Integrate-and-express models of synaptic plasticity propose that synapses integrate plasticity induction signals before expressing synaptic plasticity. By discerning trends in their induction signals, synapses can control destabilizing fluctuations in synaptic strength. In a feedforward perceptron framework with binary-strength synapses for associative memory storage, we have previously shown t...

The question of interference (how new learning affects previously acquired knowledge and vice versa) is a central theoretical issue in episodic memory research, but very few human neuroimaging studies have addressed this question. Here, we used event-related potentials (ERPs) to test the predictions of the complementary learning systems (CLS) model regarding how list strength manipulations (str...

A fundamental question in the study of cognition is whether memory strength varies continuously or whether memories sometimes fall below a threshold and fail completely. Previous studies examining this question have relied exclusively on 1 method--receiver operating characteristics--so in the current study, we addressed this issue by using a completely different approach. We tested memory for s...

When children and adults retrieve words during unconstrained recall, it is commonly supposed that words will present themselves to consciousness in decreasing order of memory strength, which means that their order of readout should be stronger --~ weaker. In contrast, fuzzy-trace theory proposes a counterintuitive nonmonotonic relationship between order of readout and memory strength. This rela...

Subjects studied either an 8- or 16-word list and later recalled the items while a voice key recorded each response latency. The trials were partitioned by recall total in order to examine the means and distributions of both latencies and interresponse times as a function of recall total. Each analysis was consistent with the view that an item's absolute strength determines whether it is recall...

resolves into an enduring feeling of contentment. Contentment from writing a song is a pretty good reward. But playing the song for band mates, and turning it into something that we perform, and then getting positive feedback from an audience is sublime. I sometimes get asked how I find time to make music. I always answer the same way. I’m a better scientist, husband, father (and every other ro...

OBJECTIVES This cross-sectional study described the prevalence of possible risk factors for increasing eligibility level of long-term care insurance in home help service users who were certified as support level 1-2 or care level 1-2 in Japan. METHODS Data were collected from October 2011 to November 2011. Variables included eligibility level, grip strength, calf circumference (CC), functiona...

To investigate potentially dissociable recognition memory responses in the hippocampus and perirhinal cortex, fMRI studies have often used confidence ratings as an index of memory strength. Confidence ratings, although correlated with memory strength, also reflect sources of variability, including task-irrelevant item effects and differences both within and across individuals in terms of applyi...

Event-related potentials (ERPs) were recorded while subjects made old/new recognition judgments on new unstudied words and old words which had been presented at study either once ('weak') or three times ('strong'). The probability of an 'old' response was significantly higher for strong than weak words and significantly higher for weak than new words. Comparisons were made initially between ERP...

We investigated how the hippocampus and its adjacent mediotemporal structures contribute to contextual and noncontextual declarative memory retrieval by manipulating the amount of contextual information across two levels of the same contextual dimension in a source memory task. A first analysis identified medial temporal lobe (MTL) substructures mediating either contextual or noncontextual retr...