Joan S. Lockard

Feasibility and Safety of Vagal Stimulation In Monkey Model

Summary: The feasibility, safety, and preliminary effects of chronic vagal stimulation were studied in an alumina‐gel monkey model. Pilot studies to perfect the equipment, determine stimulation thresholds, and insure the comfort and safety of the animals preceded this study. Four monkeys were equipped with an indwelling, 2‐electrode cuff (titanium bands spaced 7 mm apart; silicone encased; 1.5 cm total length) in contact around the right vagus nerve; avoidance of the cardiac branch was confirmed by electrocardiograms. After postsurgical recovery, the intact and awake animals received constant‐current stimulation (5 mA; 83 Hz, 143 Hz, or 50–250 Hz randomly; 0.5‐ms pulse width) at the onset of every spontaneous seizure for the duration of the seizure or every 3 h for 40 s if stimulation had not occurred in the preceding hour. Stimulation periods of 2–6 weeks, with differing levels of stimulation, were preceded and followed by at least a 2‐week baseline period of no stimulation. During the stimulation periods, the seizure rate decreased to zero in two monkeys and the interseizure intervals became invariable in the remaining two monkeys. These effects carried over temporarily into the poststimulation baseline periods. Vagal stimulation had no consistent effects on seizure severity or EEG interictal spikes. Histological studies of six vagus nerves were unable to separate electrode cuff damage from any direct effects stimulation may have had on the nerves. Although it appears that chronic vagal stimulation is feasible and that epileptogenic processes are influenced, the safety and efficacy of the procedure are still in question.

Monetary significance of the affiliative smile: A case for reciprocal altruism

Whether smiling could accrue monetary returns was tested. Two degrees of smiling to single men and women (N = 96) by a waitress in a cocktail lounge was evaluated in terms of number of drinks ordered, size of tip, and whether the customers smiled upon departure. A broad smile reaped more money than a minimal smile and more from men than from women patrons. The results are discussed in terms of reciprocal altruism.

Valproic acid: reversibly acting drug?

Valproic acid [dipropylacetic acid (DPA)] was evaluated in an alumina‐gel monkey model (N= 12) by constant‐rate intravenous infusion. The data indicated: (a) a statistically significant decrease in seizure frequency the first 2 days of drug Step I (45–55 μg/ml) and drug Step II (90–110 μg/ml) which was temporary, lasting 2 days only; (b) a later, more permanent decrease in seizure frequency which was not apparent until drug Step III (130–170 μg/ml); and a delayed return of the seizure frequency to predrug levels for 2 weeks after drug administration was discontinued, with no DPA detectable in plasma after the initial postdrug day. Whether DPA will behave as a reversibly acting drug was discussed.

Human serial polygyny: Demographic, reproductive, marital, and divorce data

Abstract Over 4,000 dyadic groupings in two large shopping malls were classified by age and sex of individual members as they passed along a well-defined exit path. The observations were carried out at times and places when a demographic cross-section of the city was likely to be seen, and where there were no rigid constraints on the group composition that appeared. The data were subjected to computer analysis, and observed frequencies of specified age-sex dyads were compared by chi-square statistics to expected frequencies based on a binomial distribution. A female mating strategy at ages 21–32 years and two different male strategies at ages 24–32 and 39–50 years were revealed. The observed strategies correlate with the reproductive, marital, and divorce statistics of the locale. The results are discussed in terms of inclusive fitness maximized by a preference for monogamy in females and the practice of serial polygyny by some males.

Maternal and Paternal Differences in Infant Carry: U.S. and African Data

Over 4,000 adult-child groupings (Seattle and Dakar) in a variety of public places were observed. They were classified by sex and age of adults accompanying children; sex and age of infant, child or juvenile; the side (right or left) on which (and the way in which) the adult was carrying, in contact with, or in proximity to the child. The United States data indicated that sex and age of infant, sex of parent, and whether the infant was accompanied by both its parents are important parameters in the way infants are carried. Adult females carried infants of less than 1 yr predominantly on the left side; the effect was strongest for male infants. Adult males exhibited no such left-side bias. The African data (Wolof tribes) suggested that infants also choose to place their heads nearer the heart on the left side. The possibility that maternal and paternal care may have different evolutionary origins is considered.

Conditioned EEG desynchronization and seizure occurrence in patients

Five patients with seizures poorly controlled by standard anticonvulsant medication, underwent EEG operant conditioning. The operant paradigm reinforced the production of low voltage fast activity while decreasing frequencies below 10 c/sec. Seizure frequency decreased in 2 patients, seizure severity was attenuated in 2 others, and one patient who was only given reinforecement for scalp EMG suppression whowed no change in seizure parameters. Pseudoconditioning and control periods ruled out placebo effects. A rationale for this phenomenon is proposed.

Smiling and laughter: Different phyletic origins?

Ethological data on 141 adult dyads support the hypothesis that the human smile had its origin in the silent bared-teeth submissive grimace of primates and that the facial expression accompanying laughter evolved from the relaxed open-mouth display of play. Affiliative smiling occurred in greeting and departure interactions, whereas frank laughter was almost exclusively seen in a recreational context. Convergence and learning may mask the original distinction, leaving the impression of a continuum of graded signals.

Absence of Seizures or Mirror Foci in Experimental Epilepsy After Excision of Alumina and Astrogliotic Scar

Summary: In 15 rhesus monkeys (Macaca mulatto) made epileptic by the sensorimotor cortical injection of alumina, the roles of alumina and of “mirror foci” were investigated by serial surgical excisions of the granuloma, surrounding epileptic focus, and contralateral homotopic sensorimotor cortex. Electroencephalographic and electrocorticographic recordings documented foci and transmitted contralateral epileptic activity. After the granuloma was re‐moved, seizures continued but without alumina. After the epileptic cortex was removed, no seizure activity remained and no contralateral independent foci occurred. These findings indicate that the epilepsy incident to alumina injection into the sensorimotor cortex in monkey is not dependent on the continual presence of alumina and is not associated with independent or “mirror foci.”

Behavioral experimental epilepsy in monkeys. I. Clinical seizure recording apparatus and initial data

Abstract A technique is described for continuously observing and recording the clinical seizure activity of chronic experimental epileptic monkeys. The equipment employed is also directly applicable to human epileptic research. The initial behavioral data on monkeys obtained by this technique are presented.

Efficacy of Standard Anticonvulsants in Monkey Model with Spontaneous Motor Seizures

Monkeys were rendered chronically epileptic by injection of alumina gel into the pre‐ and postcentral gyrus. To test the validity of this primate model, the effects of diphenylhydan‐toin (DPH), phenobarbital, and primidone on spontaneous seizures were evaluated for 8 months with a Latin‐Square experimental design. All three drugs were effective, the frequency of seizures being reduced by at least one‐half during 6 weeks with treatment as compared with 6 weeks without. In most monkeys the frequency and severity of seizures were correlated to the number of interictal spikes in the EEG, and were inversely related to the level of drug in plasma. During withdrawal of phenobarbital and primidone, epileptic activity increased over that during control periods. Side effects were minimal with all three drugs. Patterns of behavior, although they differed from one monkey to the next, exhibited trends specific to each drug but particularly DPH. The seizures of some animals seemed to be related to the sleep‐waking cycle.