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.     

Tempo discrimination of musical patterns: Effects due to pitch and rhythmic structure

The purpose of this research was to investigate a set of factors that may influence the perceived rate of an auditory event. In a paired-comparison task, subjects were presented with a set of music-like patterns that differed in their relative number of contour changes and in the magnitude of pitch skips (Experiment 1) as well as in the compatibility of rhythmic accent structure with the arrangement of pitch relations (Experiment 2). Results indicated that, relative to their standard referents, comparison melodies were judged to unfold more slowly when they displayed more changes in pitch direction, greater pitch distances, and an incompatible rhythmic accent structure. These findings are suggested to stern from animputed velocity hypo thesis, in which people overgeneralize certain invariant relations that typically occur between melodic and temporal accent structure within Western music.     

The Boundaries of the Analytic Encounter: Clinical and Ethical Dimensions: A Roundtable Discussion: January 15, 1998

The American Journal of Psychoanalysis -     

Selective attention and the breadth of learning: A developmental study

Nursery school and second-grade subjects were trained on an optional intradimensional/extradimensional shift task with (1) no overtraining, (2) overtraining on the initial problem only, (3) overtraining on the shift problem only, or (4) overtraining on both the initial and the shift problems. Predictions concerning the effects of age and training conditions on the type of solution and the breadth of learning for the shift problem were derived from selective attention theory. However, the results were not consistent with the one-look assumption of such models. Instead, a multiple-look theory in which the breadth of attention varies with task demands seems most tenable.     

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 development of language in genie: a case of language acquisition beyond the “critical period”

The present paper reports on a case of a now-16-year-old girl who for most of her life suffered an extreme degree of social isolation and experiential deprivation. It summarizes her language acquisition which is occurring past the hypothesized “critical period” and the implications of this language development as related to hemispheric maturation and the development of lateralization. The results of a series of dichotic listening tests administered to her are included.