Physiological reactivity and the perception of emotional stimuli as they relate to social adaptive functioning after traumatic brain injury / y Melonie Jane Hopkins.

Traumatic brain injury (TBI) often affects social adaptive functioning and these changes in social adaptability are usually associated with general damage to the frontal cortex. Recent evidence suggests that certain neurons within the orbitofrontal cortex appear to be specialized for the processing of faces and facial expressions. The orbitofrontal cortex also appears to be involved in self-initiated somatic activation to emotionally-charged stimuli. According to Somatic Marker Theory (Damasio, 1994), the reduced physiological activation fails to provide an individual with appropriate somatic cues to personally-relevant stimuli and this, in turn, may result in maladaptive behaviour. Given the susceptibility of the orbitofrontal cortex in TBI, it was hypothesized that impaired perception and reactivity to socially-relevant information might be responsible for some of the social difficulties encountered after TBL Fifteen persons who sustained a moderate to severe brain injury were compared to age and education matched Control participants. In the first study, both groups were presented with photographs of models displaying the major emotions and either asked to identify the emotions or simply view the faces passively. In a second study, participants were asked to select cards from decks that varied in terms of how much money could be won or lost. Those decks with higher losses were considered to be high-risk decks. Electrodermal activity was measured concurrently in both situations. Relative to Controls, TBI participants were found to have difficulty identifying expressions of surprise, sadness, anger, and fear. TBI persons were also found to be under-reactive, as measured by electrodermal activity, while passively viewing slides of negative expressions. No group difference,in reactivity to high-risk card decks was observed. The ability to identify emotions in the face and electrodermal reactivity to faces and to high-risk decks in the card game were examined in relationship to social monitoring and empathy as described by family members or friends on the Brock Adaptive Functioning Questionnaire (BAFQ). Difficulties identifying negative expressions (i.e., sadness, anger, fear, and disgust) predicted problems in monitoring social situations. As well, a modest relationship was observed between hypo-arousal to negative faces and problems with social monitoring. Finally, hypo-arousal in the anticipation of risk during the card game related to problems in empathy. In summary, these data are consistent with the view that alterations in the ability to perceive emotional expressions in the face and the disruption in arousal to personally-relevant information may be accounting for some of the difficulties in social adaptation often observed in persons who have sustained a TBI. Furthermore, these data provide modest support for Damasio's Somatic Marker Theory in that physiological reactivity to socially-relevant information has some value in predicting social function. Therefore, the assessment of TBI persons, particularly those with adaptive behavioural problems, should be expanded to determine whether alterations in perception and reactivity to socially-relevant stimuli have occurred. When this is the case, rehabilitative strategies aimed more specifically at these difficulties should be considered.

Salivary testosterone and cortisol : role of athletic setting, game outcome, and game location /

Many studies investigating the relationship between hormones and competition have focused on athletic competition. The athletic setting enables r researchers to investigate the hormone-behaviour relationship in a relatively controlled environment. However, research to date has been based on observations made from single status contests and/or weekend tournaments and as such, does not provide a clear picture of an individual's average hormonal responses to both victory and defeat. In appreciation of this limitation, the current study tracked elite hockey players throughout a hockey season, measuring pre- and post-game salivary testosterone and Cortisol as well as psychological measures. I was interested in determining whether status outcome (win vs. loss) would influence an individual's testosterone and Cortisol responses to competition. Furthermore, I was also interested in assessing whether testosterone and Cortisol responses were specific to the competitive environment or whether similar hormonal responses would occur during non-competitive practice sessions. Last, I was interested in whether there were any differences in pre-game hormonal and psychological states depending on where the status contest was held: home versus away. The results indicated that game outcome moderated the testosterone responses to competition. That is, testosterone increased significantly more after a victory compared to a defeat. Furthermore, a loss of status produced significantly hreports, the players did not show an anticipatory rise in either Cortisol or testosterone prior to competition. In addition to the effects of status outcome on hormonal levels, it was also found that these hormonal responses were specific to competition. The athletes in the current study did not demonstrate any hormonal responses to the practice sessions. Last, there were significant differences in pre-game testosterone as well as in selfconfidence, cognitive, and somatic anxiety levels depending on the location at which the status contest took place. Pre-game testosterone and self-confidence levels were significantly higher prior to games played in the home venue. In contrast, pre-game somatic and cognitive anxiety levels were significantly higher prior to games played in the away venue. The current findings add to the developing literature on the relationship between hormones and competition. This was the first study to detect a moderating effect of status outcome on testosterone responses in a team sport. Furthermore, this was also the first study in humans to demonstrate that post-contest Cortisol levels were significantly higher after a loss of status. Last, the current study also adds to the sport psychology literature by demonstrating that pre-game psychological variables differ depending on where the status contest is being held: higher self-confidence at home and higher somatic and cognitive anxiety away. Taken together, the results from the current thesis may have important practical relevance to coaches, trainers and sport psychologists who are always trying to find ways to maximize performance. post-game Cortisol levels than did an increase in status. In contrast to previous

Locomotor sensitization and conditioned place preference for amphetamine in late adolescent and adult male and female rats /

reports, the players did not show an anticipatory rise in either Cortisol or testosterone prior to competition. In addition to the effects of status outcome on hormonal levels, it was also found that these hormonal responses were specific to competition. The athletes in the current study did not demonstrate any hormonal responses to the practice sessions. Last, there were significant differences in pre-game testosterone as well as in selfconfidence, cognitive, and somatic anxiety levels depending on the location at which the status contest took place. Pre-game testosterone and self-confidence levels were significantly higher prior to games played in the home venue. In contrast, pre-game somatic and cognitive anxiety levels were significantly higher prior to games played in the away venue. The current findings add to the developing literature on the relationship between hormones and competition. This was the first study to detect a moderating effect of status outcome on testosterone responses in a team sport. Furthermore, this was also the first study in humans to demonstrate that post-contest Cortisol levels were significantly higher after a loss of status. Last, the current study also adds to the sport psychology literature by demonstrating that pre-game psychological variables differ depending on where the status contest is being held: higher self-confidence at home and higher somatic and cognitive anxiety away. Taken together, the results from the current thesis may have important practical relevance to coaches, trainers and sport psychologists who are always trying to find ways to maximize performance. the cycle. The sex-specific age differences in locomotor responses to amphetamine are not due to gonadal immaturity, as females are cycling at this stage of adolescence. However, age differences may reflect the ongoing maturation of the neural substrates that that are involved in locomotor sensitizing, but not rewarding effects of amphetamine.

The validation of heart rate variability in individuals with spinal cord injury

The current classification system for spinal cord injury (SCI) considers only somatic information and neglects autonomic damage after injiuy. Heart rate variability (HRV) has the potential to be a valuable measure of cardiac autonomic control after (SCI). Five individuals with tetraplegia and four able-bodied controls underwent 1 min continuous ECG recordings during rest, after Metoprolol administration (max dose=3x5mg) and after Atropine administration (0.02mg/kg) in both supine and 40° head-up tilt. After Metoprolol administration there was a 61.8% decrease in the LF:HF ratio in the SCI participants suggesting that the LF:HF ratio is a reflection of cardiac sympathetic outflow. After Atropine administration there was a 99.1% decrease in the HF power in the SCI participants suggesting that HF power is highly representative of cardiac parasympathetic outflow. There were no significant differences between the SCI and able-bodied participants. Thus, HRV measures are a valid index of cardiac autonomic control after SCI.

Identification of novel retinoid receptors and their roles in vertebrate and invertebrate nervous systems

In vertebrates, signaling by retinoic acid (RA) is known to play an important role in embryonic development, as well as organ homeostasis in the adult. In organisms such as adult axolotls and newts, RA is also important for regeneration of the CNS, limb, tail, and many other organ systems. RA mediates many of its effects in development and regeneration through nuclear receptors, known as retinoic acid receptors (RARs) and retinoid X receptors (RXRs). This study provides evidence for an important role of the RA receptor, RAR~2, in ,( '. regeneration ofthe spinal cord and tail of the adult newt. It has previously been proposed that the ability of the nervous system to regenerate might depend on the presence or absence of this RAR~2 isoform. Here, I show for the very first time, that the regenerating spinal cord of the adult newt expresses this ~2 receptor isoform, and inhibition of retinoid signaling through this specific receptor with a selective antagonist inhibits tail and spinal cord regeneration. This provides the first evidence for a role of this receptor in this process. Another species capable of CNS ~~generation in the adult is the invertebrate, " Lymnaea stagnalis. Although RA has been detected in a small number of invertebrates (including Lymnaea), the existence and functional roles of the retinoid receptors in most invertebrate non-chordates, have not been previously studied. It has been widely believed, however, that invertebrate non-chordates only possess the RXR class of retinoid receptors, but not the RARs. In this study, a full-length RXR cDNA has been cloned, which was the first retinoid receptor to be discovered in Lymnaea. I then went on to clone the very first full-length RAR eDNA from any non-chordate, invertebrate species. The functional role of these receptors was examined, and it was shown that normal molluscan development was altered, to varying degrees, by the presence of various RXR and RAR agonists or antagonists. The resulting disruptions in embryogenesis ranged from eye and shell defects, to complete lysis of the early embryo. These studies strongly suggest an important role for both the RXR and RAR in non-chordate development. The molluscan RXR and RAR were also shown to be expressed in the adult, nonregenerating eNS, as well as in individual motor neurons regenerating in culture. More specifically, their expression displayed a non-nuclear distfibution, suggesting a possible non-genomic role for these 'nuclear' receptors. It was shown that immunoreactivity for the RXR was present in almost all regenerating growth cones, and (together with N. Farrar) it was shown that this RXR played a novel, non-genomic role in mediating growth cone turning toward retinoic acid. Immunoreactivity for the novel invertebrate RAR was also found in the regenerating growth cones, but future work will be required to determine its functional role in nerve cell regeneration. Taken together, these data provide evidence for the importance of these novel '. retinoid receptors in development and regeneration, particularly in the adult nervous system, and the conservation of their effects in mediating RA signaling from invertebrates to vertebrates.

Social competence following mild head injury and moderate traumatic brain injury: Investigating the neuropsychological relationships between arousal, social decision-making and depression

Client-directed long-term rehabilitative goals and life satisfaction following head injury emphasize the importance of social inclusion, rather than cognitive or physical, outcomes. However, very little research has explored the socio-emotional factors that pose as barriers to social reintegration following injury. This study investigates social barriers following head injury (i.e., decision-making - Iowa Gambling Task [IGT] and mood – depression) and possible amelioration of those challenges (through treatment) in both highly functioning university students with and without mild head injury (MHI) and in individuals with moderate traumatic brain injury (TBI). An arousal manipulation using emotionally evocative stimuli was introduced to manipulate the subject’s physiological arousal state. Seventy-five university students (37.6% reporting a MHI) and 11 patients with documented moderate TBI were recruited to participate in this quasi-experimental study. Those with head injury were found to be physiologically underaroused (on measures of electrodermal activation [EDA] and pulse) and were less sensitive to the negative effects of punishment (i.e., losses) in the gambling task than those without head injury, with greater impairment being observed for the moderate TBI group. The arousal manipulation, while effective, was not able to maintain a higher state of arousal in the injury groups across trials (i.e., their arousal state returned to pre-manipulation levels more quickly than their non-injured cohort), and, subsequently, a performance improvement was not observed on the IGT. Lastly, head injury was found to contribute to the relationship between IGT performance and depressive symptom acknowledgment and mood status in persons with head injury. This study indicates the possible important role of physiological arousal on socio- emotional behaviours (decision-making, mood) in persons with even mild, non-complicated head injuries and across the injury severity continuum.

The Influence of Burnout Symptoms on the Relationship between Work-Life Balance and Self-Rated Health

The effects of stress at work are estimated to cost Canadian employers more than 20 billion dollars annually through absenteeism, sick leave and decreased productivity. Over the past two decades, Canadians have reported higher stress levels, increased work hours and more work performed outside of normal business hours. This work-life imbalance has far-reaching repercussions–affecting an employee’s performance as well as their health. Chronic exposure to these high levels of stress can also lead to burnout. The primary purpose of this study was to determine the magnitude in which burnout symptoms influence the relationship between work-life balance and self-rated health. The secondary purpose of this study was to determine if gender and age interactions exist in the relationship between burnout, work-life balance, and self-rated health. This cross-sectional study involved secondary analysis of 220 managers, workers and human service professionals who completed an Occupational Health Clinics for Ontario Workers’ Mental Injury Toolkit (MIT) survey for the launch of the MIT. The MIT survey is a modified form of the short version of the Copenhagen Psychosocial Questionnaire and includes expanded questioning around burnout, stress, sleep troubles, cognitive, and somatic symptoms. There were no significant differences in self-rated health based on a respondent’s gender or age, indicating that no interaction of gender and age would be required. Respondents with low self-rated health reported significantly higher burnout and work-life imbalance compared to those with high self-rated health. The regression analysis demonstrated that the magnitude in which burnout mediates the relationship between work-life balance and self-rated health was 96%. These findings support previous studies that associate high levels of work-life imbalance or burnout with poor self-rated health or health outcomes. In this study, the shared variance between work-life balance and burnout also supports recent efforts to redefine the context and causes of burnout to include non-work factors. Based on our findings, the potential exists for the development of workplace health promotion strategies that address maintaining a balance between work and home as they may improve employee health and reduce burnout.