Biology subjects

Lavie, N.

Publications and source records attributed to Lavie, N..

7 recordsLinked to original sources

bioRxiv2026

Sustained attention under load: Neurophysiological mechanisms and behavioural consequences

Sustained attention research demonstrates the negative consequences of declining task focus with time-on-task. Separate research demonstrates the critical role of perceptual load in task focus: increased perceptual load is shown to draw neural energy into task-relevant, rather than irrelevant, processing (Bruckmaier et al., 2020) thus improving task focus (Lavie, 2005). However, how perceptual load affects the neurophysiological mechanisms underlying sustained attention decline with time-on-task remains unknown. Moreover, research on the aperiodic component of EEG has linked the 1/f slope with excitation-inhibition (E/I) balance: steeper slopes reflecting reduced E/I ratio (Gao et al., 2017), but whether sustained attention decline can be attributed to a change in the aperiodic slope is an open question. Here we recorded EEG during gradual continuous-performance task (detecting infrequent mountain-among-city scenes), under low or high perceptual load (with or without overlaid salt-and-pepper noise, respectively), and analysed periodic and aperiodic components. Time-on-task resulted in a widespread increase in alpha power and a steeper 1/f slope in a left temporoparietal cluster, accompanied by reduced detection sensitivity, increased response variability, and increased mind wandering, with reduced thought detail. Perceptual load improved task focus, indexed by reduced mind wandering, but exacerbated the effect of time-on-task on detection sensitivity, and the 1/f slope was steeper with time-on-task in a right parieto-occipital cluster under increased load. Overall, these findings suggest that sustained attention decline with time-on-task can be attributed to depletion of neural energy needed for excitatory signalling, which is further drained with increased processing demands in tasks of high perceptual load.

neuroscience↗

bioRxiv2024

Conservation implications of dietary strategies in the critically endangered Acacia gazelle (Gazella arabica acacia)

Animals consume foods in specific quantities and ratios to meet a multi-dimensional nutrient target that maximizes their fitness. Attempts to reach this target in an ever-changing nutritional landscape often influence animal foraging behavior, habitat choice, and food-web interactions. Consequently, understanding the nutritional ecology of a species is instrumental in developing efficient management plans for its conservation. We quantified the dietary considerations of a critically endangered population of Acacia gazelles (Gazella arabica acacia), and compared their diet and nutrition to that of the sympatric Gazella dorcas, using behavioral observations coupled with nutritional and secondary metabolite quantification, and morphological measurements of trees. Acacia gazelles mainly consumed resources from two subspecies of the umbrella-thorn acacia (Vachellia tortilis) that differ in morphology, nutritional composition, and phenology, and preferred browsing on specific trees based on their nutritional and defensive traits. Gazelles maintained a narrow nutritional target, tightly regulated their protein intake, and aimed to increase consumption of non-structural carbohydrates. Dorcas gazelles consumed a very different diet from the Acacia gazelle, but converged to a similar intake target. By considering both dietary and nutritional data, we conclude that suitable habitats for Acacia gazelle reintroduction must include sympatric populations of the two V. tortilis subspecies, that nutritional deficiency is unlikely to play a major role in explaining the slow rate of population recovery, and that the seemingly low competition between the two gazelle species does not necessitate controlling the Dorcas gazelle population. Our results link species-specific dietary strategies with resource selection and resulting interspecific interactions, demonstrating the importance of nutritional ecology as a major conservation tool.

ecology↗

bioRxiv2024

Oscillatory dynamics of sustained attention states

Sustained attention allows concentration on a task over long periods of time. This ability fluctuates, with periods of effective focus ( in-the-zone) and periods of increased performance variability and susceptibility to errors ( out-of-the-zone). Little is known about the neural dynamics underlying these states and their fluctuations during sustained attention tasks. To address this, we had thirty young adults perform the gradual onset continuous performance task (gradCPT), during which their EEG and responses were recorded. States of sustained attention (out-vs. in-the-zone) were identified based on the variance time course of participants RT. Out-of-the-zone states were associated with increased errors of commission and reduced perceptual sensitivity compared to in-the-zone states, as expected. Importantly, a significant decline in theta oscillations at mid-prefrontal regions was found during out-of-the-zone (vs. in-the-zone) states over a [~]400 ms period around the transition point between stimuli, and the extent of this decline predicted commission errors and response bias. In addition, individual differences in the variability of midfrontal theta along the task were associated with RT variability. Finally, participants exhibiting greater theta variability showed a more pronounced decline in perceptual sensitivity when being out-of-the-zone and less stable RTs compared to those with lower variability. Our results suggest that states of diminished sustained attention, even during short lapses, are characterized by a reduction in midfrontal theta activity, and that fluctuations in this rhythm covary with fluctuations in attentional control.

neuroscience↗

bioRxiv2023

Sustained Selective Attention in Adolescence: Cognitive Development and Predictors of Distractibility at School

Despite much research into the development of attention in adolescence, mixed results and between-task differences have precluded clear conclusions regarding the relative early- or late-maturation of attention abilities. Moreover, although adolescents constantly face the need to pay attention to their lessons at school, it remains unclear whether laboratory measures of attention can predict their ability to sustain attention focus during school lessons. Here we therefore devised a task that was sensitive to measure both sustained and selective attention and tested whether any of our task measures can predict adolescents levels of inattention during their school lessons. 166 adolescents (aged 12-17) and 50 adults performed in our sustained-selective attention task, searching for letter targets, while ignoring salient yet-entirely-irrelevant distractor faces, under different levels of perceptual load-an established determinant of attention in adults. Inattention levels during a just-preceding classroom lesson were measured using our novel self-report classroom-distractibility checklist. The results established that sustained attention (measured with response variability) continued to develop throughout adolescence, across perceptual load levels. In contrast there was an earlier maturation of the effect of perceptual load on selective attention: load modulation of distractor interference was larger in the early adolescence compared to later periods. Both distractor interference and response variability were significant unique predictors of distractibility in the classroom, including when interest in the lesson and cognitive aptitude were controlled for. Overall, the results demonstrate divergence of development of sustained and selective attention in adolescence, and establish both as significant predictors of attention in the important educational setting of school lessons.

developmental biology↗

bioRxiv2022

Diminished distractor filtering with increased perceptual load and sustained effort explains attention deficit in post-stroke fatigue

ObjectivesPost-stroke fatigue (PSF) is a prevalent symptom associated with attention deficits. However, it is currently unclear what drives these. Here we applied Load Theory of Attention to investigate the role of perceptual load in the relationship between attention, distraction, and fatigue levels in PSF. MethodsThirty-two chronic stroke survivors performed a selective attention task under different perceptual load levels. Neural responses to targets and distractors were measured with frequency-tagged EEG responses. ResultsWe showed that Fatigue Severity Scale-7 (FSS-7) scores are predictive of slower responses, irrespective of the task level of perceptual load. Although average distractor frequency (10Hz) power was reduced with higher perceptual load, the reduction in 10Hz power with increasing task load, was smaller in those with higher FSS-7 scores. Higher FSS-7 scores were also associated with increased 10Hz distractor response as time progressed, both within task-trials and across the experiment duration. ConclusionThe results are consistent with previous reports of slower processing speed and sustained selective attention deficits. Importantly they demonstrate that higher fatigue severity is associated with a reduced ability to suppress neural response to irrelevant distractors stimuli when the task demands more attention due to its increased perceptual load. An account for attention deficit in PSF based on a distractor filtering deficit that emerges with increased perceptual load and sustained effort can explain a myriad of PSF symptoms (e.g. sensory perceptual overload, and difficulties to concentrate). Key messagesO_LIWhat is already known on this topic [tpltrtarr]Post-stroke fatigue involves mental fatigue which is exacerbated in cognitively demanding task, as well as difficulties in concentrating and sustaining attention on a task. [tpltrtarr]However previous research has not converged on a clear account of the nature of attention deficits in post-stroke fatigue, as well as on how these relate to the level of perceptual demand in a cognitive task C_LIO_LIWhat this study adds [tpltrtarr]The study suggests that attention deficits in post-stroke fatigue are attributed to a failure to attenuate neural responses to distractors with increased perceptual load in the task, as well as with increased demands on sustained attention with a longer task engagement [tpltrtarr]This pattern points to a distractor filtering deficit that is magnified by perceptual load and sustained mental effort as main drivers of attention deficits in post-stroke fatigue How this study might affect research, practice or policy [tpltrtarr]This study enhances our understanding of attentional deficit in post-stroke fatigue, within an integrative account that explains mental fatigue symptomology C_LI

neuroscience↗

bioRxiv2021

Alpha oscillations reflect suppression of distractors with increased perceptual load

Attention serves an essential role in cognition and behaviour allowing us to focus on behaviourally-relevant objects while ignoring distraction. Perceptual load theory states that attentional resources are allocated according to the requirements of the task, i.e. its load. The theory predicts that the resources left to process irrelevant, possibly distracting stimuli, are reduced when the perceptual load is high. However, it remains unclear how this allocation of attentional resources specifically relates to neural excitability and suppression mechanisms. In this magnetoencephalography (MEG) study, we show that brain oscillations in the alpha band (8-13Hz) implement the suppression of distracting objects when the perceptual load is high. In parallel, high load increased neuronal excitability for target objects, as reflected by rapid frequency tagging. We suggest that the allocation of resources in tasks with high perceptual load is implemented by a gain increase for targets, complemented by distractor suppression reflected by alpha band oscillations closing the gate for interference.

neuroscience↗

bioRxiv2017

Auditory Figure-Ground Segregation is Impaired by High Visual Load

Figure-ground segregation is fundamental to listening in complex acoustic environments. An ongoing debate pertains to whether segregation requires attention or is automatic and pre-attentive. In this magnetoencephalography (MEG) study we tested a prediction derived from Load Theory of attention1 that segregation requires attention, but can benefit from the automatic allocation of any leftover capacity under low load. Complex auditory scenes were modelled with Stochastic Figure Ground stimuli (SFG2) which occasionally contained repeated frequency component figures. Naive human subjects passively listened to these signals while performing a visual attention task of either low or high load. Whilst clear figure-related neural responses were observed under conditions of low load, high visual load essentially abolished the neural response to the figure in auditory cortex (Planum Temporale, Heschls gyrus). We conclude that fundamental figure-ground segregation in hearing is not automatic but draws on shared resources across vision and audition.

neuroscience↗