Factors mediating the sex difference observed In targeting tasks

Targeting is a skill that involves the accurate projection of an object to a target; this requires accurate integration of visual information with spatial and motor skills. Targeting tasks demonstrate a consistent male advantage. Contrary to popular belief, this male advantage is not accounted for by participants’ throwing experience or their size. The factors that mediate or account for the sex difference observed in targeting accuracy have not yet been identified. This dissertation addresses issues following from two prominent theories that attempt to explain this sex difference. The first theory proposes that the male advantage on targeting accuracy is due to the task’s proxemic and/or motoric characteristics, whereas the second theory proposes that the sex difference in targeting accuracy is due to differential exposure to androgenic or estrogenic sex hormone concentrations. The first and second studies in this dissertation follow from the first theory, examining whether changing the motoric or proxemic characteristics of targeting tasks will mediate the sex difference. The third study is related to the second theory; it examines the relations among direct and indirect measures of prenatal and circulating sex hormone concentrations and targeting accuracy within samples of men and women. Collectively the results from studies 1 and 2 indicate that the proxemic and motoric characteristics are related to the sex difference on targeting tasks; specifically, targeting tasks must involve only fine motor movements and be performed in intrapersonal space in order for the male advantage to be negated.The results from study 3 indicate that men who were exposed to relatively high prenatal testosterone concentrations and continue to have relatively high circulating testosterone concentrations perform less accurately on targeting tasks than do all other groups of men. The results from study 3 also indicate that women exposed to relatively high prenatal testosterone concentrations target significantly more accurately than women that were exposed to relatively low prenatal testosterone concentrations. As well, the results showed that women who use oral contraceptives target significantly more accurately when they are not currently taking the exogenous estrogen supplements (menstrual phase) than when they are taking the supplements (midluteal phase). These results are discussed in light of the two prominent theories explaining the sex difference in targeting accuracy. A synthesized theory is proposed, and directions for future research are discussed

A Review of Adversity, The Amygdala and the Hippocampus: A Consideration of Developmental Timing

A review of the human developmental neuroimaging literature that investigates outcomes following exposure to psychosocial adversity is presented with a focus on two subcortical structures – the hippocampus and the amygdala. Throughout this review, we discuss how a consideration of developmental timing of adverse experiences and age at measurement might provide insight into the seemingly discrepant findings across studies. We use findings from animal studies to suggest some mechanisms through which timing of experiences may result in differences across time and studies. The literature suggests that early life may be a time of heightened susceptibility to environmental stressors, but that expression of these effects will vary by age at measurement

Behavioral Assessment of Emotion Discrimination, Emotion Regulation, and Cognitive Control in Childhood, Adolescence, and Adulthood

Emotion discrimination, emotion regulation, and cognitive control are three related, yet separable processes that emerge over the course of development. The current study tested 100 children, adolescents, and adults on an Emotional Go/Nogo task, illustrating the ability of this paradigm to identify the unique developmental patterns for each of these three processes in the context of both positive (happy) and negative emotions (fear, sad, and anger), across three different age groups. Consistent with previous literature, our findings show that emotion discrimination and regulatory abilities (both cognitive control and emotion regulation) improve steadily for each age group, with each age group showing unique patterns of performance. The findings suggest that emotion regulation is constructed from basic cognition control and emotion discrimination skills. The patterns of behavior from the Emotional Go/Nogo task provide normative benchmark data across a wide range of emotions that can be used for future behavioral and neuroimaging studies that examine the developmental construction of emotion regulatory processes

Visual Exploration Strategies and the Development of Infants’ Facial Emotion Discrimination

We examined the role of visual exploration strategies in infants’ discrimination between facial emotion expressions. Twenty-eight 6- to 11-month olds were habituated to alternating models posing the same expression (happy N = 14/fearful N = 14) as eye gaze data were collected with a corneal reflection eye tracker. Gaze behavior analyses indicated that duration of gaze to the eyes and mouth was similar, consistent with what would be expected based on area subtended by those regions, and negatively correlated. This pattern did not differ as a function of age, sex, or habituation condition. There were no posthabituation performance differences as a function of age group (6- to 8-month- versus 9- to 11-month olds). Only infants habituated to happy faces showed longer looking at the novel emotion (fear) when the model was held constant from habituation to test. We found no reliable correlation between this performance and proportion of gaze directed at any one facial region. Consistent with previous work, the group habituated to fear faces showed no reliable posthabituation novelty preference. Individual differences in gaze behavior shed light on this finding. Greater proportion of gaze directed at the eyes correlated positively with preference for the novel emotion (happy). These data suggest that, as in other object classes, visual exploration strategies are an important agent of change in infants’ capacity to learn about emotion expressions

The face-specific N170 component is modulated by emotional facial expression

BACKGROUND: According to the traditional two-stage model of face processing, the face-specific N170 event-related potential (ERP) is linked to structural encoding of face stimuli, whereas later ERP components are thought to reflect processing of facial affect. This view has recently been challenged by reports of N170 modulations by emotional facial expression. This study examines the time-course and topography of the influence of emotional expression on the N170 response to faces. METHODS: Dense-array ERPs were recorded in response to a set (n = 16) of fear and neutral faces. Stimuli were normalized on dimensions of shape, size and luminance contrast distribution. To minimize task effects related to facial or emotional processing, facial stimuli were irrelevant to a primary task of learning associative pairings between a subsequently presented visual character and a spoken word. RESULTS: N170 to faces showed a strong modulation by emotional facial expression. A split half analysis demonstrates that this effect was significant both early and late in the experiment and was therefore not associated with only the initial exposures of these stimuli, demonstrating a form of robustness against habituation. The effect of emotional modulation of the N170 to faces did not show significant interaction with the gender of the face stimulus, or hemisphere of recording sites. Subtracting the fear versus neutral topography provided a topography that itself was highly similar to the face N170. CONCLUSION: The face N170 response can be influenced by emotional expressions contained within facial stimuli. The topography of this effect is consistent with the notion that fear stimuli exaggerates the N170 response itself. This finding stands in contrast to previous models suggesting that N170 processes linked to structural analysis of faces precede analysis of emotional expression, and instead may reflect early top-down modulation from neural systems involved in rapid emotional processing

Repurposing repeated remote ischemic postconditioning for multiple sclerosis

Multiple sclerosis (MS) is a chronic, autoimmune neurodegenerative disease that is characterized by nervous system demyelination and heterogenous disability. Current disease modifying treatments accessible to Canadians are limited because they are primarily targeting the neuroinflammatory component of the disease, not the neurodegenerative component. There is a need for focus on development of therapies that target the demyelinating insults that people with MS experience. In this study, we evaluate the use of repeated remote ischemic postconditioning (RIC) as a therapeutic target for promoting white matter repair and protection. Due to the novelty of the intervention in the MS field, we first wanted to identify transcriptomic and proteomic changes to the spinal cord with repeated RIC. We found that targets involved in antioxidant, protein synthesis, angiogenesis, axonogenesis, and remyelination pathways (among others) were upregulated with 14 days of consecutive RIC. Using a focal demyelinating mouse model, we also described changes to the lesion environment using the repeated intervention. Repeated RIC did not reduce the lesion size in this injury model. However, targets such as plectin and neurofascin that were upregulated in the transcriptomic and proteomic data sets were also upregulated in the lesion of animals that received treatment. An increase in myelin in the lesion area was also found in the repeated RIC group when compared to sham. Overall, repeated RIC demonstrates potential for future use as a therapy to target white matter repair and protection

Socio-Emotional Functioning and Face Recognition Ability in the Normal Population

Recent research indicates face recognition ability varies within the normal population. To date, two factors have been identified that influence this cognitive process: the age and gender of the perceiver. In this paper, we examine the influence of socio-emotional functioning on face recognition ability. We invited participants with high and low levels of empathy (as indicated by the Empathy Quotient) to take part in a face recognition test. Participants were asked to study a set of faces, and at test viewed the studied faces intermixed with novel faces. As predicted, high empaths achieved higher scores in the face recognition test compared to low empaths. This pattern of findings provides further evidence that face recognition ability varies within the normal population, and suggests socio-emotional functioning may be an additional factor that influences face recognition ability