scholarly journals The signature of undetected change: an exploratory electrotomographic investigation of gradual change blindness

2018 ◽  
Vol 119 (5) ◽  
pp. 1629-1635
Author(s):  
John E. Kiat ◽  
Michael D. Dodd ◽  
Robert F. Belli ◽  
Jacob E. Cheadle

Neuroimaging-based investigations of change blindness, a phenomenon in which seemingly obvious changes in visual scenes fail to be detected, have significantly advanced our understanding of visual awareness. The vast majority of prior investigations, however, utilize paradigms involving visual disruptions (e.g., intervening blank screens, saccadic movements, “mudsplashes”), making it difficult to isolate neural responses toward visual changes cleanly. To address this issue in this present study, high-density EEG data (256 channel) were collected from 25 participants using a paradigm in which visual changes were progressively introduced into detailed real-world scenes without the use of visual disruption. Oscillatory activity associated with undetected changes was contrasted with activity linked to their absence using standardized low-resolution brain electromagnetic tomography (sLORETA). Although an insufficient number of detections were present to allow for analysis of actual change detection, increased beta-2 activity in the right inferior parietal lobule (rIPL), a region repeatedly associated with change blindness in disruption paradigms, followed by increased theta activity in the right superior temporal gyrus (rSTG) was noted in undetected visual change responses relative to the absence of change. We propose the rIPL beta-2 activity to be associated with orienting attention toward visual changes, with the subsequent rise in rSTG theta activity being potentially linked with updating preconscious perceptual memory representations. NEW & NOTEWORTHY This study represents the first neuroimaging-based investigation of gradual change blindness, a visual phenomenon that has significant potential to shed light on the processes underlying visual detection and conscious perception. The use of gradual change materials is reflective of real-world visual phenomena and allows for cleaner isolation of signals associated with the neural registration of change relative to the use of abrupt change transients.

2013 ◽  
Vol 24 (07) ◽  
pp. 535-543 ◽  
Author(s):  
Stephanie Nagle ◽  
Frank E. Musiek ◽  
Eric H. Kossoff ◽  
George Jallo ◽  
Dana Boatman-Reich

Background: The role of the right temporal lobe in processing speech is not well understood. Although the left temporal lobe has long been recognized as critical for speech perception, there is growing evidence for right hemisphere involvement. To investigate whether the right temporal lobe is critical for auditory speech processing, we studied prospectively a normal-hearing patient who underwent consecutive right temporal lobe resections for treatment of medically intractable seizures. Purpose: To test the hypothesis that the right temporal lobe is critical for auditory speech processing. Research Design: We used a prospective, repeated-measure, single-case design. Auditory processing was evaluated using behavioral tests of speech recognition (words, sentences) under multiple listening conditions (e.g., quiet, background noise, etc.). Auditory processing of nonspeech sounds was measured by pitch pattern sequencing and environmental sound recognition tasks. Data Collection: Repeat behavioral testing was performed at four time points over a 2 yr period: before and after consecutive right temporal lobe resection surgeries. Results: Before surgery, the patient demonstrated normal speech recognition in quiet and under real-world listening conditions (background noise, filtered speech). After the initial right anterior temporal resection, speech recognition scores declined under adverse listening conditions, especially for the left ear, but remained largely within normal limits. Following resection of the right superior temporal gyrus 1 yr later, speech recognition in quiet and nonspeech sound processing (pitch patterns, environmental sounds) remained intact. However, speech recognition under adverse listening conditions was severely impaired. Conclusions: The right superior temporal gyrus appears to be critical for auditory processing of speech under real-world listening conditions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jelena Trajkovic ◽  
Francesco Di Gregorio ◽  
Francesca Ferri ◽  
Chiara Marzi ◽  
Stefano Diciotti ◽  
...  

AbstractSchizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals).


Author(s):  
Viktória Tamás ◽  
Gabriella Sebestyén ◽  
Szilvia Anett Nagy ◽  
Péter Zsolt Horváth ◽  
Ákos Mérei ◽  
...  

AbstractNeglect is a severe neuropsychological/neurological deficit that usually develops due to lesions of the posterior inferior parietal area of the right hemisphere and is characterized by a lack of attention to the left side. Our case is a proven right-handed, 30-year-old female patient with a low-grade glioma, which was located in the temporo-opercular region and also in the superior temporal gyrus of the right hemisphere. Upon presurgical planning, the motor, language, and visuospatial functions were mapped. In order to achieve this, the protocol for routine magnetic resonance imaging and navigated transcranial magnetic stimulation has been expanded, accordingly.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chloé Stengel ◽  
Marine Vernet ◽  
Julià L. Amengual ◽  
Antoni Valero-Cabré

AbstractCorrelational evidence in non-human primates has reported increases of fronto-parietal high-beta (22–30 Hz) synchrony during the top-down allocation of visuo-spatial attention. But may inter-regional synchronization at this specific frequency band provide a causal mechanism by which top-down attentional processes facilitate conscious visual perception? To address this question, we analyzed electroencephalographic (EEG) signals from a group of healthy participants who performed a conscious visual detection task while we delivered brief (4 pulses) rhythmic (30 Hz) or random bursts of Transcranial Magnetic Stimulation (TMS) to the right Frontal Eye Field (FEF) prior to the onset of a lateralized target. We report increases of inter-regional synchronization in the high-beta band (25–35 Hz) between the electrode closest to the stimulated region (the right FEF) and right parietal EEG leads, and increases of local inter-trial coherence within the same frequency band over bilateral parietal EEG contacts, both driven by rhythmic but not random TMS patterns. Such increases were accompained by improvements of conscious visual sensitivity for left visual targets in the rhythmic but not the random TMS condition. These outcomes suggest that high-beta inter-regional synchrony can be modulated non-invasively and that high-beta oscillatory activity across the right dorsal fronto-parietal network may contribute to the facilitation of conscious visual perception. Our work supports future applications of non-invasive brain stimulation to restore impaired visually-guided behaviors by operating on top-down attentional modulatory mechanisms.


2008 ◽  
Vol 20 (12) ◽  
pp. 2185-2197 ◽  
Author(s):  
Jennifer T. Coull ◽  
Bruno Nazarian ◽  
Franck Vidal

The temporal discrimination paradigm requires subjects to compare the duration of a probe stimulus to that of a sample previously stored in working or long-term memory, thus providing an index of timing that is independent of a motor response. However, the estimation process itself comprises several component cognitive processes, including timing, storage, retrieval, and comparison of durations. Previous imaging studies have attempted to disentangle these components by simply measuring brain activity during early versus late scanning epochs. We aim to improve the temporal resolution and precision of this approach by using rapid event-related functional magnetic resonance imaging to time-lock the hemodynamic response to presentation of the sample and probe stimuli themselves. Compared to a control (color-estimation) task, which was matched in terms of difficulty, sustained attention, and motor preparation requirements, we found selective activation of the left putamen for the storage (“encoding”) of stimulus duration into working memory (WM). Moreover, increased putamen activity was linked to enhanced timing performance, suggesting that the level of putamen activity may modulate the depth of temporal encoding. Retrieval and comparison of stimulus duration in WM selectively activated the right superior temporal gyrus. Finally, the supplementary motor area was equally active during both sample and probe stages of the task, suggesting a fundamental role in timing the duration of a stimulus that is currently unfolding in time.


2006 ◽  
Vol 18 (11) ◽  
pp. 1789-1798 ◽  
Author(s):  
Angela Bartolo ◽  
Francesca Benuzzi ◽  
Luca Nocetti ◽  
Patrizia Baraldi ◽  
Paolo Nichelli

Humor is a unique ability in human beings. Suls [A two-stage model for the appreciation of jokes and cartoons. In P. E. Goldstein & J. H. McGhee (Eds.), The psychology of humour. Theoretical perspectives and empirical issues. New York: Academic Press, 1972, pp. 81–100] proposed a two-stage model of humor: detection and resolution of incongruity. Incongruity is generated when a prediction is not confirmed in the final part of a story. To comprehend humor, it is necessary to revisit the story, transforming an incongruous situation into a funny, congruous one. Patient and neuroimaging studies carried out until now lead to different outcomes. In particular, patient studies found that right brain-lesion patients have difficulties in humor comprehension, whereas neuroimaging studies suggested a major involvement of the left hemisphere in both humor detection and comprehension. To prevent activation of the left hemisphere due to language processing, we devised a nonverbal task comprising cartoon pairs. Our findings demonstrate activation of both the left and the right hemispheres when comparing funny versus nonfunny cartoons. In particular, we found activation of the right inferior frontal gyrus (BA 47), the left superior temporal gyrus (BA 38), the left middle temporal gyrus (BA 21), and the left cerebellum. These areas were also activated in a nonverbal task exploring attribution of intention [Brunet, E., Sarfati, Y., Hardy-Bayle, M. C., & Decety, J. A PET investigation of the attribution of intentions with a nonverbal task. Neuroimage, 11, 157–166, 2000]. We hypothesize that the resolution of incongruity might occur through a process of intention attribution. We also asked subjects to rate the funniness of each cartoon pair. A parametric analysis showed that the left amygdala was activated in relation to subjective amusement. We hypothesize that the amygdala plays a key role in giving humor an emotional dimension.


2012 ◽  
Vol 24 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Frank Oppermann ◽  
Uwe Hassler ◽  
Jörg D. Jescheniak ◽  
Thomas Gruber

The human cognitive system is highly efficient in extracting information from our visual environment. This efficiency is based on acquired knowledge that guides our attention toward relevant events and promotes the recognition of individual objects as they appear in visual scenes. The experience-based representation of such knowledge contains not only information about the individual objects but also about relations between them, such as the typical context in which individual objects co-occur. The present EEG study aimed at exploring the availability of such relational knowledge in the time course of visual scene processing, using oscillatory evoked gamma-band responses as a neural correlate for a currently activated cortical stimulus representation. Participants decided whether two simultaneously presented objects were conceptually coherent (e.g., mouse–cheese) or not (e.g., crown–mushroom). We obtained increased evoked gamma-band responses for coherent scenes compared with incoherent scenes beginning as early as 70 msec after stimulus onset within a distributed cortical network, including the right temporal, the right frontal, and the bilateral occipital cortex. This finding provides empirical evidence for the functional importance of evoked oscillatory activity in high-level vision beyond the visual cortex and, thus, gives new insights into the functional relevance of neuronal interactions. It also indicates the very early availability of experience-based knowledge that might be regarded as a fundamental mechanism for the rapid extraction of the gist of a scene.


2019 ◽  
Author(s):  
S. A. Herff ◽  
C. Herff ◽  
A. J. Milne ◽  
G. D. Johnson ◽  
J. J. Shih ◽  
...  

AbstractRhythmic auditory stimuli are known to elicit matching activity patterns in neural populations. Furthermore, recent research has established the particular importance of high-gamma brain activity in auditory processing by showing its involvement in auditory phrase segmentation and envelope-tracking. Here, we use electrocorticographic (ECoG) recordings from eight human listeners, to see whether periodicities in high-gamma activity track the periodicities in the envelope of musical rhythms during rhythm perception and imagination. Rhythm imagination was elicited by instructing participants to imagine the rhythm to continue during pauses of several repetitions. To identify electrodes whose periodicities in high-gamma activity track the periodicities in the musical rhythms, we compute the correlation between the autocorrelations (ACC) of both the musical rhythms and the neural signals. A condition in which participants listened to white noise was used to establish a baseline. High-gamma autocorrelations in auditory areas in the superior temporal gyrus and in frontal areas on both hemispheres significantly matched the autocorrelation of the musical rhythms. Overall, numerous significant electrodes are observed on the right hemisphere. Of particular interest is a large cluster of electrodes in the right prefrontal cortex that is active during both rhythm perception and imagination. This indicates conscious processing of the rhythms’ structure as opposed to mere auditory phenomena. The ACC approach clearly highlights that high-gamma activity measured from cortical electrodes tracks both attended and imagined rhythms.


1995 ◽  
Vol 8 (2) ◽  
pp. 121-124
Author(s):  
K. Abe ◽  
R. Yokoyama ◽  
T. Yanagihara

We report a right-handed man who developed selective Kana (phonogram) agraphia following an infarct in the non-dominant right cerebral hemisphere. His ability for comprehension, reading and writing of Kanji (ideogram) was unaffected. Kana errors consisted of substitution with another letter and the number of target words was well preserved. The lesion responsible for his Kana agraphia included the right Wernicke's area (the posterior one-third or one-half of the superior temporal gyrus) on MRI, but he did not have aphasia. Based on these findings, we conclude that the language function in some dextral people may be partially lateralized to the right cerebral hemisphere.


2021 ◽  
Author(s):  
Nuno Gonçalo Gomes Fernandes Madeira ◽  
Ricardo Filipe Alves Martins ◽  
João Valente Duarte ◽  
Gabriel Nascimento Ferreira Costa ◽  
António João Ferreira Macedo Santos ◽  
...  

ABSTRACTBackgroundSocial cognition impairment is a key phenomenon in serious mental disorders such as schizophrenia (SCZ) and bipolar disorder (BPD). Although genetic and neurobiological studies have suggested common neural correlates, here we hypothesized that a fundamental dissociation of social processing occurs at an early level in these conditions.MethodsBased on the hypothesis that key structures in the social brain, namely the temporoparietal junction, should present distinctive features in SCZ and BPD during low-level social judgment, we conducted a case-control study in SCZ (n=20) and BPD (n=20) patients and controls (n=20), using task-based fMRI during a Theory-of-Mind (ToM) visual paradigm leading to interpretation of social meaning based on simple geometric figures.ResultsWe found opposite neural responses in two core ToM regions : SCZ patients showed social content-related deactivation (relative to controls and BPD) of the right supramarginal gyrus, a region which activity is required to overcome egocentric “overmentalizing”, while the opposite pattern was found in BPD; reverse patterns, relative to controls and SCZ, were found in the left posterior superior temporal gyrus, a region involved in inferring other’s intentions. Receiver-operating-characteristic curve analysis showed 88% accuracy in discriminating the two clinical groups based on these neural responses.ConclusionsThese contrasting activation patterns of the temporoparietal junction in SCZ and BPD represent mechanistic differences of social cognitive dysfunction that may be explored as biomarkers or therapeutic targets.


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