Possible Lingering Effects of Multiple Past Concussions

Background. The literature on lingering or “cumulative” effects of multiple concussions is mixed. The purpose of this study was to examine whether athletes with a history of three or more concussions perform more poorly on neuropsychological testing or report more subjective symptoms during a baseline, preseason evaluation. Hypothesis. Athletes reporting three or more past concussions would perform more poorly on preseason neurocognitive testing. Study Design. Case-control study. Methods. An archival database including 786 male athletes who underwent preseason testing with a computerized battery (ImPACT) was used to select the participants. Twenty-six athletes, between the ages of 17 and 22 with a history of three or more concussions, were identified. Athletes with no history of concussion were matched, in a case-control fashion, on age, education, self-reported ADHD, school, sport, and, when possible, playing position and self-reported academic problems. Results. The two groups were compared on the four neuropsychological composite scores from ImPACT using multivariate analysis of variance followed by univariate ANOVAs. MANOVA revealed no overall significant effect. Exploratory ANOVAs were conducted using Verbal Memory, Visual Memory, Reaction Time, Processing Speed, and Postconcussion Scale composite scores as dependent variables. There was a significant effect for only the Verbal Memory composite. Conclusions. Although inconclusive, the results suggest that some athletes with multiple concussions could have lingering memory deficits

Thermoregulatory ability and mechanism do not differ consistently between neotropical and temperate butterflies

Climate change is a major threat to species worldwide, yet it remains uncertain whether tropical or temperate species are more vulnerable to changing temperatures. To further our understanding of this, we used a standardised field protocol to (1) study the buffering ability (ability to regulate body temperature relative to surrounding air temperature) of neotropical (Panama) and temperate (the United Kingdom, Czech Republic and Austria) butterflies at the assemblage and family level, (2) determine if any differences in buffering ability were driven by morphological characteristics and (3) used ecologically relevant temperature measurements to investigate how butterflies use microclimates and behaviour to thermoregulate. We hypothesised that temperate butterflies would be better at buffering than neotropical butterflies as temperate species naturally experience a wider range of temperatures than their tropical counterparts. Contrary to our hypothesis, at the assemblage level, neotropical species (especially Nymphalidae) were better at buffering than temperate species, driven primarily by neotropical individuals cooling themselves more at higher air temperatures. Morphology was the main driver of differences in buffering ability between neotropical and temperate species as opposed to the thermal environment butterflies experienced. Temperate butterflies used postural thermoregulation to raise their body temperature more than neotropical butterflies, probably as an adaptation to temperate climates, but the selection of microclimates did not differ between regions. Our findings demonstrate that butterfly species have unique thermoregulatory strategies driven by behaviour and morphology, and that neotropical species are not likely to be more inherently vulnerable to warming than temperate species

Nonfluent/Agrammatic PPA with In-Vivo Cortical Amyloidosis and Pick’s Disease Pathology

The role of biomarkers in predicting pathological findings in the frontotemporal dementia (FTD) clinical spectrum disorders is still being explored. We present comprehensive, prospective longitudinal data for a 66 year old, right-handed female who met current criteria for the nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA). She first presented with a 3-year history of progressive speech and language impairment mainly characterized by severe apraxia of speech. Neuropsychological and general motor functions remained relatively spared throughout the clinical course. Voxel-based morphometry (VBM) showed selective cortical atrophy of the left posterior inferior frontal gyrus (IFG) and underlying insula that worsened over time, extending along the left premotor strip. Five years after her first evaluation, she developed mild memory impairment and underwent PET-FDG and PiB scans that showed left frontal hypometabolism and cortical amyloidosis. Three years later (11 years from first symptom), post-mortem histopathological evaluation revealed Pick's disease, with severe degeneration of left IFG, mid-insula, and precentral gyrus. Alzheimer’s disease (AD) (CERAD frequent/Braak Stage V) was also detected. This patient demonstrates that biomarkers indicating brain amyloidosis should not be considered conclusive evidence that AD pathology accounts for a typical FTD clinical/anatomical syndrome

Developing common protocols to measure tundra herbivory across spatial scales

Understanding and predicting large-scale ecological responses to global environmental change requires comparative studies across geographic scales with coordinated efforts and standardized methodologies. We designed, applied, and assessed standardized protocols to measure tundra herbivory at three spatial scales: plot, site (habitat), and study area (landscape). The plot- and site-level protocols were tested in the field during summers 2014–2015 at 11 sites, nine of them consisting of warming experimental plots included in the International Tundra Experiment (ITEX). The study area protocols were assessed during 2014–2018 at 24 study areas across the Arctic. Our protocols provide comparable and easy to implement methods for assessing the intensity of invertebrate herbivory within ITEX plots and for characterizing vertebrate herbivore communities at larger spatial scales. We discuss methodological constraints and make recommendations for how these protocols can be used and how sampling effort can be optimized to obtain comparable estimates of herbivory, both at ITEX sites and at large landscape scales. The application of these protocols across the tundra biome will allow characterizing and comparing herbivore communities across tundra sites and at ecologically relevant spatial scales, providing an important step towards a better understanding of tundra ecosystem responses to large-scale environmental change

Developing common protocols to measure tundra herbivory across spatial scales

Understanding and predicting large-scale ecological responses to global environmental change requires comparative studies across geographic scales with coordinated efforts and standardized methodologies. We designed, applied and assessed standardized protocols to measure tundra herbivory at three spatial scales: plot, site (habitat), and study area (landscape). The plot and site-level protocols were tested in the field during summers 2014-2015 at eleven sites, nine of them comprising warming experimental plots included in the International Tundra Experiment (ITEX). The study area protocols were assessed during 2014-2018 at 24 study areas across the Arctic. Our protocols provide comparable and easy-to-implement methods for assessing the intensity of invertebrate herbivory within ITEX plots and for characterizing vertebrate herbivore communities at larger spatial scales. We discuss methodological constraints and make recommendations for how these protocols can be used and how sampling effort can be optimized to obtain comparable estimates of herbivory, both at ITEX sites and at large landscape scales. The application of these protocols across the tundra biome will allow characterizing and comparing herbivore communities across tundra sites and at ecologically relevant spatial scales, providing an important step towards a better understanding of tundra ecosystem responses to large-scale environmental change.CGB was funded by the Estonian Research Council (grant IUT 20-28), and the European Regional Development Fund (Centre of Excellence EcolChange). JDMS was supported by the Research Council of Norway (262064). OG and LB were supported by the French Polar Institute (program “1036 Interactions”) and PRC CNRS Russie 396 (program “ICCVAT”). DSH, NL, MAG, JB and JDR were supported by the Natural Sciences and Engineering Research Council (Canada). NL, MAG, JB and JDR were supported by the Polar Continental Shelf Program. NL was supported by the Canada Research Chair program and the Canada Foundation for Innovation. NL and JB were supported by Environment Canada and Polar Knowledge Canada. NL and MAG were supported by the Government of Nunavut, the Igloolik Community, and Université de Moncton. NL, MAG and JB were supported by the Northern Scientific Training Program. JMA was funded by Carl Tryggers stiftelse för vetenskaplig forskning and Qatar Petroleum (QUEX-CAS-QP-RD-18_19). IHM-S was funded by the UK Natural Environmental Research Council Shrub Tundra (NE/M016323/1) grant. ISJ was funded by the University of Iceland Research Fund. Fieldwork in Yamal peninsula (Erkuta, Sabetta and Belyi) for DE, NS and AS was supported by the Russian Foundation for Basic Research (No: 18-05-60261 and No: 18-54-15013), Fram Centre project YaES (No: 362259), the Russian Center of Development of the Arctic, and the “Yamal-LNG” company. Fieldwork in Utqiaġvik was supported by the U.S. Fish and Wildlife Service. Fieldwork in Svalbard was supported by the Norwegian Research Council (AFG No: 246080/E10), the Norwegian Polar Institute, Climate-ecological Observatory for Arctic Tundra – COAT, the Svalbard Environmental protection fund (project number 15/20), and the University Centre in Svalbard (UNIS) and the AB-338/AB-838 students of 2018. Sampling at Billefjorden was supported by GACR 17- 20839S

Exploring the relationship between psychopathic personality traits and executive function task ability in young adults and adults genetically at-risk for frontotemporal lobar dementia

The construct of impulsivity plays an important role in personality theory, and is related to cognitive processes subsumed under the heading of executive functions. Moreover, a relationship appears to exist such that individual differences in executive function coincide with variations in impulsive personality traits. The prefrontal cortex has been proposed to be the neuroanatomical site which orchestrates the relationship between both personality and higher-order cognition. Psychopathologies and neurological disorders which display high levels of impulsivity and prefrontal cortex dysfunction, such as psychopathy and Frontotemporal Lobar dementia (FTLD), provide support for this suggestion. This thesis reports two studies which further investigate this relationship. In Study 1, undergraduate students completed the Psychopathic Personality Inventory-Revised (PPI-R) along with three tasks of executive function, the Stroop Task, Attention Networks Task (ANT) and the Iowa Gambling Task (IGT). Hierarchical regression analysis indicates that the PPI-R Factor Score, Self-Centered Impulsivity, significantly predicts inability to implement an advantageous decision making strategy on the IGT. Neither Self-Centered Impulsivity, nor the other PPI-R Factor Score, Fearless Dominance predicted performance on any of the other tasks of executive function. In Study 2, individuals at familial risk for FTLD who were either symptomatic or asymptomatic for the disease completed the PPI-R, depression and anxiety questionnaires and a battery of tasks measuring attention and executive function. Results indicate that symptomatic individuals perform significantly worse on several measures of executive function than asymptomatic individuals but did not differ significantly with respect to mean levels of psychopathic personality traits. Partial correlational analysis demonstrated a significant negative relationship between Fearless Dominance and response latency on the Stroop task and ANT. Self-Centered Impulsivity was significantly positively related to total rule violations and negatively related to response time on Trail Making Test B. Fearless Dominance was significantly related to depressive symptoms and trait anxiety. Taken together, these results partially support the position that individuals with high levels of impulsive personality traits exhibit reduced executive function performance. It also contributes to the growing literature that suggests the factors comprising psychopathic personality relate differently to executive functions.Arts, Faculty ofPsychology, Department ofGraduat

Chronic corticosterone regulates 5-HT₁A but not 5-HT₂A agonist-induced serotonin receptor-mediated functions

There has been much research on serotonin (5-HT) 1A and 2A receptor activity, and speculation on how these receptors are implicated in the etiology of depression. Moreover, interest has been focused on mechanisms through which corticosteroids interact with these receptors to produce biochemical, physiological and behavioural changes. The 5-HT[sub 1A] and 5-HT[sub 2A] receptors appear to be controlled by corticosteroids in a biphasic manner; low corticosteroid levels exert influence on 5-HT[sub 1A] receptor activity, while high levels activate 5-HT[sub 2A] receptors. It is therefore reasonable to speculate that 5-HT[sub 1A] receptor activity predominates during normal conditions, while during times of prolonged stress, receptor activity shifts to 5-HT[sub 2A]. The purpose of this research was to investigate the hypothesis that elevated corticosterone levels cause a shift from predominantly 5-H[sub 1A] to 5-HT[sub 2A] receptor activity and that this happens over a particular time course. Corticosterone (20 mg/kg) or its vehicle was chronically administered to rats for 14 days. During this time, rats were tested at six time points on a number of 5-HT[sub 1A] and 5-HT[sub 2A] receptor-mediated physiological and behavioural measures. Overall, it was found that after 12 days of administration, rats receiving corticosterone exhibited an attenuation of the hypothermic response produced by the 5-HT[sub 1A] agonist 8-hydroxy-2(di-n-propylamino) tetralin. However, over the entire course of administration, corticosterone did not potentiate any effects produced by the 5-HT[sub 2A] receptor-agonist 1-(2,5-dimethoxy-4- iodophenyl)-2-aminopropane on 5-HT[sub 2A] receptor-mediated behaviours. These results are discussed in relation to the interaction between serotonin and HPA-axis functioning in Major Depression.Arts, Faculty ofPsychology, Department ofGraduat