Selective Attention Task Research Articles

Cognitive and motor deficits contribute to longer braking time in stroke

BackgroundBraking is a critical determinant of safe driving that depends on the integrity of cognitive and motor processes. Following stroke, both cognitive and motor capabilities are impaired to varying degrees. The current study examines the combined impact of cognitive and motor impairments on braking time in chronic stroke.MethodsTwenty stroke survivors and 20 aged-matched healthy controls performed cognitive, motor, and simulator driving assessments. Cognitive abilities were assessed with processing speed, divided attention, and selective attention. Motor abilities were assessed with maximum voluntary contraction (MVC) and motor accuracy of the paretic ankle. Driving performance was examined with the braking time in a driving simulator and self-reported driving behavior.ResultsBraking time was 16% longer in the stroke group compared with the control group. The self-reported driving behavior in stroke group was correlated with braking time (r = − 0.53, p = 0.02). The stroke group required significantly longer time for divided and selective attention tasks and showed significant decrease in motor accuracy. Together, selective attention time and motor accuracy contributed to braking time (R2 = 0.40, p = 0.01) in stroke survivors.ConclusionsThis study provides novel evidence that decline in selective attention and motor accuracy together contribute to slowed braking in stroke survivors. Driving rehabilitation after stroke may benefit from the assessment and training of attentional and motor skills to improve braking during driving.

Effect of Stroop color word interference on selective attention task among healthy young adults

Background: J Ridley Stroop showed that if someone was reading information and additional contradictory inputs were introduced, the person’s reading pace would slow down. Stroop test is used to assess selective attention. Interference can occur between the controlled process and the automatic process. Psychologists have repeatedly established that the automatic nature of reading words, seeing that it is such a well-learned repeated activity can obstruct other tasks. There is additional evidence that practicing the Stroop task alters the extent of the interference effects. Aim and Objectives: The aim of this study was to assess the response time in Stroop test among healthy young adults and to compare the response time in Stroop test before and after the practice of word identification. Materials and Methods: Study included 82 2nd year medical undergraduates aged between 19 and 21 years, who gave their informed consent. Institutional ethical clearance was obtained. Stroop color-word test included three cards, the first bearing color patches, the second color words printed in congruent ink colors, and the third with color words printed in incongruent ink colors. The test required the subjects to name the colors on the first card, the words on the second card, and ink color on the third card without taking into account the printed words as fast as they can. Stopwatch was used to record the response time. Then, participants were asked to practice the above task of reading congruent and incongruent ink colors for about 6 days. After which they were again assessed for response time in Stroop test. Mean difference in response time between card two and three before and after the practice was tabulated and statistically analyzed. Results: The mean age was 20 ± 2 years. Before the practice session, the mean response time taken to read card three was significantly more (13.27 ± 2.66 min) compared to card two (6.26 ± 1.41 min) (P = 0.000, unpaired t-test). After the practice session, the mean response time taken was more for card three (12.14 ± 1.83 min) compared to card two (5.33 ± 1.21 min) (P = 0.000, unpaired t-test). However, there was no significant difference in response time before and after the practice session. Conclusion: The response time and interferences were more in incongruent Stroop test than congruent test. This indicates that the participants have delayed attention while performing Stroop test. This was in accordance with the Stroop effect. However, the study could not establish the effect of practice of word identification on Stroop test.

Training enhances the ability of listeners to exploit visual information for auditory scene analysis

The ability to use temporal relationships between cross-modal cues facilitates perception and behavior. Previously we observed that temporally correlated changes in the size of a visual stimulus and the intensity in an auditory stimulus influenced the ability of listeners to perform an auditory selective attention task (Maddox, Atilgan, Bizley, & Lee, 2015). Participants detected timbral changes in a target sound while ignoring those in a simultaneously presented masker. When the visual stimulus was temporally coherent with the target sound, performance was significantly better than when the visual stimulus was temporally coherent with the masker, despite the visual stimulus conveying no task-relevant information. Here, we trained observers to detect audiovisual temporal coherence and asked whether this changed the way in which they were able to exploit visual information in the auditory selective attention task. We observed that after training, participants were able to benefit from temporal coherence between the visual stimulus and both the target and masker streams, relative to the condition in which the visual stimulus was coherent with neither sound. However, we did not observe such changes in a second group that were trained to discriminate modulation rate differences between temporally coherent audiovisual streams, although they did show an improvement in their overall performance. A control group did not change their performance between pretest and post-test and did not change how they exploited visual information. These results provide insights into how crossmodal experience may optimize multisensory integration.

Rural and urban disparities in selective attention in Chinese young adults: An event-related potential study

Previous studies showed that attention system and its underlying neural mechanisms were profound affected by social inequalities. However, previous studies on social inequalities were mainly focused on family-based factors, such as parental education, parental occupation, and household income. In the present study, we investigated the neural mechanisms underlying more broader social context (e.g., rural verse urban) disparities in selective attention among young adults in China. Event-related potentials (ERPs) were recorded from 22 college students who had born and grown up in rural areas and 22 students who had born and grown up in urban areas during an auditory selective attention task. Although behavioral performance was not significantly different between groups, attentional differences in the negativity difference (Nd) were significantly larger in the urban group than the rural group. Whole sample analysis with hierarchical regression showed that rural/urban status still made a significant contribution to the prediction of Nd amplitudes even after the effects of age, sex, and various family SES measures (include parents’ educational levels and annual household income) were controlled for. These findings represent a first step toward understanding the ways in which broad social environmental factors shape the neural basis of selective attention.

Altered fronto-occipital connectivity during visual selective attention in regular cannabis users

Cognitive processing impairments have been associated with acute cannabis use, but there is mixed evidence regarding the cognitive effects of chronic cannabis use. Several neuroimaging studies have noted selective-attention processing differences in those who chronically use cannabis, but the neural dynamics governing the altered processing is unclear. Twenty-four adults reporting at least weekly cannabis use in the past 6months on the Cannabis Use Disorder Identification Test - Revised were compared to 24 demographically matched controls who reported no prior cannabis use. All participants completed a visual selective attention processing task while undergoing magnetoencephalography. Time-frequency windows of interest were identified using a data-driven method, and spectrally specific neural activity was imaged using a beamforming approach. All participants performed within normal range on the cognitive task. Regular cannabis users displayed an aberrant cognitive interference effect in the theta (4-8Hz) frequency range shortly after stimulus onset (i.e., 0-250ms) in the right occipital cortex. Cannabis users also exhibited altered functional connectivity between the right prefrontal cortex and right occipital cortices in comparison to controls. Individuals with a history of regular cannabis use exhibited abnormal theta interference activity in the occipital cortices, as well as altered prefrontal-occipital functional connectivity in the theta range during a visual selective attention task. Such differences may reflect compensatory processing, as these participants performed within normal range on the task. Understanding the neural dynamics in chronic, regular cannabis users may provide insight on how long-term and/or frequent use may affect neural networks underlying cognitive processes.

Auditory selective attention under working memory load

Can cognitive load enhance concentration on task-relevant information and help filter out distractors? Most of the prior research in the area of selective attention has focused on visual attention or cross-modal distraction and has yielded controversial results. Here, we studied whether working memory load can facilitate selective attention when both target and distractor stimuli are auditory. We used a letter n-back task with four levels of working memory load and two levels of distraction: congruent and incongruent distractors. This combination of updating and inhibition tasks allowed us to manipulate working memory load within the selective attention task. Participants sat in front of three loudspeakers and were asked to attend to the letter presented from the central loudspeaker while ignoring that presented from the flanking ones (spoken by a different person), which could be the same letter as the central one (congruent) or a different (incongruent) letter. Their task was to respond whether or not the central letter matched the letter presented n (0, 1, 2, or 3) trials back. Distraction was measured in terms of the difference in reaction time and accuracy on trials with incongruent versus congruent flankers. We found reduced interference from incongruent flankers in 2- and 3-back conditions compared to 0- and 1-back conditions, whereby higher working memory load almost negated the effect of incongruent flankers. These results suggest that high load on verbal working memory can facilitate inhibition of distractors in the auditory domain rather than make it more difficult as sometimes claimed.

Individual differences in working memory capacity moderate effects of post-learning activity on memory consolidation over the long term

Similar to sleeping after learning, a brief period of wakeful resting after encoding new information supports memory retention in contrast to task-related cognition. Recent evidence suggests that working memory capacity (WMC) is related to sleep-dependent declarative memory consolidation. We tested whether WMC moderates the effect of a brief period of wakeful resting compared to performing a distractor task subsequent to encoding a word list. Participants encoded and immediately recalled a word list followed by either an 8 min wakeful resting period (eyes closed, relaxed) or by performing an adapted version of the d2 test of attention for 8 min. At the end of the experimental session (after 12–24 min) and again, after 7 days, participants were required to complete a surprise free recall test of both word lists. Our results show that interindividual differences in WMC are a central moderating factor for the effect of post-learning activity on memory retention. The difference in word retention between a brief period of wakeful resting versus performing a selective attention task subsequent to encoding increased in higher WMC individuals over a retention interval of 12–24 min, as well as over 7 days. This effect was reversed in lower WMC individuals. Our results extend findings showing that WMC seems not only to moderate sleep-related but also wakeful resting-related memory consolidation.

The role of attention in listening-in-noise

Listeners of all ages are faced with having to understand speech in the presence of noise. One factor that might influence listeners' success at this task is their ability to attend selectively. We examine both adults' and toddlers' understanding of speech in the presence of nonlinguistic background noise – noise that is either easier or harder to attend to selectively. We also test the same individuals on a nonlinguistic selective attention task. Adult listeners easily take advantage of acoustic cues such as spatial location and frequency-range differences to help them attend selectively to, and comprehend, the target speech. Young toddlers (under 2 years of age) fail to use these cues. In addition, among adults, success at listening in noise is correlated with performance in a visual selective attention task, suggesting that domain-general attention skills are relevant for adults' listening in noise. This is less clearly the case for young children, however; indeed, children who were more easily distracted by extraneous sounds showed better speech understanding in noise. These findings suggest that the relationship between performance in challenging listening conditions and other cognitive skills undergoes critical changes across development.

Extradural Motor Cortex Stimulation might improve episodic and working memory in patients with Parkinson\u2019s disease

Electric Extradural Motor Cortex Stimulation (EMCS) is a neurosurgical procedure suggested for treatment of patients with advanced Parkinson’s disease (PD). We report two PD patients treated by EMCS, who experienced worsening of motor symptoms and cognition 5 years after surgery, when EMCS batteries became discharged. One month after EMCS restoration, they experienced a subjective improvement of motor symptoms and cognition. Neuropsychological assessments were carried out before replacement of batteries (off-EMCS condition) and 6 months afterward (on-EMCS condition). As compared to off-EMCS condition, in on-EMCS condition both patients showed an improvement on tasks of verbal episodic memory and backward spatial short-term/working memory task, and a decline on tasks of selective visual attention and forward spatial short-term memory. These findings suggest that in PD patients EMCS may induce slight beneficial effects on motor symptoms and cognitive processes involved in verbal episodic memory and in active manipulation of information stored in working memory.

Visual exogenous and endogenous attention and visual memory in preschool children who stutter

PurposeAttention develops gradually from infancy to the preschool years and beyond. Exogenous attention, consisting of automatic responses to salient stimuli, develops in infancy, whereas endogenous attention, or voluntary attention, begins to develop later, in the preschool years. The purpose of this study was to examine (a) exogenous and endogenous attention in young children who stutter (CWS) and children who do not stutter (CWNS) through two conditions of a visual sustained selective attention task, and (b) visual short-term memory (STM) between groups within the context of this task. Method42 CWS and 42 CWNS, ages 3;0–5;5 (years;months), were pair-matched in age, gender (31 males, 11 females per group), and socioeconomic status. Children completed a visual tracking task (Track-It Task; Fisher et al., 2013) requiring sustained selective attention and engaging exogenous and endogenous processes. Following each item, children were asked to recall the item they had tracked, as a memory check. ResultsThe CWS group demonstrated significantly less accuracy in overall tracking and visual memory for the tracked stimuli, compared to the CWNS group. Across groups, the children performed better in sustained selective attention when the target stimuli were more salient (the condition tapping both exogenous and endogenous attention) than when stimuli were less so (the condition tapping primarily endogenous processes). ConclusionsRelative to peers, preschool-age CWS, as a group, display weaknesses in visual sustained selective attention and visual STM.

Neural Representation Enhanced for Speech and Reduced for Background Noise With a Hearing Aid Noise Reduction Scheme During a Selective Attention Task.

ObjectivesSelectively attending to a target talker while ignoring multiple interferers (competing talkers and background noise) is more difficult for hearing-impaired (HI) individuals compared to normal-hearing (NH) listeners. Such tasks also become more difficult as background noise levels increase. To overcome these difficulties, hearing aids (HAs) offer noise reduction (NR) schemes. The objective of this study was to investigate the effect of NR processing (inactive, where the NR feature was switched off, vs. active, where the NR feature was switched on) on the neural representation of speech envelopes across two different background noise levels [+3 dB signal-to-noise ratio (SNR) and +8 dB SNR] by using a stimulus reconstruction (SR) method.DesignTo explore how NR processing supports the listeners’ selective auditory attention, we recruited 22 HI participants fitted with HAs. To investigate the interplay between NR schemes, background noise, and neural representation of the speech envelopes, we used electroencephalography (EEG). The participants were instructed to listen to a target talker in front while ignoring a competing talker in front in the presence of multi-talker background babble noise.ResultsThe results show that the neural representation of the attended speech envelope was enhanced by the active NR scheme for both background noise levels. The neural representation of the attended speech envelope at lower (+3 dB) SNR was shifted, approximately by 5 dB, toward the higher (+8 dB) SNR when the NR scheme was turned on. The neural representation of the ignored speech envelope was modulated by the NR scheme and was mostly enhanced in the conditions with more background noise. The neural representation of the background noise was modulated (i.e., reduced) by the NR scheme and was significantly reduced in the conditions with more background noise. The neural representation of the net sum of the ignored acoustic scene (ignored talker and background babble) was not modulated by the NR scheme but was significantly reduced in the conditions with a reduced level of background noise. Taken together, we showed that the active NR scheme enhanced the neural representation of both the attended and the ignored speakers and reduced the neural representation of background noise, while the net sum of the ignored acoustic scene was not enhanced.ConclusionAltogether our results support the hypothesis that the NR schemes in HAs serve to enhance the neural representation of speech and reduce the neural representation of background noise during a selective attention task. We contend that these results provide a neural index that could be useful for assessing the effects of HAs on auditory and cognitive processing in HI populations.

Introducing the Tactual Span: A New Task for Assessing Working Memory in the Teactile Modality.

The span paradigm is commonly used to assess working memory (WM), predominantly through the visual and auditory routes and less often through the tactile modality. The current study aimed to validate the "Tactual Span", a new task developed to evaluate WM in the tactile modality. Participants were 140 healthy young adults, who performed the Tactual Span alongside span tasks in three additional modalities (auditory, visual, and visuospatial), as well as a selective attention task and a semantic verbal fluency task. The Tactual Span and other span tasks were found to correlate, while correlations with the selective attention and semantic fluency tasks were largely nonsignificant, indicating good construct validity. Cronbach's alpha for both stages as well as skewness and kurtosis were also adequate. An exploratory factor analysis for the forward stage showed that the Tactual Span and Visuospatial Span were loaded on one factor, whereas the Auditory and Visual Spans were loaded on another factor. In the backward stage, all span tasks were loaded on a single factor. The findings provide an initial indication that the Tactual Span task is a feasible and valid tool for assessing WM in the tactile modality.

Hogyan hat a mobileszköz-használat az óvodások figyelmére és társas-kognitív készségeire?

Az érintőképernyős mobileszközöket (ÉKM: okostelefonok és tabletek) egyre többet és egyre fiatalabb korban használják a gyerekek. Ekkor az agy még nagyon plasztikus, így az ÉKM-használat befolyásolhatja a kognitív fejlődést, ami új kihívásokat támaszt a szülőkkel és pedagógusokkal szemben. Egy keresztmetszeti vizsgálatban összehasonlítottuk az ÉKM-eszközöket gyakran használó és az ilyen eszközöket nem használó óvodás korú gyerekek (szelektív és megosztott) figyelmi és szociokognitív képességeit. Majd kísérletesen vizsgáltuk, hogy miképp befolyásolja a gyerekek figyelmi teljesítményét, ha előzőleg (előkezelés) egy gyors vagy lassú sebességű digitális játékkal vagy egy nem digitális játékkal játszanak. A szelektív figyelmi feladatban a gyerekek figyelmére (ÉKM-használattól függetlenül) a globális fókusz volt jellemző (jobban teljesítettek, ha az egészre kellett figyelni, mint ha a részletre), a megosztott figyelmi feladatban azonban az ÉKM-használók atipikus, lokális fókuszt mutattak (jobban teljesítettek, amikor a kis ábra volt a célinger, mint amikor a nagy), és teljesítményük a globális próbákban elmaradt az ÉKM-eket nem használó gyerekekétől. Az ÉKM-használók gyengébb tudatelméleti teljesítményt mutattak, viszont az érzelmek felismerésében nem különböztek az ÉKM-et nem használóktól. Az előkezelésen alapuló vizsgálatunk a figyelmi működéssel kapcsolatos eredményeket kísérletesen is megerősítette: a tesztet megelőzően digitális játékkal játszó gyerekek globális fókuszt mutattak a szelektív feladatban és lokális fókuszt a megosztott figyelmi feladatban, a nem-digitális játék után viszont mindkét feladatban globális fókusz volt jellemző. Míg a nem-digitális és a lassú digitális játékkal játszó gyerekek a szelektív figyelmi feladatban jobban teljesítettek, mint a megosztottban, addig a gyors digitális játékkal játszók nem mutattak ilyen előnyt a szelektív figyelmi feladatban. Eredményeink azt mutatják, hogy az ÉKM-eszközök rövid- és hosszútávú használata és azon belül a digitális játékokkal való játék lokális figyelmi fókuszhoz vezet, talán azért, mert a digitális képernyők lokális információkban gazdagok, és ritkán látszódik egyben az egész kép. A gyors digitális játék, azáltal, hogy párhuzamosan több ingerre kell figyelni, a megosztott figyelmet fejleszti, de a szelektív figyelmet nem. Az ÉKM-használat elveszi az időt a társas tevékenységektől, ami magyarázhatja, hogy az ÉKM-használóknak nehézségeik vannak a komplexebb szociokognitív képességek terén (tudatelmélet). Eredményeink fontos ismereteket nyújtanak és irányt mutatnak a pedagógia és a pszichológia számára.

Computational modelling of attentional selectivity in depression reveals perceptual deficits.

Depression is associated with broad deficits in cognitive control, including in visual selective attention tasks such as the flanker task. Previous computational modelling of depression and flanker task performance showed reduced pre-potent response bias and reduced executive control efficiency in depression. In the current study, we applied two computational models that account for the full dynamics of attentional selectivity. Across three large-scale online experiments (one exploratory experiment followed by two confirmatory - and pre-registered - experiments; total N = 923), we measured attentional selectivity via the flanker task and obtained measures of depression symptomology as well as anhedonia. We then fit two computational models that account for the dynamics of attentional selectivity: The dual-stage two-phase model, and the shrinking spotlight (SSP) model. No behavioural measures were related to depression symptomology or anhedonia. However, a parameter of the SSP model that indexes the strength of perceptual input was consistently negatively associated with the magnitude of depression symptomatology. The findings provide evidence for deficits in perceptual representations in depression. We discuss the implications of this in relation to the hypothesis that perceptual deficits potentially exacerbate control deficits in depression.

Constructing an Instrument for Measuring the Selective Visual Attention of Basic-Stage Students in Gaza and Verifying its Psychometric Characteristics

The research aims at constructing an instrument for measuring the selective visual attention of basic education students in Gaza, and verifying its validity and reliability. The research sample consisted of 200 grade ten students in Khan Younis (for the academic year, 2018 -2019). The evidence of constructive validity and the factorial validity of the instrument were investigated. Results of the predictive factorial analysis showed that the three tasks of the instrument covered a single potential factor namely selective visual attention. All slides of the selective visual attention tasks have achieved statistically significant correlations with the overall scores of the instrument. The content of the slides was also validated in relation to the instrument. The instrument reliability was also checked with the alpha coefficient for the final form of the instrument as a whole (0,962), and the split–half reliability coefficients ranged from (0.770 – 0.907). The final form of the instrument showed three major functions.

Constructing an Instrument for Measuring the Selective Visual Attention of Basic-Stage Students in Gaza and Verifying its Psychometric Characteristics

The research aims at constructing an instrument for measuring the selective visual attention of basic education students in Gaza, and verifying its validity and reliability. The research sample consisted of 200 grade ten students in Khan Younis (for the academic year, 2018 -2019). The evidence of constructive validity and the factorial validity of the instrument were investigated. Results of the predictive factorial analysis showed that the three tasks of the instrument covered a single potential factor namely selective visual attention. All slides of the selective visual attention tasks have achieved statistically significant correlations with the overall scores of the instrument. The content of the slides was also validated in relation to the instrument. The instrument reliability was also checked with the alpha coefficient for the final form of the instrument as a whole (0,962), and the split–half reliability coefficients ranged from (0.770 – 0.907). The final form of the instrument showed three major functions.

A Virtual-Reality System Integrated With Neuro-Behavior Sensing for Attention-Deficit/Hyperactivity Disorder Intelligent Assessment.

Attention-deficit/Hyperactivity disorder(ADHD) is a common neurodevelopmental disorder among children. Traditional assessment methods generally rely on behavioral rating scales (BRS) performed by clinicians, and sometimes parents or teachers. However, BRS assessment is time consuming, and the subjective ratings may lead to bias for the evaluation. Therefore, the major purpose of this study was to develop a Virtual Reality (VR) classroom associated with an intelligent assessment model to assist clinicians for the diagnosis of ADHD. In this study, an immersive VR classroom embedded with sustained and selective attention tasks was developed in which visual, audio, and visual-audio hybrid distractions, were triggered while attention tasks were conducted. A clinical experiment with 37 ADHD and 31 healthy subjects was performed. Data from BRS was compared with VR task performance and analyzed by rank-sum tests and Pearson Correlation. Results showed that 23 features out of total 28 were related to distinguish the ADHD and non-ADHD children. Several features of task performance and neuro-behavioral measurements were also correlated with features of the BRSs. Additionally, the machine learning models incorporating task performance and neuro-behavior were used to classify ADHD and non-ADHD children. The mean accuracy for the repeated cross-validation reached to 83.2%, which demonstrated a great potential for our system to provide more help for clinicians on assessment of ADHD.

Dissociable Effects of Reward on P300 and EEG Spectra Under Conditions of High vs. Low Vigilance During a Selective Visual Attention Task.

The influence of motivation on selective visual attention in states of high vs. low vigilance is poorly understood. To explore the possible differences in the influence of motivation on behavioral performance and neural activity in high and low vigilance levels, we conducted a prolonged 2 h 20 min flanker task and provided monetary rewards during the 20- to 40- and 100- to 120-min intervals of task performance. Both the behavioral and electrophysiological measures were modulated by prolonged task engagement. Moreover, the effect of reward was different in high vs. low vigilance states. The monetary reward increased accuracy and decreased the reaction time (RT) and number of omitted responses in the low but not in the high vigilance state. The fatigue-related decrease in P300 amplitude recovered to its level in the high vigilance state by manipulating motivation, whereas the fatigue-related increase in P300 latency was not modulated by reward. Additionally, the fatigue-related increase in event-related spectral power at 1–4 Hz was sensitive to vigilance decrement and reward. However, the spectral power at 4–8 Hz was only affected by the decrease in vigilance. These electrophysiological measures were not influenced by motivation in the state of high vigilance. Our results suggest that neural processing capacity, but not the timing of processing, is sensitive to motivation. These findings also imply that the fatigue-related impairments in behavioral performance and neural activity underlying selective visual attention only partly recover after manipulating motivation. Furthermore, our results provide evidence for the dissociable neural mechanisms underlying the fatigue-related decrease vs. reward-related increase in attentional resources.

Irrelevant Predictions: Distractor Rhythmicity Modulates Neural Encoding in Auditory Cortex.

Dynamic attending theory suggests that predicting the timing of upcoming sounds can assist in focusing attention toward them. However, whether similar predictive processes are also applied to background noises and assist in guiding attention "away" from potential distractors, remains an open question. Here we address this question by manipulating the temporal predictability of distractor sounds in a dichotic listening selective attention task. We tested the influence of distractors' temporal predictability on performance and on the neural encoding of sounds, by comparing the effects of Rhythmic versus Nonrhythmic distractors. Using magnetoencephalography we found that, indeed, the neural responses to both attended and distractor sounds were affected by distractors' rhythmicity. Baseline activity preceding the onset of Rhythmic distractor sounds was enhanced relative to nonrhythmic distractor sounds, and sensory response to them was suppressed. Moreover, detection of nonmasked targets improved when distractors were Rhythmic, an effect accompanied by stronger lateralization of the neural responses to attended sounds to contralateral auditory cortex. These combined behavioral and neural results suggest that not only are temporal predictions formed for task-irrelevant sounds, but that these predictions bear functional significance for promoting selective attention and reducing distractibility.

Characterizing the orientation selectivity in V1 and V4 of macaques by quadratic phase coupling

Objective. Orientation selectivity is one of the significant characteristics of neurons in the primary visual cortex (V1). Some neurons in extrastriate visual cortical areas also exhibit certain orientation selectivity. But it is still not well understood that how the orientation selectivity generates. Most previous studies about the orientation selectivity are based on the spike firing rate. However, the spikes are prone to be biased by the detection and sorting algorithms. Then, in this paper, the local field potential (LFP) is adopted to investigate the mechanism of orientation selectivity. Approach. We used the quadratic phase coupling (QPC), which was calculated by wavelet bicoherence, to describe the characteristics of orientation selectivity available in V1 and V4. The raw wideband neural signals were recorded by two chronically implanted multi-electrode arrays, which were placed in V1 and V4 respectively in two macaques performing a selective visual attention task. Main results. There is a strong correlation between the total bicoherence (TotalBic), which is a quantization for the overall QPC of frequency pairs in gamma band, and the grating orientation. Furthermore, the QPC distribution at the non-preferred orientation is mainly concentrated in the low frequencies (30–40 Hz) of gamma; while the QPC distribution at the preferred orientation concentrates in both the low frequencies and high frequencies (60–80 Hz) of gamma. In addition, the TotalBic of the gamma-band LFP between V1 and V4 varies with the grating orientations, indicating that the QPC is available in the feedforward link and the gamma-band LFP in V1 modulates the QPC in V4. Significance. The QPC reflects the orientations of the sinusoidal grating and describes the interaction of gamma-band LFP between different brain regions. Our results suggest that the QPC is an alternative avenue to explore the mechanism for generating orientation selectivity of visual neurons effectively.