Aging neuromodulation impairs associative binding: a neurocomputational account

Relative to young adults, older adults are particularly impaired in episodic memory tasks requiring associative binding of separate components into compound episodes, such as tasks requiring item-context and item-item binding. This associative-binding deficit has been attributed to senescent changes in frontal-hippocampal circuitry but has not been formally linked to impaired neuromodulation involving this circuitry. Previous neurocomputational work showed that impaired neuromodulation could result in less distinct neurocognitive representations. Here we extend this computational principle to simulate aging-related deficits in associative binding. As expected, networks with simulated deficiency in neuromodulation resulted in less distinct internal representations than did networks simulating the processing and performance of young adults, and were also more impaired under task conditions that required associative binding. The findings suggest that senescent changes in neuromodulatory mechanisms may play a basic role in aging-related impairment in associative binding by reducing the efficacy of distributed conjunctive coding.     

Quality of life of men and women with borderline intelligence and attention deficit disorders living in community residences: a comparative study

The research studies the quality of life (QOL) of 127 men and women diagnosed as having a borderline IQ and ADHD living in two major residential programs of the Sharon region in central Israel in respect to their personal, disability, and social ecological variables. Core findings indicate that men and women differ significantly according to their educational background. Among those who studied in a regular educational environment, the main predictor of men's QOL is their monthly income, whereas the main predictor for women is their level of attention deficit symptoms. The only predictor of QOL among men who studied in a special education program is the quality of contact with their mothers, whereas no significant predictor is observed among women.     

Human preferences are biased towards associative information

There is ample evidence that the brain generates predictions that help interpret sensory input. To build such predictions the brain capitalizes upon learned statistical regularities and associations (e.g., “A” is followed by “B”; “C” appears together with “D”). The centrality of predictions to mental activities gave rise to the hypothesis that associative information with predictive value is perceived as intrinsically valuable. Such value would ensure that this information is proactively searched for, thereby promoting certainty and stability in our environment. We therefore tested here whether, all else being equal, participants would prefer stimuli that contained more rather than less associative information. In Experiments 1 and 2 we used novel, meaningless visual shapes and showed that participants preferred associative shapes over shapes that had not been associated with other shapes during training. In Experiment 3 we used pictures of real-world objects and again demonstrated a preference for stimuli that elicit stronger associations. These results support our proposal that predictive information is affectively tagged, and enhance our understanding of the formation of everyday preferences.     

Gender differences in loss of psychological resources following experimentally-induced vicarious stress

Abstract

The present research focuses on gender differences in resource loss, perceived threat, and negative affective reactions induced by experimental manipulation of vicarious stress. Israeli students (54.7% women) were randomly allocated to one of two conditions: (1) Threat Condition (n=98), in which participants were exposed to a video film depicting terror attacks and (2) Control Condition (n=30), in which participants viewed a video film depicting a series of non-emotive news broadcasts. Participants also completed measures of mastery, optimism, and self-esteem. The data indicated that whereas under the Threat Condition women scored lower on psychological resources and higher on perceived threat than men, no significant gender differences were observed under the Control Condition. A path analysis revealed that gender was directly related to perceived threat and resource loss, which, in turn, were related to negative affect. In addition, a greater sense of mastery was related to lower resource loss. Overall, these experimental findings suggest that gender and mastery bear prominent effects on cognitive and emotional reactions to vicarious life threat.     

Affective value and associative processing share a cortical substrate

The brain stores information in an associative manner so that contextually related entities are connected in memory. Such associative representations mediate the brain’s ability to generate predictions about which other objects and events to expect in a given context. Likewise, the brain encodes and is able to rapidly retrieve the affective value of stimuli in our environment. That both contextual associations and affect serve as building blocks of numerous mental functions often makes interpretation of brain activation ambiguous. A critical brain region where such activation has often resulted in equivocal interpretation is the medial orbitofrontal cortex (mOFC), which has been implicated separately in both affective and associative processing. To characterize its role more unequivocally, we tested whether activity in the mOFC was most directly attributable to affective processing, associative processing, or a combination of both. Subjects performed an object recognition task while undergoing fMRI scans. Objects varied independently in their affective valence and in their degree of association with other objects (associativity). Analyses revealed an overlapping sensitivity whereby the left mOFC responded both to increasingly positive affective value and to stronger associativity. These two properties individually accounted for mOFC response, even after controlling for their interrelationship. The role of the mOFC is either general enough to encompass associations that link stimuli both with reinforcing outcomes and with other stimuli or abstract enough to use both valence and associativity in conjunction to inform downstream processes related to perception and action. These results may further point to a fundamental relationship between associativity and positive affect.     

The effect of mental progression on mood

Mood affects the way people think. But can the way people think affect their mood? In the present investigation, we examined this promising link by testing whether mood is influenced by the presence or absence of associative progression by manipulating the scope of participants' information processing and measuring their subsequent mood. In agreement with our hypothesis, processing that involved associative progression was associated with relatively better moods than processing that was restricted to a single topic (Experiment 1). Experiment 2 ruled out the possibility that conceptual plurality alone accounted for these mood differences; results converge with the view that mood is affected by the degree to which thoughts advance conceptually.     

How the measurement of memory processes can affect memory performance: the case of remember/know judgments

Relatively little attention has been paid thus far in memory research to the effects of measurement instruments intended to assess memory processes on the constructs being measured. The current article investigates the influence of employing the popular remember/know (R/K) measurement procedure on memory performance itself. This measurement procedure was extensively used in the past to assess the respective contributions of 2 processes to memory judgments, one based on familiarity and the other on recollection. Two experiments using unrelated word pairs showed that the use of an R/K procedure can alter memory performance. Specifically, the R/K procedure improved associative memory among older but not younger adults compared to conditions in which participants were not asked to provide R/K judgments. Such an effect was not observed in item memory performance. Potential mechanisms mediating these differential memory measurement effects are outlined, and the measurement effects' implications for memory and cognitive research are discussed.     

On the ethics of facial transplantation research

Transplantation continues to push the frontiers of medicine into domains that summon forth troublesome ethical questions. Looming on the frontier today is human facial transplantation. We develop criteria that, we maintain, must be satisfied in order to ethically undertake this as-yet-untried transplant procedure. We draw on the criteria advanced by Dr. Francis Moore in the late 1980s for introducing innovative procedures in transplant surgery. In addition to these we also insist that human face transplantation must meet all the ethical requirements usually applied to health care research. We summarize the achievements of transplant surgery to date, focusing in particular on the safety and efficacy of immunosuppressive medications. We also emphasize the importance of risk/benefit assessments that take into account the physical, aesthetic, psychological, and social dimensions of facial disfiguration, reconstruction, and transplantation. Finally, we maintain that the time has come to move facial transplantation research into the clinical phase.     

A multidimensional approach to explore cross-cultural differences in coping behavior: comparing Druze and Jews in Israel

Assuming that culture is a multidimensional variable, the current study explored the possibility that the interactions between ethnicity and other culture-related variables--rather than ethnicity alone--will better describe differences in coping behavior. In the study, cross-cultural differences among Israeli Jews and Israeli Druze in the use of various ways of coping were examined while also taking into account respondents' gender, age, self-esteem, sense of coherence, national identification, and religiosity. Comparing Israeli Jews and Israeli Druze, results indicate significant differences in levels of religiosity and coherence. Referring to coping behavior, findings show that differences in ways of coping could be attributed mainly to gender differences rather than ethnic differences Thus, at least in the case of comparing Israeli Jews vs. Israeli Druze, religiosity and gender are powerful determinants of coping behavior, while ethnicity has only a limited contribution in explaining variance in a preferred way of coping. It is suggested that ethnicity has a moderating role in shaping coping behavior, as it might influence person's self-perception and level of emotionality, which in turn shape the person's ways of coping. Future explorations among various age and ethnic groups are needed to enable generalization of the current study findings.