Publications by authors named "Andrew M Brooks"

The overall goal of this work was to measure the efficacy of fMRI for predicting whether a dog would be a successful service dog. The training and imaging were performed in 49 dogs entering service training at 17-21 months of age. 33 dogs completed service training and were matched with a person, while 10 were released for behavioral reasons (4 were selected as breeders and 2 were released for medical reasons.

View Article and Find Full Text PDF

Understanding dogs' perceptual experience of both conspecifics and humans is important to understand how dogs evolved and the nature of their relationships with humans and other dogs. Olfaction is believed to be dogs' most powerful and perhaps important sense and an obvious place to begin for the study of social cognition of conspecifics and humans. We used fMRI in a cohort of dogs (N=12) that had been trained to remain motionless while unsedated and unrestrained in the MRI.

View Article and Find Full Text PDF

There is mounting evidence that the mesolimbic dopamine system carries valuation signals not only for appetitive or gain-related stimuli, with which it is traditionally associated, but also for aversive and loss-related stimuli. Cellular-level studies demonstrate that the neuronal architecture to support aversive stimuli encoding in this system does exist. Both cellular-level and human neuroimaging research suggest the co-existence of appetitive and aversive prediction-error signals within the mesocorticolimbic system.

View Article and Find Full Text PDF

Because of dogs' prolonged evolution with humans, many of the canine cognitive skills are thought to represent a selection of traits that make dogs particularly sensitive to human cues. But how does the dog mind actually work? To develop a methodology to answer this question, we trained two dogs to remain motionless for the duration required to collect quality fMRI images by using positive reinforcement without sedation or physical restraints. The task was designed to determine which brain circuits differentially respond to human hand signals denoting the presence or absence of a food reward.

View Article and Find Full Text PDF

The disposition effect is a phenomenon in which investors hold onto losing assets longer than they hold onto gaining assets. In this study, we used functional magnetic resonance imaging (fMRI) to measure the response of valuation regions in the brain during the decision to keep or to sell an asset that followed a random walk in price. The most common explanation for the disposition effect is preference-based: namely, that people are risk-averse over gains and risk-seeking over losses.

View Article and Find Full Text PDF

The majority of decision-related research has focused on how the brain computes decisions over outcomes that are positive in expectation. However, much less is known about how the brain integrates information when all possible outcomes in a decision are negative. To study decision-making over negative outcomes, we used fMRI along with a task in which participants had to accept or reject 50/50 lotteries that could result in more or fewer electric shocks compared to a reference amount.

View Article and Find Full Text PDF

Clinical information suggests that opioid dependence is a major contributor to poor outcomes involving health status and to increased length of stay in hospital settings. Before spine surgery, 150 patients who were using an opioid medication for pain relief were interviewed using the six World Health Organization (WHO) guidelines for the diagnosis of opioid dependence. Three groups were defined: opioid-dependent, nonopioid-dependent, and a subclinical group.

View Article and Find Full Text PDF