An Electrical Conductivity Sensor for the Selective Determination of Soil Salinity.

The measurement of electrical conductivity (EC) has long been a tool for understanding soil properties. Previous studies concluded that EC measurement is not an ion-selective method, but these papers did not address the measurement frequency. An experimental tool and method were developed for semi-factory conditions in a large-scale soil trough at the Institute of Technology of the Hungarian University of Agricultural and Life Sciences. A specially designed and built test apparatus mounted on the tractor's three-point hitch was used as a measuring device. The wear-resistant steel elements of the measuring device were also the sensors for measuring EC. This paper describes the conditions of the measurement series, the measurement results, and our conclusions from the experiments with the soil sensor. Different characteristics were measured in soil moistened with K and Ca solutions at different concentrations. The EC values show an increasing tendency with increasing salt concentration, and we also found that the rate of change of EC is different for different solution ratios. Based on our measurements, we found that the best method to isolate concentration differences is to use the test frequency range 20 Hz-250 kHz.

Task-relevance and change detection in action-effect binding.

Features of actions are bound to coincidentally occurring stimuli so that re-encountering a stimulus retrieves a previous action episode. One hallmark of the purported mechanism in binding/retrieval tasks is a reliable reaction time advantage for repeating a previous response if tone stimuli repeat rather than alternate across trials. Other measures than reaction times yielded surprisingly mixed results, however. This is particularly true for continuous response features like force or response duration. We therefore conducted two experiments to resolve this disconnect between different measures. Experiment 1 tested for a potentially inflated effect in reaction time data, whereas Experiment 2 took the converse approach of studying conditions that would elicit similarly strong effects on alternative measures. Our results show that confounds in terms of auditory change detection do not inflate reaction time differences, reinforcing an interpretation of these effects as reflecting binding and retrieval. Moreover, strong effects on alternative measures appeared if these features were rendered task-relevant and came with sufficient variability. These observations provide critical evidence for binding and retrieval accounts, especially by showing that these accounts extend from binary decisions to continuous features of an actual motor response.

Binding of Task-Irrelevant Action Features and Auditory Action Effects.

Discrete task-relevant features of an overt response, such as response location, are bound to, and retrieved by coincidentally occurring auditory stimuli. Here we studied whether continuous, task-irrelevant response features like force or response duration also become bound to, and retrieved by such stimuli. In two experiments we asked participants to carry out a pinch which produced a certain auditory effect in a prime part of each trial. In a subsequent probe part, tones served as imperative stimuli which either repeated or changed as compared to the effect tone in the prime. We conjectured that the repetition of tones should result in more similar responses in terms of force output and duration as compared to tone changes. Most parameters did not show notable indications for such similarity increases, including peak force or area under force curve, though the correlation between response durations in prime and probe was higher when tones repeated rather than changed from prime to probe. We discuss these results regarding perceptual discriminability and deployment of attention to different nominally task-irrelevant aspects of pinch responses.

Turning a blind eye to motor differences leads to bias in estimating action-related auditory ERP attenuation.

Event-related potential (ERP) studies investigating the processing of self-induced stimuli often rely on the assumption that ballistic actions and motor ERPs are constant across different sets of action effects. Since recent studies challenge this motor equivalence assumption, we examined whether neglecting effect-related motor differences can bias the estimation of auditory ERPs in a typical action-related ERP attenuation paradigm. We increased action variability with a force production task and selected an event subset in which the motor equivalence assumption was true. ERP attenuation estimated in this subset was compared with attenuation obtained in the standard task, where motor differences were not controlled. Violation of the motor equivalence assumption resulted in a positive deflection overlapping auditory ERPs elicited by self-induced sounds, leading to the overestimation of N1- and underestimation of P2-attenuation. This demonstrates that sensory-effect-related motor differences should be considered when separating sensory and motor components in ERPs elicited by self-induced stimuli.

Force and electromyography reflections of sensory action-effect weighting during pinching.

Ideomotor theories suggest that different action-effects are not equally important in goal-directed actions, and that task-relevant information are weighted stronger during the representation of actions. This stronger weighting of task-relevant action-effects might also enable to utilize them as retrieval cues of the corresponding motor patterns. The aim of the present study was to investigate how the consistent presence or absence of a sound action-effect influenced the retrieval of the motor components of a simple, everyday action (pinching) as reflected by the pattern of force application and surface electromyogram (sEMG) recorded from the abductor pollicis brevis (APB) and first dorsal interosseous (FDI). Participants applied pairs of pinch impulses to a force sensitive resistor (FSR). The presence or absence of a sound action-effect and the between-action interval (BAI, 2 or 4 s) were manipulated blockwise, whereas the target force level (low or high) was randomly cued from trial to trial. When actions resulted in a sound, force and sEMG activity were reduced. This effect was more pronounced for low target force level trials, which is compatible with a stronger weighting of the sound action-effect when the intensity of the tactile and proprioceptive action-effects is low. Surprisingly, the FDI activity was more variable within actions pairs in the 2 s BAI conditions, which suggests that action pairs separated by the longer time interval might have been represented differently from those separated by the shorter interval.

The emergence of action-effect-related motor adaptation amidst outcome unpredictability.

Previous research indicates that quick, repetitive actions (pinches, taps, button presses) are executed with smaller force when followed by predictable and salient action effects (tones, light flashes). It has been suggested that successive actions become gradually softer until an optimum is reached, which presumably reflects a balance between the ability to maintain a high probability of action success, and the reduction of exerted force to conserve energy. In the present experiments, we investigated whether this action-effect-related motor adaptation appeared when the arrival of the action effect was unpredictable. Young adult participants produced evenly spaced pinches (Experiment 1) or taps (Experiment 2), which resulted in a tone in 50% of the trials. The presence of the tone effect varied randomly from trial to trial, leading to action sequences with various tone-elicitation patterns. We have found that pinches and taps preceded by sequences of tone-eliciting actions were softer than actions preceded by sequences of tone-absent trials. In the case of pinches, actions were also modulated on the fly, with the current action being softer and briefer when a tone was elicited. Our results demonstrate that action effects can modulate subsequent and ongoing actions even when the arrival of these effects is unpredictable. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Word class and word frequency in the MMN looking glass.

The effects of lexical meaning and lexical familiarity on auditory deviance detection were investigated by presenting oddball sequences of words, while participants ignored the stimuli. Stimulus sequences were composed of words that were varied in word class (nouns vs. functions words) and frequency of language use (high vs. low frequency) in a factorial design with the roles of frequently presented stimuli (Standards) and infrequently presented ones (Deviants) were fully crossed. Deviants elicited the Mismatch Negativity component of the event-related brain potential. Modulating effects of lexical meaning were obtained, revealing processing advantages for denotationally meaningful items. However, no effect of word frequency was observed. These results demonstrate that an apparently low-level function, such as auditory deviance detection utilizes information from the mental lexicon even for task-irrelevant stimuli.

Processing and utilization of auditory action effects in individual and social tasks.

The influence of action-effect integration on motor control and sensory processing is often investigated in arrangements featuring human-machine interactions. Such experiments focus on predictable sensory events produced through participants' interactions with simple response devices. Action-effect integration may, however, also occur when we interact with human partners. The current study examined the similarities and differences in perceptual and motor control processes related to generating sounds with or without the involvement of a human partner. We manipulated the complexity of the causal chain of events between the initial motor and the final sensory event. In the self-induced condition participants generated sounds directly by pressing a button, while in the interactive condition sounds resulted from a paired reaction-time task, that is, the final sound was generated indirectly, by relying on the contribution of the partner. Auditory event-related potentials (ERPs) and force application patterns were similar in the two conditions, suggesting that social action effects produced with the involvement of a second human agent in the causal sequence are processed, and utilized as action feedback in the same way as direct consequences of one's actions. The only reflection of a processing difference between the two conditions was a slow, posterior ERP waveform that started before the presentation of the auditory stimulus, which may reflect differences in stimulus expectancy or task difficulty.

Action-related auditory ERP attenuation is not modulated by action effect relevance.

Event-related potentials (ERPs) elicited by self-induced sounds are often smaller than ERPs elicited by identical, but externally generated sounds. This action-related auditory ERP attenuation is more pronounced when self-induced sounds are intermixed with similar sounds generated by an external source. The current study explored whether attentional factors contributed to this phenomenon. Participants performed tone-eliciting actions, while the action-tone contingency and the set of additional action effects (tactile only, tactile and visual) were manipulated in a blocked manner. Previous action-tone contingence-effects were replicated, but the addition of other sensory action consequences did not influence the magnitude of auditory ERP attenuation. This suggests that the amount of attention allocated to concurrent non-auditory action effects does not substantially affect the magnitude of action-related auditory ERP attenuation and is on a par with the assumption that action-related auditory ERP attenuation might be related to the process of distinguishing self-induced stimuli from externally generated ones.

Pre-attentive auditory change detection for rapid auditory transient combinations: Insight from age-related processing changes.

The N1 event-related potential (ERP) enhancement to auditory transients preceded briefly by another transient has been interpreted as a reflection of latent inhibition, or alternatively, as a superimposing mismatch negativity (MMN) to rare transient event combinations. In a previous study (Volosin, Gaál, & Horváth, 2017a), when rare glides preceded frequent gaps by 150 ms in continuous tones, gap-related N1 was enhanced in younger adults while P2 was attenuated both in younger and older adults, which could be parsimoniously explained by MMN overlap which was delayed with aging. The present study replicated and extended these results with a condition in which the roles of the two event types were reversed. Transients separated by 150 ms elicited delayed MMN in older adults, supporting the MMN interpretation over the latent inhibition account. Furthermore, the divergence of N1 and MMN elicitation patterns demonstrated the independence of N1 and MMN.

Insights into graphene oxide interaction with human serum albumin in isolated state and in blood plasma.

The interactions of graphene oxide (GO), a 2-dimensional nanomaterial with hydrophilic edges, hydrophobic basal plane and large flat surfaces, with biological macromolecules, are of key importance for the development of novel nanomaterials for biomedical applications. To gain more insight into the interaction of GO flakes with human serum albumin (HSA), we examined GO binding to HSA in its isolated state and in blood plasma. Calorimetric data reveal that GO strongly stabilizes free isolated HSA against a thermal challenge at low ionic strength, indicating strong binding interactions, confirmed by the drop in ζ-potential of the HSA/GO assemblies compared to bare GO flakes. However, calorimetry also revealed that the HSA-GO molecular interaction is hampered in blood plasma, the ionic strength being particularly important for the interactions. Molecular modelling calculations are in full concert with these experimental findings, indicating a considerably higher binding affinity for HSA to GO in its partially unfolded state, characteristic to low-ionic-strength environment, than for the native protein conformation, observed under physiological conditions. Therefore, for the first time we demonstrate an impeded interaction between HSA and GO nanoflakes in blood plasma, and suggest that the protein is protected from the plausible toxic effects of GO under native conditions.

Task difficulty modulates voluntary attention allocation, but not distraction in an auditory distraction paradigm.

Keeping task-relevant sensory events in the focus of attention while ignoring irrelevant ones is crucial for optimizing task behavior. This attention-distraction balance might change with the perceptual demands of the ongoing task: while easy tasks might be performed with low attentional effort, difficult ones require enhanced attention. The goal of the present study was to investigate how task difficulty affected allocation of attention and distractibility in an auditory distraction paradigm. Participants performed a tone duration discrimination task in which tones were rarely, occasionally presented at a rare pitch (distracters), and task difficulty was manipulated by the duration difference between short and long tones. Short tones were consistently 200 ms long, while long tone duration was 400 ms in the easy, and 260 ms in the difficult condition. Behavioral results and deviant-minus-standard event-related potential (ERP) waveforms suggested similar magnitudes of distraction in both conditions. ERPs without such a subtraction showed that tone onsets were preceded by a negative-going trend, suggesting that participants prepared for tone onsets. In the difficult condition, N1 amplitudes to tone onsets were enhanced, indicating that participants invested more attentional resources. Increased difficulty also slowed down tone offset processing as reflected by significantly delayed offset-related P1 and N1/N2 waveforms. These results suggest that although task difficulty compels participants to attend the tones more strongly, this does not have significant impact on distraction-related processing.

The role of auditory context in action-effect-related motor adaptation.

Previous research indicates that adding auditory effects to a (silent) action can lead to substantial efficiency gains in the performance of the action, while compromising the connection between the motor and the auditory event (e.g., by removing, or by delaying the auditory effects), leads the agent to compensate for the loss of auditory feedback by executing actions in a way which increases the probability of success or enhances feedback in other modalities, thus departing from the optimal action performance. The current study explored how this motor adaptation was affected when the quality of auditory feedback was reduced by contextual factors, while keeping the physical link between the action and auditory effect intact. In two experiments, participants elicited pure tones by pinching a force sensitive resistor (FSR). In some of the conditions action-effect contingency was reduced by intermixing externally initiated tones with the self-induced ones. Pinch-force measurements indicated that action optimization was affected by contextual factors. The influence of auditory context was the most pronounced when the discrimination of self-induced and external tones was made difficult by the similarity and temporal proximity of the self-induced and external tones. In these conditions, tone eliciting actions were more forceful in comparison to conditions in which no external tones were presented, and in comparison to conditions in which the external tones were easily distinguishable from self-induced ones. This suggests that contextual factors can induce similar motor adjustments as manipulating the physical connection between the action and its sensory consequences.

Temporal constraints in the use of auditory action effects for motor optimization.

For quick ballistic movements the possibility of making online adjustments is limited. However, when the same action (e.g., pressing a button) is repeated multiple times, trial-by-trial adjustments are possible: Previous studies found that participants utilized auditory effects as feedback to optimize the applied force for such tone eliciting actions. In the current study, it was examined whether this action-effect-related motor adaptation also occurred if a delay was inserted between the action and its auditory effect. In 2 experiments, participants applied force impulses to a force-sensitive resistor in a self-paced schedule. Action-effect delay was manipulated between experimental blocks in the 0- to 1,600-ms range. The level of motor adaptation diminished as a function of action-effect delay, with no adaptation observable for delays longer than 200 ms, which indicates that action-effect contingency in itself is not sufficient to warrant that sensory effects will be useful for action control. A third experiment also showed that the observed temporal constraint was not absolute: Adaptation at 200-ms delay was stronger in a group of participants who were exposed to 400-ms action-tone delays before testing, than in a group exposed to a 0-ms action-tone delay, suggesting that action-effect-related motor adaptation is influenced by prior experience. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Action-effect related motor adaptation in interactions with everyday devices.

Human action planning relies on integrated representations of motor acts and the associated consequences, which implies that changing the set of effects associated to a motor act might directly influence action planning and control. The present study investigated the hypothesis that action-effect manipulations also affected the motor components of the actions even when only a single action option was available. Participants performed simple everyday actions (pinched a plastic sheet, pressed a button, tapped on a table) in two conditions. In the motor-auditory condition actions resulted in the presentation of a tone, whereas no tones were presented in the motor condition. The applied force was softer in the motor-auditory than in the motor condition for all three types of actions. The temporal characteristics of force application showed that action-effect related motor adaptation occurred during action planning, but possibly also during action execution. This demonstrates that even in simple, well-defined interactions with everyday devices we take all (even seemingly task-irrelevant) action-effects into account during action planning, which affects the motor component of the action. The results also imply that in experiments manipulating contingent action effects, one cannot rely on the assumption that the motor part of the action is invariant between conditions.

Plasma phospholipid profiling of a mouse model of anxiety disorder by hydrophilic interaction liquid chromatography coupled to high-resolution mass spectrometry.

Glycerophospholipids (PLs), as amphipathic small molecules and the main constituents of biological membranes, play an important role in several cellular processes, even though their accurate identification from complex biological samples remains a challenge. In this paper, we report a fast and comprehensive HILIC-ESI-MS method for the analysis of glycerophospholipid classes using high-resolution mass spectrometry in negative mode. The final method enabled the quantitative analysis of 130 endogenous PL species in mouse plasma. The application of the method developed was to find differences of plasma PL composition in a mouse model of anxiety disorder. In the case of four PL classes and 35 PL species, significant differences were observed comparing low anxiety-related behavior with high anxiety-related behavior groups. The most characteristic trend was up-regulation in both the PL classes and PL species, and decreases were only detected in two phosphatidylcholines among 35 species in mice having elevated anxiety.

The detection of higher-order acoustic transitions is reflected in the N1 ERP.

The auditory system features various types of dedicated change detectors enabling the rapid parsing of auditory stimulation into distinct events. The activity of such detectors is reflected by the N1 ERP. Interestingly, certain acoustic transitions show an asymmetric N1 elicitation pattern: whereas first-order transitions (e.g., a change from a segment of constant frequency to a frequency glide [c-to-g change]) elicit N1, higher-order transitions (e.g., glide-to-constant [g-to-c] changes) do not. Consensus attributes this asymmetry to the absence of any available sensory mechanism that is able to rapidly detect higher-order changes. In contrast, our study provides compelling evidence for such a mechanism. We collected electrophysiological and behavioral data in a transient-detection paradigm. In each condition, a random (50%-50%) sequence of two types of tones occurred, which did or did not contain a transition (e.g., c-to-g and constant stimuli or g-to-c and glide tones). Additionally, the rate of pitch change of the glide varied (i.e., 10 vs. 40 semitones per second) in order to increase the number of responding neural assemblies. The rate manipulation modulated transient ERPs and behavioral detection performance for g-to-c transitions much stronger than for c-to-g transitions. The topographic and tomographic analyses suggest that the N1 response to c-to-g and also to g-to-c transitions emerged from the superior temporal gyrus. This strongly supports a sensory mechanism that allows the fast detection of higher-order changes.

Comprehensive phospholipid and sphingomyelin profiling of different brain regions in mouse model of anxiety disorder using online two-dimensional (HILIC/RP)-LC/MS method.

A novel online system including two-dimensional liquid chromatography coupled to high-resolution mass spectrometry (2D-LC/MS) was developed and applied for comprehensive phospholipid (PL) and sphingomyelin (SM) profiling of dorsal hippocampus (DHPC), ventral (VHPC) and prefrontal cortex (PFC) brain regions in a mouse model of anxiety disorder. In the first dimension, lipid classes were distinguished by hydrophilic interaction liquid chromatography (HILIC), while the second dimensional separation of individual PL and SM species was achieved by reversed-phase (RP) chromatography. For the enrichment of lipid species in diluted HILIC effluent, two RP trapping columns were used separately. The developed fully-automated 2D method allowed the quantitative analysis of over 150 endogenous PL and SM species in mouse brain regions within 40min. The developed method was applied in a pilot study, which aimed to find alteration of PL and SM composition in a mouse model of anxiety disorder. In the case of 37 PL and SM species, significant differences were observed between high anxiety-related behavior (AX) and low anxiety-related behavior (nAX) mice. In mice having elevated anxiety, the most typical trend was the downregulation of PL species, in particular, in VHPC.

Age-related processing delay reveals cause of apparent sensory excitability following auditory stimulation.

When background auditory events lead to enhanced auditory event-related potentials (ERPs) for closely following sounds, this is generally interpreted as a transient increase in the responsiveness of the auditory system. We measured ERPs elicited by irrelevant probes (gaps in a continuous tone) at several time-points following rare auditory events (pitch glides) in younger and older adults, who watched movies during stimulation. Fitting previous results, in younger adults, gaps elicited increasing N1 auditory ERPs with decreasing glide-gap separation. N1 increase was paralleled by an ERP decrease in the P2 interval. In older adults, only a glide-gap separation dependent P2 decrease, but no N1-effect was observable. This ERP pattern was likely caused by a fronto-central negative waveform, which was delayed in the older adult group, thus overlapping N1 and P2 in the younger, but overlapping only P2 in the older adult group. Because the waveform exhibited a polarity reversal at the mastoids, it was identified as a mismatch negativity (MMN). This interpretation also fits previous studies showing that gap-related MMN is delayed in older adults, reflecting an age-related deterioration of fine temporal auditory resolution. These results provide a plausible alternative explanation for the ERP enhancement for sounds following background auditory events.

Sound offset-related brain potentials show retained sensory processing, but increased cognitive control activity in older adults.

It has been hypothesized that age-related hearing loss is caused not only by peripheral but also central changes in the auditory system. Many studies used event-related potentials (ERPs) elicited by sound onsets to characterize the age-related differences in central auditory processing. Age-related ERP enhancements in such studies have often been interpreted in terms of elevated sensitivity to auditory stimulation. Such ERPs, however, comprise various components reflecting different aspects of auditory and task-related processing. The composition of the waveforms may considerably differ for ERPs elicited by other auditory events. In the present study, ERPs elicited by tone offsets were used to characterize processing differences between younger and older adults in a short-go, tone-duration discrimination paradigm. Whereas the onset-related auditory ERP was enhanced in the older adult group, no age-related differences were found in the offset-related auditory ERPs observable at temporal electrodes. In older adults, however, offset-related processing was dominated by an N2 that could reflect enhanced cognitive control activities. Because N2 was present regardless discrimination difficulty, younger adults may have framed the task as offset detection, whereas older adults represented the task as "genuine" discrimination.