Differential Effects of Lowered Arousal on Covert and Overt Shifts of Attention

2015 ◽  
Vol 21 (7) ◽  
pp. 545-557 ◽  
Author(s):  
Bruno Fimm ◽  
Klaus Willmes ◽  
Will Spijkers

AbstractBased on previous studies demonstrating detrimental effects of reduced alertness on attentional orienting our study seeks to examine covert and overt attentional orienting in different arousal states. We hypothesized an attentional asymmetry with increasing reaction times to stimuli presented to the left visual field in a state of maximally reduced arousal. Eleven healthy participants underwent sleep deprivation and were examined repeatedly every 4 hr over 28 hr in total with two tasks measuring covert and overt orienting of attention. Contrary to our hypothesis, a reduction of arousal did not induce any asymmetry of overt orienting. Even in participants with profound and significant attentional asymmetries in covert orienting no substantial reaction time differences between left- and right-sided targets in the overt orienting task could be observed. This result is not in agreement with assumptions of a tight coupling of covert and overt attentional processes. In conclusion, we found differential effects of lowered arousal induced by sleep deprivation on covert and overt orienting of attention. This pattern of results points to a neuronal non-overlap of brain structures subserving these functions and a differential influence of the norepinephrine system on these modes of spatial attention. (JINS, 2015,21, 545–557)

2018 ◽  
Author(s):  
Amelie Reynaud ◽  
Mathilda Froesel ◽  
Carole Guedj ◽  
Sameh Ben Hadj Hassen ◽  
Justine Clery ◽  
...  

The role of norepinephrine (NE) in visuo-spatial attention remains poorly understood. Our goal was to identify the attentional processes under the influence of NE and to characterize these influences. We tested the effects of atomoxetine injections (ATX), a NE-reuptake inhibitor that boosts the level of NE in the brain, on seven monkeys performing a saccadic cued task in which cues and distractors were used to manipulate spatial attention. We found that when the cue accurately predicted the location of the upcoming cue in 80% of the trials, ATX consistently improved attentional orienting, as measured from reaction times (RTs). These effects were best accounted for by a faster accumulation rate in the valid trials, rather than by a change in the decision threshold. By contrast, the effect of ATX on alerting and distractor interference was more mitigated. Finally, we also found that, under ATX, RTs to non-cued targets were longer when these were presented separately from cued targets. This suggests that the impact of NE on visuo-spatial attention depends on the context, such that the adaptive changes elicited by the highly informative value of the cues in the most frequent trials were accompanied by a cost in the less frequent trials.


Author(s):  
Diana Martella ◽  
Andrea Marotta ◽  
Luis J. Fuentes ◽  
Maria Casagrande

In this study, we assessed whether unspecific attention processes signaled by general reaction times (RTs), as well as specific facilitatory (validity or facilitation effect) and inhibitory (inhibition of return, IOR) effects involved in the attentional orienting network, are affected by low vigilance due to both circadian factors and sleep deprivation (SD). Eighteen male participants performed a cuing task in which peripheral cues were nonpredictive about the target location and the cue-target interval varied at three levels: 200 ms, 800 ms, and 1,100 ms. Facilitation with the shortest and IOR with the longest cue-target intervals were observed in the baseline session, thus replicating previous related studies. Under SD condition, RTs were generally slower, indicating a reduction in the participants’ arousal level. The inclusion of a phasic alerting tone in several trials partially compensated for the reduction in tonic alertness, but not with the longest cue-target interval. With regard to orienting, whereas the facilitation effect due to reflexive shifts of attention was preserved with sleep loss, the IOR was not observed. These results suggest that the decrease of vigilance produced by SD affects both the compensatory effects of phasic alerting and the endogenous component involved in disengaging attention from the cued location, a requisite for the IOR effect being observed.


2019 ◽  
Vol 116 (19) ◽  
pp. 9665-9670 ◽  
Author(s):  
Nina M. Hanning ◽  
Martin Szinte ◽  
Heiner Deubel

Both patients with eye movement disorders and healthy participants whose oculomotor range had been experimentally reduced have been reported to show attentional deficits at locations unreachable by their eyes. Whereas previous studies were mainly based on the evaluation of reaction times, we measured visual sensitivity before saccadic eye movements and during fixation at locations either within or beyond participants’ oculomotor range. Participants rotated their heads to prevent them from performing large rightward saccades. In this posture, an attentional cue was presented inside or outside their oculomotor range. Participants either made a saccade to the cue or maintained fixation while they discriminated the orientation of a visual noise patch. In contrast to previous reports, we found that the cue attracted visual attention regardless of whether it was presented within or beyond participants’ oculomotor range during both fixation and saccade preparation. Moreover, when participants aimed to look to a cue that they could not reach with their eyes, we observed no benefit at their actual saccade endpoint. This demonstrates that spatial attention is not coupled to the executed oculomotor program but instead can be deployed unrestrictedly also toward locations to which no saccade can be executed. Our results are compatible with the view that covert and overt attentional orienting are guided by feedback projections of visual and visuomotor neurons of the gaze control system, irrespective of oculomotor limitations.


2019 ◽  
Vol 33 (2) ◽  
pp. 109-118
Author(s):  
Andrés Antonio González-Garrido ◽  
Jacobo José Brofman-Epelbaum ◽  
Fabiola Reveca Gómez-Velázquez ◽  
Sebastián Agustín Balart-Sánchez ◽  
Julieta Ramos-Loyo

Abstract. It has been generally accepted that skipping breakfast adversely affects cognition, mainly disturbing the attentional processes. However, the effects of short-term fasting upon brain functioning are still unclear. We aimed to evaluate the effect of skipping breakfast on cognitive processing by studying the electrical brain activity of young healthy individuals while performing several working memory tasks. Accordingly, the behavioral results and event-related brain potentials (ERPs) of 20 healthy university students (10 males) were obtained and compared through analysis of variances (ANOVAs), during the performance of three n-back working memory (WM) tasks in two morning sessions on both normal (after breakfast) and 12-hour fasting conditions. Significantly fewer correct responses were achieved during fasting, mainly affecting the higher WM load task. In addition, there were prolonged reaction times with increased task difficulty, regardless of breakfast intake. ERP showed a significant voltage decrement for N200 and P300 during fasting, while the amplitude of P200 notably increased. The results suggest skipping breakfast disturbs earlier cognitive processing steps, particularly attention allocation, early decoding in working memory, and stimulus evaluation, and this effect increases with task difficulty.


2020 ◽  
Author(s):  
B R Geib ◽  
R Cabeza ◽  
M G Woldorff

Abstract While it is broadly accepted that attention modulates memory, the contribution of specific rapid attentional processes to successful encoding is largely unknown. To investigate this issue, we leveraged the high temporal resolution of electroencephalographic recordings to directly link a cascade of visuo-attentional neural processes to successful encoding: namely (1) the N2pc (peaking ~200 ms), which reflects stimulus-specific attentional orienting and allocation, (2) the sustained posterior-contralateral negativity (post-N2pc), which has been associated with sustained visual processing, (3) the contralateral reduction in oscillatory alpha power (contralateral reduction in alpha > 200 ms), which has also been independently related to attentionally sustained visual processing. Each of these visuo-attentional processes was robustly predictive of successful encoding, and, moreover, each enhanced memory independently of the classic, longer-latency, conceptually related, difference-due-to memory (Dm) effect. Early latency midfrontal theta power also promoted successful encoding, with at least part of this influence being mediated by the later latency Dm effect. These findings markedly expand current knowledge by helping to elucidate the intimate relationship between attentional modulations of perceptual processing and effective encoding for later memory retrieval.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 652-653
Author(s):  
Emily Urban-Wojcik ◽  
Soomi Lee ◽  
Susan Charles ◽  
David Almeida ◽  
Richard Davidson ◽  
...  

Abstract The hippocampus, implicated in learning, memory, and spatial navigation, is one of the few brain structures that demonstrates neurogenesis across the lifespan. Hippocampal volume (HV), then, may be a marker of exposure to and engagement with novel events and environments, which may in turn be related to cognitive functioning. The present study examined the relationship between HV and activity diversity (AD), which characterizes the range and evenness of participation in daily activities. In 52 participants who completed the daily-diary and neuroscience projects of the Midlife in the United States Refresher study, greater levels of AD across an 8-day period were related to greater HV averaged across the left and right hemispheres when adjusting for overall brain volume, total activity time, time between projects, and relevant sociodemographic variables, b=1128mm3, t(43)=2.54, p=.015. These findings may point to a mechanism through which AD has been related to better cognitive and mental health outcomes.


2021 ◽  
Vol 4 (3) ◽  
pp. 156-162
Author(s):  
André Sevenius Nilsen ◽  
Bjørn Erik Juel ◽  
Nadine Farnes ◽  
Luis Romundstad ◽  
Johan Frederik Storm

AbstractBackground and aimsWhile psychedelic agents are known to have powerful, but largely unexplained, effects on contents of consciousness, there is an increasing interest in the potential clinical usefulness of such drugs for therapy, and legalization is discussed in some countries. Thus, it is relevant to study the effects of psychedelic compounds not only on experience, but also on behavioral performance.MethodsSeven healthy participants performed a motor response inhibition task before, during, and after sub-anesthetic doses of intravenously administered ketamine. The infusion rate was individually adjusted to produce noticeable subjective psychedelic effects.ResultsWe observed no statistically significant impact of sub-anesthetic ketamine on reaction times, omission errors, or post error slowing, relative to the preceding drug-free condition. However, we did observe significant correlations between performance impairment and self-reported, subjective altered states of consciousness, specifically experience of “anxiety” and “complex imagery.”ConclusionsConsidering the limited number of participants and large variation in strength of self-reported experiences, further studies with wider ranges of ketamine doses and behavioral tasks are needed to determine the presence and strength of potential behavioral effects.


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