Contaminación por mercurio y las malformaciones congénitas detectadas en el nacimiento en Porto Velho, Brasil, entre 1997 y 2007

The possible negative impacts of mercury contamination in the Madeira river, State of Rondonia, Brazil, on newborn babies health were evaluated. The incidence of congenital malformations was surveyed from the records of newborns in the main hospital of Porto Velho, Rondonia, from 1997 to 2007. The type of malformations between local population and cases transferred from other areas in Rondonia were compared. Neurological related malformations were found in 45% of the cases. The proportion of neurological defects in the local population was slightly higher than in transferred cases. Non-neurological malformations represented 43% of the sample and, 11.4% were unspecified. The incidence of general (including non-neurological) congenital malformations was similar to the region’s average. This is indicative of Hg contamination during pregnancy.Los posibles impactos negativos de la contaminación por mercurio en el río Madeira, Estado de Rondonia, Brasil, en la salud de los bebés recién nacidos fueron evaluados. La incidencia de malformaciones congénitas fue examinado en los registros de los recién nacidos en el principal hospital de Porto Velho, Rondonia, de 1997 a 2007. El tipo de malformaciones entre la población local y los casos transferidos de otras zonas de Rondonia fueron comparados. Malformaciones neurológicas relacionadas se encontraron en el 45% de los casos. La proporción de defectos neurológicos en la población local fue levemente superior en los casos transferidos. Malformaciones non neurológicas representó el 43% de la muestra y, el 11,4% sin especificar. La incidencia de la general (incluyendo non neurológicas) malformaciones congénitas fue similar al promedio de la región. Esto es indicativo de contaminación de mercurio durante el embarazo

Time-dependent changes in cortisol and tympanic temperature lateralization during food deprivation stress in marmoset monkeys

Temporal information about food availability can be easily entrained, as in the case of fixed feeding routines of captive animals. A sudden unintentional or deliberate delay (e.g., food deprivation—FD) leads to frustration and psychological stress due to the loss of temporal predictability. How marmosets—an increasingly used small primate—process and respond to FD stress has not been previously assessed. Here we delayed the routine feeding of adult captive marmosets for 3 or 6 h. Blood cortisol concentration was used as a hormonal measure of the stress response. Changes in the left/right baseline tympanic membrane temperature (TMT) were used as an indirect ipsilateral indicator of hemisphere activity. Marmosets that were deprived for 3 h had higher cortisol levels than non-deprived controls. Cortisol concentration in the marmosets deprived for 6 h did not differ from controls possibly due to adaptative mechanisms against the detrimental effects of prolonged high cortisol levels. Interestingly, FD stress may have been processed more symmetrically at first, as indicated by the bilateral increase in TMT at the 3 h interval. As the event progressed (i.e., 6 h), a clear rightward TMT bias suggests that hemisphere activity had become asymmetrical. Therefore, the sudden loss of temporal predictability of an entrained routine feeding schedule induces time-dependent changes in the cortisol stress response and shifts in the TMT (and potentially hemisphere activity) lateralization bias of adult captive marmosets

Scopolamine induces deficits in spontaneous object-location recognition and fear-learning in marmoset monkeys

The non-selective muscarinic receptor antagonist scopolamine (SCP) induces memory deficits in both animals and humans. However, few studies have assessed the effects of amnesic agents on memory functions of marmosets – a small-bodied neotropical primate that is becoming increasingly used as a translational model for several neuropathologies. Here we assessed the effects of an acute SCP administration (0.03 mg/kg, sc) on the behavior of adult marmoset monkeys in two tasks. In the spontaneous object-location (SOL) recognition task, two identical neutral stimuli were explored on the sample trial, after which preferential exploration of the displaced versus the stationary object was analyzed on the test trial. In the fear-motivated behavior (FMB) procedure, the same subjects were submitted to an initial baseline trial, followed by an exposure period to a snake model and lastly a post-exposure trial. All trials and inter-trial intervals lasted 10 min for both tests. Results showed that on the SOL test trial, the saline group explored the displaced object significantly longer than its identical stationary counterpart, whereas SCP-treated marmosets explored both objects equivalently. In the FMB test, the saline group – but not the SCP-treated animals – spent significantly less time where the stimulus had been specifically encountered and more time being vigilant of their surroundings, compared to pre-exposure levels. Drug-related effects on general activity, overall exploration (SOL task) and behavioral response to the aversive stimulus (FMB task) were not observed. SCP thus impaired the marmosets’ short-term ability to detect changes associated with the spatial location of ethologically irrelevant (SOL task) and relevant stimuli (FMB task). Similar results have been reported in other animal species. Marmosets may thus help reduce the translational gap between pre-clinical studies and memory-associated human pathologies

Cannabidiol affects MK-801-induced changes in the PPI Learned Response of Capuchin Monkeys (Sapajus spp.)

There are several lines of evidence indicating a possible therapeutic action of cannabidiol (CBD) in schizophrenia treatment. Studies with rodents have demonstrated that CBD reverses MK-801 effects in prepulse inhibition (PPI) disruption, which may indicate that CBD acts by improving sensorimotor gating deficits. In the present study, we investigated the effects of CBD on a PPI learned response of capuchin monkeys (Sapajus spp.). A total of seven monkeys were employed in this study. In Experiment 1, we evaluated the CBD (doses of 15, 30, 60 mg/kg, i.p.) effects on PPI. In Experiment 2, the effects of sub-chronic MK-801 (0.02 mg/kg, i.m.) on PPI were challenged by a CBD pre-treatment. No changes in PPI response were observed after CBD-alone administration. However, MK-801 increased the PPI response of our animals. CBD pre-treatment blocked the PPI increase induced by MK-801. Our findings suggest that CBD’s reversal of the MK-801 effects on PPI is unlikely to stem from a direct involvement on sensorimotor mechanisms, but may possibly reflect its anxiolytic properties

Fast detector/first responder : interactions between the superior colliculus-pulvinar pathway and stimuli relevant to primates

Primates are distinguished from other mammals by their heavy reliance on the visual sense, which occurred as a result of natural selection continually favoring those individuals whose visual systems were more responsive to challenges in the natural world. Here we describe two independent but also interrelated visual systems, one cortical and the other subcortical, both of which have been modified and expanded in primates for different functions. Available evidence suggests that while the cortical visual system mainly functions to give primates the ability to assess and adjust to fluid social and ecological environments, the subcortical visual system appears to function as a rapid detector and first responder when time is of the essence, i.e., when survival requires very quick action. We focus here on the subcortical visual system with a review of behavioral and neurophysiological evidence that demonstrates its sensitivity to particular, often emotionally charged, ecological and social stimuli, i.e., snakes and fearful and aggressive facial expressions in conspecifics. We also review the literature on subcortical involvement during another, less emotional, situation that requires rapid detection and response—visually guided reaching and grasping during locomotion—to further emphasize our argument that the subcortical visual system evolved as a rapid detector/first responder, a function that remains in place today. Finally, we argue that investigating deficits in this subcortical system may provide greater understanding of Parkinson's disease and Autism Spectrum disorders (ASD)

Neuronal response sto face-like and facial stimuli in the monkey superior colliculus

The superficial layers of the superior colliculus (sSC) appear to function as a subcortical visual pathway that bypasses the striate cortex for the rapid processing of coarse facial information. We investigated the responses of neurons in the monkey sSC during a delayed non-matching-to-sample (DNMS) task in which monkeys were required to discriminate among five categories of visual stimuli [photos of faces with different gaze directions, line drawings of faces, face-like patterns (three dark blobs on a bright oval), eye-like patterns, and simple geometric patterns]. Of the 605 sSC neurons recorded, 216 neurons responded to the visual stimuli. Among the stimuli, face-like patterns elicited responses with the shortest latencies. Low-pass filtering of the images did not influence the responses. However, scrambling of the images increased the responses in the late phase, and this was consistent with a feedback influence from upstream areas. A multidimensional scaling (MDS) analysis of the population data indicated that the sSC neurons could separately encode face-like patterns during the first 25-ms period after stimulus onset, and stimulus categorization developed in the next three 25-ms periods. The amount of stimulus information conveyed by the sSC neurons and the number of stimulus-differentiating neurons were consistently higher during the 2nd to 4th 25-ms periods than during the first 25-ms period. These results suggested that population activity of the sSC neurons preferentially filtered face-like patterns with short latencies to allow for the rapid processing of coarse facial information and developed categorization of the stimuli in later phases through feedback from upstream areas

Morphometric and statistical analysis of the palmaris longus muscle in human and non-human primates

The palmaris longus is considered a phylogenetic degenerate metacarpophalangeal joint flexor muscle in humans, a small vestigial forearm muscle; it is the most variable muscle in humans, showing variation in position, duplication, slips and could be reverted. It is frequently studied in papers about human anatomical variations in cadavers and in vivo, its variation has importance in medical clinic, surgery, radiological analysis, in studies about high-performance athletes, in genetics and anthropologic studies.Most studies about palmaris longus in humans are associated to frequency or case studies, but comparative anatomy in primates and comparative morphometry were not found in scientific literature. Comparative anatomy associated to morphometry of palmaris longus could explain the degeneration observed in this muscle in two of three of the great apes. Hypothetically, the comparison of the relative length of tendons and belly could indicate the pathway of the degeneration of this muscle, that is, the degeneration could be associated to increased tendon length and decreased belly from more primitive primates to those most derivate, that is, great apes to modern humans. In conclusion, in primates, the tendon of the palmaris longus increase fromLemuriformes tomodern humans, that is, from arboreal to terrestrial primates and the muscle became weaker and tending to be missing

Population coding of facial information in the monkey superior colliculus and pulvinar

The superior colliculus (SC) and pulvinar are thought to function as a subcortical visual pathway that bypasses the striate cortex and detects fundamental facial information. We previously investigated neuronal responses in the SC and pulvinar of monkeys during a delayed nonmatching-to-sample task, in which the monkeys were required to discriminate among 35 facial photos of five models and other categories of visual stimuli, and reported that population coding by multiple SC and pulvinar neurons well discriminated facial photos from other categories of stimuli (Nguyen et al., 2013, 2014). However, it remains unknown whether population coding could represent multiple types of facial information including facial identity, gender, facial orientation, and gaze direction. In the present study, to investigate population coding of multiple types of facial information by the SC and pulvinar neurons, we reanalyzed the same neuronal responses in the SC and pulvinar; the responses of 112 neurons in the SC and 68 neurons in the pulvinar in serial 50-ms epochs after stimulus onset were reanalyzed with multidimensional scaling (MDS). The results indicated that population coding by neurons in both the SC and pulvinar classified some aspects of facial information, such as face orientation, gender, and identity, of the facial photos in the second epoch (50–100 ms after stimulus onset). The Euclidean distances between all the pairs of stimuli in the MDS spaces in the SC were significantly correlated with those in the pulvinar, which suggested that the SC and pulvinar function as a unit. However, in contrast with the known population coding of face neurons in the temporal cortex, the facial information coding in the SC and pulvinar was coarse and insufficient. In these subcortical areas, identity discrimination was face orientation-dependent and the left and right profiles were not discriminated. Furthermore, gaze direction information was not extracted in the SC and pulvinar. These results suggest that the SC and pulvinar, which comprise the subcortical visual pathway, send coarse and rapid information on faces to the cortical system in a bottom-up process

Snakes elicit earlier, and monkey faces, later, gamma oscillations in macaque pulvinar neurons

Gamma oscillations (30–80 Hz) have been suggested to be involved in feedforward visual information processing, and might play an important role in detecting snakes as predators of primates. In the present study, we analyzed gamma oscillations of pulvinar neurons in the monkeys during a delayed non-matching to sample task, in which monkeys were required to discriminate 4 categories of visual stimuli (snakes, monkey faces, monkey hands and simple geometrical patterns). Gamma oscillations of pulvinar neuronal activity were analyzed in three phases around the stimulus onset (Pre-stimulus: 500 ms before stimulus onset; Early: 0–200 ms after stimulus onset; and Late: 300–500 ms after stimulus onset). The results showed significant increases in mean strength of gamma oscillations in the Early phase for snakes and the Late phase for monkey faces, but no significant differences in ratios and frequencies of gamma oscillations among the 3 phases. The different periods of stronger gamma oscillations provide neurophysiological evidence that is consistent with other studies indicating that primates can detect snakes very rapidly and also cue in to faces for information. Our results are suggestive of different roles of gamma oscillations in the pulvinar: feedforward processing for images of snakes and cortico-pulvinar-cortical integration for images of faces