Training stimulus

It is elear from these results that, in MDMA- or MBDB-trained rats, complete generalization of the training cue to the typical hallucinogenic drugs LSD, DOM, and mescaline does not occur. Furthermore, transfer of the training stimulus does not oecur to MDMA or MBDB in animals trained to diseriminate LSD from saline (Nichols et al. 1986). Although MDMA has been shown to substitute for mescaline (Callahan and Appel 1987). 

Repetitive and identical work processes trigger a training stimulus and will yield improved output. This is valid for all physical functions in general and may, e.g., encompass simple training of muscles or the adaptability to heat or height. Improved output is most noticeable during the first phase of training. 

Surface EMG was used to observe the various activities of muscles in different stabilization exercises that were the major concern in previous studied. Marshall et al studied four kinds of different core stabilization exercises on ball, and used surface EMG to record muscle activations of RA, EO, TA, and ES[4]. While subjects performed tasks of the single-leg hold and at the top of the press-up on the ball, there was significant increase in muscle activation of RA, implying that the ball could provide an increased training stimulus for the RA compared with doing on stable surface. 

The following are some human factors aspects relevant to training but they are meant only as a stimulus to further study and consideration and not as an authoritative and exhaustive checklist. 

The computational paradigm in an ANN is based on an idealized model of a biological unit called a neuron. The unique characteristics of this ANN model are the inputs of signal from stimulus in a training environment. It is important to note that each neuron works independently of the other neurons. The specific characteristics of ANN models that attract industrial application are ... 

Figure 2. Muscle stimulation, a) a single nerve impulse (stimulus) causes a single contraction (a twitch). There is a small delay following the stimulus before force rises called the latent period, b) A train of stimuli at a low frequency causes an unfused tetanus. Force increases after each progressive stimulus towards a maximum, as calcium levels in the myofibrillar space increase. But there is enough time between each stimulus for calcium to be partially taken back up into the sarcoplasmic reticulum allowing partial relaxation before the next stimulus occurs, c) A train of stimuli at a higher frequency causes a fused tetanus, and force is maximum. There is not enough time for force to relax between stimuli. In the contractions shown here, the ends of the muscle are held fixed the contractions are isometric.

There is no single underlying cause for the myotonia seen in the muscles of myotonic patients. The typical myotonic response is a train of action potentials generated in a muscle fiber in response to a single stimulus. Experimental work has shown that such a response can be generated in normal muscle fibers in which chloride conductance is suppressed, and this may be the cause of the myotonia of Thomsen s disease (see Barchi, 1988 for examples). It is almost certainly not the cause of myotonia in myotonic dystrophy in which there is an associated fall in... 

Hundt W, Holter SM, Spanagel R Discriminative stimulus effects of glutamate release inhibitors in rats trained to discriminate ethanol. Pharmacol Biochem Behav 59 691-695, 1998... 

These data clearly illustrate the enantioselectivity of the (-l-)-isomers of MDA, MDMA, and MBDB in producing an MDMA-like stimulus and underscore the fact that in vitro studies of the biochemical pharmacology of these substances should reveal similar selectivity, once the primary pharmacological process underlying the interoceptive cue is identified. The data also indicate that (-l-)-MDA is the most potent of all the drugs tested in MDMA- or in (-t)-MBDB-trained animals. The faet that (-l-)-MDA does not substitute in amphetamine-trained animals in our studies supports the argument that the pharmacology of this enantiomer of MDA is MDMA-like and is not like amphetamine. 

To summarize the data in table 1, neither MDMA nor MBDB has hallu-cinogen-like discriminative stimulus properties. Symmetrical transfer of the MDMA and MBDB stimulus indicates that their primary discriminative stimulus effects are very similar. For both MDMA and MBDB, there is enantioselectivity for the S isomer, with about a twofold eudismic ratio. Finally, the substitution of (- )-amphetamine and cocaine in MDMA-trained rats may indicate that MDMA has some psychostimulant-like properties, while hffiDB seems to lack this activity. 

However, the specific serotonin uptake inhibitor fluoxetine failed to produce an MBDB-like cue and failed to block the stimulus effects of MBDB when it was given prior to a training dose of MBDB. Table 3 summarizes results of fluoxetine testing in MBDB-trained rats. In other exploratory studies, pretreatment of MDMA-trained rats with either methysergide or ketanserin failed to block completely the MDMA-discriminative stimulus. 

Based on the modest ability of the (+)-isomers of MDMA and MBDB to inhibit the reuptake of norepinephrine (NE) into hypothalamic synaptosomes (Steele et al. 1987). it seemed possible that noradrenergic pathways might be involved in the eue. In ano er series of drug discrimination experiments designed to test this hypothesis, the specific NE uptake inhibitor (-)-tomoxctine was tested for stimulus transfer in doses up to 10 mg/kg in MDMA-trained rats. At 5 mg/kg, 67 percent of the animals responded on, the drug lever. However, pretreatment with tomoxetine in six rats trained to discriminate MDMA from saline had no effect on the discrimination of a subsequent dose of MDMA. 

ANSWER We have tried ketanserin, but it did not antagonize the stimulus. I do not believe we have tested fluoxetine in the MBDB-trained animals. It has only been tested in the MDMA-trained animals. We have not found an antagonist to the cue yet. 

Callahan, P.M., and Appel, J.B. Differences in the stimulus properties of 3,4-methylenedioxyamphetamine (MDA) and N-Methyl-l-(3,4-methylene-dioxyamphetamine) MDMA in animals trained to discriminate hallucinogens from saline. Abstr Soc Neurosci 476.2, 1987. 

Winter, J.C. Effects of the phenethylamine derivatives BL-3912, fenfluramine, and Seh-12679, in rats trained with LSD as a discriminative stimulus. Psychopharmacology 68 159-162, 1980. 

TABLE 4. Results of stimulus generalization studies using rats trained to discriminate 1.5 mg/kg of racemic MDA from saline... 

It is probably important to note that although there may be differences between the effects produced by MDMA and MDE, there are also significant similarities. For example, preliminary data using MDMA-trained animals suggest that racemic MDMA and MDE produce similar stimulus... 

RESPONSE This is what, propylhexedrine We have looked at propylhexedrine, and it does retain amphetamine-like activity, but it is less potent. In rats trained to discriminate 1.5 mg/kg of racemic MDMA from saline (ED5o=0.76 mg/kg), the ED50 values for stimulus generalization to MDE and N-OH MDA are 0.73 and 0.47 mg/kg, respectively (Glermon and Misenheimer, unpublished observations). 

Brady, K.T. Balster, R.L. and May, E.L. Discriminative stimulus properties of stereoisomers of N-allylnormetazocine in phencyclidine-trained squirrel monkeys and rats. Science 215 178-180, 1982. 

Figure 1.4 Effects of MnPN stimulation on EEG patttern and PLH neuronal activity. Upper An MnPN 6 s stimulus train suppressed PLH neuronal discharge, evoked EEG synchronization, and reduced EMG activity. The sweep display shows effects of successive stimulus trains. The events display shows averaged PLH neuronal discharge rate in conjunction with train stimulation. Lower Raster plot showing neuronal discharge during single pulse stimulation. In this example, PLH neuronal activity was inhibited with a latency of about 10 ms inhibition lasted about 110 ms. Activation of MnPN neurons during NREM sleep would result in suppression of PLH neuronal activity.

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