Casuistic contribution to the differential diagnosis of the myoclonic syndrome]

Involuntary muscle twitches, which are accompanied by a more or less pronounced effect of motion and which may last for several hours, are a common guiding symptom of a number of neurological syndromes. This paper reports the case of a 24-year-old male who had been suffering since his sixth year from episodic muscular spasms accompanied by attacks of petit mal. These are regarded as representing a myoclonic-epileptic syndrome. In this connection, a distinction has to be made, by differential diagnosis, between the "true" myoclonic syndrome which is characterized by the absence of complications due to attacks of grand mal or petit mal, Kojewnikoff's epilepsy, and the myoclonic-epileptic dementia form of syndrome.     

Observation of an absence status in the EEG without clinically detected psychopathology

It is reported that a patient suffering from generalized idiopathic epilepsy accidentally showed continuous epileptic activity as spike-wave pattern during an electroencephalographic lead without observing any clinical changes to whom. This state having been ended by a grand mal, the patient could give unspecific subjective complaints for the period of the "bioelectrical petit mal state", but he was fully able to remember. It is referred to that the phenomenon of the clinical inconspicuous appearance and the missing amnesia are special features.     

Effects of methylphenidate on working memory in pigeons

To assess the effects of methylphenidate on working memory, pigeons were trained in a delayed matching-to-sample task. Delay interval duration (0.2, 1, 3, 6, or 12 sec) was varied within sessions in order to separate delay-dependent from delay-independent effects of the drug on performance. A reduction in the sample response requirement from five responses to one response effectively reduced attention to the stimulus and impaired overall accuracy. Methylphenidate was administered in doses of 0.0 (saline control), 0.25, 2.5, and 10 mg/kg. Relative to performance with saline, accuracy was significantly reduced with 10 mg/kg methylphenidate to the same extent in both fixed ratio (FR) 1 and FR 5 conditions. The smaller doses had no effect, and there was no evidence that accuracy improved with drug administration. Intercepts and slopes of exponential functions fitted to measures of discriminability plotted as a function of delay showed that methylphenidate affected delay-independent aspects of performance (initial discriminability), but not delay-dependent aspects (rate of forgetting).     

Relative and absolute density of reinforcement as factors influencing the peak shift

Four groups of six pigeons each were given nondifferential training on multiple variable-interval variable-interval reinforcement schedules and then were switched to differential training involving a multiple schedule in which reinforcement density was reduced in one of the two components. The multiple schedules used in the four groups had mean interreinforcement intervals of 1 min and 1 min in the two components changed to 1 min, 5 min; 2.5 min, 2.5 min changed to 2.5 min, 5 min; 12 sec, 12 sec changed to 12 sec, 24 sec; and 12 sec, 12 sec changed to 12 sec, 60 sec. In subsequently administered wavelength generalization tests, some peak shifts were observed in each condition and occurred occasionally in the absence of behavioral contrast or rate reduction in the less-reinforced component. The best predictor of peak shift was a high proportion of total responses emitted during the more-reinforced component at the end of differential training.     

Effects of acute,subchronic and intermittent MDMA (‘ECSTASY’) administration on agonistic interactions between male mice

Recent studies suggest that acute administration of 3,4‐methylenedioxymethamphetamine (MDMA), an amphetamine derivative popularly known as “ecstasy,” produces an antiaggressive effect in male mice. However, there is no evidence with respect to the development of tolerance or sensitization after its subchronic or intermittent administration. In this study, we examined the action of low to moderate doses of MDMA (1.25, 2.5 and 5 mg/kg, i.p), administered acutely, subchronically (for 7 days) or intermittently, on agonistic behavior elicited by isolation in male mice. Individually housed mice were exposed to anosmic “standard opponents” 30 minutes after the drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. Acute treatment with MDMA provoked a significant reduction of aggressive behaviors, without altering immobility. However, this action was only selective at 1.25 mg/kg. With the intermediate (2.5 mg/kg) and the highest doses (5 mg/kg) of the drug, it was observed a significant decrease of offensive behaviors, accompanied by an increase of exploration from a distance, avoidance/flee and defense/submission behaviors. This ethopharmacological profile could indicate the existence of an anxiogenic‐like effect of MDMA. The overall picture of the effects of MDMA was very similar in the acutely, intermittently and daily treated animals. No tolerance or sensitization to the actions of the drug was developed after its repeated or intermittent administration.     

Variable-interval schedules of timeout from avoidance: effects of chlordiazepoxide, CGS 8216, morphine, and naltrexone.

Rats were trained on concurrent schedules in which pressing one lever postponed shock and pressing the other occasionally (variable-interval schedule) produced a 2-min timeout during which the shock-postponement schedule was suspended and its correlated stimuli were removed. These procedures provided a baseline for studying the effects of drugs on behavior maintained by different sources of negative reinforcement (shock avoidance and timeout from avoidance). Experiment 1 studied a benzodiazepine agonist, chlordiazepoxide, and antagonist, CGS 8216. Chlordiazepoxide (2.5-30 mg/kg) had little effect on avoidance responding except at higher doses, when it reduced responding. By comparison, responding on the timeout lever was increased in 5 of 6 rats. These effects were reversed by CGS 8216 (2.5-5 mg/kg) in the 2 rats tested, but CGS 8216 had no effect by itself. Experiment 2 studied an opiate agonist, morphine, and antagonist, naltrexone, with 3 rats. Morphine's (2.5-20 mg/kg) effects were opposite those of chlordiazepoxide: At doses that either increased or had no effect on avoidance responding, morphine depressed timeout responding. Naltrexone (5 mg/kg) reversed these actions but had no effect by itself.     

Magnitude and frequency of reinforcement and frequencies of interresponse times

The relative magnitude and relative frequency of reinforcement for two concurrent interresponse times (1.5 to 2.5 sec and 3.5 to 4.5 sec) were simultaneously varied in an experiment in which pigeons obtained grain by pecking on a single key. Visual discriminative stimuli accompanied the two time intervals in which reinforcements were arranged by a one-minute variable-interval schedule. The resulting interresponse times of each of three pigeons fell into two groups; "short" (1.0 to 2.5 sec) and "long" (3.0 to 4.5 sec). Steady-state relative frequencies of these interresponse times were orderly functions of both reinforcement variables. The combined effects of both independent variables were well summarized by a linear function of one variable, relative access to food. Unlike corresponding two-key concurrent variable-interval schedules, the present schedule did not produce an equality between the relative frequency of an operant and either the relative magnitude or the relative frequency of reinforcement of that operant. A tentative account is provided for this difference between one-key and two-key functions.     

Ibuprofen effects on behavioral thermoregulation with microwave radiation in albino rats

This study determined whether ibuprofen causes a disruptive behavior pattern similar to aspirin yet contrary to acetaminophen regarding thermoregulatory effects. 8 Sprague-Dawley rats (3 males and 5 females) were drawn from a population of rats which had been conditioned to press a lever for food reinforcement in an undergraduate course in operant conditioning. Animals were conditioned in a refrigerated Skinner Box on a fixed-interval 2-min. (FI-2 min.) schedule of microwave radiation (5 sec. of radiation per exposure occasion) in a repeated-measures reversal (within-subjects) design. The rats were injected intraperitoneally with doses of ibuprofen in amounts of 10-50 mg/kg or methyl-cellulose control vehicle of equal volume over 8-hr. daily sessions. A multivariate analysis of variance showed significant differences due to doses (mg/kg) of ibuprofen for number of microwave heat reinforcers per hour and rate of responding (ns) both measures of which were significantly higher during the first 2 hours of the session. Comparative differences in behavioral thermoregulation in humans reflect the likelihood of underlying biochemical mechanisms based on research by Murphy, Badia, Myers, Boecker, and Wright in 1994.     

Two temporal parameters of food postponement

Rats were trained to press a lever under schedules of food postponement. In the absence of lever presses, food was delivered periodically (food-food interval). Responses initiated a second interval (response-food interval) that was reset by each additional response. Performance was first studied at different response-food intervals with the food-food interval fixed at 30 or 60 sec, or 10 min. Response-food intervals were examined in ascending order and then recovery was studied at shorter intervals. Finally, the food-food interval was manipulated with response-food interval fixed at 30 sec. At food-food intervals of 30 and 60 sec, responding first increased and then decreased as the response-food interval increased. At the 10-min food-food interval, responding decreased with increasing response-food interval. In general, very low rates of responding occurred when the response-food interval was 60 sec or more and when it equalled or exceeded the food-food interval. However, responding was maintained in one animal when the food-food interval was decreased from 120 to 15 sec with the response-food interval at 30 sec. Results, in terms of several dependent variables, are compared with data on shock avoidance. Effects of response-independent and response-produced food and shock are discussed.     

Sidman avoidance in the fish

Goldfish trained in a shuttle box under conditions in which changing compartments postponed shock for 20 sec showed a substantial, negatively accelerated increase in rate of crossing. That the avoidance-contingency was responsible for the change in behavior is suggested by the fact that no significant increase in rate of crossing appeared in control animals which were paired with the experimentals and shocked whenever the experimental animals were shocked; there is some evidence, indeed, that the control animals were handicapped in their subsequent adjustment to the avoidance condition. The introduction of a warning stimulus (light) in the last 5 sec of the response-shock interval decreased the rate of crossing in the first 15 sec and increased the rate of crossing in the last 5 sec. Reducing the shock-shock interval from 20 sec to 2.5 sec had no marked effect. The results are compared with those obtained in analogous experiments with higher animals.     

Auditory delayed matching in the bottlenose dolphin

A bottlenose dolphin, already highly proficient in two-choice auditory discriminations, was trained over a nine-day period on auditory delayed matching-to-sample and then tested on 346 unique matching problems, as a function of the delay between the sample and test sounds. Each problem used new sounds and was from five to 10 trials long, with the same sound used as the sample for all trials of a problem. At each trial, the sample was projected underwater for 2.5 sec, followed by a delay and then by a sequence of two 2.5-sec duration test sounds. One of the test sounds matched the sample and was randomly first or second in the sequence, and randomly appeared at either a left or right speaker. Responses to the locus of the matching test sound were reinforced. Over nine, varying-sized blocks of problems, the longest delay of a set of delays in a block was progressively increased from 15 sec initially to a final value of 120 sec. There was a progressive increase across the early blocks in the percentage of correct Trial 1 responses. A ceiling-level of 100% correct responses was then attained over the final six blocks, during which there were 169 successive Trial 1 responses bracketed by two Trial 1 errors (at 24- and 120-sec delays). Performance on trials beyond the first followed a similar trend. Finally, when the sample duration was decreased to 0.2 sec or less, matching performance on Trial 1 of new problems dropped to chance levels.     

Control of key pecking by the duration of a visual stimulus

Pigeons' key pecks were brought under the control of the duration of a visual stimulus in one-key and two-key procedures. In the one-key procedure, pecks were reinforced after presentations of a long-duration stimulus but not after presentations of a short-duration stimulus. In the two-key procedure, left-key pecks were reinforced after the long-duration stimulus and right-key pecks after the short-duration stimulus. In both procedures, the long-duration stimulus was 10 sec, and the short-duration stimulus was increased from 1 to 8 sec in 1-sec steps. Discriminative control developed with both procedures, but with greater accuracy in the two-key procedure, in which a difference threshold was obtained at short-duration values between 7 and 8 sec, or about 2.5 sec shorter than the long-duration stimulus.     

The relative influence of pitch and timbre on the apparent location of sound in the median sagittal plane

Listeners were requested to locate sounds originating in the median sagittal plane (MSP). The stimuli, 75-Msec pulses, were repeated at a rate of 200 times/sec and were filtered to transmit narrow bands centered about 0.63, 1.6, 2.5, or 6.3 kHz. Despite the sameness of pitch generated by all stimuli, Os perceived the 0.63-, 1.6-, and 2.5-kHz-centered sounds as originating low, middle, and high, respectively, in the MSP, regardless of their actual positions. The stimuli centered about 6.3 kHz, on the other hand, were located accurately by most Os. These findings were interpreted to mean that under conditions of inadequate auditory cues, timbre, not pitch, influences perceived elevation. The implication is that timbre also served as the cue for the apparent elevation of those sounds which, due to their high-frequency components, can be located accurately.     

Rethinking desire: the objet petit a in Lacanian theory

The concept of the objet petit a is central to Lacan's theory of desire, which arguably represents his major contribution to psychoanalysis. It is an expression of the lack inherent in human beings, whose incompleteness and early helplessness produce a quest for fulfillment beyond the satisfaction of biological needs. The objet petit a is a fantasy that functions as the cause of desire; as such, it determines whether desire will be expressed within the limits of the pleasure principle or "beyond," in pursuit of an unlimited jouissance, an impossible and even deadly enjoyment. Parallels between the objet petit a and Winnicott's transitional object are explored and its functions illustrated through analysis of Pedro Almodovar's film Talk to Her. A clinical case is presented in which the question of desire seemed crucial.     

Post-training ethanol disrupts trace conditioned fear in rats: effects of timing of ethanol, dose and trace interval duration

Ethanol has complex effects on memory performance, although hippocampus-dependent memory may be especially vulnerable to disruption by acute ethanol intoxication occurring during or shortly after a training episode. In the present experiments, the effects of post-training ethanol on delay and trace fear conditioning were examined in adolescent rats. In Experiment 1, 30-day-old Sprague-Dawley rats were given delay or trace conditioning trials in which a 10s flashing light CS was paired with a 0.5 mA shock US. For trace groups, the trace interval was 10 s. On days 31-33, animals were administered ethanol once daily (0.0 or 2.5 g/kg via intragastric intubation), and on day 34 animals were tested for CS-elicited freezing. Results showed that post-training ethanol affected the expression of trace, but had no effect on delay conditioned fear. Experiment 2 revealed that this effect was dose-dependent; doses lower than 2.5 g/kg were without effect. Experiment 3 evaluated whether proximity of ethanol to the time of training or testing was critical. Results show that ethanol administration beginning 24h after training was more detrimental to trace conditioned freezing than administration that was delayed by 48 h. Finally, in Experiment 4 animals were trained with one of three different trace intervals: 1, 3 or 10s. Results indicate that post-training administration of 2.5 g/kg ethanol disrupted trace conditioned fear in subjects trained with a 10s, but not with a 1 or 3s, trace interval. Collectively the results suggest that ethanol administration impairs post-acquisition memory processing of hippocampus-dependent trace fear conditioning.     

The information-capacity of the human motor-system in pursuit tracking

Human performance at a typical pursuit tracking task has been analysed by information theory. Without preview of the course, the channel-capacity was found to be about 4 bits per sec. With preview performance ceased to be perfect at about 2 bits per sec. but continued to improve up to at least 8 bits per sec., at about half the ideal slope. The findings are discussed in relation to the information-capacities measured in other tasks, and it is suggested that with full preview the rate should reach a maximum of about 10 bits per sec. Without preview the rate appears to be lowered by the need to offset response lag by predicting course behaviour.     

Effect of caffeine on motor performance by caffeine-naive and -familiar subjects.

The purpose of this investigation was to assess the effect of caffeine on selected manipulation skills by caffeine-naive and caffeine-familiar subjects. The subjects were 20 caffeine-naive (less than 90 mg/d) and 20 caffeine-familiar (greater than 750 mg/d) college-age (21 +/- 1.7 yr.) women. Measurements included steadiness error time and frequency, duration of tracing, error time and frequency, and dexterity. Doses of 2.5, 5.0 mg.kg-1 body weight caffeine or a placebo (200 mg. methylcellulose) were administered randomly to all subjects on three separate occasions. A 2 x 3 repeated-measures analysis of variance yielded a significant group difference for steadiness error time between the 5 mg.kg-1 and 2.5 mg.kg-1 dose and between 5 mg.kg-1 and the placebo. For frequency of steadiness errors, the nonuser group posted significant gains for both 5.0 and 2.5 mg.kg-1 over the placebo control. On tracing error time and error frequency, 5.0 mg.kg-1 resulted in significant increases from both 2.5 mg.kg-1 and the placebo group. In the caffeine-naive group, both doses of caffeine led to significant increases in dexterity time from the placebo, and the 5.0 mg.kg-1 dose was significantly different from the 2.5 mg.kg-1 trial. It was concluded that caffeine had detrimental effects on selected performance skills of caffeine-naive women but not in caffeine-familiar women.     

Adaptation to auditory motion in the horizontal plane: effect of prior exposure to motion on motion detectability.

Thresholds for auditory motion detectability were measured in a darkened anechoic chamber while subjects were adapted to horizontally moving sound sources of various velocities. All stimuli were 500-Hz lowpass noises presented at a level of 55 dBA. The threshold measure employed was the minimum audible movement angle (MAMA)--that is, the minimum angle a horizontally moving sound must traverse to be just discriminable from a stationary sound. In an adaptive, two-interval forced-choice procedure, trials occurred every 2-5 sec (Experiment 1) or every 10-12 sec (Experiment 2). Intertrial time was "filled" with exposure to the adaptor--a stimulus that repeatedly traversed the subject's front hemifield at ear level (distance: 1.7 m) at a constant velocity (-150 degrees/sec to +150 degrees/sec) during a run. Average MAMAs in the control condition, in which the adaptor was stationary (0 degrees/sec,) were 2.4 degrees (Experiment 1) and 3.0 degrees (Experiment 2). Three out of 4 subjects in each experiment showed significantly elevated MAMAs (by up to 60%), with some adaptors relative to the control condition. However, there were large intersubject differences in the shape of the MAMA versus adaptor velocity functions. This loss of sensitivity to motion that most subjects show after exposure to moving signals is probably one component underlying the auditory motion aftereffect (Grantham, 1989), in which judgments of the direction of moving sounds are biased in the direction opposite to that of a previously presented adaptor.     

The time course of prepration

The time course of the adjustments triggered by a warning signal was studied by measuring choice reaction times (RTs) at different predictable foreperiods after such a signal. Before the warning signal, a high time uncertainty situation was created by imposing either a long constant foreperiod of 5 sec. or one varying in the range 1.5 to 5 sec. The warning signal was a click. Foreperiods ranging from 0 to 300 millisec. were used in different blocks of trials. The stimulus was the onset of one of two lamps calling for the pressing of one of two keys. A control condition, without click, was used also. RTs were found to decrease continuously when the forperiod was increased from 0 to 100-150 millisec. The click delivered simultaneously with the stimulus permitted reactions significantly faster than in the control condition. It is concluded (a) that the latency of preparation can be much shorter than the 2 to 4 sec. reported by Woodrow; (b) that the warning signal can be used as a time cue to start preparatory adjustments without starting a refractory period of the order of magnitude found in experiments with pairs of successive reactions, and thus that such refractory periods are not the inevitable cost of paying attention to a signal. There is also some suggestion that in this situation the click not only triggers preparatory adjustments, but also causes an immediate facilitation of the reaction to the visual stimulus.     

Cognitive Processing Therapy Delivered in 5 Days via Telehealth to a Gay Latino Adolescent: A Clinical Case Study

Cognitive Processing Therapy (CPT) has been thoroughly investigated as an efficacious treatment for posttraumatic stress disorder (PTSD). However, for many, the barriers to receiving treatment in the traditional weekly, in-person format prevent engagement. Recent evidence suggests alternative modalities, such as telehealth, and condensed administration of treatment protocols may reduce barriers, increasing treatment completion. This case study reports the treatment of a gay-identifying adolescent Latino male who received 10 sessions of CPT over the course of 5 consecutive days (CPT-5). The patient experienced significant reduction in PTSD symptoms over the course of treatment, dropping below the clinical threshold for PTSD diagnosis by the 10th session. Treatment gains were maintained, and continued, 6 weeks posttreatment. Further, the patient reported marked reduction in suicidality and substance use. In conclusion, the administration of CPT-5 via telehealth holds promise as an effective evidence-based treatment for adolescents with PTSD, including those holding multiple historically marginalized identities, though further investigation through clinical trials is warranted.