Varied effects of conventional antiepileptics on responding maintained by negative versus positive reinforcement.

We analyzed the effects of four conventional antiepileptic drugs (AEDs) - carbamazepine (CBZ), ethosuximide (ETH), phenytoin (PHT), and valproate (VPA) - on operant behavior maintained by negative or positive reinforcement contingencies. Rats were trained to lever press on a free-operant avoidance schedule or variable-interval (VI) schedule of appetitive reinforcement. Dose-effect functions were separately established on each reinforcement contingency for CBZ (12.5-100 mg/kg), ETH (25-200 mg/kg), PHT (12.5-50 mg/kg), and VPA (50-400 mg/kg). CBZ and PHT reduced responding on free-operant avoidance and VI appetitive reinforcement tasks, with positively reinforced behavior reduced at lower drug dosages than negatively reinforced responding. ETH and VPA reduced responding on the VI appetitive reinforcement task, but did not alter behavior maintained on the free-operant avoidance schedule. Our results suggest that conventional AEDs vary in their effect on operant behavior, depending on the type of reinforcement process maintaining responding.

Descriptive analysis of epileptic seizures and problem behavior in adults with developmental disabilities.

We studied possible relations between seizures and problem behavior in 3 adults with developmental disabilities. Each person was observed for between 56 and 92 days to record occurrences of seizures and problem behavior. Results of our descriptive analysis indicated an association between seizures and problem behavior for each participant. For Stan, most problem behavior occurred following absence seizures. For Tom, problem behaviors only occurred before tonic-clonic seizures but showed no relation to absence seizures. For Mick, problem behaviors began before absence seizures, but no consistent relation was established between problem behavior and tonic-clonic seizures. Findings suggest that seizures and problem behaviors can be associated, but these patterns appear to be highly idiosyncratic across individuals.

Functional analysis of tardive dyskinesia: implications for assessment and treatment.

We conducted an analogue functional analysis contrasting motor tasks with varying types of social consequences for movements associated with tardive dyskinesia (TD) in 2 men who had been diagnosed with developmental disabilities and TD. Our findings suggest that TD-related movements were not a function of social reinforcement contingencies. However, motor-activation tasks decreased TD-related movements, suggesting a possible novel intervention.

Medical and behavioral symptoms as potential medication side effects in adults with developmental disabilities.

The incidence of medical and behavioral symptoms that could occur as side effects of psychotropic medication was assessed in a sample of 30 adults with developmental disabilities. Using a retrospective chart review method, we measured symptoms in six a priori classes of potential side effects over a 2-year period. The majority of side effects involved apparent effects of the psychotropic medications on behavior, mood, or sleep. Different patterns of changes in medication prescription, in relation to recorded side effects, were observed. Overall, there was a significant positive relation between the number of potential side effects recorded and the number of psychotropic medication changes made. Our findings suggest several patterns of side effects associated with psychotropic medication use.

Analogue functional analysis of movements associated with tardive dyskinesia.

We studied whether movements associated with tardive dyskinesia (TD) served operant functions in 2 men with developmental disabilities. We found that TD-related movements occurred more frequently in the alone and attention conditions and less frequently in control and demand conditions. Our findings suggest that TD-related movements may not be maintained by social reinforcers and that decreases in TD movements are possibly a result of engagement in activities that are incompatible with TD movements.

Possible role for the 5-HT1A receptor in the behavioral effects of REM sleep deprivation on free-operant avoidance responding in rat.

RATIONALE: REM sleep deprivation (REMSD) has been shown to increase rates of free-operant avoidance responding. Depletion of 5-hydroxytryptamine (5-HT, serotonin) levels produces similar effects on responding. OBJECTIVE: We studied whether the pharmacological activation of the 5-HT1A receptor would produce effects on avoidance responding similar to REMSD and depleted 5-HT levels. METHODS: Rats were trained to lever press on a free-operant avoidance task. Dose-effect functions were established for 8-OH-DPAT (a 5-HT1A receptor agonist) (0.1-1.0 mg/kg) and WAY 100635 (a 5-HT1A receptor antagonist) (0.1-1.0 mg/kg). Rats were then exposed to REMSD (48 h) or equivalent control conditions, and then administered 8-OH-DPAT (0.6 mg/kg) and/or WAY 100635 (0.025-0.1 mg/kg). RESULTS: Injections of 8-OH-DPAT increased rates of avoidance responding in a dose-dependent manner, while WAY 100635 did not alter responding. The effect of 8-OH-DPAT was antagonized by pre-injection of WAY 100635. REMSD and injections of 8-OH-DPAT increased rates of avoidance responding and the effects of both manipulations were reversed by pre-injection of WAY 100635. CONCLUSIONS: Activation of the 5-HT1A receptor may be a mechanism by which REMSD increases rates of free-operant avoidance responding.

Differential effects of carbamazepine on negatively versus positively reinforced responding.

To assess its effects on negatively versus positively reinforced operant behavior, carbamazepine (CBZ) or vehicle was acutely administered to rats. Negative reinforcement baselines consisted of a free-operant avoidance task with 5-s shock-shock and 20-s response-shock intervals. Positive reinforcement baselines consisted of responding for food pellets on a variable interval 30-s schedule. Ascending dose-effect functions were established using CBZ for negatively reinforced responding (vehicle, 25, 50, 100 mg/kg ip) and positively reinforced responding (vehicle, 12.5, 25, 50, 100 mg/kg ip). Negatively reinforced responses and avoided shocks were significantly reduced by CBZ injections at 100 mg/kg. Positively reinforced responses and food pellet deliveries were significantly reduced by CBZ injections at 25, 50, and 100 mg/kg. The results show that CBZ has differential, dose-dependent effects on negatively versus positively reinforced responding.