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Mammals evolved a potent fear-motivated defensive system capable of single-trial fear learning that shows no forgetting over the lifespan of the animal. The basolateral amygdala complex (BLA) is considered an essential component of this conditional fear learning system. However, recent studies challenge this view and suggest that plasticity within other(More)
It is well established that the cerebellum and its associated circuitry are essential for classical conditioning of the eyeblink response and other discrete motor responses (e.g., limb flexion, head turn, etc.) learned with an aversive unconditioned stimulus (US). However, brain mechanisms underlying extinction of these responses are still relatively(More)
Mammalian associative learning is organized into separate anatomically defined functional systems. We illustrate the organization of two of these systems, Pavlovian fear conditioning and Pavlovian eyeblink conditioning, by describing studies using mutant mice, brain stimulation and recording, brain lesions and direct pharmacological manipulations of(More)
BACKGROUND Mild traumatic brain injury (cerebral concussion) results in cognitive and emotional dysfunction. These injuries are a significant risk factor for the development of anxiety disorders, including posttraumatic stress disorder. However, because physically traumatic events typically occur in a highly emotional context, it is unknown whether(More)
The basolateral amygdala (BLA), consisting of the lateral and basal nuclei, is considered to be essential for fear learning. Using a temporary inactivation technique, we found that rats could acquire a context-specific long-term fear memory without the BLA but only if intensive overtraining was used. BLA-inactivated rats' learning curves were characterized(More)
Rabbits (Oryctolagus cuniculus) were presented with 7 daily sessions of tone-alone training after conditioning. Before the beginning of each of the first 4 extinction sessions, an artificial tear solution or tetracaine hydrochloride was administered to the cornea of rabbits in the control group (n = 6) and experimental group (n = 7), respectively. There(More)
The basolateral amygdala (BLA) is thought to be essential for fear learning. However, extensive training can overcome the loss of conditional fear evident following lesions and inactivation of the BLA. Such results suggest the existence of a primary BLA-dependent and a compensatory BLA-independent neural circuit. We tested the hypothesis that the bed nuclei(More)
A large body of evidence indicates that the cerebellum is essential for the acquisition, retention, and expression of the standard delay conditioned eyeblink response and that the basic memory trace appears to be established in the anterior interpositus nucleus (IP). Adaptive timing of the conditioned response (CR) is a prominent feature of classical(More)
BACKGROUND Traumatic experience can result in life-long changes in the ability to cope with future stressors and emotionally salient events. These experiences, particularly during early development, are a significant risk factor for later life anxiety disorders such as posttraumatic stress disorder (PTSD). However, because traumatic experience typically(More)
The conditioning context arises from the relatively static features of the training environment. In rabbit eyeblink conditioning, procedures that retard acquisition (conditioned stimulus [CS] preexposure, unconditioned stimulus preexposure, blocking manipulations) are attenuated by context changes. In this article the authors investigate the effect of(More)