Conscious Detection Research Articles

Electrophysiological evidence of preserved hearing at the end of life

This study attempts to answer the question: “Is hearing the last to go?” We present evidence of hearing among unresponsive actively dying hospice patients. Individual ERP (MMN, P3a, and P3b) responses to deviations in auditory patterns are reported for conscious young, healthy control participants, as well as for hospice patients, both when the latter were conscious, and again when they became unresponsive to their environment. Whereas the MMN (and perhaps too the P3a) is considered an automatic response to auditory irregularities, the P3b is associated with conscious detection of oddball targets. All control participants, and most responsive hospice patients, evidenced a “local” effect (either a MMN, a P3a, or both) and some a “global” effect (P3b) to deviations in tone, or deviations in auditory pattern. Importantly, most unresponsive patients showed evidence of MMN responses to tone changes, and some showed a P3a or P3b response to either tone or pattern changes. Thus, their auditory systems were responding similarly to those of young, healthy controls just hours from end of life. Hearing may indeed be one of the last senses to lose function as humans die.

M137. HIGH CONFIDENCE FOR VISUOMOTOR ACTION RECRUITS THE VENTRAL STRIATUM – A METACOGNITIVE APPROACH FOR UNDERSTANDING NEGATIVE SYMPTOMS?

BackgroundMetacognition refers to the ability to discriminate between one’s own correct and incorrect decisions, thus representing a key function for goal-oriented behavior. The neurobiological underpinnings of metacognition have mainly been studied in perceptual decision-making and memory-related processes; therefore, mechanisms and neural correlates underlying metacognitive processes during visuomotor actions are still poorly characterized and the specific role of confidence remains to be elucidated. This is of particular interest as deficits in goal-directed behavior and insight both are a hallmark of the negative symptoms of schizophrenia.MethodsWe examined 31 healthy controls who were asked to draw straight reaching trajectories towards a visual target, while measuring their brain activity with functional Magnetic Resonance Imaging (fMRI). Deviations were introduced in 70% of the trajectories seen on the screen. Participants then reported awareness of deviations (first-order), followed by (second-order) confidence in their response. The amount of deviation was titrated to reach a 71% average detection rate using an adaptive staircase procedure. Metacognition was measured using the M-Ratio, which estimates the ratio of first-order information available for confidence computation (Maniscalco & Lau, 2012). Whole brain activity was analyzed via a parametric general linear model (GLM).ResultsParticipants showed good metacognitive abilities at evaluating the correctness of their first-order responses (M-Ratio: 0.98±0.25). Movements were decomposed into two phases based on peaks in the variance of the trajectory deviation and actual joystick position. We found that confidence ratings after deviated trials were explained by a combination of the trajectory deviation in the initial phase (p=0.006; linear mixed model) and the amount of motor correction in the final phase of the movement (p<0.001). At the neural level, as expected, conscious detection of deviation engages strongly the visual cortex, whereas higher visuomotor corrections engage primarily the primary motor cortex. Importantly, we show that high confidence specifically recruits the ventral striatum bilaterally (p<0.05 corrected for multiple comparisons), suggesting a role for confidence in motivating action.DiscussionTaken together, these results show for the first time in healthy controls that confidence for visuomotor action strongly engages motivational regions in line with a key role of metacognition in goal directed behavior and accurate insight into self-performed actions. These results in healthy controls are currently being tested in a cohort of schizophrenia patients and our hypothesis is that patients with higher level of apathy will display lower metacognitive confidence and lower ventral striatum activity

Resting-State NIRS-EEG in Unresponsive Patients with Acute Brain Injury: A Proof-of-Concept Study.

Neurovascular-based imaging techniques such as functional MRI (fMRI) may reveal signs of consciousness in clinically unresponsive patients but are often subject to logistical challenges in the intensive care unit (ICU). Near-infrared spectroscopy (NIRS) is another neurovascular imaging technique but low cost, can be performed serially at the bedside, and may be combined with electroencephalography (EEG), which are important advantages compared to fMRI. Combined NIRS-EEG, however, has never been evaluated for the assessment of neurovascular coupling and consciousness in acute brain injury. We explored resting-state oscillations in eight-channel NIRS oxyhemoglobin and eight-channel EEG band-power signals to assess neurovascular coupling, the prerequisite for neurovascular-based imaging detection of consciousness, in patients with acute brain injury in the ICU (n = 9). Conscious neurological patients from step-down units and wards served as controls (n = 14). Unsupervised adaptive mixture-independent component analysis (AMICA) was used to correlate NIRS-EEG data with levels of consciousness and clinical outcome. Neurovascular coupling between NIRS oxyhemoglobin (0.07-0.13Hz) and EEG band-power (1-12Hz) signals at frontal areas was sensitive and prognostic to changing consciousness levels. AMICA revealed a mixture of five models from EEG data, with the relative probabilities of these models reflecting levels of consciousness over multiple days, although the accuracy was less than 85%. However, when combined with two channels of bilateral frontal neurovascular coupling, weighted k-nearest neighbor classification of AMICA probabilities distinguished unresponsive patients from conscious controls with > 90% accuracy (positive predictive value 93%, false discovery rate 7%) and, additionally, identified patients who subsequently failed to recover consciousness with > 99% accuracy. We suggest that NIRS-EEG for monitoring of acute brain injury in the ICU is worthy of further exploration. Normalization of neurovascular coupling may herald recovery of consciousness after acute brain injury.

Rapid implicit extraction of abstract orthographic patterns of Chinese characters during reading.

Orthographic processing is crucial in reading. For the Chinese language, sub-lexical processing has already taken place at radical level. Previous literature reported early position-specific radical representations and later position-general radical representations, implying a possible separating process of abstract position information irrespective of radicals per se from radical representations during orthographic processing. However, it remains largely unclear whether the abstract pattern of spatial arrangement of radicals can be rapidly extracted, and if so, whether this extraction takes place at the visual cortex, the very first processing center. As the visual cortex is documented to actively participate in orthographic processing, it may also play a role in the possible extraction of abstract orthographic patterns of Chinese characters. Hence, we hypothesize that abstract orthographic patterns of Chinese characters are covertly extracted at the visual cortex during reading. In this study, we investigated whether the visual cortex could rapidly extract abstract structural patterns of Chinese characters, using the event-related potential (ERP) technique. We adopted an active oddball paradigm with two types of deviant stimuli different only in one feature, structural or tonal, from standard stimuli; in each of the two sessions, subjects focused conscious attention on one feature and neglected the other. We observed that the ERPs recorded at occipital electrodes responded differentially to standard and structural deviant stimuli in both sessions, especially within the time range of the occipital P200 component. Then, we extracted three source waves arising from different levels of the visual cortex. Early response differences (from 88 to 456 ms after stimulus onset) were observed between the source waves, probably arising from left primary/secondary and bilateral associative visual cortices, in response to standard and deviant stimuli that violated abstract structural patterns, whether subjects focused their attention on the character structure or not. This suggests rapid extraction of abstract structural patterns of Chinese characters in the visual cortex, no matter the abstract structural pattern was explicit or implicit to subjects. Note that the source waves arising from right primary/secondary visual cortices in response to standard and structural deviant stimuli did not differ at all, indicating that this extraction of the abstract structural pattern of Chinese characters was left-lateralized. Besides, no difference was observed between source waves originating from any level of the visual cortex to standard and deviant stimuli that violated abstract tonal patterns, until 768 ms when a late effect related to conscious detection of targets occurred at higher levels of the visual cortex. Note that at late stages (later than 698 ms after stimulus onset), responses arising from bilateral associative visual cortices to standard and target stimuli differed for both sessions, no matter the structural or tonal feature was attended to. Our findings support the primitive intelligence of visual cortex to rapidly extract abstract orthographic patterns of Chinese characters that might be engaged in further lexical processing. Our findings also suggest that this rapid extraction can take place implicitly during reading.

Dissociating preferences from evaluations following subliminal conditioning

Preferences towards unfamiliar drink brands may be influenced through subliminal conditioning. This can involve associating unfamiliar brands (CS) with positively valenced attributes (US) under constrained visual conditions to prevent the former's conscious detection. According to learning theory, CS associated with positive US should become increasingly preferred as the latter's positive valences generalizes (transfer) across associated CS. Similarly, correlating CS with negative US should reduce CS-associated preferences. There is some evidence that CS-associated preferences can be reliably influenced through subliminal conditioning (Elgendi et al., 2018). Conversely, there is also evidence that subliminal conditioning does not effectively alter evaluations of CS valence (Heycke et al., 2018). Those works suggest CS preferences may be more susceptible to subliminal valence transfer relative to CS evaluations. We explored this hypothesis presently, where four pairs of supraliminal/visible and subliminal trigrams (CS) were respectively associated with four US categories varied along aggregate valence (100% positive, 80% positive, 20% positive, 0% positive). CS evaluations and preferences were recorded before and after conditioning. Bayesian analyses revealed US valence manipulations were likely to shift preferences, but not evaluations, of subliminal CS. Across supraliminal CS, Bayesian and frequentist analyses indicated US valence was significant and likely to shift preferences and evaluations. The present study demonstrates preferences may be influenced through subliminal conditioning even as evaluations are not.

Developing malevolent node-based protection system against jamming attack in agent assisted CRN

Recent advancements in CRN realises many applications such as industrials, future fifth generation network, vehicular network and so on. However, CRN is vulnerable to security attacks which are held on different layers of the network. Many research works are followed up on CRN in the security perspective but none of them is able to secure network from multiple attacks. This paper presents a malevolent node-based protection system (MNPS) to mitigate SSDF attack and jamming attack in agent assisted CRN. Network is prevented from unauthorised SUs with the aid of certificate aware hash chaining (CAHC) algorithm-based authentication process. Malevolent SUs in the network are detected by analysing sensing reports of SUs and SA. SSDF attack detection is carried out using trust conscious attacker detection (TCAD) scheme in which improved k-means (IK-means) algorithm is involved for report analysis. Malevolent SU is act as supporter node in order to mitigate jamming attack in the network. Best channel that attracts attackers towards it is assigned for supporter node by hybrid cuckoo search with firefly algorithm (HCS-FFA). Extensive experimental results show promising results in delay, packet delivery ratio, secrecy rate, signal to interference and noise ratio (SINR), and probability of false-alarm.

Causal manipulation of feed-forward and recurrent processing differentially affects measures of consciousness.

It has been theorized that cortical feed-forward and recurrent neural activity support unconscious and conscious cognitive processes, respectively. Here we causally tested this proposition by applying event-related transcranial magnetic stimulation (TMS) at early and late times relative to visual stimuli, together with a pulse designed to suppress conscious detection. Consistent with pre-registered hypotheses, early TMS affected residual, reportedly ‘unseen’ capacity. However, conscious perception also appeared critically dependent upon feed-forward processing to a greater extent than the later recurrent phase. Additional exploratory analyses suggested that these early effects dissociated from top-down criterion measures, which were most affected by later TMS. These findings are inconsistent with a simple dichotomy where feed-forward and recurrent processes correspond to unconscious and conscious mechanisms. Instead, different components of awareness may correspond to different phases of cortical dynamics in which initial processing is broadly perceptual whereas later recurrent processing might relate to decision to report.

Which behaviours are first to emerge during recovery of consciousness after severe brain injury?

Early detection of consciousness after severe brain injury is critical for establishing an accurate prognosis and planning appropriate treatment. To determine which behavioural signs of consciousness emerge first and to estimate the time course to recovery of consciousness in patients with severe acquired brain injury. Retrospective observational study using the Coma Recovery Scale-Revised and days to recovery of consciousness in 79 patients (51 males; 34 with traumatic brain injury; median [IQR] age 48 [26-61] years; median time since injury 26 [20-36] days) who transitioned from coma or unresponsive wakefulness syndrome (UWS)/vegetative state (VS) to the minimally conscious state (MCS) or emerged from MCS during inpatient rehabilitation. Visual pursuit was the most common initial sign of MCS (41% of patients; 95% CI [30-52]), followed by reproducible command-following (25% [16-35]) and automatic movements (24% [15-33]). Ten other behaviours emerged first in less than 16% of cases. Median [IQR] time to recovery of consciousness was 44 [33-59] days. Etiology did not significantly affect time to recovered consciousness. Recovery of consciousness after severe brain injury is most often signalled by reemergence of visual pursuit, reproducible command-following and automatic movements. Clinicians should use assessment measures that are sensitive to these behaviours because early detection of consciousness is critical for accurate prognostication and treatment planning.

Genioglossus muscle responses to resistive loads in severe OSA patients and healthy control subjects.

This study aimed to determine whether there is impairment of genioglossus neuromuscular responses to small negative pressure respiratory stimuli, close to the conscious detection threshold, in obstructive sleep apnea (OSA). We compared genioglossus electromyogram (EMGgg) responses to midinspiratory resistive loads of varying intensity (≈1.2-6.2 cmH2O·L-1·s), delivered via a nasal mask, between 16 severe OSA and 17 control participants while the subjects were awake and in a seated upright position. We examined the relationship between stimulus intensity and peak EMGgg amplitude in a 200-ms poststimulus window and hypothesized that OSA patients would have an increased activation threshold and reduced sensitivity in the relationship between EMGgg activation and stimulus intensity. There was no significant difference between control and OSA participants in the threshold (P = 0.545) or the sensitivity (P = 0.482) of the EMGgg amplitude vs. stimulus intensity relationship, where change in epiglottic pressure relative to background epiglottic pressure represented stimulus intensity. These results do not support the hypothesis that deficits in neuromuscular response to negative upper airway pressure exist in OSA during wakefulness; however, the results are likely influenced by a counterintuitive and novel genioglossus muscle suppression response observed in a significant proportion of both OSA and healthy control participants. This suppression response may relate to the inhibition seen in inspiratory muscles such as the diaphragm in response to sudden-onset negative pressure, and its presence provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.NEW & NOTEWORTHY Our study used a novel midinspiratory resistive load stimulus to study upper airway neuromuscular responses to negative pressure during wakefulness in obstructive sleep apnea (OSA). Although no differences were found between OSA and healthy groups, the study uncovered a novel and unexpected suppression of neuromuscular activity in a large proportion of both OSA and healthy participants. The unusual response provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.

When temporal prediction errs: ERP responses to delayed action-feedback onset

Sensory suppression effects observed in electroencephalography (EEG) index successful predictions of the type and timing of self-generated sensory feedback. However, it is unclear how precise the timing prediction of sensory feedback is, and how temporal delays between an action and its sensory feedback affect perception. The current study investigated how prediction errors induced by delaying tone onset times affect the processing of sensory feedback in audition. Participants listened to self-generated (via button press) or externally generated tones. Self-generated tones were presented either without or with various delays (50, 100, or 250 ms; in 30% of trials).Comparing listening to externally generated and self-generated tones resulted in action-related P50 amplitude suppression to tones presented immediately or 100 ms after the button press. Subsequent ERP responses became more sensitive to the type of delay. Whereas the comparison of actual and predicted sensory feedback (N1) tolerated temporal uncertainty up to 100 ms, P2 suppression was modulated by delay in a graded manner: suppression decreased with an increase in sensory feedback delay. Self-generated tones occurring 250 ms after the button press additionally elicited an enhanced N2 response.These findings suggest functionally dissociable processes within the forward model that are affected by the timing of sensory feedback to self-action: relative tolerance of temporal delay in the P50 and N1, confirming previous results, but increased sensitivity in the P2. Further, they indicate that temporal prediction errors are treated differently by the auditory system: only delays that occurred after a temporal integration window (∼100 ms) impact the conscious detection of altered sensory feedback.

Change in Iris Dimensions as a Potential Human Consciousness Level Indicator

Detection of human consciousness is vital for validating a legal or official statement whether in the form of written or verbal. A statement given under unconsciousness state is considered null and void as the person is not fully awarded about the consequences of the statement. Several factors affects human consciousness like effect of alcohol, drowsiness, effect of anesthesia, sleeping pills, natural sleeping hours etc. The present available methods for detection of level of consciousness works in a specific condition only. For instance Alcohol Meter can detect the level of alcohol in the breath but not the effects sleeping pills or partial conscious due to drowsiness. In this research we propose a new technique which can detect all types of unconsciousness irrespective of reasons. We used the feature of iris light sensitivity which dilates inversely to pupil. Consciousness and iris dilation is directly proportional i.e. iris dilation increases with increase of consciousness and decreases with decrease of consciousness. We tested this method on 66 volunteers with 99.83% accuracy for 0.03mm iris dilation threshold value unconscious under alcohol effect and under drossiness conditions. Results shows that iris sensitivity decreases significantly during unconscious state, for any reasons. This feature can be used for validation of contracts before signing legal contracts.

Becoming aware of subliminal responses: An EEG/EMG study on partial error detection and correction in humans

In experimental settings, most overt behavioral errors are consciously perceived. They are, however, only the tip of the iceberg, and electromyographic recording of the muscles involved in the response reveals subthreshold incorrect response activations. Although they are all efficiently corrected, such “partial errors” are poorly consciously detected. Electroencephalographic recordings (CSD estimate), revealed the sequence of cortical activities that lead, or not, to conscious detection. Besides medio-prefrontal activities related to action monitoring and error detection, the motor command sent by the primary motor cortices also differed between detected and undetected partial errors: while it develops identically, it is stopped earlier for the latter than for the former, suggesting a critical role in partial error detection. Second, the analysis of the “Error positivity” – Pe, classically linked to error awareness, confirmed its absence just after partial errors, be they detected or not. However, a Pe occurs after the corrective response of partial errors that were detected, suggesting that we become aware of our partial errors only after their correction. The implication of these results for the link between consciousness and cognitive control are discussed.

Interactions between cardiac activity and conscious somatosensory perception.

Fluctuations in the heart's activity can modulate the access of external stimuli to consciousness. The link between perceptual awareness and cardiac signals has been investigated mainly in the visual and auditory domain. Here, we investigated whether the phase of the cardiac cycle and the prestimulus heart rate influence conscious somatosensory perception. We also tested how conscious detection of somatosensory stimuli affects the heart rate. Electrocardiograms (ECG) of 33 healthy volunteers were recorded while applying near-threshold electrical pulses at a fixed intensity to the left index finger. Conscious detection was not uniformly distributed across the cardiac cycle but significantly higher in diastole than in systole. We found no evidence that the heart rate before a stimulus influenced its detection, but hits (correctly detected somatosensory stimuli) led to a more pronounced cardiac deceleration than misses. Our findings demonstrate interactions between cardiac activity and conscious somatosensory perception, which highlights the importance of internal bodily states for sensory processing beyond the auditory and visual domain.

Automated pupillometry to detect command following in neurological patients: a proof-of-concept study.

BackgroundLevels of consciousness in patients with acute and chronic brain injury are notoriously underestimated. Paradigms based on electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) may detect covert consciousness in clinically unresponsive patients but are subject to logistical challenges and the need for advanced statistical analysis.MethodsTo assess the feasibility of automated pupillometry for the detection of command following, we enrolled 20 healthy volunteers and 48 patients with a wide range of neurological disorders, including seven patients in the intensive care unit (ICU), who were asked to engage in mental arithmetic.ResultsFourteen of 20 (70%) healthy volunteers and 17 of 43 (39.5%) neurological patients, including 1 in the ICU, fulfilled prespecified criteria for command following by showing pupillary dilations during ≥4 of five arithmetic tasks. None of the five sedated and unconscious ICU patients passed this threshold.ConclusionsAutomated pupillometry combined with mental arithmetic appears to be a promising paradigm for the detection of covert consciousness in people with brain injury. We plan to build on this study by focusing on non-communicating ICU patients in whom the level of consciousness is unknown. If some of these patients show reproducible pupillary dilation during mental arithmetic, this would suggest that the present paradigm can reveal covert consciousness in unresponsive patients in whom standard investigations have failed to detect signs of consciousness.

Semantic Knowledge Enhances Conscious Awareness of Visual Objects.

It is becoming increasingly established that information from long-term memory can influence early perceptual processing, a finding that is in line with recent theoretical approaches to cognition such as the predictive coding framework. Notwithstanding, the impact of semantic knowledge on conscious perception and the temporal dynamics of such an influence remain unclear. To address this question, we presented pictures of novel objects to participants as the second of two targets in an attentional blink paradigm. We found that associating newly acquired semantic knowledge to objects increased overall conscious detection in comparison to objects associated with minimal knowledge while controlling for object familiarity. Additionally, event-related brain potentials revealed a corresponding modulation beginning 100 msec after stimulus presentation in the P1 component. Furthermore, the size of this modulation was correlated with participant's subjective reports of conscious perception. These findings suggest that semantic knowledge can shape the contents of consciousness by affecting early stages of perceptual processing.

Emotional consciousness preserved in patients with disorders of consciousness?

Increasing evidence from studies of brain responses to subject’s own name (SON) indicates that residual consciousness is preserved in patients with disorders of consciousness (DOC) and that specific network activation might provide evidence of consciousness. However, it remains unclear whether SON is suitable for detection of emotional consciousness; moreover, the particular aspects of brain network organization that are critical for consciousness are unknown. The present study used an innovative approach to explore affective consciousness in patients with DOC during emotional stimuli. EEG data were acquired from 15 patients and 15 healthy volunteers. We analyzed brain potentials and functional network connectivity with a passive emotional paradigm based on graph theoretical methods. Larger N1 or P3a was detected in patients upon exposure to emotional sound, relative to neutral stimuli. Brain topology revealed that emotional sound evoked significantly stronger network linkages in healthy controls; additionally, it evoked several connectivity changes in patients with DOC. In conclusion, emotional consciousness might be partially preserved in patients with DOC; moreover, EEG network patterns could provide new insights into the neural activity of emotional perception in these patients.

Delirium is associated with frequency band specific dysconnectivity in intrinsic connectivity networks: preliminary evidence from a large retrospective pilot case-control study

BackgroundPathophysiological concepts in delirium are not sufficient to define objective biomarkers suited to improve clinical approaches. Advances in neuroimaging have revalued electroencephalography (EEG) as a tool to assess oscillatory network activity in neuropsychiatric disease. Yet, research in the field is limited to small populations and largely confined to postoperative delirium, which impedes generalizability of findings and planning of prospective studies in other populations. This study aimed to assess effect sizes of connectivity measures in a large mixed population to demonstrate that there are measurable EEG differences between delirium and control patients.MethodsThis retrospective pilot study investigated EEG measures as biomarkers in delirium using a case-control design including patients diagnosed with delirium (DSM-5 criteria) and age-/gender-matched controls drawn from a database of 9980 patients (n = 129 and 414, respectively). Assessors were not blinded for groups. Power spectra and connectivity estimates, using the weighted phase log index, of continuous EEG data were compared between conditions. Alterations of information flow through nodes of intrinsic connectivity networks (ICN; default mode, salience, and executive control network) were evaluated in source space using betweenness centrality. This was done frequency specific and network nodes were defined by the multimodal human cerebral cortex parcellation based on human connectome project data.ResultsDelirium and control patients exhibited distinct EEG power, connectivity, and network characteristics (F(72,540) = 70.3, p < .001; F(493,1079) = 2.69, p < .001; and F(718,2159) = 1.14, p = .007, respectively). Connectivity analyses revealed global alpha and regional beta band disconnectivity that was accompanied by theta band hyperconnectivity in delirious patients. Source and network analyses yielded that these changes are not specific to single intrinsic connectivity networks but affect multiple nodes of networks engaged in level of consciousness, attention, working memory, executive control, and salience detection. Effect sizes were medium to strong in this mixed population of delirious patients.ConclusionsWe quantified effect sizes for EEG connectivity and network analyses to be expected in delirium. This study implicates that theta band hyperconnectivity and alpha band disconnectivity may be essential mechanisms in the pathophysiology of delirium. Upcoming prospective studies will build upon these results and evaluate the clinical utility of identified EEG measures as therapeutic and prognostic biomarkers.

Task-Related Reorganization of Functional Connectivity in Early Detection of Consciousness in Patients With Severe Brain Injury

In recent years the number of patients with early postcomatosis long-term states of unconsciousness is increasing in the world. Accurate assessment of current functional state of patients in unconscious states is very important for correct treatment strategy and rehabilitation activities especially in cases when the difference between those states is not clinically obvious. To investigate features of resting-state wavelet synchrony in unconscious patients with severe brain injury and how TMS-therapy can affect resting state functional connectivity. We used stimulus-based EEG paradigm to detect changes of functional connectivity after TMS-therapy. Fifteen patients were recruited. They had the diagnosis of minimally conscious state (MCS) (male = 9, female = 2; n = 11), vegetative state/unresponsive wakefulness syndrome (VS/UWS) (male = 4, n = 4). We analyzed functional connectivity, values of wavelet synchrony in resting state and for responses on stimuli of patients before and after TMS-therapy. Of the 15 patients, eleven (eight MCS, two VS/UWS) had positive clinical dynamics including improvement of moving, emergence of glance fixation and gaze tracking, speech understanding and attempts of speech productions. The appearance of interhemispheric and diagonal connections is a favorable prognostic sign. TMStherapy makes it possible to include activate functional networks in resting state.

Connectivity of Frontoparietal Regions Reveals Executive Attention and Consciousness Interactions.

The executive control network is involved in the voluntary control of novel and complex situations. Solving conflict situations or detecting errors have demonstrated to impair conscious perception of near-threshold stimuli. The aim of this study was to explore the neural mechanisms underlying executive control and its interaction with conscious perception using functional magnetic resonance imaging and diffusion-weighted imaging. To this end, we used a dual-task paradigm involving Stroop and conscious detection tasks with near-threshold stimuli. A set of prefrontal and frontoparietal regions were more strongly engaged for incongruent than congruent trials while a distributed set of frontoparietal regions showed stronger activation for consciously than nonconsciously perceived trials. Functional connectivity analysis revealed an interaction between executive control and conscious perception in frontal and parietal nodes. The microstructural properties of the middle branch of the superior longitudinal fasciculus were associated with neural measures of the interaction between executive control and consciousness. These results demonstrate that conscious perception and executive control share neural resources in frontoparietal networks, as proposed by some influential models.

An attentional blink in the absence of spatial attention: a cost of awareness?

The attentional blink refers to the finding that when two visual targets appear within 200-500 ms, observers often miss the second target. In three experiments, we disentangle the roles of spatial attention to and conscious report of the first event in eliciting this cost. We show that allocating spatial attention to the first event is not necessary for a blink to occur: the full temporal pattern of the blink arises when the first event is consciously detected, despite the fact that it is not spatially attended, whereas no cost is observed when the first event is missed. We then show that spatial attention is also not sufficient for eliciting a blink, though it can deepen the blink when accompanied by conscious detection. These results demonstrate that there is no cost associated with the initiation of an attentional episode, whereas explicit conscious detection comes at a price. These findings demonstrate the temporal flexibility of attention and underscore the potential role of subjective awareness in understanding processing limitations, although this role may be contingent on the encoding in working memory necessary for conscious report.