scholarly journals Late cortical potentials are not a reliable marker of somatosensory awareness

2020 ◽  
Author(s):  
Pia Schröder ◽  
Till Nierhaus ◽  
Felix Blankenburg

AbstractTwo types of scalp-recorded event-related potentials have been proposed as neural correlates of perceptual awareness in humans: an early, modality-specific negativity and a late, modality-independent positivity. However, whether these potentials genuinely reflect perception or result from task demands remains controversial. To address this question, we compared results from a classical somatosensory detection task (direct report task) to a somatosensory-visual matching task, in which overt reports were decorrelated from target detection, equated the behavioural relevance of detected and undetected stimuli, and mitigated the influence of attentional processes. By means of Bayesian model selection, we show that the early N140 component was the first to reflect target detection in both tasks, whereas the late P300 component was task dependent, with strong detection effects in the direct report task that were absent in the matching task. We conclude that the P300 is not a genuine correlate of somatosensory awareness but reflects postperceptual processing.

2005 ◽  
Vol 19 (3) ◽  
pp. 216-231 ◽  
Author(s):  
Albertus A. Wijers ◽  
Maarten A.S. Boksem

Abstract. We recorded event-related potentials in an illusory conjunction task, in which subjects were cued on each trial to search for a particular colored letter in a subsequently presented test array, consisting of three different letters in three different colors. In a proportion of trials the target letter was present and in other trials none of the relevant features were present. In still other trials one of the features (color or letter identity) were present or both features were present but not combined in the same display element. When relevant features were present this resulted in an early posterior selection negativity (SN) and a frontal selection positivity (FSP). When a target was presented, this resulted in a FSP that was enhanced after 250 ms as compared to when both relevant features were present but not combined in the same display element. This suggests that this effect reflects an extra process of attending to both features bound to the same object. There were no differences between the ERPs in feature error and conjunction error trials, contrary to the idea that these two types of errors are due to different (perceptual and attentional) mechanisms. The P300 in conjunction error trials was much reduced relative to the P300 in correct target detection trials. A similar, error-related negativity-like component was visible in the response-locked averages in correct target detection trials, in feature error trials, and in conjunction error trials. Dipole modeling of this component resulted in a source in a deep medial-frontal location. These results suggested that this type of task induces a high level of response conflict, in which decision-related processes may play a major role.


2012 ◽  
Vol 24 (2) ◽  
pp. 396-415 ◽  
Author(s):  
Valia Rodríguez ◽  
Russell Thompson ◽  
Mark Stokes ◽  
Matthew Brett ◽  
Indira Alvarez ◽  
...  

In this study, we explored the neural correlates of perceptual awareness during a masked face detection task. To assess awareness more precisely than in previous studies, participants employed a 4-point scale to rate subjective visibility. An event-related fMRI and a high-density ERP study were carried out. Imaging data showed that conscious face detection was linked to activation of fusiform and occipital face areas. Frontal and parietal regions, including the pre-SMA, inferior frontal sulcus, anterior insula/frontal operculum, and intraparietal sulcus, also responded strongly when faces were consciously perceived. In contrast, no brain area showed face-selective activity when participants reported no impression of a face. ERP results showed that conscious face detection was associated with enhanced N170 and also with the presence of a second negativity around 300 msec and a slow positivity around 415 msec. Again, face-related activity was absent when faces were not consciously perceived. We suggest that, under conditions of backward masking, ventral stream and fronto-parietal regions show similar, strong links of face-related activity to conscious perception and stress the importance of a detailed assessment of awareness to examine activity related to unseen stimulus events.


2014 ◽  
Vol 29 (8) ◽  
pp. 463-472 ◽  
Author(s):  
S. Corbera ◽  
S. Ikezawa ◽  
M.D. Bell ◽  
B.E. Wexler

AbstractEmpathy is crucial for maintaining effective social interactions. Research has identified both an early-emotional sharing and a late-cognitive component of empathy. Although considered a functionally vital social cognition process, empathy has scarcely been studied in schizophrenia (SZ). We used event-related potentials (ERPs) to study the temporal dynamics of empathic response in 19 patients with SZ and 18 matched healthy controls (HC) using an empathy for physical pain paradigm. Participants responded to pictures of hands in neutral and painful situations in an active empathic condition and one manipulated by task demands. Additionally, subjective ratings of the stimuli and empathic self-reports were collected. People with SZ had (1) decreased early-emotional ERP responses to pictures of others in pain; (2) decreased modulation by attention of late-cognitive ERP responses; (3) lower ratings of perspective taking and higher ratings of personal distress which were both related to decreased modulation of late-cognitive empathic responses; (4) a significant relationship between high affective overlap between somebody else's pain and their own pain and decreased modulation of late-cognitive empathic responses; (5) a distinct relationship between regulatory deficits in late-cognitive empathy and functioning. Patients had present but reduced early and late empathy-related ERPs. Patients also reported increased personal distress when faced with distress in others. The late ERP responses are thought to be associated with self-regulation and response modulation. The magnitude of these late responses was inversely associated with reported levels of personal distress in both patients and controls. Additionally, regulatory deficits in cognitive empathy were highly related with deficits in functioning. Decreased ability to regulate one's own emotional engagement and response to emotions of others may be an important source of distress and dysfunction in social situations for patients with schizophrenia.


Author(s):  
Vesa Putkinen ◽  
Mari Tervaniemi

Studies conducted during the last three decades have identified numerous differences between musicians and non-musicians in neural correlates of sensory, motor, and higher-order cognitive functions. Research employing event-related potentials/fields has been particularly important in this framework. This chapter reviews the evidence that has emerged from these studies with emphasis on longitudinal studies comparing functional brain development in children taking music lessons and those engaged in non-musical activities. The literature provides empirical and theoretical grounds for concluding that musical training enhances sound encoding skills that are relevant for both music and speech processing. The question whether the benefits of musical training transfer to more distantly related cognitive functions remains controversial, however. Finally, it appears likely that training-induced plasticity alone does not account for the differences in brain function between musicians and non-musicians and, conversely, that predisposing factors also play a role.


2019 ◽  
Author(s):  
Rémy Masson ◽  
Yohana Lévêque ◽  
Geneviève Demarquay ◽  
Hesham ElShafei ◽  
Lesly Fornoni ◽  
...  

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.


2002 ◽  
Vol 14 (2) ◽  
pp. 210-227 ◽  
Author(s):  
S. Campanella ◽  
P. Quinet ◽  
R. Bruyer ◽  
M. Crommelinck ◽  
J.-M. Guerit

Behavioral studies have shown that two different morphed faces perceived as reflecting the same emotional expression are harder to discriminate than two faces considered as two different ones. This advantage of between-categorical differences compared with within-categorical ones is classically referred as the categorical perception effect. The temporal course of this effect on fear and happiness facial expressions has been explored through event-related potentials (ERPs). Three kinds of pairs were presented in a delayed same–different matching task: (1) two different morphed faces perceived as the same emotional expression (within-categorical differences), (2) two other ones reflecting two different emotions (between-categorical differences), and (3) two identical morphed faces (same faces for methodological purpose). Following the second face onset in the pair, the amplitude of the bilateral occipito-temporal negativities (N170) and of the vertex positive potential (P150 or VPP) was reduced for within and same pairs relative to between pairs. This suggests a repetition priming effect. We also observed a modulation of the P3b wave, as the amplitude of the responses for the between pairs was higher than for the within and same pairs. These results indicate that the categorical perception of human facial emotional expressions has a perceptual origin in the bilateral occipito-temporal regions, while typical prior studies found emotion-modulated ERP components considerably later.


2009 ◽  
Vol 21 (7) ◽  
pp. 1435-1446 ◽  
Author(s):  
Dominique Lamy ◽  
Moti Salti ◽  
Yair Bar-Haim

The aim of the present study was to dissociate the ERP (Event Related Potentials) correlates of subjective awareness from those of unconscious perception. In a backward masking paradigm, participants first produced a forced-choice response to the location of a liminal target presented for an individually calibrated duration, and then reported on their subjective awareness of the target's presence. We recorded (Event-Related Potentials) ERPs and compared the ERP waves when observers reported being aware vs. unaware of the target but localized it correctly, thereby isolating the neural correlates of subjective awareness while controlling for differences in objective performance. In addition, we compared the ERPs when participants were subjectively unaware of the target's presence and localized it correctly versus incorrectly, thereby isolating the neural correlates of unconscious perception. All conditions involved stimuli that were physically identical and were presented for the same duration. Both behavioral measures were associated with modulation of the amplitude of the P3 component of the ERP. Importantly, this modulation was widely spread across all scalp locations for subjective awareness, but was restricted to the parietal electrodes for unconscious perception. These results indicate that liminal stimuli that do not affect performance undergo considerable processing and that subjective awareness is associated with a late wave of activation with widely distributed topography.


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