Multimodal encoding in a simplified model of intracellular calcium signaling

Many cells use calcium signaling to carry information from the extracellular side of the plasma membrane to targets in their interior. Since virtually all cells employ a network of biochemical reactions for Ca²⁺ signaling, much effort has been devoted to understand the functional role of Ca²⁺ responses and to decipher how their complex dynamics is regulated by the biochemical network of Ca²⁺-related signal transduction pathways. Experimental observations show that Ca²⁺ signals in response to external stimuli encode information via frequency modulation (FM) or alternatively via amplitude modulation (AM). Although minimal models can capture separately both types of dynamics, they fail to exhibit different and more advanced encoding modes. By arguments of bifurcation theory, we propose instead that under some biophysical conditions more complex modes of information encoding can also be manifested by minimal models. We consider the minimal model of Li and Rinzel and show that information encoding can occur by AM of Ca²⁺ oscillations, by FM or by both modes (AFM). Our work is motivated by calcium signaling in astrocytes, the predominant type of cortical glial cells that is nowadays recognized to play a crucial role in the regulation of neuronal activity and information processing of the brain. We explain that our results can be crucial for a better understanding of synaptic information transfer. Furthermore, our results might also be important for better insight on other examples of physiological processes regulated by Ca²⁺ signaling.     

Helping to improve the group stereotype: on the strategic dimension of prosocial behavior

Three studies consider a basis for intergroup helping. Specifically, they show that group members may help others to disconfirm a stereotype of their own group as mean. Study 1 shows that Scots believe they are seen as mean by the English, resent this stereotype, are motivated to refute it, and believe out-group helping is a particularly effective way of doing so. Study 2 shows that increasing the salience of the English stereotype of the Scottish as mean leads Scots to accentuate the extent to which Scots are depicted as generous. Study 3 shows that increasing the salience of the stereotype of the Scots as mean results in an increase in the help volunteered to out-group members. These results highlight how strategic concerns may result in out-group helping. In turn, they underscore the point that helping others may be a means to advance a group's interest.     

On the Mirror Stage with Henry and Eliza or Play-ing with Pygmalion in Five Acts

This play-ful paper examines the Pygmalion myth as interpreted by George Bernard Shaw in the 1938 film, an adaptation of his 1912 play. This myth of creation is discussed as a cautionary parable for the psychoanalytic treatment situation; mirroring is viewed from the perspectives of Winnicott, Kohut, and Lacan. It is suggested that the wish to create and to be created may play a role in all analyses.     

Perceptual asymmetry for chimeric faces across the life span

Perceptual asymmetries for processing chimeric faces were investigated in dextral subjects, ranging in age from 5 years to elderly adults. The task involved deciding which member of a pair of face chimeras presented in free vision looks happier, the one with the smile to the left or its mirror image with the smile to the right (Levy, Heller, Banich, & Burton, 1983a, Brain and Cognition, 2, 404-419). A leftward bias was found for all age groups. However, kindergarteners' mean asymmetry score was lower than that of all other groups combined, most likely due to noise in their data. The direction in which subjects drew circles with their left and right hands was also observed as an index of interhemispheric communication. All groups showed a bias toward drawing the circles in concordant directions except the kindergarteners. The relation between subjects' performance on the circle drawing and facebook tasks is discussed.     

Role of health locus of control beliefs and expectations of treatment efficacy in adjustment to cancer

We examined the effects of health locus of control beliefs (self-, doctor, and chance control) and expectations of treatment efficacy on short-term psychological adjustment in a sample of newly diagnosed cancer patients. The role of these beliefs and expectations in moderating the relation between (perceived and actual) disease severity and depression was also examined. The data were collected within one week of diagnosis. The relation between perceptions of disease severity and depression was weaker for those who believed that they could personally control their health and for those who held positive expectations about the effects of complying with medical treatment. Similar patterns were found when disease severity was defined in terms of prognosis for survival. Strong negative correlations between self-control/treatment expectations and depression were found for those who perceived that their illness was very severe. The results for chance and doctor control were less consistent. The stability of health control beliefs and treatment expectations over the course of a serious long-term illness is discussed.     

Neural network principles for theoretical psychology

Neural networks are an increasingly important tool for the mechanistic understanding of psychological phenomena. Three commonly used principles in neural-network design (associative learning, competition, and opponent processing) are outlined here, and two examples of their use in behavior-modeling architectures are discussed. One example relates to an instance of reinforcement learning; that is, of an organism controlling its environment to maximize positive reinforcement or to minimize negative reinforcement. The other example relates to some characteristic deviations from reinforcement learning that occur in people or monkeys with frontal-lobe damage.     

Heart rate during group flooding therapy for PTSD

The objective of this study was to assess, via heart rate, the arousal levels of participants in group trauma reexposure therapy for posttraumatic stress disorder, and so to better understand this common mode of treatment, particularly in regards to its presumed curative factor, extinction. Six Vietnam combat-related PTSD inpatients participated twice weekly in group trauma reexposure therapy during which their electrocardiograms were recorded. Heart rate was quantified continuously off-line. Heart rates of participantsnot directly engaged in imaginal reexposure to their personal combat traumas consistently exhibited mild linear declines from the beginnings to the ends of the approximately 2.5 hour sessions. Participants actively engaged in personal combat trauma reexposure exhibited higher whole-session heart rates. Most also exhibited more specific elevation extending over the later portions of therapy sessions during which intensive reexposure usually occurred. Surprisingly, no patients exhibitedfocal increases in heart rate concurrent with periods of most intensive traumatic incident review as judged from videotape. Administering imaginal reexposure in a group context does not preclude substantial physiological (sympathetic) arousal, as is preconditional for extinction. Under conditions in which the actively engaged reexposure patient is reliably identified, group trauma reexposure therapy may not provide an opportunity for “vicarious” flooding in nonengaged participants.