Potential role of mushroom beta-glucans in immunity and inflammation in viral infections and COVID-19

According to the concept of trained immunity (TRIM), by stimulating the immune response with one pathogen, one can strengthen it against infection by another. With this understanding, one can take advantage of such immune responses with a stimulant such as β-glucan, which does not actually cause disease in humans, but has the advantage of generating primed immune cells that will respond to a variety of deadly infections. Mushroom β-glucans are known to act as training agents that leads to an increase in immune responses when these trained cells are subjected to a secondary stimulus. Understanding whether the TRIM processes are responsible for antiviral responses will undoubtedly provide a deeper understanding of other potential antiviral strategies, as the new SARS-CoV-2 is not the first- or last-time humanity has to deal with viral pandemics. More studies and clinical evidence are necessary for better understanding of the role of β-glucans in viral infections and COVID-19.

Dual-Task Costs in Gait Speed Differs Across Age Groups

With age, there are simultaneous reductions in gait speed (GS). This decrease in GS has been associated with an increased fall risk and negatively impacts independence. Further, GS naturally declines with the addition of a secondary stimulus (i.e., cognitive requirements). Combined, these decrements can be additive in nature potentially leading to robust declines with advancing age. Therefore, the aim of this study was to examine age-related effects of dual-task cost (DTC) while walking. Adults (N = 145), over the age of 45 years, completed two walking trials for each GS condition: habitual (HAB) and fast (FST), with and without a DT (i.e., counting backwards by serials of three). Subjects were classified into four age groups: youngest-old (YG ≤ 64 years, n = 24), young-old (YO, 65-74 years, n = 46), middle-old (MO = 75-84 years, n = 54), and oldest-old (OO ≥ 85 years, n = 21). DTC was calculated and ANOVAs were used to assess differences between the groups. There was no difference in HAB DTC between the age groups (p=.61). However, there was a significant difference in FST DTC (p=.04) between the YO (M±SD: -14 ± -11%) and OO (M±SD: -24 ± -12%). These data indicate there was an age-related affect for fast dual-task cost, but not for habitual dual-task cost while walking. An increase in dual-task cost among the oldest-old may be associated with an inability to properly maintain a faster cadence while performing an arithmetic task which may be related to task prioritization.

Cost of Dual-Task Performance in Tactile Perception Is Greater for Competing Tasks of the Same Type

This study examines dual-task performance in the tactile modality and tests whether dual-task cost depends on task type. Experiment 1 involved competing tasks of the same type, using a primary localisation task on the left hand and a secondary localisation task on the right hand. In Experiment 2, the primary task on the left hand remained the same, while an intensity discrimination task was used as the secondary task on the right hand. Subjects in both experiments completed three conditions: the primary task alone, a dual-task condition, and the primary task with the secondary stimulus present but no response required. Across both experiments, performance on the primary task was best when it was presented alone, and there was a performance decrement when the secondary stimulus was present but not responded to. Performance on the primary task was further decreased when participants had to respond to the secondary stimulus, and the decrease was larger when the secondary task was localisation rather than discrimination. This result indicates that task type in the tactile modality may modulate the attentional cost of dual-task performance and implies partially shared resources underlie localisation and intensity discrimination.

Effects of Self-Evaluation on the P300 Event-Related Potential

The effects of self evaluation on the P300 event-related potential (ERP) were explored with 56 participants (16 men, 40 women; M age = 23.4 yr., SD = 1.2) across three conditions. The conditions included (1) a standard ERP auditory oddball discrimination between a random target (15% occurrence) and standard stimuli (85% occurrence), (2) the oddball task followed by the additional cognitive task of maintaining a mental count of the target tones, and (3) the oddball task followed by the additional cognitive task of self-evaluating whether they felt surprised by the current occurrence of the target tone. The added cognitive requirements for Conditions 2 and 3 required the subjects to maintain a cognitive readiness for the secondary stimulus-related task during their sensory discrimination response for the standard oddball task. During the self-evaluation condition, the P300 amplitude was significantly larger across all recording locations than the regular oddball condition and the cognitive count condition.