Overview of Sigma-1R Subcellular Specific Biological Functions and Role in Neuroprotection.

For the past several years, fundamental research on Sigma-1R (S1R) protein has unveiled its necessity for maintaining proper cellular homeostasis through modulation of calcium and lipid exchange between the endoplasmic reticulum (ER) and mitochondria, ER-stress response, and many other mechanisms. Most of these processes, such as ER-stress response and autophagy, have been associated with neuroprotective roles. In fact, improving these mechanisms using S1R agonists was beneficial in several brain disorders including neurodegenerative diseases. In this review, we will examine S1R subcellular localization and describe S1R-associated biological activity within these specific compartments, i.e., the Mitochondrion-Associated ER Membrane (MAM), ER-Lipid Droplet (ER-LD) interface, ER-Plasma Membreane (ER-PM) interface, and the Nuclear Envelope (NE). We also discussed how the dysregulation of these pathways contributes to neurodegenerative diseases, while highlighting the cellular mechanisms and key binding partners engaged in these processes.

Usefulness of the rivermead postconcussion symptoms questionnaire and the trail-making test for outcome prediction in patients with mild traumatic brain injury.

The aim of the study was to determine if the Rivermead Postconcussion Symptoms Questionnaire (RPQ) is a better tool for outcome prediction than an objective neuropsychological assessment following mild traumatic brain injury (mTBI). The study included 47 patients with mTBI referred to an outpatient rehabilitation clinic. The RPQ and a brief neuropsychological battery were performed in the first few days following the trauma. The outcome measure used was the Mayo-Portland Adaptability Inventory-4 (MPAI-4) which was completed within the first 3 months. The only variable associated with results on the MPAI-4 was the RPQ score (p < .001). The predictive outcome model including age, education, and the results of the Trail-Making Test-Parts A and B (TMT) had a pseudo-R(2) of .02. When the RPQ score was added, the pseudo-R(2) climbed to .19. This model indicates that the usefulness of the RPQ score and the TMT in predicting moderate-to-severe limitations, while controlling for confounders, is substantial as suggested by a significant increase in the model chi-square value, delta (1df) = 6.517, p < .001. The RPQ and the TMT provide clinicians with a brief and reliable tool for predicting outcome functioning and can help target the need for further intervention and rehabilitation following mTBI.

Inhibition impairments in Alzheimer's disease, mild cognitive impairment and healthy aging: effect of congruency proportion in a Stroop task.

The goal of this study was to assess inhibition and goal maintenance in persons with Alzheimer's disease, mild cognitive impairment, healthy older adults and younger adults. This was done by using a task that compared the Stroop effect in pure blocks, that comprised only incongruent trials, with the Stroop effect in mixed blocks, in which 25% of trials were incongruent and 75% were congruent (Kane & Engle, 2003). Those conditions were administered to 20 healthy younger and 20 older control participants, and to 20 participants meeting criteria for MCI and 11 for AD. Results show reduced resistance to interference as a consequence of healthy aging and only partially impaired goal-maintenance capacities. Interference and goal maintenance are also impaired when comparing MCI and AD to healthy older adults, with AD suffering from a more severe impairment than MCI. In addition, there is a partial preservation of goal-maintenance capacities in MCI because reducing response speed allows them to maintain a level of error rate similar to that of healthy older adults. In contrast, AD persons suffer from a complete breakdown of goal-maintenance capacities, as is suggested by deficits on both response time and error rates.

Personality and psychological health in persons with mild cognitive impairment.

An increasing number of studies have documented the cognitive profile of individuals with mild cognitive impairment (MCI), but few studies have investigated the individuals' psychological health and personality traits or how these factors interact with cognition. In the present study, 27 healthy older adults and 30 persons with MCI completed questionnaires covering psychological health, morale, personality, self-efficacy, and self-actualization. The results indicated that individuals with MCI are more depressed, anxious, hostile, and have lower morale than matched healthy older adults. Furthermore, our results show a positive association between the level of depression of MCI persons and the severity of their cognitive dysfunctions. In contrast, there were no group differences on measures of personality traits. Thus, while psychological distress is present in persons with MCI, those individuals are not characterized by differences in personality traits relative to older adults who experience no cognitive impairment.

Semantic inhibition impairment in mild cognitive impairment: a distinctive feature of upcoming cognitive decline?

This study aimed to measure semantic inhibitory capacities in persons with a diagnosis of Alzheimer's disease (AD) or mild cognitive impairment (MCI), in healthy older and younger adults. This was done by relying on a computerized adaptation of the Hayling task, designed to diminish the likelihood of using alternative noninhibitory strategies. Participants with both AD and MCI showed impaired performance on the inhibition condition. Participants with AD showed both poorer score and an increased number of errors, whereas persons with MCI obtained lower score. There was also an effect of normal aging in the inhibition condition when considering reaction time only. In participants with MCI and AD, there was a significant correlation between lexico-semantic capacities and performance on the automatic condition. Follow-up analysis revealed that participants with MCI who experienced a subsequent significant cognitive decline had impaired performance in the inhibition condition at the time of the experiment, while participants with MCI who remained stable did not. Overall, results indicate that semantic inhibition of a prepotent response is impaired in participants with MCI and may have predictive value regarding future decline, supporting its prognostic role in the early identification of dementia.