Biology subjects

Mattos, P.

Publications and source records attributed to Mattos, P..

3 recordsLinked to original sources

bioRxiv2021

Age-linked suppression of lipoxin A4 mediates cognitive deficits in mice and humans

Age increases the risk for cognitive impairment and is the single major risk factor for Alzheimers disease (AD), the most prevalent form of dementia in the elderly. The pathophysiological processes triggered by aging that render the brain vulnerable to dementia involve, at least in part, changes in inflammatory mediators. Here we show that lipoxin A4 (LXA4), a lipid mediator of inflammation resolution known to stimulate endocannabinoid signaling in the brain, is reduced in the aging central nervous system. We demonstrate that genetic suppression of 5-lipoxygenase (5-LOX), the enzyme mediating LXA4 synthesis, promotes learning impairment in mice. Conversely, administration of exogenous LXA4 attenuated cytokine production and memory loss induced by inflammation in mice. We further show that cerebrospinal fluid LXA4 is reduced in patients with dementia and positively associates with memory performance, brain-derived neurotrophic factor (BDNF), and AD-linked amyloid-. Our findings suggest that reduced LXA4 levels may lead to vulnerability to age-related cognitive disorders and that promoting LXA4 signaling may comprise an effective strategy to prevent early cognitive decline in AD.

neuroscience↗

bioRxiv2019

Association between uncontrolled eating and caudate responses to reward cues

Reward sensitivity has been hypothesized to play a significant role in a range of eating behaviors, including overeating. Previous functional magnetic resonance imaging (fMRI) findings in overweight individuals indicate heightened responses to food, but also to other reward types, suggesting generalized overactivity of the reward system. The current fMRI study investigated the relationship between general reward sensitivity and eating behavior in normal-weight individuals, while controlling for trait impulsivity. Participants were young adults, some demonstrating ADHD symptoms, allowing for a range of impulsivity profiles. A classical conditioning task was used to measure striatal responses to monetary reward stimuli. Uncontrolled eating scores from the Three Eating Factor Questionnaire were positively correlated with caudate responses to reward predicting cues. This association was not explained by self-reported impulsivity. The current findings provide support for heightened reward anticipation as a neural phenotype contributing to overeating.

neuroscience↗

bioRxiv2019

Development of Pavlovian-to-instrumental transfer (PIT) task to examine the effects of reward-predicting cues on behavioral activation in young adults

There is a growing recognition that much of human behavior is governed by the presence of classically conditioned cues. The Pavlovian-to-Instrumental Transfer (PIT) paradigm offers a way to measure the effects of classically conditioned stimuli on behavior. In the current study, a novel PIT paradigm was developed for use in conjunction with an fMRI classical conditioning task. This could allow for a measurement of BOLD responses to anticipated rewards, unconfounded by operant responses, while providing a behavioral measure of conditioning effects. Twenty-four healthy young adults completed 1) instrumental training, 2) Pavlovian conditioning, and 3) Transfer test. During instrumental training, participants learned to apply force on a handgrip to win money from slot machines pictured on a computer screen. During Pavlovian conditioning, slot machines appeared with one of two abstract symbols (cues), one symbol was predictive of monetary reward. During the Transfer test, participants again applied force on a handgrip to win more money. This time, slot machines were presented with the Pavlovian cues, but with the outcomes hidden. The results indicated increased effort on the instrumental task, i.e., higher response frequency and greater force, in the presence of a reward-predicting cue. Our findings add to a growing number of studies demonstrating PIT effects in humans. This paradigm was proved to be useful in measuring the effects of a conditioned stimulus on behavioral activation.

neuroscience↗