The functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain and spinal cord that coordinates the activity of the bladder and urethral outlet. Experimental studies in animals indicate that urine storage is modulated by reflex mechanisms in the spinal cord, whereas voiding is mediated by a spinobulbospinal pathway passing through a coordination centre in the rostral brain stem. Many of the neural circuits controlling micturition exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. This study summarizes the anatomy and physiology of the spinal and supraspinal micturition switching circuitry and describes a computer model of these circuits that mimics the switching functions of the bladder and urethra at the onset of micturition.

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The purpose of the present experiment was to determine whether some of the principles of Pavlovian conditioning may also be operating in the process which has been called pseudoconditioning.If a series of fairly strong unconditioned stimuli is presented alone and that series is followed by a previously neutral stimulus, it is found that this previously neutral stimulus now produces a response similar to the one given to the unconditioned stimulus-this, although the two stimuli have never been paired. This phenomenon, now called pseudo-conditioning, first was observed as the result of controls which were run in some typical conditioning experiments (i,10, II,12,13,14,15). That such a modification of behavior could occur through the mere presentation of the unconditioned stimulus alone was obviously significant in the interpretation and evaluation of most conditioning experiments. Despite this fact, only an occasional investigator in the field of conditioning employed this control. The term pseudo-conditioning was not applied until 1938, when Grether (4) observed the phenomenon in experiments with monkeys, named it, and pointed out its importance. Since that time, there have been a few studies directed specifically towards determining the functional characteristics of pseudo-conditioning itself (2,3,5,6,7,8,9).Several interpretations of pseudo-conditioning have been offered, all of them being at a definitely speculative level.One hypothesis advanced by Sears (10) and supported by Harlow (5), is couched in neurological terms and assumes that the phenomenon of pseudo-conditioning is a cortical dominant, brought about, in this case, by external stimulation rather than by the hormal or visceral afferent stimulation to which the dominant is usually attributed. No experimental evidence is offered as crucial support for this theory, nor does the experiment herein reported either support or refute it.A second interpretation of pseudo-conditioning assumes that the repeated presentation of the unconditioned stimulus develops an 'attitude of expectancy' in the organism (4,6). Once this attitude of expectancy has been established, and apparently because the

The research of this article investigates the possibility that memory for the conditioned response (CR) may be subject to the same sorts of interference that have been found to operate in verbal and in perceptual-motor memory situations. If interfering experiences can indeed contribute to the forgetting of a CR, then the need to postulate a special memory system for this class of behavior would be seriously questioned, and we might move in the direction of a general theory of memory.In the classical conditioning paradigm used, cats that were suspended in a webbed sling received shocks on either forepaw. A shock was the unconditioned stimulus, flexions of one paw or another were the unconditioned responses, the conditioned stimulus could be either a light or a tone, and the CR was a movement of the appropriate paw. By manipulation of the two conditioned stimuli and the two parallel unconditioned responses, we devised and introduced different kinds of potentially interfering experience. Experiment 1, a retroactive design, used the various stimulus and response manipulations of verbal-learning research and determined that the CR did indeed show retention loss when interference was introduced. Experiment 2, a proactive design, measured the effect of prior, random, and uncorrelated presentations of shock stimuli and lights or tones on later conditioning and retention and found that the uncorrelated experience had a profound effect on retention tested 10 weeks after the end of original conditioning, although it had little impact upon acquisition of the CR.The Discussion sections consider theoretical implications of findings as they relate to several topics: (a) the operation of interference paradigms in conditioning that are parallel to those in other types of learning, (b) generality of the concept of spontaneous recovery, (c) transfer effects as functions of experimental manipulations, (d) the implications for training and therapy that lie in our interference data, (e) the possible contrast between the effect of correlated experience on memory and that of a random noncorrelated experience, (f) the influence of a prior random schedule upon subsequent learning and especially upon memory, and (g) the relation of our paradigm to the typical learned helplessness phenomenon.