scholarly journals Learning temporal context shapes prestimulus alpha oscillations and improves visual discrimination performance

2017 ◽  
Vol 118 (2) ◽  
pp. 771-777 ◽  
Author(s):  
Tahereh Toosi ◽  
Ehsan K. Tousi ◽  
Hossein Esteky
Keyword(s):  
Human Brain ◽  
Visual Processing ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Temporal Context ◽  
Alpha Power ◽  
Alpha Oscillations ◽  
External Event ◽  
Context Shapes

It is not well understood how the uncertainty in the timing of an external event affects its processing, particularly at subsecond scales. Here we demonstrate how a predictable timing scheme improves visual processing. We found that learning the predictable scheme gradually shaped the prestimulus alpha power. These findings indicate that the human brain is able to extract implicit subsecond patterns in the temporal context of events.

scholarly journals Visual discrimination of optical material properties: a large-scale study

2019 ◽  
Author(s):  
Masataka Sawayama ◽  
Yoshinori Dobashi ◽  
Makoto Okabe ◽  
Kenchi Hosokawa ◽  
Takuya Koumura ◽  
...  
Keyword(s):  
Visual Processing ◽  
Visual Discrimination ◽  
Large Scale ◽  
Discrimination Performance ◽  
Developmental Studies ◽  
Strongly Correlated ◽  
Experimental Conditions ◽  
Response Data ◽  
Spatial Consistency ◽  
Physically Based

AbstractComplex visual processing involved in perceiving the object materials can be better elucidated by taking a variety of research approaches. Sharing stimulus and response data is an effective strategy to make the results of different studies directly comparable and can assist researchers with different backgrounds to jump into the field. Here, we constructed a database containing a variety of material images annotated with visual discrimination performance. We created various material images by using physically-based computer graphics techniques and conducted psychophysical experiments using them in both laboratory and crowdsourcing settings. The observer’s task was to discriminate materials on six dimensions (gloss contrast, gloss sharpness, translucent vs. opaque, metal vs. plastic, metal vs. glass, and glossy vs. painted) with several task difficulties. The illumination consistency and object geometry were also varied. We used a non-verbal procedure (an oddity task) so that our database could be used in diverse cross-cultural, cross-species, clinical, and developmental studies. The results showed that discrimination performance was affected by the illumination condition and object geometry, in agreement with previous studies on gloss perception, although the pattern of effects was slightly different for some material dimensions. We also found that the ability to discriminate the spatial consistency of specular highlights in glossiness perception showed larger individual differences than in other tasks. The results obtained through crowdsourcing were strongly correlated with those obtained in the laboratory, which suggests that our database can be used even when the experimental conditions are not strictly controlled. Several projects using our dataset are underway.

Theta and alpha oscillations reflect differences in memory strategy and visual discrimination performance in patients with Parkinson's disease

2005 ◽  
Vol 388 (3) ◽  
pp. 138-143 ◽  
Author(s):  
Christina Schmiedt ◽  
Anette Meistrowitz ◽  
Günter Schwendemann ◽  
Manfred Herrmann ◽  
Canan Basar-Eroglu
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Alpha Oscillations ◽  
Memory Strategy

scholarly journals Top–Down Control of Alpha Phase Adjustment in Anticipation of Temporally Predictable Visual Stimuli

2018 ◽  
Vol 30 (8) ◽  
pp. 1157-1169 ◽  
Author(s):  
Rodolfo Solís-Vivanco ◽  
Ole Jensen ◽  
Mathilde Bonnefond
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Alpha Phase ◽  
Stimulus Onset ◽  
Gamma Activity ◽  
Alpha Power ◽  
Top Down ◽  
Alpha Oscillations ◽  
Phase Adjustment ◽  
Visual Areas

Alpha oscillations (8–14 Hz) are proposed to represent an active mechanism of functional inhibition of neuronal processing. Specifically, alpha oscillations are associated with pulses of inhibition repeating every ∼100 msec. Whether alpha phase, similar to alpha power, is under top–down control remains unclear. Moreover, the sources of such putative top–down phase control are unknown. We designed a cross-modal (visual/auditory) attention study in which we used magnetoencephalography to record the brain activity from 34 healthy participants. In each trial, a somatosensory cue indicated whether to attend to either the visual or auditory domain. The timing of the stimulus onset was predictable across trials. We found that, when visual information was attended, anticipatory alpha power was reduced in visual areas, whereas the phase adjusted just before the stimulus onset. Performance in each modality was predicted by the phase of the alpha oscillations previous to stimulus onset. Alpha oscillations in the left pFC appeared to lead the adjustment of alpha phase in visual areas. Finally, alpha phase modulated stimulus-induced gamma activity. Our results confirm that alpha phase can be top–down adjusted in anticipation of predictable stimuli and improve performance. Phase adjustment of the alpha rhythm might serve as a neurophysiological resource for optimizing visual processing when temporal predictions are possible and there is considerable competition between target and distracting stimuli.

Power and Phase of Alpha Oscillations Reveal an Interaction between Spatial and Temporal Visual Attention

2017 ◽  
Vol 29 (3) ◽  
pp. 480-494 ◽  
Author(s):  
Sayeed A. D. Kizuk ◽  
Kyle E. Mathewson
Keyword(s):  
Visual Processing ◽  
Alpha Phase ◽  
Alpha Power ◽  
Alpha Band ◽  
Target Onset ◽  
Alpha Oscillations ◽  
Perceptual Performance ◽  
Neural Entrainment ◽  
Sensory Activity ◽  
Bias Attention

Oscillatory brain rhythms can bias attention via phase and amplitude changes, which modulate sensory activity, biasing information to be processed or ignored. Alpha band (7–14 Hz) oscillations lateralize with spatial attention and rhythmically inhibit visual activity and awareness through pulses of inhibition. Here we show that human observers' awareness of spatially unattended targets is dependent on both alpha power and alpha phase at target onset. Following a predictive directional cue, alpha oscillations were entrained bilaterally using repetitive visual stimuli. Subsequently, we presented either spatially cued or uncued targets at SOAs either validly or invalidly predicted in time by the entrainers. Temporal validity maximally modulated perceptual performance outside the spatial focus of attention and was associated with both increased alpha power and increased neural entrainment of phase in the hemisphere processing spatially unattended information. The results demonstrate that alpha oscillations represent a pulsating inhibition, which impedes visual processing for unattended space.

scholarly journals Post-stimulus alpha oscillations influence visual discrimination performance

2015 ◽  
Vol 15 (12) ◽  
pp. 225
Author(s):  
Stephanie Nelli ◽  
Sarah Fraley ◽  
John Serences
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Alpha Oscillations

scholarly journals Linking the Rapid Cascade of Visuo-Attentional Processes to Successful Memory Encoding

2020 ◽  
Author(s):  
B R Geib ◽  
R Cabeza ◽  
M G Woldorff
Keyword(s):  
Visual Processing ◽  
Memory Retrieval ◽  
Current Knowledge ◽  
High Temporal Resolution ◽  
Alpha Power ◽  
Attentional Orienting ◽  
Memory Encoding ◽  
Attentional Processes ◽  
Neural Processes ◽  
Dm Effect

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.

fMRI-Guided TMS on Cortical Eye Fields: The Frontal But Not Intraparietal Eye Fields Regulate the Coupling Between Visuospatial Attention and Eye Movements

2009 ◽  
Vol 102 (6) ◽  
pp. 3469-3480 ◽  
Author(s):  
H. M. Van Ettinger-Veenstra ◽  
W. Huijbers ◽  
T. P. Gutteling ◽  
M. Vink ◽  
J. L. Kenemans ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Visual Processing ◽  
Discrimination Performance ◽  
Visual Image ◽  
Single Pulse ◽  
Visuospatial Attention ◽  
Movement Direction ◽  
Key Factor ◽  
And Shifts

It is well known that parts of a visual scene are prioritized for visual processing, depending on the current situation. How the CNS moves this focus of attention across the visual image is largely unknown, although there is substantial evidence that preparation of an action is a key factor. Our results support the view that direct corticocortical feedback connections from frontal oculomotor areas to the visual cortex are responsible for the coupling between eye movements and shifts of visuospatial attention. Functional magnetic resonance imaging (fMRI)–guided transcranial magnetic stimulation (TMS) was applied to the frontal eye fields (FEFs) and intraparietal sulcus (IPS). A single pulse was delivered 60, 30, or 0 ms before a discrimination target was presented at, or next to, the target of a saccade in preparation. Results showed that the known enhancement of discrimination performance specific to locations to which eye movements are being prepared was enhanced by early TMS on the FEF contralateral to eye movement direction, whereas TMS on the IPS resulted in a general performance increase. The current findings indicate that the FEF affects selective visual processing within the visual cortex itself through direct feedback projections.

scholarly journals Confidence in perceptual decision-making is preserved in schizophrenia

2019 ◽  
Author(s):  
Nathan Faivre ◽  
Matthieu Roger ◽  
Michael Pereira ◽  
Vincent de Gardelle ◽  
Jean-Christophe Vergnaud ◽  
...  
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Perceptual Decision Making ◽  
Task Execution ◽  
Bayesian Analyses ◽  
Functional Deficits ◽  
Evidence Accumulation ◽  
Narrative Assessment ◽  
Mental Operations ◽  
Healthy Participants

AbstractMetacognition is the set of reflexive processes allowing humans to evaluate the accuracy of their mental operations. Deficits in synthetic metacognition have been described in schizophrenia using mostly narrative assessment and linked to several key symptoms. Here, we assessed metacognitive performance by asking individuals with schizophrenia or schizoaffective disorder (N=20) and matched healthy participants (N = 21) to perform a visual discrimination task and subsequently report confidence in their performance. Metacognitive performance was defined as the adequacy between visual discrimination performance and confidence. Bayesian analyses revealed equivalent metacognitive performance in the two groups despite a weaker association between confidence and trajectory tracking during task execution among patients. These results were reproduced using a bounded evidence accumulation model which showed similar decisional processes in the two groups. The inability to accurately attune confidence to perceptual decisions in schizophrenia remains to be experimentally demonstrated, along with the way such impairments may underpin functional deficits.

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