late positivity. This indicates that touch sensitizes ongoing cognitive and emotional processes and that this sensitization is mediated by bottom-up somatosensory processing. Moreover, touch seems to be a special sensory signal that influences recipients in the absence of conscious reflection and that promotes prosocial behavior.

Unattended musical beats enhance visual processing.

The present study investigated whether and how a musical rhythm entrains a listener's visual attention. To this end, participants were presented with pictures of faces and houses and indicated whether picture orientation was upright or inverted. Participants performed this task in silence or with a musical rhythm playing in the background. In the latter condition, pictures could occur off-beat or on a rhythmically implied, silent beat. Pictures presented without the musical rhythm and off-beat were responded to more slowly than pictures presented on-beat. This effect was comparable for faces and houses. Together these results indicate that musical rhythm both synchronizes and facilitates concurrent stimulus processing.

Emotional MMN: Anxiety and heart rate correlate with the ERP signature for auditory change detection.

OBJECTIVE: Previous work established the mismatch negativity (MMN) as a correlate of pre-attentive auditory change detection. The present study aimed at investigating the relationship between the MMN and emotional processes associated with the detection of change. METHODS: To this end, we assessed state anxiety with a questionnaire and subsequently recorded the electroencephalogram (EEG) and heart rate while participants watched a silent movie and listened to a task-irrelevant auditory oddball sequence. The oddball sequence comprised meaningless syllables of which some were deviants spoken with an angry or neutral voice. RESULTS: The MMN to angry voice deviants was larger than that to neutral deviants and correlated positively with ensuing heart rate acceleration. Additionally, both the MMN and heart rate acceleration to angry voice deviants were increased with increasing state anxiety. A similar effect for neutral voice deviants was non-significant. CONCLUSION: Taken together, these results suggest that the pre-attentive processing of threat, as reflected by the MMN, is linked to an activation of the sympathetic nervous system. Moreover, this link is more strongly activated in individuals with high state anxiety. SIGNIFICANCE: Thus, the MMN may be used as a marker for an individual's state dependent sensitivity to unattended, emotionally relevant change.

Spatiotemporal changes in the genetic diversity of a bloom-forming Microcystis aeruginosa (cyanobacteria) population.

The variations in microcystin concentrations during cyanobacterial blooms in freshwater ecosystems appear to depend on numerous factors, which have still not been fully identified. To contribute to clarify the situation, we have developed a spatial sampling approach to determine the dynamics and genetic diversity of a bloom-forming population of Microcystis aeruginosa in a large French reservoir, and the variations in the proportions of microcystin-producing genotypes. We demonstrated that marked changes occurred in the internal transcribed spacer (ITS) genotype composition of the M. aeruginosa population during the development of the bloom. These changes led progressively to the selection of one dominant ITS genotype throughout the entire reservoir when the cell number reached its maximum. At the same time, we identified a decrease in the proportion of the mcyB+ genotype, and a significant negative correlation between this proportion and that of the dominant ITS genotype during the bloom. Thus, it appeared that favorable conditions for Microcystis cell growth led to the selection, within the Microcystis population, of a non-microcystin-producing genotype, whereas potentially microcystin-producing genotypes were dominant in this population before and after the bloom, when environmental conditions were less favorable for growth.

What grabs his attention but not hers? Estrogen correlates with neurophysiological measures of vocal change detection.

Prior research revealed sex differences in the processing of unattended changes in speaker prosody. The present study aimed at investigating the role of estrogen in mediating these effects. To this end, the electroencephalogram (EEG) was recorded while participants watched a silent movie with subtitles and passively listened to a syllable sequence that contained occasional changes in speaker prosody. In one block, these changes were neutral, whereas in another block they were emotional. Estrogen values were obtained for each participant and correlated with the mismatch negativity (MMN) amplitude elicited in the EEG. As predicted, female listeners had higher estrogen values than male listeners and showed reduced MMN amplitudes to neutral as compared to emotional change in speaker prosody. Moreover, in both, male and female listeners, MMN amplitudes were negatively correlated with estrogen when the change in speaker prosody was neutral, but not when it was emotional. This suggests that estrogen is associated with reduced distractibility by neutral, but not emotional, events. Emotional events are spared from this reduction in distractibility and more likely to penetrate voluntary attention directed elsewhere. Taken together, the present findings provide evidence for a role of estrogen in human cognition and emotion.

When vocal processing gets emotional: on the role of social orientation in relevance detection by the human amygdala.

Previous work on vocal emotional processing provided little evidence for involvement of emotional processing areas such as the amygdala or the orbitofrontal cortex (OFC). Here, we sought to specify whether involvement of these areas depends on how relevant vocal expressions are for the individual. To this end, we assessed participants' social orientation--a measure of the interest and concern for other individuals and hence the relevance of social signals. We then presented task-irrelevant syllable sequences that contained rare changes in tone of voice that could be emotional or neutral. Processing differences between emotional and neutral vocal change in the right amygdala and the bilateral OFC were significantly correlated with the social orientation measure. Specifically, higher social orientation scores were associated with enhanced amygdala and OFC activity to emotional as compared to neutral change. Given the presumed role of the amygdala in the detection of emotionally relevant information, our results suggest that social orientation enhances this detection process and the activation of emotional representations mediated by the OFC. Moreover, social orientation may predict listener responses to vocal emotional cues and explain interindividual variability in vocal emotional processing.

Listen up! Processing of intensity change differs for vocal and nonvocal sounds.

Changes in the intensity of both vocal and nonvocal sounds can be emotionally relevant. However, as only vocal sounds directly reflect communicative intent, intensity change of vocal but not nonvocal sounds is socially relevant. Here we investigated whether a change in sound intensity is processed differently depending on its social relevance. To this end, participants listened passively to a sequence of vocal or nonvocal sounds that contained rare deviants which differed from standards in sound intensity. Concurrently recorded event-related potentials (ERPs) revealed a mismatch negativity (MMN) and P300 effect for intensity change. Direction of intensity change was of little importance for vocal stimulus sequences, which recruited enhanced sensory and attentional resources for both loud and soft deviants. In contrast, intensity change in nonvocal sequences recruited more sensory and attentional resources for loud as compared to soft deviants. This was reflected in markedly larger MMN/P300 amplitudes and shorter P300 latencies for the loud as compared to soft nonvocal deviants. Furthermore, while the processing pattern observed for nonvocal sounds was largely comparable between men and women, sex differences for vocal sounds suggest that women were more sensitive to their social relevance. These findings extend previous evidence of sex differences in vocal processing and add to reports of voice specific processing mechanisms by demonstrating that simple acoustic change recruits more processing resources if it is socially relevant.

Toxicity to medaka fish embryo development of okadaic acid and crude extracts of Prorocentrum dinoflagellates.

Chronic and subchronic toxicity following exposure to the DSP (Diarrhetic shellfish poisoning) toxin okadaic acid (OA) is receiving increasing attention as a public human health biohazard. However information on ecological impacts induced by proliferation of the OA producing dinoflagellate Prorocentrum is scarce. In order to analyse the toxicity of these substances, in vivo experiments were conducted on medaka fish (Oryzias latipes) embryos used as an experimental model. The study was focused on two strains of benthic Prorocentrum species, P. arenarium and P. emarginatum, naturally found in the Indian Ocean. Sample extracts (crude extracts, CE) were obtained from algal cultures and their toxic potential was explored. Their OA (and derivatives) content was evaluated by two methods: one based on chemical analysis using HPLC-MS, the other based on screening the inhibiting effect on protein phosphatase PP2A. P. arenarium extracts inhibit PP2A and the active toxin was confirmed as being OA by HPLC-MS. In contrast, P. emarginatum showed negative results regardless of the method used. The development of medaka fish embryos kept in medium containing pure OA or Prorocentrum CE was examined. Survival rates were reduced up to 100% depending on the concentrations used of both OA and CE of P. arenarium, while no effect was observed with CE of P. emarginatum. Anatomopathological studies of surviving embryos indicate that OA treatment resulted in significant increases in liver and digestive tract areas compared to controls. P. arenarium treated surviving embryos exhibited significant quantitative increases of global body and vitellus areas. Together, our results indicate that the toxic effects to medaka embryos development of pure OA and P. arenarium extracts containing OA are distinguishable. The differences may indicate the presence of additional toxic substance(s) (or molecules able to modulate OA impact) in the P. arenarium CE that probably are not present in P. emarginatum.