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.     

Teaching the Introduction to Religions: Religious Pluralism in a Post-Colonial World

Taking seriously the implications of post-colonial theory, the authors revisit the introductory course (normally “World Religions”) as a course on the plurality of religions in contemporary U.S. culture. They explain the structure of the course, and discuss practical and ethical issues around student field visits to learn about other religions.     

Father identification,achievement, and occupational behavior of rural youth: One year follow-up

Rural economically deprived adolescent males, who had been previously surveyed as high school seniors concerning their post-high school plans, were surveyed again 1 yr later concerning their present occupational status and feelings of personal satisfaction. The Ss had been divided in an earlier study into two groups, low identification males (LIM) and high identification males (HIM) based upon independent evaluators' judgments of the adequacy of their fathers as identification models. Each group's responses to the survey were compared. The results indicate that there are no statistically significant differences between the two groups on the variables of satisfaction, having received counseling from others and optimism about the future. There are statistically significant differences between the current occupational status and future occupational plans of the two groups.     

W-shaped and U-shaped functions obtained for monoptic and dichoptic disk-disk masking

For nonmetacontrast (disk-disk) masking, if the outer diameter of the mask equals that of an annulus which produces typical metacontrast functions, U- and W-shaped functions will be obtained if (1) the stimuli are viewed dichoptically and monoptically, respectively. and (2) the mask is no more than about 10 times the energy (luminance x duration) of the target. As this energy ratio is approached, both types of functions become monotonic. These shapes suggest that interactions at different visual-pathway loci may he mapped by visual masking functions.