Read by QxMD icon Read

Neural correlates of consciousness

Anna Nigri, Eleonora Catricalà, Stefania Ferraro, Maria Grazia Bruzzone, Ludovico D'Incerti, Davide Sattin, Davide Rossi Sebastiano, Silvana Franceschetti, Giorgio Marotta, Riccardo Benti, Matilde Leonardi, Stefano F Cappa
There is a growing interest in the use of functional imaging to assess brain activity in the absence of behavioural responses in patients with disorders of consciousness (DOC). In the present study, we applied a hierarchical auditory stimulation paradigm to functional magnetic resonance (fMRI) in a group of long-term DOC adult patients. Brain response to pairs of pseudowords, of unrelated words and of semantically related words, i.e. stimuli differing in lexical status (words vs. pseudowords) and semantic relatedness (related vs...
October 13, 2016: Brain Imaging and Behavior
Bing Cao, Jun Wang, Mahadi Shahed, Beth Jelfs, Rosa H M Chan, Ying Li
Vagus nerve stimulation (VNS) can enhance memory and cognitive functions in both rats and humans. Studies have shown that VNS influenced decision-making in epileptic patients. However, the sites of action involved in the cognitive-enhancement are poorly understood. By employing a conscious rat model equipped with vagus nerve cuff electrode, we assess the role of chronic VNS on decision-making in rat gambling task (RGT). Simultaneous multichannel-recordings offer an ideal setup to test the hypothesis that VNS may induce alterations of in both spike-field-coherence and synchronization of theta oscillations across brain areas in the anterior cingulate cortex (ACC) and basolateral amygdala (BLA)...
October 12, 2016: Scientific Reports
Cui Su, Zhenhu Liang, Xiaoli Li, Duan Li, Yongwang Li, Mauro Ursino
OBJECTIVE: Multiscale permutation entropy (MSPE) is becoming an interesting tool to explore neurophysiological mechanisms in recent years. In this study, six MSPE measures were proposed for on-line depth of anesthesia (DoA) monitoring to quantify the anesthetic effect on the real-time EEG recordings. The performance of these measures in describing the transient characters of simulated neural populations and clinical anesthesia EEG were evaluated and compared. METHODS: Six MSPE algorithms-derived from Shannon permutation entropy (SPE), Renyi permutation entropy (RPE) and Tsallis permutation entropy (TPE) combined with the decomposition procedures of coarse-graining (CG) method and moving average (MA) analysis-were studied...
2016: PloS One
Anthony J Gifuni, Adam Kendal, Fabrice Jollant
Guilt is a self-conscious emotion associated with the negative appraisal of one's behavior. In recent years, several neuroimaging studies have investigated the neural correlates of guilt, but no meta-analyses have yet identified the most robust activation patterns. A systematic review of literature found 16 functional magnetic resonance imaging studies with whole-brain analyses meeting the inclusion criteria, for a total of 325 participants and 135 foci of activation. A meta-analysis was then conducted using activation likelihood estimation...
October 4, 2016: Brain Imaging and Behavior
Zhong S Zheng, Nicco Reggente, Evan Lutkenhoff, Adrian M Owen, Martin M Monti
Previous studies have suggested that disorders of consciousness (DOC) after severe brain injury may result from disconnections of the thalamo-cortical system. However, thalamo-cortical connectivity differences between vegetative state (VS), minimally conscious state minus (MCS-, i.e., low-level behavior such as visual pursuit), and minimally conscious state plus (MCS+, i.e., high-level behavior such as language processing) remain unclear. Probabilistic tractography in a sample of 25 DOC patients was employed to assess whether structural connectivity in various thalamo-cortical circuits could differentiate between VS, MCS-, and MCS+ patients...
September 13, 2016: Human Brain Mapping
Carlo Cipolli, Michele Ferrara, Luigi De Gennaro, Giuseppe Plazzi
Recent advances in electrophysiological [e.g., surface high-density electroencephalographic (hd-EEG) and intracranial recordings], video-polysomnography (video-PSG), transcranial stimulation and neuroimaging techniques allow more in-depth and more accurate investigation of the neural correlates of dreaming in healthy individuals and in patients with brain-damage, neurodegenerative diseases, sleep disorders or parasomnias. Convergent evidence provided by studies using these techniques in healthy subjects has led to a reformulation of several unresolved issues of dream generation and recall [such as the inter- and intra-individual differences in dream recall and the predictivity of specific EEG rhythms, such as theta in rapid eye movement (REM) sleep, for dream recall] within more comprehensive models of human consciousness and its variations across sleep/wake states than the traditional models, which were largely based on the neurophysiology of REM sleep in animals...
July 28, 2016: Sleep Medicine Reviews
Ana B Chica, Dimitri J Bayle, Fabiano Botta, Paolo Bartolomeo, Pedro M Paz-Alonso
Only a small fraction of all the information reaching our senses can be the object of conscious report or voluntary action. Although some models propose that different attentional states (top-down amplification and vigilance) are necessary for conscious perception, few studies have explored how the brain activations associated with different attentional systems (such as top-down orienting and phasic alerting) lead to conscious perception of subsequent visual stimulation. The aim of the present study was to investigate the neural mechanisms associated with endogenous spatial attention and phasic alertness, and their interaction with the conscious perception of near-threshold stimuli...
2016: Scientific Reports
Mar Gonzalez-Franco, Anna I Bellido, Kristopher J Blom, Mel Slater, Antoni Rodriguez-Fornells
We designed an observational study where participants (n = 17) were exposed to pictures and look-alike avatars pictures of themselves, a familiar friend or an unfamiliar person. By measuring participants' brain activity with electroencephalography (EEG), we found face-recognition event related potentials (ERPs) in the visual cortex, around 200-250 ms, to be prominent for the different familiarity levels. A less positive component was found for self-recognized pictures (P200) than pictures of others, showing similar effects in both real faces and look-alike avatars...
2016: Frontiers in Human Neuroscience
Sascha Benjamin Fink
A main goal of the neuroscience of consciousness is: find the neural correlate to conscious experiences (NCC). When have we achieved this goal? The answer depends on our operationalization of "NCC." Chalmers (2000) shaped the widely accepted operationalization according to which an NCC is a neural system with a state which is minimally sufficient (but not necessary) for an experience. A deeper look at this operationalization reveals why it might be unsatisfactory: (i) it is not an operationalization of a correlate for occurring experiences, but of the capacity to experience; (ii) it is unhelpful for certain cases which are used to motivate a search for neural correlates of consciousness; (iii) it does not mirror the usage of "NCC" by scientists who seek for unique correlates; (iv) it hardly allows for a form of comparative testing of hypotheses, namely experimenta crucis...
2016: Frontiers in Psychology
Paul M Matthews, Adam Hampshire
Recent advances in connectomics have led to a synthesis of perspectives regarding the brain's functional organization that reconciles classical concepts of localized specialization with an appreciation for properties that emerge from interactions across distributed functional networks. This provides a more comprehensive framework for understanding neural mechanisms of normal cognition and disease. Although fMRI has not become a routine clinical tool, research has already had important influences on clinical concepts guiding diagnosis and patient management...
August 3, 2016: Neuron
Ralf-Peter Behrendt
If hallucinations are not fundamentally different from normal wakeful experiences, then the neural basis of hallucinations has to be essentially that of consciousness in general. The additional insight that consciousness reflects the formation (as opposed to consolidation) of event (episodic) memories links the pathophysiology of hallucinations to the hippocampus. Perceptions and misperceptions, insofar as they are consciously experienced, constitute contextualized and unitary phenomena (which are embedded as discrete events in the stream of consciousness); they are experiential manifestations of activity patters that recurrently emerge in the CA3 network of the hippocampus (and that are secondarily consolidated into retrievable and declarable memories)...
November 3, 2016: Progress in Neuro-psychopharmacology & Biological Psychiatry
Maria Sekutowicz, Katharina Schmack, Rosa Steimke, Lena Paschke, Philipp Sterzer, Henrik Walter, Christine Stelzel
Our brain continuously evaluates different perceptual interpretations of the available sensory data in order to enable flexible updates of conscious experience. Individuals' perceptual flexibility can be assessed using ambiguous stimuli that cause our perception to continuously switch between two mutually exclusive interpretations. Neural processes underlying perceptual switching are thought to involve the visual cortex, but also non-sensory brain circuits that have been implicated in cognitive processes, such as frontal and parietal regions...
November 1, 2016: NeuroImage
Kristian Sandberg, Stefan Frässle, Michael Pitts
No abstract text is available yet for this article.
July 28, 2016: Nature Reviews. Neuroscience
Guy Meiri, Sa'ar Lanir, Anne Minert, Marshall Devor
Transient loss of consciousness (TLOC), frequently triggered by perturbation in essential physiological parameters such as pCO2or O2, is considered a passive consequence of generalized degradation in high-level cerebral functioning.However, the fact that it is almost always accompanied by atonia and loss of spinal nocifensive reflexes suggests that it might actually be part of a "syndrome" mediated by neural circuitry, and ultimately be adaptive. Widespread suppression by molecules distributed in the vasculature is also the classical explanation of general anesthesia...
July 22, 2016: Experimental Neurology
Darren F Hight, Logan J Voss, Paul S García, Jamie W Sleigh
During emergence from anesthesia patients regain their muscle tone (EMG). In a typical population of surgical patients the actual volatile gas anesthetic concentrations in the brain (CeMAC) at which EMG activation occurs remains unknown, as is whether EMG activation at higher CeMACs is correlated with subsequent severe pain, or with cortical activation. Electroencephalographic (EEG) and EMG activity was recorded from the forehead of 273 patients emerging from general anesthesia following surgery. We determined CeMAC at time of EMG activation and at return of consciousness...
July 21, 2016: Journal of Clinical Monitoring and Computing
Recep A Ozdemir, Jose L Contreras-Vidal, Beom-Chan Lee, William H Paloski
To date, no systematic research investigating cortical correlates of performance changes in dual tasking has been reported in the elderly population. Thus, we monitored whole-scalp cortical activations (EEG) during both single task and posture-cognition dual tasking with the main goal of understanding cortical activity modulations underlying age-related differences on posture-cognition dual tasking conditions. Postural and cognitive data analyses showed that elderly people had decreased cognitive performance even during challenging single cognitive tasks...
July 21, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Zara M Bergström, David G Williams, Mariam Bhula, Dinkar Sharma
Distractibility can lead to accidents and academic failures as well as memory problems. Recent evidence suggests that intentional recognition memory can be biased by unintentional recognition of distracting stimuli in the same environment. It is unknown whether unintentional and intentional recognition depend on the same underlying neurocognitive mechanisms. We assessed whether human participants' recognition of previously seen (old) or not seen (new) target stimuli was affected by whether a to-be-ignored distractor was old or new...
July 15, 2016: Journal of Cognitive Neuroscience
Jun Jiang, Kira Bailey, Ling Xiang, Li Zhang, Qinglin Zhang
Although previous studies have suggested that conflict control can occur in the absence of consciousness, the brain mechanisms underlying unconscious and conscious conflict control remain unclear. The current study used a rapid event-related functional magnetic resonance imaging design to collect data from 24 participants while they performed a masked Stroop priming task under both conscious and unconscious conditions. The results revealed that the fronto-parietal conflict network, including medial frontal cortex (MFC), left and right dorsal lateral prefrontal cortex (DLPFC), and posterior parietal cortex (PPC), was activated by both conscious and unconscious Stroop priming, even though in MFC and left DLPFC the activations elicited by unconscious Stroop priming were smaller than conscious Stroop priming...
2016: Frontiers in Human Neuroscience
Francesca Pistoia, Antonio Carolei
Disorders of consciousness and locked-in syndrome are two completely different neurological conditions which share unresponsiveness or minimal responsiveness at an observable behavioral level. The key element of disorders of consciousness is the loss of self- and environmental awareness, while the main feature of locked-in syndrome is extreme motor entrapment despite preserved awareness. In both cases accurate diagnosis may come late and patients are at risk of being wrongly diagnosed and missing out on appropriate rehabilitative opportunities...
2016: Open Neuroimaging Journal
Liuting Diao, Senqing Qi, Mengsi Xu, Zhiai Li, Cody Ding, Antao Chen, Yan Zheng, Dong Yang
Consciously initiated cognitive control is generally determined by motivational incentives (e.g., monetary reward). Recent studies have revealed that human cognitive control processes can nevertheless operate without awareness. However, whether monetary reward can impinge on unconscious cognitive control remains unclear. To clarify this issue, a task consisting of several runs was designed to combine a modified version of the reward-priming paradigm with an unconscious version of the Go/No-Go task. At the beginning of each run, participants were exposed to a high- or low-value coin, followed by the modified Go/No-Go task...
September 2016: International Journal of Psychophysiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"