Biomedical subjects

Baiju C Gohil

Publications and source records attributed to Baiju C Gohil.

3 recordsLinked to original sources

PubMed2004

Early appearance of the metabolic syndrome in socially reared bonnet macaques.

Among 250 laboratory-born bonnet macaques living in social groups and maintained on commercial monkey chow, we measured weight, crown-rump length, sagittal abdominal diameter (SAD), and fasting serum insulin, glucose, triglycerides, high-density lipoproteins, low-density lipoproteins, and total cholesterol. Body mass index (BMI = weight/crown-rump length(2)), and insulin resistance determined by the insulin/glucose ratio (IGR) and homeostasis model assessment, were measured. We defined the metabolic syndrome using a composite score based on morphometry, insulin resistance, and serum lipid levels, analogous to clinical criteria. Elevated BMI was associated with significantly greater SAD, insulin, IGR, homeostasis model assessment, and triglycerides. Among 120 adult monkeys aged 5-17 yr, males (n = 48) had higher BMI, SAD, insulin, and IGR levels than females, independent of age. Sixteen of 113 adult monkeys and five of 36 peripubertal subjects, aged 3-4 yr (14%), met our criteria for the metabolic syndrome, as did four of 12 monkeys, aged 20-28 yr. Markers of the metabolic syndrome are present by 3-4 yr of age in our colony and are observed across the life span in the absence of conventional obesifying interventions. Socially reared and housed bonnet macaques may provide a useful model for studying the pathogenesis, prevention, and treatment of the metabolic syndrome.

Animals↗

PubMed2004

Detecting location-specific neuronal firing rate increases in the hippocampus of freely-moving monkeys.

The spatial properties of the firing of hippocampal neurons have mainly been studied in (a) freely moving rodents, (b) non-human primates seated in a moveable primate chair with head fixed, and (c) epileptic patients subjected to virtual navigation. Although these studies have all revealed the ability of hippocampal neurons to generate spatially selective discharges, the detected firing patterns have been found to be considerably different, even conflicting, in many respects. The present cellular electrophysiological study employed squirrel monkeys (Saimiri sciureus), which moved freely on the walls and floor of a large test chamber. This permitted the examination of the spatial firing of hippocampal neurons in nearly ideal conditions, similar to those used in rodents, yet in a species that belongs to the primate Suborder Anthropoidea. The major findings were that: (1) a group of slow-firing complex-spike cells increased their basal, awake firing rate more than 20-fold, often above 30 spikes/s, when the monkey was in a particular location in the chamber, (2) these location-specific discharges occurred consistently, forming 4-25 s action potential volleys, and (3) fast-firing cells displayed no such electrical activity. Thus, during free movement in three dimensions, primate hippocampal complex-spike cells do generate high-frequency, location-specific action potential volleys. Since these cells are components of the medial temporal lobe memory system, their uncovered firing pattern may well be involved in the formation of declarative memories on places.

Action Potentials↗

PubMed2003

Spatial memory performance of freely-moving squirrel monkeys.

Few experiments have addressed the problem of cognitive map formation in non-human primates. Therefore, a paradigm was developed to assess spatial memory formation in squirrel monkeys (Saimiri sciureus) moving freely in three dimensions. While moving on the walls and floor of a large test chamber, the animals learned to collect pieces of cereal from baited food-ports interspersed among non-baited ports. The cereal-pellets were not visible to the monkeys, so the animals needed to develop spatial memory to visit only the baited ports for food and avoid the non-baited ones. A session consisted of ten consecutive trials, and 3 successive sessions were conducted on each day for a 5-day period. For each trial, correct choices (CC; number of visited baited-ports) and incorrect choices (IC; number of visited non-baited ports) were registered, and spatial memory performance index (SMPI; ranging from 0.00 to 1.00) was calculated as follows: SMPI=(CC-IC)/CC. For each session, mean SMPI, session duration, total reaches into the non-baited ports, and total reaches into the baited ports were documented. In an 8-port task, where 4 food-ports were baited and 4 were non-baited, the mean SMPI was higher than 0 in the first session (day 1), indicating the development of short-term spatial memory. By the fifth session (day 2), this index was significantly higher than in the first session, indicating the build-up of long-term spatial memory. These changes were related to a significant decrease in the total reaches into the non-baited ports. At the same time, the duration of the sessions and the total reaches into the baited ports did not change significantly. This paradigm can be used for (1) studying cognitive map formation in primates, (2) examining the underlying cellular and molecular mechanisms in integrative neurobiological experiments, and (3) screening cognition-enhancer drugs in a monkey model.

Analysis of Variance↗