Human patellar reflex and conditioned reflex compared electromyographically

Inspite of continued work on the stretch reflex and “voluntary” movement study of the conditioned stretch reflex declined early in this century. The present experiments surveyed seven classical conditioning regimens for the human rectus femoris EMG seen after a blow to the patellar tendon. It was possible to (1) rule out conditioning to a knee touch that occured together with the tap, (2) establish weak conditioned stimulus, Sc, control for a tape recorder click and subsequent fist clench that preceded the tap by variable elapsed times, and (3) establish strong Sc control for a tone that sounded an invariant 0.27 sec before the tap. There were large differences, however, in Sc power across subjects, as measured by amplitude, latency, and frequency of conditioned EMG activity that occured prior to tap or when the tap was omitted. Purely reflexive responses, especially later EMG segments, also varied in amplitude and frequency, to support a conclusion that numerous controlling stimuli added or competed from trial to trial. Further disclosure of Sc contributions, including those from movement-generated stimulation, is warranted, especially for behaviors whose rhythmic timings, as in locomotion, might favor Pavlovian conditioning.     

A note on conditional reflex studies of schizophrenia in France

In France, beginning with 1946, the method of Ivanov-Smolenski was used to study schizophrenia, but after 1957, sensory conditioning procedures have been employed (EEG sound-light, evoked potentials in children, SAE conditioning in adults) and more recently eye blink and operant conditioning).     

A note on ROC analysis and non-parametric estimate of sensitivity

In the signal detection paradigm, the non-parametric index of sensitivity A′, as first introduced by Pollack and Norman (1964), is a popular alternative to the more traditional d′ measure of sensitivity. Smith (1995) clarified a confusion about the interpretation of A′ in relation to the area beneath proper receiver operating characteristic (ROC) curves, and provided a formula (which he called A′′) for this commonly held interpretation. However, he made an error in his calculations. Here, we rectify this error by providing the correct formula (which we call A) and compare the discrepancy that would have resulted. The corresponding measure for bias b is also provided. Since all such calculations apply to “proper” ROC curves with non-decreasing slopes, we also prove, as a separate result, the slope-monotonicity of ROC curves generated by likelihood-ratio criterion.This revised article was published online in August 2005 with the PDF paginated correctly.     

A note on constant error shifts in post-perturbation responses

Response biasing was examined in the production of well-learned discrete timing responses. Interpolated movements consisted of trials which were briefly perturbed by an accelerating or decelerating force with subjects requested to amend the response in order to complete the trial successfully. Movement time analysis indicated that the response immediately following the perturbation trial demonstrated large biasing effects with the direction of the constant error shift a function of the direction of the perturbation. Responses following deceleration perturbations were produced too rapidly and those following acceleration perturbations were produced too slowly. Analysis of kinematic variables associated with these responses showed that post perturbation trials were characterized by systematic changes in peak acceleration and peak deceleration as well as the timing of these parameters. The biasing effects were temporary and showed other similarities to findings from short-term motor memory investigations. A number of differences were also noted along with methodological considerations for perturbation paradigms.     

A television technique for quantifying conditioned and unconditioned responses of planarians

A technique tor quantifying responses of the planarian, using television recording, is described. The planarian swims in a watch crystal filled with spring water, with a TV camera directly under the crystal aimed upward. Shock is administered via four electrodes placed 90 deg apart around the perimeter of the crystal. Magnitude of response to shock is expressed in terms of percent reduction in body length. Latency of response onset is also available by counting synchronizing pulses equalling 1/60 sec. Data from two worms which received 20 shocks/day for 5 days indicated that the magnitude and latency measures were similar for the two animals and were reasonably reliable. The average latency of the UR to shock was about 100 msec, similar to that of the human eyeblink. Extension of the technique for studying CRs was also described, indicating that greater sophistication in quantifying URs and CRs in planarians is now available.     

Modulation of a discrete Pavlovian conditioned reflex by a putative emotive Pavlovian conditioned stimulus

Three experiments showed the modulation of a rabbit eyeblink conditioned response (CR) to a Pavlovian conditioned stimulus (CS) by 30-s stimuli (A & B) that had been differentially paired with paraorbital shock. The CS (Y) was a 1,050-ms cue that had been paired with paraorbital shock outside A or B. In testing, the amplitude of CRs was greater when Y was presented within A than within B. Differential modulation occurred whether shock in A had been preceded by another 1,050-ms cue, X(AX+,BX-;Experiment 1) or not (A+B-;Experiment 2). Experiment 3 compared the technique of Experiment 1 (AX+) with that of Experiment 2 (A+) and found the latter to be advantageous for facilitation of CRs to Y by A. These data are consistent with the predictions of a model of Pavlovian conditioning (AESOP, Wagner & Brandon, 1989) that distinguishes between emotive and sensory conditioning as did Konorski (1967).     

A note on responses to ethyl alcohol before and after smoking1

Differential sensitivity was measured before and after smoking a cigarette by 10 smokers, using 10 nonsmokers as controls. Stimuli consisted of reagent grade ethanol in eight concentrations ranging from 4% to 12%. No significant differences were observed between smokers and nonsmokers or before vs after smoking, although slightly higher overall correct responses and correspondingly smaller jnds were obtained for the nonsmokers. No practice affects were noted among the control group between the first and second set of samples. The findings confirm previous results which had been recently questioned.     

Retention of a classically conditioned reflex response in spinal cat

Retention of classically conditioned flexion reflex facilitation was examined in unanesthetized, decerebrate, acute spinal cats. Flexion reflex facilitation, recorded from the tibialis anterior muscle, was obtained by pairing saphenous nerve stimulation (the conditioned stimulus) with superficial peroneal nerve stimulation (the unconditioned stimulus). The flexion reflex declined in control animals receiving the same number of nerve stimuli over the same time span, but in an explicitly unpaired sequence. To investigate retention, conditioned stimuli were presented at 5-min intervals following acquisition for a 2 1/2-h period. During this time a significant difference between conditioning and control groups was maintained even to the last trial, with no indication that the difference was subsiding over time. The results support the possibility that a classical conditioning paradigm applied to the spinal cord can induce alterations in spinal reflexes of long duration. Furthermore, the results appear to rule out post-tetanic potentiation as a mechanism producing the observed long-term effects.     

The treatment of childhood encopresis by conditioned gastro-ileal reflex training

The indications for conditioned gastro-ileal reflex training are discussed and the method of treatment for childhood encopresis is described. Twenty-four children were treated by this method. Nineteen were successfully treated in less than 1 year (mean = 5 months), three were successfully treated in more than 1 year (mean = 17 months) and two children made no response. During a follow-up period ranging from 6 months to 6 years (mean = 29 months) the symptom had recurred in 4 children.