Protein synthesis and memory: a review

Neuroleptic drugs disrupt the learning and performance of operant habits motivated by a variety of positive reinforcers, including food, water, brain stimulation, intravenous opiates, stimulants, and barbiturates. This disruption has been demonstrated in several kinds of experiments with doses that do not significantly limit normal response capacity. With continuous reinforcement neuroleptics gradually cause responding to cease, as in extinction or satiation. This pattern is not due to satiation, however, because it also occurs with nonsatiating reinforcement (such as saccharin or brain stimulation). Repeated tests with neuroleptics result in earlier and earlier response cessation reminiscent of the kind of decreased resistance to extinction caused by repeated tests without the expected reward. Indeed, withholding reward can have the same effect on responding under later neuroleptic treatment as prior experience with neuroleptics themselves; this suggests that there is a transfer of learning (really unlearning) from nonreward to neuroleptic conditions. These tests under continuous reinforcement schedules suggest that neuroleptics blunt the ability of reinforcers to sustain responding at doses which largely spare the ability of the animal to initiate responding. Animals trained under partial reinforcement, however, do not respond as well during neuroleptic testing as animals trained under continuous reinforcement. Thus, neuroleptics can also impair responding (though not response capacity) that is normally sustained by environmental stimuli (and associated expectancies) in the absence of the primary reinforcer. Neuroleptics also blunt the euphoric impact of amphetamine in humans. These data suggest that the most subtle and interesting effect of neuroleptics is a selective attenuation of motivational arousal which is (a) critical for goal-directed behavior, (b) normally induced by reinforcers and associated environmental stimuli, and (c) normally accompanied by the subjective experience of pleasure. Because these drugs are used to treat schizophrenia and because they cause parkinsonian-like side effects, this action has implications for a better understanding of human pathology as well as normal motivational processes.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0140525X00010372

Neuroleptics and operant behavior: The anhedonia hypothesis

Memory formation: the sequence of biochemical events in the hippocampus and its connection to activity in other brain structures.

Multiple parallel memory systems in the brain of the rat.

Animal studies suggest that fear inhibits pain whereas anxiety enhances it; however it is unclear whether these effects generalize to humans. The present study examined the effects of experimentally induced fear and anxiety on radiant heat pain thresholds. Sixty male and female human subjects were randomly assigned to 1 of 3 emotion induction conditions: (1) fear, induced by exposure to three brief shocks; (2) anxiety, elicited by the threat of shock; (3) neutral, with no intervention. Pain thresholds were tested before and after emotion induction. Results suggest that findings from animal studies extend to humans: fear resulted in decreased pain reactivity, while anxiety led to increased reactivity. Pain rating data indicated that participants used consistent subjective criteria to indicate pain thresholds. Both subjective and physiological indicators (skin conductance level, heart rate) confirmed that the treatment conditions produced the targeted emotional states. These results support the view that emotional states modulate human pain reactivity.

Fear and anxiety: divergent effects on human pain thresholds

Rats trained on an eight-arm radial maze were challenged by placing the maze in new spatial environments. Administration of opiate antagonists, either naloxone or diprenorphine, after exposure to the new environments significantly improved subsequent performance. The effect of naloxone on spatial memory was attenuated when drug administration occurred 2 hours after maze exposure.

Opiate antagonists improve spatial memory

The effect of neurotensin on food consumption in the rat

Retrograde amnesia: Storage failure versus retrieval failure

Visual input to the pons was studied by anatomical and physiological methods. Cortical area 18 sends a dense projection to the rostral pons. Pontine cells respond best to targets moving in a preferred direction over a large receptive field, which usually includes the center of gaze. The results suggest a role for pontocerebellar pathways in visual control of movement.

Richard A. King

Papers

Opiate antagonists improve spatial memory

The effect of neurotensin on food consumption in the rat

Retrograde amnesia: Storage failure versus retrieval failure

Visual input to pontine nuclei

Visual input to the pontine nuclei.