scholarly journals Impaired conscious access and abnormal attentional amplification in schizophrenia

2017 ◽  
Author(s):  
L Berkovitch ◽  
A Del Cul ◽  
M Maheu ◽  
S Dehaene
Keyword(s):  
Brain Activity ◽  
Event Related Potentials ◽  
Focused Attention ◽  
Conscious Perception ◽  
Top Down ◽  
Bottom Up ◽  
Essentially Normal ◽  
Related Potentials ◽  
P3 Component ◽  
The Brain

AbstractPrevious research suggests that the conscious perception of a masked stimulus is impaired in schizophrenia, while unconscious bottom-up processing of the same stimulus, as assessed by subliminal priming, can be preserved. Here, we test this postulated dissociation between intact bottom-up and impaired top-down processing and evaluate its brain mechanisms using high-density recordings of event-related potentials. Sixteen patients with schizophrenia and sixteen controls were exposed to peripheral digits with various degrees of visibility, under conditions of either focused attention or distraction by another task. In the distraction condition, the brain activity evoked by masked digits was drastically reduced in both groups, but early bottom-up visual activation could still be detected and did not differ between patients and controls. By contrast, under focused top-down attention, a major impairment was observed: in patients, contrary to controls, the late non-linear ignition associated with the P3 component was reduced. Interestingly, the patients showed an essentially normal attentional amplification of the PI and N2 components. These results suggest that some but not all top-down attentional amplification processes are impaired in schizophrenia, while bottom-up processing seems to be preserved.

scholarly journals Auditory attention alterations in migraine: a behavioral and MEG/EEG study

2019 ◽  
Author(s):  
Rémy Masson ◽  
Yohana Lévêque ◽  
Geneviève Demarquay ◽  
Hesham ElShafei ◽  
Lesly Fornoni ◽  
...  
Keyword(s):  
Event Related Potentials ◽  
Orienting Response ◽  
List Type ◽  
Top Down ◽  
Attention Task ◽  
Bottom Up ◽  
Attentional Processes ◽  
Related Potentials ◽  
The Right ◽  
Task Irrelevant

AbstractObjectivesTo evaluate alterations of top-down and/or bottom-up attention in migraine and their cortical underpinnings.Methods19 migraineurs between attacks and 19 matched control participants performed a task evaluating jointly top-down and bottom-up attention, using visually-cued target sounds and unexpected task-irrelevant distracting sounds. Behavioral responses and MEG/EEG were recorded. Event-related potentials and fields (ERPs/ERFs) were processed and source reconstruction was applied to ERFs.ResultsAt the behavioral level, neither top-down nor bottom-up attentional processes appeared to be altered in migraine. However, migraineurs presented heightened evoked responses following distracting sounds (orienting component of the N1 and Re-Orienting Negativity, RON) and following target sounds (orienting component of the N1), concomitant to an increased recruitment of the right temporo-parietal junction. They also displayed an increased effect of the cue informational value on target processing resulting in the elicitation of a negative difference (Nd).ConclusionsMigraineurs appear to display increased bottom-up orienting response to all incoming sounds, and an enhanced recruitment of top-down attention.SignificanceThe interictal state in migraine is characterized by an exacerbation of the orienting response to attended and unattended sounds. These attentional alterations might participate to the peculiar vulnerability of the migraine brain to all incoming stimuli.HighlightsMigraineurs performed as well as healthy participants in an attention task.However, EEG markers of both bottom-up and top-down attention are increased.Migraine is also associated with a facilitated recruitment of the right temporo-parietal junction.

scholarly journals Looking for effects of qualia on event-related brain potentials of close others in search for a cause of the similarity of qualia assumed across individuals

F1000Research ◽  
2018 ◽  
Vol 3 ◽  
pp. 316
Author(s):  
Sheila Bouten ◽  
Hugo Pantecouteau ◽  
J. Bruno Debruille
Keyword(s):  
Time Window ◽  
Brain Activity ◽  
Conscious Experience ◽  
Event Related Potentials ◽  
The Other ◽  
Brain Potentials ◽  
Frontal Electrode ◽  
Related Potentials ◽  
The Individual ◽  
The Brain

Qualia, the individual instances of subjective conscious experience, are private events. However, in everyday life, we assume qualia of others and their perceptual worlds, to be similar to ours. One way this similarity is possible is if qualia of others somehow contribute to the production of qualia by our own brain and vice versa. To test this hypothesis, we focused on the mean voltages of event-related potentials (ERPs) in the time-window of the P600 component, whose amplitude correlates positively with conscious awareness. These ERPs were elicited by images of the international affective picture system in 16 pairs of friends, siblings or couples going side by side through hyperscanning without having to interact. Each of the 32 members of these 16 pairs faced one half of the screen and could not see what the other member was presented with on the other half. One stimulus occurred on each half simultaneously. The sameness of these stimulus pairs was manipulated as well as the participants’ belief in that sameness by telling subjects’ pairs that they were going to be presented with the same stimuli in two blocks and with different ones in the two others. ERPs were more positive at all electrode subsets for stimulus pairs that were inconsistent with the belief than for those that were consistent. In the N400 time window, at frontal electrode sites, ERPs were again more positive for inconsistent than for consistent stimuli. As participants had no way to see the stimulus their partner was presented with and thus no way to detect inconsistence, these data might reveal an impact of the qualia of a person on the brain activity of another. Such impact could provide a research avenue when trying to explain the similarity of qualia across individuals.

The Similarity of Brain Activity Associated with True and False Recognition Memory Depends On Test Format

1997 ◽  
Vol 8 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Marcia K. Johnson ◽  
Scott F. Nolde ◽  
Mara Mather ◽  
John Kounios ◽  
Daniel L. Schacter ◽  
...  
Keyword(s):  
Source Monitoring ◽  
Brain Activity ◽  
Event Related Potentials ◽  
Emission Tomography ◽  
Test Format ◽  
Test Items ◽  
Positron Emission ◽  
Related Potentials ◽  
False Recognitions ◽  
The Brain

Event-related potentials (ERPs) were compared for correct recognitions of previously presented words and false recognitions of associatively related, nonpresented words (lures) When the test items were presented blocked by test type (old, new, lure), waveforms for old and lure items were different, especially at frontal and left parietal electrode sites, consistent with previous positron emission tomography (PET) data (Schacter, Reiman, et al, 1996) When the test format randomly intermixed the types of items, waveforms for old and lure items were more similar We suggest that test format affects the type of processing subjects engage in, consistent with expectations from the source-monitoring framework (Johnson, Hashtroudi, & Lindsay, 1993) These results also indicate that brain activity as assessed by neuroimaging designs requiring blocked presentation of trials (e.g., PET) do not necessarily reflect the brain activity that occurs in cognitive-behavioral paradigms, in which types of test trials are typically intermixed

Automatic Versus Contingent Mechanisms of Sensory-Driven Neural Biasing and Reflexive Attention

2005 ◽  
Vol 17 (8) ◽  
pp. 1341-1352 ◽  
Author(s):  
Joseph B. Hopfinger ◽  
Anthony J. Ries
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Response Times ◽  
Event Related Potentials ◽  
Top Down ◽  
Manual Response ◽  
Reflexive Attention ◽  
Manual Responses ◽  
Related Potentials ◽  
The Brain

Recent studies have generated debate regarding whether reflexive attention mechanisms are triggered in a purely automatic stimulus-driven manner. Behavioral studies have found that a nonpredictive “cue” stimulus will speed manual responses to subsequent targets at the same location, but only if that cue is congruent with actively maintained top-down settings for target detection. When a cue is incongruent with top-down settings, response times are unaffected, and this has been taken as evidence that reflexive attention mechanisms were never engaged in those conditions. However, manual response times may mask effects on earlier stages of processing. Here, we used event-related potentials to investigate the interaction of bottom-up sensory-driven mechanisms and top-down control settings at multiple stages of processing in the brain. Our results dissociate sensory-driven mechanisms that automatically bias early stages of visual processing from later mechanisms that are contingent on top-down control. An early enhancement of target processing in the extrastriate visual cortex (i.e., the P1 component) was triggered by the appearance of a unique bright cue, regardless of top-down settings. The enhancement of visual processing was prolonged, however, when the cue was congruent with top-down settings. Later processing in posterior temporal-parietal regions (i.e., the ipsilateral invalid negativity) was triggered automatically when the cue consisted of the abrupt appearance of a single new object. However, in cases where more than a single object appeared during the cue display, this stage of processing was contingent on top-down control. These findings provide evidence that visual information processing is biased at multiple levels in the brain, and the results distinguish automatically triggered sensory-driven mechanisms from those that are contingent on top-down control settings.

scholarly journals Increase of both bottom-up and top-down attentional processes in high dream recallers

2021 ◽  
Author(s):  
Perrine Ruby ◽  
Rémy Masson ◽  
Benoît Chatard ◽  
Roxane S Hoyer ◽  
Laure Bottemane ◽  
...  
Keyword(s):  
Event Related Potentials ◽  
Group Differences ◽  
Active Listening ◽  
Dream Recall ◽  
Top Down ◽  
Attention Task ◽  
Bottom Up ◽  
Attentional Processes ◽  
Attentional Functioning ◽  
Related Potentials

Event-related potentials (ERPs) associated with the involuntary orientation of (bottom-up) attention towards an unexpected sound are of larger amplitude in high dream recallers (HR) than in low dream recallers (LR) during passive listening, suggesting different attentional functioning. We measured bottom-up and top-down attentional performance and their cerebral correlates in 18 HR (11 women, age = 22.7 +/- 4.1 years, dream recall frequency = 5.3 +/- 1.3 days with a dream recall per week) and 19 LR (10 women, age = 22.3, DRF = 0.2 +/- 0.2) using EEG and the Competitive Attention Task. Between-group differences were found in ERPs but not in behavior. The results confirm that HR present larger ERPs to distracting sounds than LR during active listening, suggesting enhanced bottom-up processing of irrelevant sounds. HR also presented a larger contingent negative variation during target expectancy and a larger P3b response to target sounds than LR, speaking for an enhanced recruitment of top-down attention. Enhancement of both top-down and bottom-up processes in HR leads to an apparently preserved attentional balance since similar performance were observed in the two groups. Therefore, different neurophysiological profiles can result in similar cognitive performance, with some profiles possibly costlier in term of resource/energy consumption.

scholarly journals Brain activity in an awake chimpanzee in response to the sound of her own name

2009 ◽  
Vol 6 (3) ◽  
pp. 311-313 ◽  
Author(s):  
Ari Ueno ◽  
Satoshi Hirata ◽  
Kohki Fuwa ◽  
Keiko Sugama ◽  
Kiyo Kusunoki ◽  
...  
Keyword(s):  
Brain Activity ◽  
Event Related Potentials ◽  
Stimulus Onset ◽  
Auditory Stimuli ◽  
Negative Shift ◽  
Related Potentials ◽  
Own Name ◽  
Group Member ◽  
The Brain

The brain activity of a fully awake chimpanzee being presented with her name was investigated. Event-related potentials (ERPs) were measured for each of the following auditory stimuli: the vocal sound of the subject's own name (SON), the vocal sound of a familiar name of another group member, the vocal sound of an unfamiliar name and a non-vocal sound. Some differences in ERP waveforms were detected between kinds of stimuli at latencies at which P3 and Nc components are typically observed in humans. Following stimulus onset, an Nc-like negative shift at approximately 500 ms latency was observed, particularly in response to SON. Such specific ERP patterns suggest that the chimpanzee processes her name differently from other sounds.

Brain Imaging Technologies: How, What, When and Why?

1999 ◽  
Vol 33 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Evian Gordon
Keyword(s):  
Brain Imaging ◽  
Single Photon ◽  
Brain Activity ◽  
Photon Emission ◽  
Event Related Potentials ◽  
Current Status ◽  
Emission Computed Tomography ◽  
Imaging Technologies ◽  
Related Potentials ◽  
The Brain

Objective: Innovations in physics and computing technology over the past two decades have provided a powerful means of exploring the overall structure and function of the brain using a range of computerised brain imaging technologies (BITs). These technologies offer the means to elucidate the patterns of pathophysiology underlying mental illness. The aim of this paper is to explore the current status and some of the future directions in the application of BITs to psychiatry. Method: Brain imaging technologies provide unambiguous measures of brain structure (computerised tomography and magnetic resonance imaging [MRI]) and also index complementary measures of when (electroencephalography, event related potentials, magnetoencephalography) and where (functional MRI, single photon emission computed tomography, positron emission tomography) aspects of brain activity occur. Results: The structural technologies are primarily used to exclude a biological cause in cases of a suspected psychiatric disorder. The functional technologies show considerable potential to delineate subgroups of patients (that may have different treatment outcomes), and evaluate objectively the effects of treatment on the brain as a system. What is seldom emphasised in the literature are the numerous inconsistencies, the lack of specificity of findings and the simplistic interpretation of much of the data. Conclusion: Brain imaging technologies show considerable utility, but we are barely scratching the surface of this potential. Simplistic over-interpretation of results can be minimised by: replication of BIT findings, judicious combination of complementary methodologies, use of appropriate activation tasks, analysis with respect to large normative databases, control for performance, examining the data ‘beyond averaging’, delineating clinical subtypes, exploring the severity of symptoms, specificity of findings and effects of treatment in the same patients. The technological innovation of BITs still far outstrips the sophistication of their use; it is essential that the meaning and mechanisms underlying BITmeasures are always evaluated with respect to prevailing models of brain function across disciplines.

scholarly journals Pupil dilation and P3 reflect subjective surprise about decision outcome

2020 ◽  
Author(s):  
Jan Willem de Gee ◽  
Camile M.C. Correa ◽  
Matthew Weaver ◽  
Tobias H. Donner ◽  
Simon van Gaal
Keyword(s):  
Animal Cognition ◽  
Event Related Potentials ◽  
Decision Task ◽  
Internal Factors ◽  
The Face ◽  
Related Potentials ◽  
P3 Component ◽  
Physiological Markers ◽  
The Brain

AbstractCentral to human and animal cognition is the ability to learn from feedback in order to optimize future rewards. Such a learning signal might be encoded and broadcasted by the brain’s arousal systems, including the noradrenergic locus coeruleus. Pupil responses and the P3 component of event-related potentials reflect rapid changes in the arousal level of the brain. Here we ask whether and how these variables may reflect “subjective surprise”: the mismatch between one’s expectation about being correct and the outcome of a decision, when expectations fluctuate due to internal factors (e.g., engagement). We show that during an elementary decision-task in the face of uncertainty both physiological markers of phasic arousal reflect subjective surprise. We further show that pupil responses and P3 are unrelated to each other, and that subjective prediction error computations depend on feedback awareness. These results further advance our understanding of the role of central arousal systems in decision-making under uncertainty.

scholarly journals Distinct Patterns of Neural Activity during Memory Formation of Nonwords versus Words

2007 ◽  
Vol 19 (11) ◽  
pp. 1776-1789 ◽  
Author(s):  
Leun J. Otten ◽  
Josefin Sveen ◽  
Angela H. Quayle
Keyword(s):  
Neural Activity ◽  
Brain Activity ◽  
Item Type ◽  
Event Related Potentials ◽  
Memory Formation ◽  
Electrical Brain Activity ◽  
Related Potentials ◽  
Neural Underpinnings ◽  
Incidental Encoding ◽  
The Brain

Research into the neural underpinnings of memory formation has focused on the encoding of familiar verbal information. Here, we address how the brain supports the encoding of novel information that does not have meaning. Electrical brain activity was recorded from the scalps of healthy young adults while they performed an incidental encoding task (syllable judgments) on separate series of words and “nonwords” (nonsense letter strings that are orthographically legal and pronounceable). Memory for the items was then probed with a recognition memory test. For words as well as nonwords, event-related potentials differed depending on whether an item would subsequently be remembered or forgotten. However, the polarity and timing of the effect varied across item type. For words, subsequently remembered items showed the usually observed positive-going, frontally distributed modulation from around 600 msec after word onset. For nonwords, by contrast, a negative-going, spatially widespread modulation predicted encoding success from 1000 msec onward. Nonwords also showed a modulation shortly after item onset. These findings imply that the brain supports the encoding of familiar and unfamiliar letter strings in qualitatively different ways, including the engagement of distinct neural activity at different points in time. The processing of semantic attributes plays an important role in the encoding of words and the associated positive frontal modulation.

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