Perforant path activation modulates the induction of long-term potentiation of the schaffer collateral--hippocampal CA1 response: theoretical and experimental analyses

In one computational model of hippocampal function, the entorhinal cortical input to CA1 is hypothesized to play a key role in the ability of CA1 to decode CA3 recodings. Here, we develop a modification of this CA1 decoder hypothesis that is applicable to several computational theories of hippocampal function, and then we electrophysiologically investigate one assumption of this new hypothesis. First, using biologically realistic estimates, we calculate that CA3-induced CA1 excitation is too high and that inhibition plausibly plays a role in this CA1 decoder model. Thus motivated, we turn to a physiological demonstration to substantiate the plausibility of the proposed mechanism. Using the rat hippocampal slice, we examine an interlaminar interaction between the distal perforant path input to hippocampal CA1 stratum moleculare and the more proximal Schaffer collateral input to stratum radiatum. Perforant path activation provides sufficient inhibition to block homosynaptic long-term potentiation elicited by a suitably strong stratum radiatum input. For this interlaminar interaction to be most effective, perforant path activation must both precede and follow Schaffer collateral activation. Perforant path-evoked inhibition in CA1 can thus serve as a viable mechanism in the learned decoder theory of hippocampal CA1.     

Operator behavior in a dynamic visual signal detection task

The effects of changes in signal-to-noise ratio (SIN) and feedback state on the operator’s detection behavior, particularly derived operator thresholds, were investigated using a discrete visual signal. It was found that: (1) the operator behaves as if he has established different thresholds as a function of S/N; (2) his decision thresholds are relatively independent of the presence or absence of feedback; and (3) the operator will change his threshold accordingly for a change from one S/N to another. A model of the operator’s behavior, which introduced the concept of “operator” noise. yielded predictions of detection and false alarm probabilities which were extremely close to the observed values.     

The sweetness of surrender: Glucose enhances self-control by signaling environmental richness

According to the ego-depletion account of loss of self-control, self-control is, or depends on, a depletable resource. Advocates of this account have argued that what is depleted is actually glucose. However, there is experimental evidence that indicates that glucose replenishment is not necessary for regaining self-control, as well as theoretical reasons for thinking that it is not depleted by exercises of self-control. I suggest that glucose restores self-control not because it is a resource on which it relies, but because it serves as a signal of environment quality. I suggest that the evidence is better explained by a rival opportunity costs model of self-control than by the ego-depletion account.     

Shlomit Levy: a Pioneer in the Structural Theory of Well-Being

Applied Research in Quality of Life -     

Social cognitive predictors of prosocial behavior toward same and alternate race children among white pre-schoolers

Social cognitive predictors of 36 White preschoolers' (18 boys, 18 girls) tendencies to say they would act prosocially toward White and African-American children were examined. White preschoolers completed measures of their tendency to engage in prosocial behaviors directed toward White and African-American children, positive racial beliefs about White and African-American persons, and race schematicity. Consistent with previous research examining prosocial behavior in preschoolers, girls were more likely than boys to say they would act prosocially. White preschoolers' age in months did not correlate significantly with their tendencies to engage in prosocial behaviors toward White children. However, age in months was negatively correlated with White preschoolers' inclinations to direct prosocial behaviors toward African-American children. Consistent with an emerging literature concerning the role of social cognitive factors in young children's race schema development, White preschoolers' race schematicity was significantly predictive of their tendencies to say they would engage in prosocial behaviors toward African-American children. Patterns of results partially replicate previous prosocial behavior research, and demonstrate the importance of social cognitive variables on young children's prosocial behaviors. This research was undertaken as part of a graduate program in psychology at the University of Wyoming by the first author under the direction of the second author. The authors express gratitude to Karen Bartsch, Ph.D., and Bernita Quoss, Ph.D., and Jesse Barber, Sylvia Jones, and Nicole Martin of the University of Wyoming and to Nancy Eisenberg, Ph.D., of Arizona State University.