- Homepage
- Programme
- Registration
- Practical Guide
- About Neuronus
Marcin Koculak1,2 and Michał Wierzchoń1,2
1Consciousness Lab, Jagiellonian University
2Centre for Brain Science, Jagiellonian University
Identifying the brain mechanisms that support consciousness is one of the most challenging tasks that science faces today. In this project, we investigated whether currently available state of the art measures of consciousness can be used to study the variability of consciousness in healthy awake humans at rest.
To achieve this goal, we created a suite of resting state conditions, from classical version where participants were not exposed to any stimulation and had either opened or closed eyes, up to watching short fictional stories that included a plot. We designed them to vary both sensory as well as non-sensory informational content.
Collected data created a unique database of more than six hundred participants and total number of individual recording sessions exceeding 1600. Taken together, it formed a extensive database of high-quality EEG resting state data that to our knowledge does not have a precedence in publicly available datasets. We analysed the data with most popular complexity measures (Lempel-Ziv complexity, multiscale entropy, and detrended fluctuation analysis) to verify their claimed potential in tracking conscious activity in brain signals. We found that Lempel-Ziv complexity was the best at separating experimental conditions as well as scoring higher in those that were designed as containing more content. This was true for both increased sensory and conceptual information.
Funding: Financed from grants 2016/23/N/HS6/00844 and 2019/33/B/HS6/02233 awarded by the Polish National Science Centre.
Klaudia Krystecka1, Magdalena Stanczyk1, Mikolaj Magnuski1, Elzbieta Szelag1, Aneta Szymaszek1
1Laboratory of Neurophysiology of Mind, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
Temporal Information Processing (TIP) constitutes a base of our cognitive functioning. Little is known about the neuronal underpinnings of TIP, however it has been associated with gamma oscillations so far. Recently, researches have focused not only on the oscillatory, but also in non-oscillatory brain activity which reflects the quality of neural communications. Our study aimed to verify whether TIP efficiency is associated with specific EEG resting state cortical activity patterns. 84 young healthy subjects participated in this study. They underwent two tasks: 1) Temporal Order Judgement (TOJ) task to measure TIP efficiency and 2) EEG resting-state to assess oscillatory and non-oscillatory brain activity. Based on the TOJ task, participants were classified into two groups with high and low TIP efficiency. The results revealed group differences in non-oscillatory component across the 30–80 Hz range in fronto-central topography. Participants with low TIP efficiency display higher levels of non-oscillatory component, which may reflect poorer quality and speed of neural processing.
Funding: Supported by National Science Centre, Poland, grant no. 2018/29/B/HS6/02038
Urszula Górska-Klimowska1,2, Anna Leśniewska2, Małgorzata Hołda2, Marek Binder2
1Department of Psychiatry, University of Wisconsin-Madison, US
2Institute of Psychology, Jagiellonian University in Krakow, Krakow, Poland
During sleep, the level of consciousness varies, but most of the time, we remain disconnected from auditory inputs. Auditory steady-state responses (ASSRs) have been shown to be sensitive to the level of arousal, but it remains unclear whether this effect is related to disconnection and/ or unconsciousness.
In this study, we analyzed EEG responses to 25-55Hz range chirp modulated stimulation in the group of 22 healthy volunteers, 18 of whom were participating in serial awakenings study (54 reports). We evaluated ASSRs with intertrial phase clustering (ITPC) from frontocentral channels.
We found significant effects (p<0.05) of reduced ITPC values in the low gamma band range (37-43 Hz) from wakefulness to both N2 and N3 NREM sleep, but not to REM sleep, and from REM sleep to both N2 and N3 NREM sleep. Moreover, we found significant effects (p<0.05) of reduced ITPC values in 37-43 Hz band between no-dreaming vs dreaming reports in which auditory experience was present, but not when it was absent (although the latter was not significantly differed from wakefulness).
Overall, these results suggest that low gamma (about 40 Hz) ASSR is both sensitive to changes in the level of arousal (dropping in NREM sleep), and in the level of consciousness (decreasing during no-dreaming unconsciousness). The latter effect might be related to the functionality of the auditory pathway (disconnection). I will interpret these results in comparison to current literature and preliminary findings from a serial awakening intracranial EEG study, where we observed decreased delta and increased high gamma during dreams vs no-dreams. The current findings strengthen the notion of low gamma ASSRs as a tool for reliable discrimination between levels of consciousness, suitable for clinical applications.
Funding: Opus grant, National Science Center in Poland, 2018/31/B/HS6/03920
Anna Leśniewska1 and Mirosław Wyczesany1, Marek Binder1, Małgorzata Hołda1, Urszula Górska1,2
1Institute of Psychology, Jagiellonian University, Krakow, Poland
2Department of Neurology, University of Wisconsin-Madison, Madison, USA
As we transition to sleep, auditory perception weakens, with 40Hz auditory steady-state responses (ASSRs) notably decreasing during reduced arousal states. However, the precise changes in network connectivity in cortical brain structures with diminished ASSRs remain unclear.
To evoke 40Hz ASSRs, we utilized series of rapid and periodical stimuli, click sounds series, each representing a slice of noise at 40Hz and duration of 500ms. These stimuli were presented to 22 healthy volunteers. Our project aimed to to investigate brain connectivity responses during wakefulness and sleep stages. (N2, N3 NREM, and REM). EEG source-based effective connectivity analysis employed the Direct Transfer Function (DTF) method, focusing on causal relations between signals. Isolating specific brain areas was essential for DTF analysis, including cortical networks crucial for consciousness maintenance, such as the 'central area' and frontal-parietal connections. Analysis encompassed activity in resting-state networks (RSNs), including the default-mode network (DMN), salience network (SAL), central executive network (CEN), and the primary auditory cortex (AC).
We hypothesize diminished information exchange regarding periodic auditory stimulation among RSNs during deep sleep, particularly in the anterior ROI during SWS. Additionally, we expect to observe heightened DMN activity during N1/REM phases and decreased activity when periodic auditory stimulation is present compared to SAL and CEN. SAL exhibited increased activity during N1/REM under ASSR, potentially facilitating DMN-CEN coordination. However, the precise role of the CEN in these dynamics remains uncertain.
Our research sheds light on how the brain's connectivity responds to variations in periodical auditory stimuli processing across different arousal states. It aims to discern neuronal networks and investigate whether information propagation within them favors long-distance connections or local circuits.
Funding: Project funded by the NCN n. 2018/31/B/HS6/03920; Principal investigator: dr hab. Marek Binder
and NCN n. 2018/31/G/HS6/02490; Principal investigator: dr hab. Mirosław Wyczesany
