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Accumulating evidence indicates that phobic and posttraumatic anxiety disorders likely result from a failure to extinguish fear memories. Extinction normally depends on a new learning that competes with the original fear memory and is driven by medial prefrontal cortex (mPFC) projections to the amygdala. Although mPFC stimulation was reported to inhibit the(More)
In humans, learning to produce correct visually guided movements to adapt to new sensorimotor conditions requires the formation of an internal model that represents the new transformation between visual input and the required motor command. When the new environment requires adaptation to directional errors, learning generalizes poorly to untrained locations(More)
Many recent studies describe learning-related changes in sensory and motor areas, but few have directly probed for improvement in neuronal coding after learning. We used information theory to analyze single-cell activity from the primary motor cortex of monkeys, before and after learning a local rotational visuomotor task. We show that after learning,(More)
Acquisition and retention of sensorimotor skills have been extensively investigated psychophysically, but little is known about the underlying neuronal mechanisms. Here we examine the evolution of neural activity associated with adaptation to new kinematic tasks in two cortical areas: the caudal supplementary motor area (SMA proper), and the primary motor(More)
Inner-product operators, often referred to as kernels in statistical learning, define a mapping from some input space into a feature space. The focus of this letter is the construction of biologically motivated kernels for cortical activities. The kernels we derive, termed Spikernels, map spike count sequences into an abstract vector space in which we can(More)
Emotions generally facilitate memory, an effect mediated by the basolateral amygdala (BLA). To study the underlying mechanisms, we recorded BLA, perirhinal and entorhinal neurons during an appetitive trace-conditioning task. We focused on the rhinal cortices because they constitute the interface between the hippocampus, a mediator of memory consolidation,(More)
Memory consolidation is thought to involve the gradual transfer of transient hippocampal-dependent traces to distributed neocortical sites via the rhinal cortices. Recently, medial prefrontal (mPFC) neurons were shown to facilitate this process when their activity becomes synchronized. However, the mechanisms underlying this enhanced synchrony remain(More)
Animal studies of discriminative fear conditioning traditionally use stimuli that are distant in physical features and thus easily distinguished perceptually. Independently, human studies have shown that training mostly improves discrimination thresholds. We found that aversive learning actually induced an increase in discrimination thresholds in humans and(More)
Time perception is compromised in emotional situations, yet our ability to remember these events is enhanced. Here we suggest how the two phenomena might be functionally linked and describe the neural networks that underlie this association. We found that participants perceived an emotionally aversive stimulus longer than it was, compared to an immediately(More)
The ability to distinguish danger from safety is crucial for survival. On the other hand, anxiety disorders can result from failures to dissociate safe cues from those that predict dangerous outcomes. The amygdala plays a major role in learning and signaling danger, and recently, evidence accumulates that it also acquires information to signal safety.(More)