Spatial Stimuli Research Articles

Can you count on what you see? Numerosity extraction and its association with verbal number skills in early childhood.

In young children in particular, processing numerical magnitudes is influenced by spatial characteristics of those magnitudes (e.g., extent). Gradually, children will learn to dissociate numerosity from spatial information and understand that objects represent discrete numerical quantities. In the present study, we investigated whether 5-year-old children extract numerosity disregarding spatial stimulus characteristics and in what way numerosity extraction is associated with verbal number skills (counting and initial addition). Five-year-old children were presented with a newly developed task to measure numerosity extraction on two timepoints, several months apart. Each item contained three rows of differently sized rectangles. Children had to identify which two rows contained the same number of rectangles. On congruent items, these two rows were similar in length. On incongruent items, the two rows equal in numerosity varied in length. Analyses indicated that some 5-year-old children showed numerosity extraction, but others had difficulties to disentangle numerosity from spatial characteristics. Numerosity extraction was predicted over time by initial addition but not counting skills, although there was a concurrent association between counting skills and numerosity extraction at timepoint 2. Numerosity extraction did not predict either initial addition or counting over time. These results suggest that the ability to disentangle numerosity from spatial characteristics is still developing around 5 years of age and that verbal number skills foster this development. Verbal number skills probably further refine nonsymbolic magnitude processing (in this study, numerosity extraction), while nonsymbolic magnitude processing does not underlie verbal number skills. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Trabecular meshwork cell differentiation in response to collagen and TGFβ-2 spatial interactions

Primary open-angle glaucoma (POAG) is currently the most prevalent cause of irreversible blindness globally. To date, few in vitro models that can faithfully recapitulate the complex architecture of the trabecular meshwork (TM) and the specialised trabecular meshwork cell (TMC) characteristics that are local to the structurally opposing regions. This study aimed to investigate the parameters that govern TMC phenotype by adapting the extracellular matrix structure to mimic the juxtacanalicular tissue (JCT) region of the TM. Initially, TMC phenotypic characteristics were investigated within type I collagen matrices of controlled fiber density and anisotropy, generated through confined plastic compression (PC). Notably, PC-collagen presented biophysical cues that induced JCT cellular characteristics (elastin, α-β-Crystallin protein expression, cytoskeletal remodelling, increased mesenchymal markers and JCT-specific genetic markers). In parallel, a pathological mesenchymal phenotype associated with POAG was induced through localised transforming growth factor -beta 2 (TGFβ-2) exposure. This resulted in a profile of alternative mesenchymal states (fibroblast/smooth muscle or myofibroblast) displayed by the TMC in vitro. Overall, the study provides an advanced insight into the biophysical cues that modulate TMC fate, inducing a JCT-specific phenotype and transient mesenchymal characteristics that reflect healthy and pathological scenarios. Statement of significanceGlaucoma is a leading cause of blindness, with a lack of long-term efficacy within current drug candidates. Reliable trabecular meshwork (TM) in vitro models will be critical for enhancing the fields understanding of healthy and disease states for pre-clinical testing.Trabecular meshwork cells (TMCs) display heterogeneity throughout the hierarchical TM, however our understanding into recapitulating these phenotypes in vitro, remains elusive. This study hypothesizes the importance of specific matrix/growth factor spatial stimuli in governing TMCs phenotype. By emulating certain biophysical/biochemical in vivo parameters, we introduce an advanced profile of distinct TMC phenotypic states, reflecting healthy and disease scenarios. A notion that has not be stated prior and a fundamental consideration for future 3D TM in vitro modelling.

Memory traces of duration and location in the right intraparietal sulcus

Time and space form an integral part of every human experience, and for the neuronal representation of these perceptual dimensions, previous studies point to the involvement of the right-hemispheric intraparietal sulcus and structures in the medial temporal lobe. Here we used multi-voxel pattern analysis (MVPA) to investigate long-term memory traces for temporal and spatial stimulus features in those areas. Participants were trained on four images associated with short versus long durations and with left versus right locations. Our results demonstrate stable representations of both temporal and spatial information in the right posterior intraparietal sulcus. Building upon previous findings of stable neuronal codes for directly perceived durations and locations, these results show that the reactivation of long-term memory traces for temporal and spatial features can be decoded from neuronal activation patterns in the right parietal cortex.

Spatiotemporal nonlinear dynamics and chaos in a mechanical Duffing-type system

This paper investigates spatiotemporal nonlinear dynamics and chaos in a dissipative mechanical Duffing-type system subjected to external stimulus. A nonlinear wave equation with cubic nonlinearity governs the system dynamics. A perturbation description is employed to build mathematical tools that represent different aspects of system dynamics, from local to global behaviors. Lyapunov exponents are defined from the different perturbations allowing the evaluation of local, convective and mean exponents. Different dynamical regimes are investigated considering homogeneous and heterogeneous spatial stimuli. Distinct dynamical responses are observed including periodic, quasi-periodic and chaotic behaviors. A novel concept of chaotic wave is employed to explain the spatial transport of chaos through the media considering heterogeneous conditions. Chaotic wave velocity is measured by the convective Lyapunov exponents.

Influence of peripheral axon geometry and local anatomy on magnetostimulation chronaxie

Objective. Rapid switching of magnetic resonance imaging (MRI) gradient fields induces electric fields that can cause peripheral nerve stimulation (PNS) and so accurate characterization of PNS is required to maintain patient safety and comfort while maximizing MRI performance. The minimum magnetic gradient amplitude that causes stimulation, the PNS threshold, depends on intrinsic axon properties and the spatial and temporal properties of the induced electric field. The PNS strength–duration curve is widely used to characterize simulation thresholds for periodic waveforms and is parameterized by the chronaxie and rheobase. Safety limits to avoid unwanted PNS in MRI rely on a single chronaxie value to characterize the response of all nerves. However, experimental magnetostimulation peripheral nerve chronaxie values vary by an order of magnitude. Given the diverse range of chronaxies observed and the importance of this number in MRI safety models, we seek a deeper understanding of the mechanisms contributing to chronaxie variability. Approach. We use a coupled electromagnetic-neurodynamic PNS model to assess geometric sources of chronaxie variability. We study the impact of the position of the stimulating magnetic field coil relative to the body, along with the effect of local anatomical features and nerve trajectories on the driving function and the resulting chronaxie. Main results. We find realistic variation of local axon and tissue geometry can modulate a given axon’s chronaxie by up to two-fold. Our results identify the temporal rate of charge redistribution as the underlying determinant of the chronaxie. Significance. This charge distribution is a function of both intrinsic axon properties and the spatial stimulus along the nerve; thus, examination of the local tissue topology, which shapes the electric fields, as well as the nerve trajectory, are critical for better understanding chronaxie variations and defining more biologically informed MRI safety guidelines.

How Hearing Loss and Cochlear Implantation Affect Verbal Working Memory: Evidence From Adolescents.

Verbal working memory is poorer for children with hearing loss than for peers with normal hearing (NH), even with cochlear implantation and early intervention. Poor verbal working memory can affect academic performance, especially in higher grades, making this deficit a significant problem. This study examined the stability of verbal working memory across middle childhood, tested working memory in adolescents with NH or cochlear implants (CIs), explored whether signal enhancement can improve verbal working memory, and tested two hypotheses proposed to explain the poor verbal working memory of children with hearing loss: (a) Diminished auditory experience directly affects executive functions, including working memory; (b) degraded auditory inputs inhibit children's abilities to recover the phonological structure needed for encoding verbal material into storage. Fourteen-year-olds served as subjects: 55 with NH; 52 with CIs. Immediate serial recall tasks were used to assess working memory. Stimuli consisted of nonverbal, spatial stimuli and four kinds of verbal, acoustic stimuli: nonrhyming and rhyming words, and nonrhyming words with two kinds of signal enhancement: audiovisual and indexical. Analyses examined (a) stability of verbal working memory across middle childhood, (b) differences in verbal and nonverbal working memory, (c) effects of signal enhancement on recall, (d) phonological processing abilities, and (e) source of the diminished verbal working memory in adolescents with cochlear implants. Verbal working memory remained stable across middle childhood. Adolescents across groups performed similarly for nonverbal stimuli, but those with CIs displayed poorer recall accuracy for verbal stimuli; signal enhancement did not improve recall. Poor phonological sensitivity largely accounted for the group effect. The central executive for working memory is not affected by hearing loss or cochlear implantation. Instead, the phonological deficit faced by adolescents with CIs denigrates the representation in storage and augmenting the signal does not help.

Green digital finance and technology diffusion

Technology diffusion is essential for sustainable development. However, traditional financing faces structural problems in supporting technological innovation and diffusion. Fortunately, greening and digitalisation have become important directions for the financial development. It’s well worth examining whether green digital finance would promote the diffusion of technology among regions. Therefore, this study explores the causal relationship between green digital finance and technology diffusion using the panel data of 35,532 ‘citing city-cited city’ pair observations from 2002 to 2015. Considering different spatial spillover effects of administrative boundaries and geographic distances, it applies and extends the classic spatial Dubin model with a dual-weighted boundary and distance. The main findings of this study are as follows. First, green digital finance shows significant and considerable spatial stimulus effects, particularly in terms of spatial diffusion across cities. A slight cumulative phenomenon is revealed for different technology diffusion durations. Green digital credit, investment, and support have better stimulating effects on technology diffusion. Second, digital economy and market integration are effective mechanism pathways during this stimulating process of green digital finance on technology diffusion. Digitalisation innovation has a better mechanism effect than others. Third, considering the direction of technology diffusion, the diffusion effect from the east-region cities was better than that from the central-west-region cities.

Voluntary task switching is affected by modality compatibility and preparation

Cognitive task control can be examined in task-switching studies. Performance costs in task switches are usually smaller with compatible stimulus-response modality mappings (visual-manual and auditory-vocal) than with incompatible mappings (visual-vocal and auditory-manual). Modality compatibility describes the modality match of sensory input and of the anticipated response effect (e.g., vocal responses produce auditory effects, so that auditory stimuli are modality-compatible with vocal responses). Fintor et al. (Psychological Research, 84(2), 380–388, 2020) found that modality compatibility also biased task choice rates in voluntary task switching (VTS). In that study, in each trial participants were presented with a visual or auditory spatial stimulus and were free to choose the response modality (manual vs. vocal). In this free-choice task, participants showed a bias to create more modality-compatible than -incompatible mappings. In the present study, we assessed the generality of Fintor et al.’s (2020) findings, using verbal rather than spatial stimuli, and more complex tasks, featuring an increased number of stimulus-response alternatives. Experiment 1 replicated the task-choice bias to preferentially create modality-compatible mappings. We also found a bias to repeat the response modality just performed, and a bias to repeat entire stimulus-response modality mappings. In Experiment 2, we manipulated the response-stimulus interval (RSI) to examine whether more time for proactive cognitive control would help resolve modality-specific crosstalk in this free-choice paradigm. Long RSIs led to a decreased response-modality repetition bias and mapping repetition bias, but the modality-compatibility bias was unaffected. Together, the findings suggest that modality-specific priming of response modality influences task choice.

Частотно-зависимый эффект транскраниальной стимуляции тета-вспышками префронтальной коры на когнитивные функции

Theta-burst stimulation (TBS) is widely used due to induction of the long-lasting effects with short protocol duration. To reduce the variability of the effect, approaches to personalize it, such as using theta-gamma coupling frequencies (TGC), are being investigated. The study was aimed to develop the personalized protocol of navigated intermittent theta-burst stimulation (iTBS-ind) based on TGC, and to compare this protocol with the standard one (iTBS-5/50) and sham stimulation (iTBS-sham). The study involved 16 healthy volunteers (М — 7; 29.6 years), who were randomized to receive one session of each protocol of the left dorsolateral prefrontal cortex iTBS. The effects were estimated using the n-back test with simultaneous presentation of verbal and spatial stimuli (n = 2, 3), Digit Span test, Corsi blocks task, Tower of London test; testing was performed immediately before, immediately after and 60 min after stimulation. No severe adverse events were reported. Significant effect was obtained when performing assessment after 60 min for iTBS-5/50 in the n-back test with spatial stimuli (n = 3) (pcorr = 0.018), for all protocols in the Tower of London test (pcorr = 0.039 for iTBS-5/50, pcorr = 0.045 for iTBS-ind, pcorr = 0.003 for iTBS-sham). The iTBS-5/50 effect was significantly higher compared to iTBS-sham in the spatial n-back test (n = 3) (pcorr = 0.039), but lower compared to iTBS-ind and iTBS-sham in the Corsi blocks task (pcorr = 0.038 and 0.048, respectively). Thus, we failed to confirm the personalized protocol efficacy and superiority to the standard protocol and sham stimulation. Considering the effect of standard protocol, its further investigation can be promising.

Energy controls wave propagation in a neural network with spatial stimuli

Nervous system has distinct anisotropy and some intrinsic biophysical properties enable neurons present various firing modes in neural activities. In presence of realistic electromagnetic fields, non-uniform radiation activates these neurons with energy diversity. By using a feasible model, energy function is obtained to predict the growth of synaptic connections of these neurons. Distribution of average value of the Hamilton energy function vs. intensity of noisy disturbance can predict the occurrence of coherence resonance, which the neural activities show high regularity by applying noisy disturbance with moderate intensity. From physical viewpoint, the average energy value has similar role average power for the neuron. Non-uniform spatial disturbance is applied and energy is injected into the neural network, statistical synchronization factor is calculated to predict the network synchronization stability and wave propagation. The intensity for field coupling is adaptively controlled by energy diversity between adjacent neurons. Local energy balance will terminate further growth of the coupling intensity; otherwise, heterogeneity is formed in the network due to energy diversity. Furthermore, memristive channel current is introduced into the neuron model for perceiving the effect of electromagnetic induction and radiation, and a memristive neuron is obtained. The circuit implement of memristive circuit depends on the connection to a magnetic flux-controlled memristor into the mentioned neural circuit in an additive branch circuit. The connection and activation of this memristive neural network are controlled under external spatial electromagnetic radiation by capturing enough field energy. Continuous energy collection and exchange generate energy diversity and synaptic connection is created to regulate the synchronous firing patterns and energy balance.

Eye Movement Evidence for Simultaneous Cognitive Processing in Reading.

Measuring simultaneous processing, a reliable predictor of reading development and reading difficulties (RDs), has traditionally involved cognitive tasks that test reaction or response time, which only capture the efficiency at the output processing stage and neglect the internal stages of information processing. However, with eye-tracking methodology, we can reveal the underlying temporal and spatial processes involved in simultaneous processing and investigate whether these processes are equivalent across chronological or reading age groups. This study used eye-tracking to investigate the simultaneous processing abilities of 15 Grade 6 and 15 Grade 3 children with RDs and their chronological-age controls (15 in each Grade). The Grade 3 typical readers were used as reading-level (RL) controls for the Grade 6 RD group. Participants were required to listen to a question and then point to a picture among four competing illustrations demonstrating the spatial relationship raised in the question. Two eye movements (fixations and saccades) were recorded using the EyeLink 1000 Plus eye-tracking system. The results showed that the Grade 3 RD group produced more and longer fixations than their CA controls, indicating that the pattern of eye movements of young children with RD is typically deficient compared to that of their typically developing counterparts when processing verbal and spatial stimuli simultaneously. However, no differences were observed between the Grade 6 groups in eye movement measures. Notably, the Grade 6 RD group outperformed the RL-matched Grade 3 group, yielding significantly fewer and shorter fixations. The discussion centers on the role of the eye-tracking method as a reliable means of deciphering the simultaneous cognitive processing involved in learning.

Spatial-numerical associations of manual response codes are strongly asymmetrical

The spatial-numerical association of response codes (SNARC) effect denotes the observation that humans respond faster and more accurately with a left-side response to smaller numbers and a right-side response to larger numbers, as compared to the opposite mapping. Existing accounts, such as the mental number line hypothesis or the polarity correspondence principle, differ in whether they assume symmetrical associations between numerical and spatial stimulus and response codes or not. In two experiments, we investigated the reciprocity of the SNARC effect in manual choice-response tasks with two conditions. In the number-location task, participants pressed a left or right key to a number stimulus (dots in Experiment 1, digits in Experiment 2). In the location-number task, participants made one or two consecutive keypresses with one hand to a left- or right-side stimulus. Both tasks were performed with a compatible (one-left, two-right; left-one, right-two) and an incompatible (one-right, two-left; left-two, right-one) mapping. In both experiments, results showed a strong compatibility effect in the number-location task, reflecting the typical SNARC effect. In contrast, in both experiments, there was no mapping effect in the location-number task when outliers were excluded. However, when outliers were not excluded, small reciprocal SNARC effects occurred in Experiment 2. Together, the findings suggest that priming of spatial responses by numerical stimuli is much stronger than priming of numerical responses by spatial stimuli. The results are consistent with some accounts of the SNARC effect (e.g., the mental number line hypothesis), but not with others (e.g., the polarity correspondence principle).

Improving causality perception judgments in schizophrenia spectrum disorder via transcranial direct current stimulation.

Deficient causality perception and attribution may underlie key symptoms of schizophrenia spectrum disorder (SSD), such as delusions and ideas of reference. Although transcranial direct current stimulation (tDCS) can increase the influence of spatial information on perceptual causality judgments among healthy participants, its effect among patients with SSD remains unknown. We sought to determine whether tDCS modulates the contribution of stimulus characteristics to perceptual causality judgments among patients with SSD; we predicted that right parietal tDCS would increase the influence of spatial stimulus characteristics on patients' causality perception. Patients with SSD received frontal, parietal, frontoparietal and sham tDCS in 4 separate sessions. Pre- and post-tDCS, patients viewed video clips of ball A colliding with ball B. Spatial linearity (ball B's angle of egress) and temporal contiguity (delay between collision and ball B's movement) varied parametrically. After each launching event, patients rated perceived causality. Among 19 patients with SSD, we found a brain region-dependent effect of tDCS regarding sensitivity to violations of spatial linearity. After right parietal anodal tDCS, the influence of angle variations on patients' perceptual causality judgments increased, reflected by a higher probability of perceived causality for stimuli with small angles and a lower probability of perceived causality for stimuli with high angles. Transcranial direct current stimulation increased the influence of spatial stimulus characteristics on causality perception among patients with SSD. Future research should explore potential links between tDCS-induced changes in basic perceptual processes and clinical symptoms, such as delusions and ideas of reference.

Multi-sensory feedback improves spatially compatible sensori-motor responses

To interact with machines, from computers to cars, we need to monitor multiple sensory stimuli, and respond to them with specific motor actions. It has been shown that our ability to react to a sensory stimulus is dependent on both the stimulus modality, as well as the spatial compatibility of the stimulus and the required response. However, the compatibility effects have been examined for sensory modalities individually, and rarely for scenarios requiring individuals to choose from multiple actions. Here, we compared response time of participants when they had to choose one of several spatially distinct, but compatible, responses to visual, tactile or simultaneous visual and tactile stimuli. We observed that the presence of both tactile and visual stimuli consistently improved the response time relative to when either stimulus was presented alone. While we did not observe a difference in response times of visual and tactile stimuli, the spatial stimulus localization was observed to be faster for visual stimuli compared to tactile stimuli.

Spatial stimuli in films: Uncovering the relationship between cognitive emotion and perceived environmental quality

The research paper establishes the impact of spatial stimulus on human cognition and emotion by studying environmental events as cues to understand how people perceive spatial qualities. The medium of film to implement visually disruptive events was used in the research to find the relationship between the subjective evaluation of space and emotional responses. Ninety participants participated in watching three films showcasing unexpected spatial stimuli, thus impacting their psychological state. Standard questionnaires involving Aesthetic chills and The Self-Assessment Manikin (SAM) model were used to capture emotional responses, and Normalized Accumulated Quality (NAQ) model was used to receive space quality assessments. The Pearson correlation coefficient was subsequently used to find the association of chills and The SAM with NAQ. Univariate and multivariate regression models were also conducted to find the impact of emotional responses on NAQ. A significant association of NAQ with chills (p-value: 0.001), pleasure (p-value <0.001), arousal (p-value: 0.016), and dominance (p-value: 0.015) was witnessed in film 1. In film 2, NAQ was significantly associated with pleasure (p-value <0.001), while in film 3, NAQ was highly associated with arousal (p-value: 0.043). According to the adjusted impact of variables on NAQ in film 1, significant impacts of chills (p-value: 0.028), arousal (p-value: 0.117), pleasure (p-value <0.001), and dominance (p-value: 0.113) on NAQ were observed. In film 2, pleasure (p-value <0.001) and dominance (p-value: 0.113) impacted NAQ using the univariate model, while only pleasure had an impact on NAQ in the multivariate model. In film 3, arousal was the only variable to impact NAQ (p-value: 0.043) in a univariate model. In regression analyses, higher slopes were witnessed for models in film 1. The experiment highlighted that using affect-based video clips can help us capture the relationship between emotional responses and perceived quality of space. The appearance of spatial stimuli can engage learning, expectation, and attention, leading to a superior improvement of cognitive ability and mental health in space. This level of understanding can help design a more sustainable place.

Retaining memory after hibernation: Performance varies independently of activity levels in wild grey mouse lemurs

AbstractHibernation, a hypometabolic state associated with low body temperature and reduced metabolic and activity rates, represents one adaptation to harsh seasonal environmental conditions. As a consequence of hypometabolism, energetically costly neuronal processes also ought to be reduced. Since active neuronal pathways are prerequisites for learning and memory, and because previous studies revealed variable patterns, it remains unclear whether and how hibernating animals retain memories, however. Here, we investigated the effect of seasonally reduced activity on memory retention in 36 wild grey mouse lemurs (Microcebus murinus). Data from activity loggers confirmed that female grey mouse lemurs entered hibernation during the cool dry season, whereas males exhibited episodic bursts of activity throughout the austral winter. Thus, compared to males, we predicted females to show lower memory retention of visual and spatial stimulus–reward associations learned before hibernation. In contrast to our prediction, all individuals performed worse in the post‐hibernation testing session in both types of tests, compared to the pre‐hibernation learning session, and males (N = 11) performed even worse than females (N = 14) in the post‐hibernation testing session. Although females (N = 9) equipped with activity loggers tended to be less active than males (N = 4), sex‐specific activity levels were unrelated to interindividual differences in memory retention. Hence, the post‐hibernation decrease in performance of grey mouse lemurs may reflect a more general disability to retain stimulus–reward associations than a lack of memory retention due to seasonal hypometabolism, as suggested for some species of bats or squirrels.

Effect of electric-acoustic cochlear implant stimulation and coding strategies on spatial cues of speech signals in reverberant room

The comparison of spatial cues changes in different setups and coding strategies used in cochlear implants (CI) is investigated. In this experiment, we implement three voice coder setups, such as bilateral CI, bimodal CI, and electro-acoustic stimulation (EAS). Two well-known coding strategies are used, which are continuous interleaved sampling (CIS) and spectral peak (SPEAK). Speech signals are convoluted with appropriate binaural room impulse response (BRIR), creating reverberant spatial stimuli. Five different reverberant conditions (including anechoic) were applied to the stimuli. Interaural level and time differences (ILD and ITD) are evaluated objectively and subjectively, and their relationship with the intelligibility of speech is observed. Prior objective evaluation with CIS reveals that clarity (C50) becomes a more important factor in spatial cue change than reverberation time. Vocoded conditions (bilateral CI) show an increment in ILD value (compression has not been implemented yet on the vocoder processing), when the value of ITD gets more different (decreased) from the middle point. Reverberation degrades the intelligibility rate at various rates depending on the C50 value, both in unvocoded and vocoded conditions. In the vocoded condition, decrement on spatial cues was also followed by the decreement on the intelligibility of spatial stimuli.

Neural Dynamics Underlying Cognitive Control Modulated by Reinforcement Learning of Irrelevant Stimulus-Response Associations.

Human behavioral studies have shown that reward has multifaceted (motivational, learning, and emotional) effects on cognitive control. Past studies have extensively explored the neural underpinning of the motivational effect of reward on cognitive control, but less is known on the other components. The present study investigates the learning effect of reward on cognitive control with a novel paradigm reinforcing task-irrelevant stimulus-response (S-R) associations. We manipulated the contingency of irrelevant spatial stimulus-response-reward between participants (n = 54) in an orthogonal Simon task during EEG recording. The behavioral results showed that the orthogonal Simon effect in RTs and error rates increased or reversed when performance-contingent reward always followed spatially compatible or incompatible trials. The EEG results showed that the initial incorrect activation of the lateralized readiness potential, reflecting response preparation based on irrelevant spatial S-R associations, was present in the incompatible or compatible condition when reward always followed compatible or incompatible trials. Meanwhile, the P3b amplitude also showed a similar pattern of increase or reversal depending on the contingency of irrelevant stimulus-response-reward. These findings suggest that the brain used reward-strengthened irrelevant spatially compatible or incompatible S-R associations to predict responses. Moreover, the frontocentral N2 amplitude and theta band (4-8 Hz) power showed similar reward-related increase or reversal in the conflict effect, suggesting that there was conflict when the response predicted by the reward-strengthened irrelevant S-R associations was different from the correct response. Taken together, these results suggest that reinforcement learning of irrelevant spatial S-R associations can modulate cognitive control.

Anterior thalamic nuclei: A critical substrate for non-spatial paired-associate memory in rats.

Injury or dysfunction in the anterior thalamic nuclei (ATN) may be the key contributory factor in many instances of diencephalic amnesia. Experimental ATN lesions impair spatial memory and temporal discriminations, but there is only limited support for a more general role in non-spatial memory. To extend evidence on the effects of ATN lesions, we examined the acquisition of biconditional associations between odour and object pairings presented in a runway, either with or without a temporal gap between these items. Intact adult male rats acquired both the no-trace and 10-s trace versions of this non-spatial task. Intact rats trained in the trace version showed elevated Zif268 activation in the dorsal CA1 of the hippocampus, suggesting that the temporal component recruited additional neural processing. ATN lesions completely blocked acquisition on both versions of this association-memory task. This deficit was not due to poor inhibition to non-rewarded cues or impaired sensory processing, because rats with ATN lesions were unimpaired in the acquisition of simple odour discriminations and simple object discriminations using similar task demands in the same apparatus. This evidence challenges the view that impairments in arbitrary paired-associate learning after ATN lesions require the use of multimodal spatial stimuli. It suggests that diencephalic amnesia associated with the ATN stems from degraded attention to stimulus-stimulus associations and their representation across a distributed memory system.

Microfluidic Lab-on-a-Chip for Studies of Cell Migration under Spatial Confinement.

Understanding cell migration is a key step in unraveling many physiological phenomena and predicting several pathologies, such as cancer metastasis. In particular, confinement has been proven to be a key factor in the cellular migration strategy choice. As our insight in the field improves, new tools are needed in order to empower biologists’ analysis capabilities. In this framework, microfluidic devices have been used to engineer the mechanical and spatial stimuli and to investigate cellular migration response in a more controlled way. In this work, we will review the existing technologies employed in the realization of microfluidic cellular migration assays, namely the soft lithography of PDMS and hydrogels and femtosecond laser micromachining. We will give an overview of the state of the art of these devices, focusing on the different geometrical configurations that have been exploited to study specific aspects of cellular migration. Our scope is to highlight the advantages and possibilities given by each approach and to envisage the future developments in in vitro migration studies under spatial confinement in microfluidic devices.