Dopamine plays a critical role in behavioral tasks requiring interval timing (time perception in a seconds-to-minutes range). Although some studies demonstrate the role of dopamine receptors as a controller of the speed of the internal clock, other studies demonstrate their role as a controller of motivation. Both D1 dopamine receptors (D1DRs) and…

It is commonly assumed that memories contribute to value-based decisions. Nevertheless, most theories of value-based decision-making do not account for memory influences on choice. Recently, new interest has emerged in the interactions between these two fundamental processes, mainly using reinforcement-based paradigms. Here, we aimed to study the…

According to dual-process theory, recognition memory performance draws upon two processes, familiarity and recollection. The relative contribution to recognition memory are commonly distinguished in humans by analyzing receiver-operating-characteristics (ROC) curves; analogous methods are more complex and very rare in animals but fast familiarity…

This study aimed to determine whether attentional prioritization of stimuli associated with reward transfers across conceptual knowledge independently of physical features. Participants successively performed two color-word Stroop tasks. In the learning phase, neutral words were associated with high, low, or no monetary reward. In the…

Previous research has demonstrated that areas in the medial temporal lobe and prefrontal cortex (PFC) show increased activation during retrieval of overlapping sequences. In this study, we designed a task in which degree of overlap varied between conditions in order to parse out the contributions of hippocampal and prefrontal subregions as overlap…

Humans are capable of rapidly extracting regularities from environmental input, a process known as statistical learning. This type of learning typically occurs automatically, through passive exposure to environmental input. The presumed function of statistical learning is to optimize processing, allowing the brain to more accurately predict and…

Seven monkeys performed variants of two short-term memory tasks that others have used to differentiate between selective and nonselective memory mechanisms. The first task was to view a list of sequentially presented images and identify whether a test matched any image from the list, but not a distractor from a preceding list. Performance was best…

We report a hitherto unknown form of side-specific learning in honeybees. We trained bees individually by coupling gustatory and mechanical stimulation of each antenna with either increasing or decreasing volumes of sucrose solution offered to the animal's proboscis along successive learning trials. Next, we examined their proboscis extension…

Sleep has been shown to promote the generation of explicit knowledge as indicated by the gain of insight into previously unrecognized task regularities. Here, we explored whether this generation of explicit knowledge depends on pre-sleep implicit knowledge, and specified the differential roles of slow-wave sleep (SWS) vs. rapid eye movement (REM)…

Studies into interactions between explicit and implicit motor sequence learning have yielded mixed results. Some of these discrepancies have been attributed to difficulties in isolating implicit learning. In the present study, the effect of explicit knowledge on implicit learning was investigated using a modified version of the Alternating Serial…

The present study investigated reinstatement of conditioned responses in humans by using a differential Pavlovian conditioning procedure. Evidence for reinstatement was established in a direct (fear rating) and in an indirect measure (secondary reaction time task) of conditioning. Moreover, the amount of reinstatement in the secondary reaction…

Memory consolidation is defined as the time window during which the memory trace is susceptible to behavioral, electrical, or pharmacological interventions. Here, the authors presented rats with two novel tastes at consecutive time intervals. Clear interference was evident when a novel taste formed the second taste input whereby, surprisingly, the…

In two H[subscript 2] [superscript 15]O PET scan experiments, we investigated the cerebral correlates of explicit and implicit knowledge in a serial reaction time (SRT) task. To do so, we used a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious…

The anterior cingulate cortex (ACC) plays a critical role in stimulus-reinforcement learning and reward-guided selection of actions. Here we conducted a series of experiments to further elucidate the role of the ACC in instrumental behavior involving effort-based decision-making and instrumental learning guided by reward-predictive stimuli. In…

In two experiments, the time course of the expression of fear in trace (hippocampus-dependent) versus delay (hippocampus-independent) conditioning was characterized with a high degree of temporal specificity using fear-potentiated startle. In experiment 1, groups of rats were given delay fear conditioning or trace fear conditioning with a 3- or…