Aperiodic activity differences in individuals with high and low temporal processing efficiency.

It is known that Temporal Information Processing (TIP) underpins our cognitive functioning. Previous research has focused on the relationship between TIP efficiency and oscillatory brain activity, especially the gamma rhythm; however, non-oscillatory (aperiodic or 1/f) brain activity has often been missed. Recent studies have identified the 1/f component as being important for the functioning of the brain. Therefore, the current study aimed to verify whether TIP efficiency is associated with specific EEG resting state cortical activity patterns, including oscillatory and non-oscillatory (aperiodic) brain activities. To measure individual TIP efficiency, we used two behavioral tasks in which the participant judges the order of two sounds separated by millisecond intervals. Based on the above procedure, participants were classified into two groups with high and low TIP efficiency. Using cluster-based permutation analyses, we examined between-group differences in oscillatory and non-oscillatory (aperiodic) components across the 1-90 Hz range. The results revealed that the groups differed in the aperiodic component across the 30-80 Hz range in fronto-central topography. In other words, participants with low TIP efficiency exhibited higher levels of aperiodic activity, and thus a flatter frequency spectrum compared to those with high TIP efficiency. We conclude that participants with low TIP efficiency display higher levels of 'neural noise', which is associated with poorer quality and speed of neural processing.

A common timing mechanism across different millisecond domains: evidence from perceptual and motor tasks.

Temporal information processing (TIP) constitutes a complex construct that underlies many cognitive functions and operates in a few hierarchically ordered time domains. This study aimed to verify the relationship between the tens of milliseconds and hundreds of milliseconds domains, referring to perceptual and motor timing, respectively. Sixty four young healthy individuals participated in this study. They underwent two auditory temporal order judgement tasks to assess their performance in the tens of milliseconds domain; on this basis, groups of high-level performers (HLP) and low-level performers (LLP) were identified. Then, a maximum tapping task was used to evaluate performance in the hundreds of milliseconds domain. The most remarkable result was that HLP achieved a faster tapping rate and synchronised quicker with their "internal clock" during the tapping task than did LLP. This result shows that there is a relationship between accuracy in judging temporally asynchronous stimuli and ability to achieve and maintain the pace of a movement adequate to one's internal pacemaker. This could indicate the strong contribution of a common timing mechanism, responsible for temporal organisation and coordination of behaviours across different millisecond domains.

Cognitive training incorporating temporal information processing improves linguistic and non-linguistic functions in people with aphasia.

People with aphasia (PWA) often present deficits in non-linguistic cognitive functions, such as executive functions, working memory, and temporal information processing (TIP), which intensify the associated speech difficulties and hinder the rehabilitation process. Therefore, training targeting non-linguistic cognitive function deficiencies may be useful in the treatment of aphasia. The present study compared the effects of the novel Dr. Neuronowski® training method (experimental training), which particularly emphasizes TIP, with the linguistic training commonly applied in clinical practice (control training). Thirty four PWA underwent linguistic and non-linguistic assessments before and after the training as well as a follow-up assessment. Patients were randomly assigned to either experimental (n = 18) or control groups (n = 16). The experimental training improved both non-linguistic functions (TIP and verbal short-term and working memory) and linguistic functions: phoneme discrimination, sentence comprehension, grammar comprehension, verbal fluency, and naming. In contrast, the control training improved only grammar comprehension and naming. The follow-up assessment confirmed the stability of the effects of both trainings over time. Thus, in PWA, Dr. Neuronowski® training appears to have broader benefits for linguistic and non-linguistic functions than does linguistic training. This provides evidence that Dr. Neuronowski® may be considered a novel tool with potential clinical applications.

Age as a moderator of the relationship between planning and temporal information processing.

Planning is a fundamental mental ability related to executive functions. It allows to select, order and execute subgoals to achieve a goal. Studies have indicated that these processes are characterised by a specific temporal dynamics reflected in temporal information processing (TIP) in some tens of millisecond domain. Both planning and TIP decline with age but the underlying mechanisms are unclear. The novel value of the present study was to examine these mechanisms in young (n = 110) and elderly (n = 91) participants in Tower of London task, considering two structural properties of problems: search depth related to static maintenance in working memory, and goal ambiguity reflecting dynamic cognitive flexibility. Results revealed that TIP predicted planning accuracy both directly and indirectly (via preplanning) but only in young participants in problems characterised by high goal ambiguity. Better planning is related to longer preplanning and more efficient TIP. This result demonstrates for the first time age-related differences in the contribution of TIP to planning. In young participants TIP contributed to dynamic cognitive flexibility, but not to static maintenance processes. In elderly such relation was not observed probably because the deficient planning might depend on working memory maintenance rather than on cognitive flexibility.

Sub- and Supra-Second Timing in Auditory Perception: Evidence for Cross-Domain Relationships.

Previous studies indicate that there are at least two levels of temporal processing: the sub- and supra-second domains. The relationship between these domains remains unclear. The aim of this study was to test whether performance on the sub-second level is related to that on the supra-second one, or whether these two domains operate independently. Participants were 118 healthy adults (mean age = 23 years). The sub-second level was studied with a temporal-order judgment task and indexed by the Temporal Order Threshold (TOT), on which lower values corresponded to better performance. On the basis of TOT results, the initial sample was classified into two groups characterized by either higher temporal efficiency (HTE) or lower temporal efficiency (LTE). Next, the efficiency of performance on the supra-second level was studied in these two groups using the subjective accentuation task, in which participants listened to monotonous sequences of beats and were asked to mentally accentuate every n-th beat to create individual rhythmic patterns. The extent of temporal integration was assessed on the basis of the number of beats being united and better performance corresponded to longer units. The novel results are differences between groups in this temporal integration. The HTE group integrated beats in significantly longer units than did the LTE group. Moreover, for tasks with higher mental load, the HTE group relied more on a constant time strategy, whereas the LTE group relied more on mental counting, probably because of less efficient temporal integration. These findings provide insight into associations between sub- and supra-second levels of processing and point to a common time keeping system, which is active independently of temporal domain.

Application of the In Vitro HoxB8 Model System to Characterize the Contributions of Neutrophil-LPS Interaction to Periodontal Disease.

(1) Background: Studying neutrophils in vitro is difficult since these cells are terminally differentiated and are easily activated during isolation. At the same time, most of the available model cell lines are associated with certain limitations, such as functional deficiency or a lack of expression of surface markers characteristic of neutrophils. P. gingivalis is a periodontopathogen that causes dysbiosis in subgingival bacterial biofilm. This triggers the accumulation of functional neutrophils in the periodontium. However, until now, the specific effects of P. gingivalis-derived lipopolysaccharide on neutrophil functions have not been analyzed. (2) Methods: The impact of two variants of commercially available P. gingivalis endotoxin on neutrophil functions was tested using the HoxB8 in vitro system that is well suited to analyze neutrophil response to different stimuli in a controlled manner. (3) Results: The Standard P. gingivalis lipopolysaccharide (LPS), known to activate cells through Toll-like receptor 2 (TLR2)- and Toll-like receptor 4 (TLR4)-dependent pathways, prolonged neutrophil survival and exhibited pro-inflammatory effects. In contrast, Ultrapure LPS, binding exclusively to TLR4, neither protected neutrophils from apoptosis, nor induced an inflammatory response. (4) Conclusion: Two variants of P. gingivalis-derived LPS elicited effects on neutrophils and, based on the obtained results, we concluded that the engagement of both TLR2 and TLR4 is required for the manipulation of survival and the stimulation of immune responses of HoxB8 neutrophils.