scholarly journals A reduced level of consciousness affects non-conscious processes

NeuroImage ◽  
2021 ◽  
Vol 244 ◽  
pp. 118571
Author(s):  
A. Fontan ◽  
L. Lindgren ◽  
T. Pedale ◽  
C. Brorsson ◽  
F. Bergström ◽  
...  
2020 ◽  
Author(s):  
A. Fontan ◽  
L. Lindgren ◽  
T. Pedale ◽  
C. Brorsson ◽  
F. Bergström ◽  
...  

AbstractBeing conscious is a profound aspect of human existence, and understanding its function and its inception is considered one of the truly grand scientific challenges. However, the nature of consciousness remains enigmatic, to a large part because “being conscious” can refer to both the content (phenomenology) and the level (arousal) of consciousness, and how these different aspects are related remains unclear. To empirically assess the relation between level and content of consciousness, we manipulated these two aspects by presenting stimuli consciously or non-consciously and by using Propofol sedation, while brain activity was measured using fMRI. We observed that sedation greatly affected non-conscious processes, which starkly contrasts the notion that anesthetics selectively reduce consciousness. Our findings reveal that level and content of consciousness are separate phenomena, and imply that one may need to reconsider what “being conscious” means.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 335-335
Author(s):  
Jaclyn Maher ◽  
Derek Hevel ◽  
Kourtney Sappenfield ◽  
Heidi Scheer ◽  
Christine Zecca ◽  
...  

Abstract Accumulating evidence suggests that sedentary behavior (SB), or time spent sitting, is regulated by both conscious (e.g., intentions) and non-conscious (e.g., habits) motivational processes. Much of the work investigating these processes has employed summary-based measures of typical motivation and behavior. This study employed ecological momentary assessment (EMA) methods and accelerometry to determine the extent to which conscious and non-conscious processes regulate minority older adults’ momentary decisions to engage in SB. Over the course of the 8-day study, minority older adults (N=91; age range: 60-89 years, 96% Black/African American) answered 6 EMA questionnaires/day on a mobile phone and wore an ActivPAL activity monitor to measure SB. EMA questionnaires assessed momentary intentions to limit SB over the next two hours. SB habit strength was self-reported at an introductory session. Results from a multilevel linear regression model indicated that on occasions when individuals had stronger intentions than usual to limit SB, they subsequently engaged in less SB (b=-3.72, p<0.01). Individuals who had stronger SB habits, tended to engage in more SB (b=3.00, p<0.01). An additional multilevel model revealed that habits did not significantly moderate the association between momentary intentions and subsequent SB (b=-1.06, p=0.09). In conclusion, minority older adults’ momentary SB appears to be directly influenced by both conscious and non-conscious motivational processes, though the interactive effects are unclear. Interventions to reduce minority older adults’ SB should include content to increase intentions to limit SB (e.g., information on instrumental and affective consequences) and disrupt habitual SB (e.g., action planning).


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Manon Carrière ◽  
Helena Cassol ◽  
Charlène Aubinet ◽  
Rajanikant Panda ◽  
Aurore Thibaut ◽  
...  

Abstract Auditory localization (i.e. turning the head and/or the eyes towards an auditory stimulus) is often part of the clinical evaluation of patients recovering from coma. The objective of this study is to determine whether auditory localization could be considered as a new sign of minimally conscious state, using a multimodal approach. The presence of auditory localization and the clinical outcome at 2 years of follow-up were evaluated in 186 patients with severe brain injury, including 64 with unresponsive wakefulness syndrome, 28 in minimally conscious state minus, 71 in minimally conscious state plus and 23 who emerged from the minimally conscious state. Brain metabolism, functional connectivity and graph theory measures were investigated by means of 18F-fluorodeoxyglucose positron emission tomography, functional MRI and high-density electroencephalography in two subgroups of unresponsive patients, with and without auditory localization. These two subgroups were also compared to a subgroup of patients in minimally conscious state minus. Auditory localization was observed in 13% of unresponsive patients, 46% of patients in minimally conscious state minus, 62% of patients in minimally conscious state plus and 78% of patients who emerged from the minimally conscious state. The probability to observe an auditory localization increased along with the level of consciousness, and the presence of auditory localization could predict the level of consciousness. Patients with auditory localization had higher survival rates (at 2-year follow-up) than those without localization. Differences in brain function were found between unresponsive patients with and without auditory localization. Higher connectivity in unresponsive patients with auditory localization was measured between the fronto-parietal network and secondary visual areas, and in the alpha band electroencephalography network. Moreover, patients in minimally conscious state minus significantly differed from unresponsive patients without auditory localization in terms of brain metabolism and alpha network centrality, whereas no difference was found with unresponsive patients who presented auditory localization. Our multimodal findings suggest differences in brain function between unresponsive patients with and without auditory localization, which support our hypothesis that auditory localization should be considered as a new sign of minimally conscious state. Unresponsive patients showing auditory localization should therefore no longer be considered unresponsive but minimally conscious. This would have crucial consequences on these patients’ lives as it would directly impact the therapeutic orientation or end-of-life decisions usually taken based on the diagnosis.


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