Virginia M. Gunderson

Visual recognition memory deficits in methylmercury-exposed Macaca fascicularis infants

Infant Macaca fascicularis exposed prenatally to maternal subclinical levels of methylmercury (MeHg) and their nonexposed controls were administered a test of visual recognition memory beginning at 210 days postconception (mean postnatal age = 51.88 days, SD = 5.30). The test consisted of a series of problems in which two identical 35 mm slides of a monkeys face were presented for a study period, followed by a test trial in which the previously exposed stimulus was paired with a novel one, and the looking time to each was recorded. The nonexposed group showed differential visual attention to the novel stimuli, indicating visual recognition abilities. The exposed groups visual attention to the novel stimuli was random. These results, in conjunction with earlier findings, suggest that prenatal MeHg exposure is associated with impaired visual recognition memory performance.

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.

The Family Environment

Considerable research has been conducted on families—how families create, experience, and respond to the world in which they live. The purpose of this chapter is to describe a conceptual framework for studying the family environment which (1) incorporates recent advances in understanding multiple social influences on behavior, (2) recognizes both common and idiosyncratic characteristics of families as social units, (3) identifies research strategies to assess families, and (4) generates hypotheses about the reasons families vary in their functioning. The framework derives from theories and research in psychology, ethology, sociology, anthropology, and demography. We rely most heavily on empirical work in social ecology and in decision making, incorporating elements from existing theories and combining them operationally in our formulation of the family environment.

Development of a model of status epilepticus in pigtailed macaque infant monkeys.

Seizures, particularly multiple episodes and/or status epilepticus (SE) are prevalent in pediatric patients. Pediatric SE is associated with brain changes that have been hypothesized to contribute to the onset of temporal lobe epilepsy (TLE). In order to gain insight into the effects of seizures on the immature brain and the risk for later TLE, we have developed a model of limbic SE in the pigtailed macaque monkey. In separate studies, bicuculline methiodide or a bicuculline ‘cocktail’ was infused into three regions of the brain (area tempestas, hippocampus, entorhinal cortex) to induce seizures. Measures included MRI, electrophysiology, behavior and morphology. Our results suggest that monkey models of SE may provide useful tools for understanding the effects of prolonged seizures during infancy and the origins of TLE in humans.

Infant Macaque Monkeys Respond to Pictorial Depth

The studies described here are the first to demonstrate that a nonhuman primate species is capable of responding to pictorial depth information during infancy. In two experiments, pigtailed macaque (Macaca nemestrina) infants were tested for responsivity to the pictorial depth cues of texture gradient/linear perspective and relative size. The procedures were adapted from human studies and are based on the proclivity of infants to reach more frequently to closer objects than to objects that are farther away. The stimulus displays included two equidistant objects that, when viewed monocularly, appear separated in space because of an illusion created by pictorial depth cues. When presented with these displays, animals reached significantly more often to the apparently closer objects under monocular conditions than under binocular conditions. These findings suggest that infant macaques are sensitive to pictorial depth information, the implication being that this ability has ancient phylogenetic origins and is not learned from exposure to the conventions of Western art.

Infant monkeys' visual responses to drawings of normal and distorted faces

Face‐like patterns attract attention from both human and nonhuman primates. The present study explored the facial preferences in infant pigtailed macaques (Macaca nemestrina). Twenty‐five subjects looked at 20 paired drawings of adult conspecific monkey faces, and their looking time was recorded. The facial features in the drawings were arranged in positions ranging from a normal to a scrambled face. The subjects looked at the normal face more than expected by chance (P < .02), suggesting a preference, whereas the distorted faces were observed randomly. The normal face may have been preferred because the eyes were in a normal position within the facial outline. Am. J. Primatol. 44:169–174, 1998.

Cross-modal transfer in high- and low-risk infant pigtailed macaque monkeys

Etude des aptitudes de transfert entre modalites sensorielles chez des nourrissons Macaca nemestrina presentant un risque eleve ou faible de troubles cognitifs.

Morphological Plasticity in an Infant Monkey Model of Temporal Lobe Epilepsy

Summary: Purpose/Methods: Seizures in early life are thought to contribute to the development of human temporal lobe epilepsy. To examine the consequences of early seizures, we elicited status epilepticus in immature, 5.5‐ to 7.0‐month‐old pigtailed macaques by unilateral microinfusion of bicuculline methiodide into the entorhinal cortex.

A demonstration of the memory savings effect in infant monkeys

In Experiment I, it was found that a 10-s cumulative study time would elicit a robust novelty response in infant monkeys, whereas a 5-s cumulative study time would not. In Experiment 2, infant monkeys were given a 10-s cumulative familiarization period. Following a 48-hr delay, they then were given 6 visual paired-comparison test trials-3 were preceded by a 5-s cumulative refamiliarization period and 3 were not. The infant monkeys exhibited a novelty response only after refamiliarization. These findings suggest savings (the phenomenon whereby prior exposure to information facilitates the relearning of the material) and parallel E. H. Cornells (1979) work on human infants. Results are discussed in terms of implicit and explicit memory.

Some observations on the ecology ofColobus badius temmincki, Abuko Nature Reserve, the Gambia, West Africa

Three groups of red colobus (Colobus badius temmincki) were observed at the Abuko Nature Reserve in the Gambia, West Africa between December 1973 and August 1974. The population of the three groups ranged from 24–40 animals with home ranges measuring 4.3–12.8 hectares. The red colobus fed on a wide variety of flora and their diet included fruit, flowers, shoots, and bark, as well as new and mature leaves. There was a change in diurnal activity patterns over the two seasons (dry and rainy), with more definitive activity peaks occurring during the dry season.