Decision-Making Competence and Attempted Suicide

Objective: The propensity of people vulnerable to suicide to make poor life decisions is increasingly well documented. Do they display an extreme degree of decision biases? The present study used a behavioral decision approach to examine the susceptibility of low-lethality and high-lethality suicide attempters to common decision biases, which may ultimately obscure alternative solutions and deterrents to suicide in a crisis. Method: We assessed older and middle-aged individuals who made high-lethality (medically serious; N=31) and low-lethality suicide attempts (N=29). Comparison groups included suicide ideators (N=30), non-suicidal depressed (N=53), and psychiatrically healthy participants (N=28). Attempters, ideators, and non-suicidal depressed participants had unipolar non-psychotic major depression. Decision biases included sunk cost (inability to abort an action for which costs are irrecoverable), framing (responding to superficial features of how a problem is presented), under/overconfidence (appropriateness of confidence in knowledge), and inconsistent risk perception. Data were collected between June of 2010 and February of 2014. Results: Both high- and low-lethality attempters were more susceptible to framing effects, as compared to the other groups included in this study (p< 0.05, ηp2 =.06). In contrast, low-lethality attempters were more susceptible to sunk costs than both the comparison groups and high-lethality attempters (p< 0.01, ηp2 =.09). These group differences remained after accounting for age, global cognitive performance, and impulsive traits. Premorbid IQ partially explained group differences in framing effects. Conclusion: Suicide attempters’ failure to resist framing may reflect their inability to consider a decision from an objective standpoint in a crisis. Low-lethality attempters’ failure to resist sunk cost may reflect their tendency to confuse past and future costs of their behavior, lowering their threshold for acting on suicidal thoughts

Cognitive control of eye movements in reading and visual search: Evidence from frequency-based effects

Experiments in this dissertation investigate the role of cognition in eye-movement behavior during scanning and reading. Shorter and fewer fixations on the more frequent and predictable words have been observed during reading, but not when scanning text for a target word, e.g., zebra (e.g., Rayner & Raney, 1996). Past research has employed these effects of word frequency and predictability to argue that cognition drives eye movements during reading, but not during scanning. Similarly, the present studies use effects of stimulus frequency and predictability to index cognitive control of eye-movement behavior. Experiments 1 and 2 focus on the frequency effects for non-word and word stimuli, respectively. Experiment 1 employed clusters of Landolt Cs to examine how the gap size of and frequency of exposure to clusters affected eye movements during a scanning task. The findings demonstrated that, in parallel to word frequency effects observed in reading, more frequent clusters elicited fewer and shorter fixations. Experiment 2 compared eye-movement behavior on fully-crossed high- and low-frequency adjective-noun pairs embedded in paragraphs when participants were reading vs. scanning for a target word with an asterisk (e.g., “h*rse”), a word containing the letter "q" (e.g., “quilt”), or a word rhyming with "blue" (e.g., “shoe”). The results demonstrated that eye-movement measures are affected by frequency in the tasks requiring in-depth processing, such as reading and rhyme-judgment, but not in shallow-processing tasks like asterisk-detection. Experiments 3 and 4 focus on the frequency-based predictability effects for non-word and word stimuli, respectively. Experiment 3 employed similar materials to Experiment 1 and, in addition, manipulated frequency for pairs of clusters. The more predictable clusters in the repeating pairs elicited fewer fixations, providing tentative evidence of transitional predictability effects during scanning. Experiment 4 examined the effect of transitional probability in reading by increasing the frequency of co-occurrence for pairs of words (e.g., tulip’s blossoms) in paragraphs of text. The more predictable words elicited shorter first fixation durations, suggesting that co-occurrence frequency may result in forming short-term predictions during reading. Cumulatively, the findings demonstrate that cognitive effects are not unique to reading, and afford a more sophisticated characterization of the cognitive-oculomotor coordination

Thermal Control of Plasmonic Surface Lattice Resonances

Plasmonic metasurfaces exhibiting collective responses known as surface lattice resonances (SLRs) show potential for realizing tunable and flat photonic components for wavelength-selective processes, including lasing and optical nonlinearities. However, post-fabrication tuning of SLRs remains challenging, limiting the applicability of SLR-based components. Here, we demonstrate how the properties of high quality factor SLRs are easily modified by breaking the symmetry of the nanoparticle surroundings. We break the symmetry by changing the refractive index of the overlying immersion oil simply by controlling the ambient temperature of the device. We show that already modest temperature changes of 10{\deg}C can increase the quality factor of the investigated SLR from 400 to 750. Our results demonstrate accurate and reversible modification of the properties of the SLRs, paving the way towards tunable SLR-based photonic devices. On a more general level, our results demonstrate how symmetry breaking of the surrounding dielectric environment can be utilized for efficient and potentially ultrafast modification of the SLR properties

Effects of adverse early-life events on aggression and anti-social behaviours in animals and humans

We review the impact of early adversities on the development of violence and antisocial behaviour in humans, and present three aetiological animal models of escalated rodent aggression, each disentangling the consequences of one particular adverse early-life factor. A review of the human data, as well as those obtained with the animal models of repeated maternal separation, post-weaning social isolation and peripubertal stress, clearly shows that adverse developmental conditions strongly affect aggressive behaviour displayed in adulthood, the emotional responses to social challenges and the neuronal mechanisms activated by conflict. Although similarities between models are evident, important differences were also noted, demonstrating that the behavioural, emotional and neuronal consequences of early adversities are to a large extent dependent on aetiological factors. These findings support recent theories on human aggression, which suggest that particular developmental trajectories lead to specific forms of aggressive behaviour and brain dysfunctions. However, dissecting the roles of particular aetiological factors in humans is difficult because these occur in various combinations; in addition, the neuroscientific tools employed in humans still lack the depth of analysis of those used in animal research. We suggest that the analytical approach of the rodent models presented here may be successfully used to complement human findings and to develop integrative models of the complex relationship between early adversity, brain development and aggressive behaviour. © 2014 British Society for Neuroendocrinology

Cortisol and externalizing behavior in children and adolescents: Mixed meta-analytic evidence for the inverse relation of basal cortisol and cortisol reactivity with externalizing behavior

An inverse relation between cortisol (re)activily and externalizing behavior has been hypothesized, but research findings seem equivocal. We tested this hypo(re)activity hypothesis in two meta-analyses, one for basal cortisol (k = 72 studies, N = 5,480) and one for cortisol reactivity to a stressor (k = 29 studies, N = 2,601). No association was found between cortisol reactivity and externalizing behaviors (r = -.04, 95% CI = -.11, .02). However, the relation between basal cortisol and externalizing behavior was significant but small (r = -.05, 95% CI = -.10, -.002). The age of the children significantly moderated this relation: Externalizing behavior was associated with higher basal cortisol (hyperactivity) in preschoolers (r =.09, 95% CI =.002, .17), and with lower basal cortisol (hypoactivity) in elementary school-aged children (r = -.14, 95% CI = -.19, -.08). There was no significant relation between cortisol and externalizing behavior in adolescents. © 2008 Wiley Periodicals, Inc

Hypertrophic cardiomyopathy comorbid with coronary heart disease: 6-year follow-up

A clinical case presented, of 6-year follow-up of a patient with apical hypertrophic cardiomyopathy (HCMP) and angina syndrome. The challenges discussed, of differential diagnostics of HCMP and coronary heart disease (CHD) in patient with angina and repolarization disorder on ECG. Specifics of the case presented, was hyperdiagnostics of CHD at the onset of clinical presentation, and intact coronary arteries. In 6 years of follow-up this patient developed coronary lesions required the stenting of left anterior descending artery. Comorbid CHD in older age with apical CHD worsened clinical picture and underlined the issue of comorbidity in CHD and HCMP