scholarly journals Spectral distribution dynamics across different attentional priority states

2021 ◽  
Author(s):  
Mattia Pietrelli ◽  
Jason Samaha ◽  
Bradley R. Postle
Keyword(s):  
Time Course ◽  
Physiological State ◽  
Alpha Power ◽  
Alpha Band ◽  
Distribution Dynamics ◽  
Band Power ◽  
Human Participants ◽  
And Shifts ◽  
Secondary Consequence ◽  
Rule Out

AbstractAnticipatory covert spatial attention improves performance on tests of visual detection and discrimination, and shifts are accompanied by decreases and increases of alpha-band power at EEG electrodes corresponding to the attended and unattended location, respectively. Although the increase at the unattended location is often interpreted as an active mechanism (e.g., inhibiting processing at the unattended location), most experiments cannot rule out the alternative possibility that it is a secondary consequence of selection elsewhere. To adjudicate between these accounts, we designed a Posner-style cuing task in which male and female human participants made orientation judgments of targets appearing at one of four locations: up, down, right, or left. Critically, trials were blocked such that within a block the locations along one meridian alternated in status between attended and unattended, and targets never appeared at the other two, making them irrelevant. Analyses of the concurrently measured EEG signal were carried out on traditional narrowband alpha (8-14 Hz), as well as on two components resulting from the decomposition of this signal: periodic alpha; and the slope of the aperiodic 1/f-like component. Although data from right-left blocks replicated the familiar pattern of lateralized asymmetry in narrowband alpha power, with neither alpha signal could we find evidence for any difference in the time course at unattended versus irrelevant locations, an outcome consistent with the secondary-consequence interpretation of attention-related dynamics in the alpha band. Additionally, 1/f slope was lower at attended and unattended locations, relative to irrelevant, suggesting a tonic adjustment of physiological state.

Spontaneous Neural Fluctuations Predict Decisions to Attend

2014 ◽  
Vol 26 (11) ◽  
pp. 2578-2584 ◽  
Author(s):  
Jesse J. Bengson ◽  
Todd A. Kelley ◽  
Xiaoke Zhang ◽  
Jane-Ling Wang ◽  
George R. Mangun
Keyword(s):  
Decision Making ◽  
Neural Activity ◽  
Intrinsic Property ◽  
Alternative View ◽  
Alpha Band ◽  
Band Power ◽  
Trial Basis ◽  
Human Participants ◽  
Neural Signaling ◽  
The Brain

Ongoing variability in neural signaling is an intrinsic property of the brain. Often this variability is considered to be noise and ignored. However, an alternative view is that this variability is fundamental to perception and cognition and may be particularly important in decision-making. Here, we show that a momentary measure of occipital alpha-band power (8–13 Hz) predicts choices about where human participants will focus spatial attention on a trial-by-trial basis. This finding provides evidence for a mechanistic account of decision-making by demonstrating that ongoing neural activity biases voluntary decisions about where to attend within a given moment.

scholarly journals Prestimulus alpha-band power biases visual discrimination confidence, but not accuracy

2016 ◽  
Author(s):  
Jason Samaha ◽  
Luca Iemi ◽  
Bradley R. Postle
Keyword(s):  
Cortical Excitability ◽  
Orientation Discrimination ◽  
Alpha Power ◽  
Alpha Band ◽  
Decision Confidence ◽  
Band Power ◽  
Power Prior ◽  
Perceptual Confidence ◽  
Eeg Recordings ◽  
Visual Cortical

AbstractOscillations in the alpha-band (8-13 Hz) of human electroencephalographic (EEG) recordings are thought to reflect cortical excitability. As such, the magnitude of alpha power prior to the onset of a near threshold visual stimulus has been shown to predict stimulus detectability. Mechanistically, however, non-specific increases in visual-cortical excitability should result in amplified signal as well as amplified noise, leaving actual discriminability unchanged. Using a two-choice orientation discrimination task with equally probable stimuli, we found that discrimination accuracy was unaffected by fluctuations in prestimulus alpha-band power. Decision confidence, on the other hand, was strongly negatively correlated with prestimulus alpha power. This finding constitutes a clear dissociation between objective and subjective measures of visual perception as a function of prestimulus cortical excitability. This dissociation is predicted by models of perceptual confidence under which the balance of evidence in favor of each choice drives objective performance but only the magnitude of evidence in favor of the chosen stimulus drives subjective reports, suggesting that human perceptual confidence can be suboptimal.

scholarly journals Multivariate analysis of EEG activity indexes contingent and non-contingent attentional capture

2019 ◽  
Author(s):  
Jaap Munneke ◽  
Johannes Fahrenfort ◽  
David Sutterer ◽  
Jan Theeuwes ◽  
Edward Awh
Keyword(s):  
Multivariate Analysis ◽  
Attentional Capture ◽  
Time Course ◽  
Time Window ◽  
Early Time ◽  
Search Display ◽  
Alpha Power ◽  
Attentional Orienting ◽  
Alpha Band ◽  
Eeg Activity

AbstractIt is well known that salient yet irrelevant singleton can capture attention, even when this is inconsistent with the current goals of the observer (Theeuwes, 1992; 2010). Others however have claimed that capture is critically contingent on the goals of the observer: Capture is strongly modulated (or even eliminated) when the irrelevant singleton does not match the target-defining properties (Folk, Remington, & Johnston, 1992). There has been a long-standing debate on whether attentional capture can be explained by goal-driven and/or stimulus-driven accounts. Here, we shed further light on this phenomenon by using EEG activity (raw EEG and alpha power) to provide a time-resolved index of attentional orienting. Participants searched for a target defined by a pre-specified color. The search display was preceded by a singleton cue that either matched the color of the upcoming target (contingent cues), or that appeared in an irrelevant color (non-contingent cues). Multivariate analysis of raw EEG and alpha power revealed preferential tuning to the location of both contingent and non-contingent cues, with a stronger bias towards contingent than non-contingent cues. The time course of these effects, however, depended on the neural signal. Raw EEG data revealed attentional orienting towards the cue early on in the trial (>156 ms), while alpha power revealed sustained spatial selection in the cued locations at a later moment in the trial (>250 ms). Moreover, while raw EEG showed stronger capture by contingent cues during this early time window, the advantage for contingent cues arose during a later time window in alpha band activity. Thus, our findings suggest that raw EEG activity and alpha-band power tap into distinct neural processes that index movements of covert spatial attention. Both signals provide clear neural evidence that both contingent and non-contingent cues can capture attention, and that this process is robustly shaped by the target-defining properties in the current block of trials.

scholarly journals Implicit motor learning within three trials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer E. Ruttle ◽  
Bernard Marius ’t Hart ◽  
Denise Y. P. Henriques
Keyword(s):  
Motor Learning ◽  
Implicit Learning ◽  
Time Course ◽  
Skills Training ◽  
Implicit Processes ◽  
Training Performance ◽  
Slow Development ◽  
Implicit Motor Learning ◽  
Implicit Motor ◽  
And Shifts

AbstractIn motor learning, the slow development of implicit learning is traditionally taken for granted. While much is known about training performance during adaptation to a perturbation in reaches, saccades and locomotion, little is known about the time course of the underlying implicit processes during normal motor adaptation. Implicit learning is characterized by both changes in internal models and state estimates of limb position. Here, we measure both as reach aftereffects and shifts in hand localization in our participants, after every training trial. The observed implicit changes were near asymptote after only one to three perturbed training trials and were not predicted by a two-rate model’s slow process that is supposed to capture implicit learning. Hence, we show that implicit learning is much faster than conventionally believed, which has implications for rehabilitation and skills training.

scholarly journals Passive sensorimotor stimulation triggers long lasting alpha-band fluctuations in visual perception

2018 ◽  
Vol 119 (2) ◽  
pp. 380-388 ◽  
Author(s):  
Alice Tomassini ◽  
Alessandro D’Ausilio
Keyword(s):  
Visual Perception ◽  
Median Nerve ◽  
Movement Planning ◽  
Sensorimotor System ◽  
Alpha Power ◽  
Alpha Band ◽  
Movement Initiation ◽  
Visual Contrast ◽  
Sensorimotor Processes ◽  
Stimulation Of

Movement planning and execution rely on the anticipation and online control of the incoming sensory input. Evidence suggests that sensorimotor processes may synchronize visual rhythmic activity in preparation of action performance. Indeed, we recently reported periodic fluctuations of visual contrast sensitivity that are time-locked to the onset of an intended movement of the arm. However, the origin of the observed visual modulations has so far remained unclear because of the endogenous (and thus temporally undetermined) activation of the sensorimotor system that is associated with voluntary movement initiation. In this study, we activated the sensorimotor circuitry involved in the hand control in an exogenous and controlled way by means of peripheral stimulation of the median nerve and characterized the spectrotemporal dynamics of the ensuing visual perception. The stimulation of the median nerve triggers robust and long-lasting (∼1 s) alpha-band oscillations in visual perception, whose strength is temporally modulated in a way that is consistent with the changes in alpha power described at the neurophysiological level after sensorimotor stimulation. These findings provide evidence in support of a causal role of the sensorimotor system in modulating oscillatory activity in visual areas with consequences for visual perception. NEW & NOTEWORTHY This study shows that the peripheral activation of the somatomotor hand system triggers long-lasting alpha periodicity in visual perception. This demonstrates that not only the endogenous sensorimotor processes involved in movement preparation but also the passive stimulation of the sensorimotor system can synchronize visual activity. The present work suggests that oscillation-based mechanisms may subserve core (task independent) sensorimotor integration functions.

scholarly journals Stimulus-secretion coupling in the neurohypophysis of the jerboa Jaculus orientalis.

1994 ◽  
Vol 195 (1) ◽  
pp. 19-34
Author(s):  
A Raji ◽  
J J Nordmann
Keyword(s):  
Time Course ◽  
Physiological State ◽  
Nerve Endings ◽  
Neurosecretory System ◽  
Channel Blockers ◽  
Vasopressin Release ◽  
Oxytocin Release ◽  
Stimulus Secretion Coupling ◽  
Stimulation Of

1. In many mammals, severe dehydration is known to cause exhaustion of the vasopressin content of the neural lobe. Here, we have examined the physiological state of the neurohypophysis of the jerboa Jaculus orientalis, a rodent inhabitant of a semi-desert climate. 2. Isolated neurohypophyses and neurosecretory nerve endings were perfused in vitro and vasopressin and oxytocin release were determined by radioimmunoassay. 3. Electrical stimulation of the neurohypophysis with bursts of pulses mimicking the activity of hypersecreting neuroendocrine neurones induced similar increases of secretion in both control animals and animals dehydrated for up to 2 months. Neurohormone release was greatly potentiated when the bursts of pulses were separated by silent intervals. 4. Prolonged stimulation of neurohypophyses from both control and dehydrated animals induced a sustained increase of vasopressin release; in contrast, oxytocin release under similar conditions showed a biphasic secretory pattern consisting of a transient increase that subsequently decreased to a steady level whose amplitude was similar to that for vasopressin. 5. K(+)-induced secretion was largely inhibited by the Ca2+ channel blockers nicardipine and omega-conotoxin, suggesting that in this neurosecretory system both L- and N-type calcium channels play a major role in stimulus-secretion coupling. Depolarization of isolated nerve endings using a fast-flow perifusion system showed that there was no difference in the amplitude and the time course of the secretory response in dehydrated and hydrated animals. 6. The results demonstrate that, despite the climatic conditions in which the jerboas live, their neural lobes retain the capacity to release, upon depolarization of the plasma membrane of the nerve endings, large amounts of neurohormone. It is concluded that the neurohypophyseal peptidergic release system in the dehydrated jerboa functions adequately even under extreme environmental stress.

scholarly journals Increased Alpha-Band Power during the Retention of Shapes and Shape-Location Associations in Visual Short-Term Memory

2011 ◽  
Vol 2 ◽  
Author(s):  
Jeffrey S. Johnson ◽  
David W. Sutterer ◽  
Daniel J. Acheson ◽  
Jarrod A. Lewis-Peacock ◽  
Bradley R. Postle
Keyword(s):  
Short Term Memory ◽  
Alpha Band ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Band Power

scholarly journals Propofol Requirement and EEG Alpha Band Power During General Anesthesia Provide Complementary Views on Preoperative Cognitive Decline

2020 ◽  
Vol 12 ◽  
Author(s):  
Cyril Touchard ◽  
Jérôme Cartailler ◽  
Charlotte Levé ◽  
José Serrano ◽  
David Sabbagh ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
General Anesthesia ◽  
Logistic Models ◽  
Alpha Band ◽  
Target Concentration ◽  
Operative Morbidity ◽  
Band Power ◽  
Cognitive Evaluation ◽  
Eeg Alpha ◽  
Better Than

Background: Although cognitive decline (CD) is associated with increased post-operative morbidity and mortality, routinely screening patients remains difficult. The main objective of this prospective study is to use the EEG response to a Propofol-based general anesthesia (GA) to reveal CD.Methods: 42 patients with collected EEG and Propofol target concentration infusion (TCI) during GA had a preoperative cognitive assessment using MoCA. We evaluated the performance of three variables to detect CD (MoCA < 25 points): age, Propofol requirement to induce unconsciousness (TCI at SEF95: 8–13 Hz) and the frontal alpha band power (AP at SEF95: 8–13 Hz).Results: The 17 patients (40%) with CD were significantly older (p < 0.001), had lower TCI (p < 0.001), and AP (p < 0.001). We found using logistic models that TCI and AP were the best set of variables associated with CD (AUC: 0.89) and performed better than age (p < 0.05). Propofol TCI had a greater impact on CD probability compared to AP, although both were complementary in detecting CD.Conclusion: TCI and AP contribute additively to reveal patient with preoperative cognitive decline. Further research on post-operative cognitive trajectory are necessary to confirm the interest of intra operative variables in addition or as a substitute to cognitive evaluation.

scholarly journals Early and Late Modulation of Saccade Deviations by Target Distractor Similarity

2009 ◽  
Vol 102 (3) ◽  
pp. 1451-1458 ◽  
Author(s):  
Manon Mulckhuyse ◽  
Stefan Van der Stigchel ◽  
Jan Theeuwes
Keyword(s):  
Time Course ◽  
Relevant Information ◽  
Dependent Measure ◽  
Saccade Latency ◽  
Oculomotor Control ◽  
Opposite Pattern ◽  
Selection Processes ◽  
Time Courses ◽  
Saccade Trajectory ◽  
Rule Out

In this study, we investigated the time course of oculomotor competition between bottom-up and top-down selection processes using saccade trajectory deviations as a dependent measure. We used a paradigm in which we manipulated saccade latency by offsetting the fixation point at different time points relative to target onset. In experiment 1, observers made a saccade to a filled colored circle while another irrelevant distractor circle was presented. The distractor was either similar (i.e., identical) or dissimilar to the target. Results showed that the strength of saccade deviation was modulated by target distractor similarity for short saccade latencies. To rule out the possibility that the similar distractor affected the saccade trajectory merely because it was identical to the target, the distractor in experiment 2 was a square shape of which only the color was similar or dissimilar to the target. The results showed that deviations for both short and long latencies were modulated by target distractor similarity. When saccade latencies were short, we found less saccade deviation away from a similar than from a dissimilar distractor. When saccade latencies were long, the opposite pattern was found: more saccade deviation away from a similar than from a dissimilar distractor. In contrast to previous findings, our study shows that task-relevant information can already influence the early processes of oculomotor control. We conclude that competition between saccadic goals is subject to two different processes with different time courses: one fast activating process signaling the saliency and task relevance of a location and one slower inhibitory process suppressing that location.

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