Previous experience disrupts d-amphetamine-induced stereotypic diving in rats

Rats given d-amphetamine and placed in a tank of water repeatedly dive towards the bottom of the tank. Two experiments investigated this stereotypy. The first established a dose-response function for the stereotypy and the second showed that experience with the apparatus prior to drug administration disrupted the stereotypy. The latter result is consistent with the findings of previous work and thus provides a degree of generality for the role of experience interacting with CNS drugs to induce stereotypies

Complete amnesia induced by ECS and complete recovery of memory following reinstatement treatment

Amnesia of fear conditioning in ECS animals was found to be equal to animals not conditioned. However, memory was shown to recover in ECS animals when different combinations of conditioning cues were presented 96 hr after training. The degree of memory recovered in ECS animals appeared to be a function of the type of reinstatement treatment given with apparent complete recovery obtained under one condition. Modification of retention by the reinstatement procedures was restricted to animals conditioned and made amnesic by ECS. These results are interpreted as indicating that ECS produces amnesia by interfering with memory retrieval processes and that the degree of memory recovered in ECS animals is a function of the type of reinstatement procedure used and the time at which it is administered

The amnesia gradient: inadequate as evidence for a memory consolidation process

Rats were conditioned to fear a tone paired with shock to the feet. Retention tests 4 days later showed that consolidation had occurred. Other animals were not tested for retention at 4 days, but the tone was presented in order to reactivate their memories of the conditioning. An amnesia gradient was generated by low-intensity electrical stimulation of the amygdaloid complex at different intervals after the tone, but stimulation was without effect either when given to rats not previously conditioned or when given to conditioned rats without preceding memory reactivation. Thus, stimulation of the amygdaloid complex can can affect memory retrieval. Moreover, the data call into question the assumption that an amnesia gradient indicates that the memory consolidation process has been modified

Presentation of a flashing light following training produces amnesia

Long—Evans rats given exposure to a flashing-light stimulus following one-trial fear conditioning showed amnesia relative to controls not given the flashing-light experience. Together with previous results obtained in this laboratory, it is apparent that the flashing light modulates memory processing

Positive Interanimal Transfer with a Control for Arousal

Three experiments used rats and a non-shock passive avoidance task to differentiate between learning and non-specific arousal hypotheses of the interanimal transfer phenomenon. In the first experiment with 57 rats, a multi-trial training procedure was used and positive transfer was obtained from rats receiving “trained-brain” extract injections but not from rats receiving injections of extracts from aroused controls. The second experiment used a one-trial training procedure with 49 rats and reproduced the results of Exp. 1. The third experiment with 56 rats showed some evidence of extinction and spontaneous recovery while this was not found with rats receiving injections from aroused controls. A fourth experiment indicated that the brain-extract solutions of Exps. 1 to 3 contained relatively high concentrations of protein. No detectable concentrations of RNA were discerned. The behavioral results were consistent with the notion that the interanimal transfer resulted from a learning transfer rather than a nonspecific arousal transfer

Computer software and hardware to determine contrast sensitivity using three methods: Tracking, limits, and constant stimuli

The software and hardware to obtain contrast sensitivity functions in a single session with monkeys are described. The versatility of the software allows the program to be used in a variety of sensory systems with only minor programming modifications. It will permit absolute or difference threshold measurements with any one of three methods of threshold testing: (1) method of tracking, (2) method of limits, and (3) method of constant stimuli. Human and monkey contrast sensitivity functions measured with the software and hardware are provided