Amy L Loriaux | University of Texas Southwestern Medical Center at Dallas (original) (raw)

Papers by Amy L Loriaux

Research paper thumbnail of Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior

Journal of Neurophysiology, 2013

Our behavior is powerfully driven by environmental cues that signal the availability of rewarding... more Our behavior is powerfully driven by environmental cues that signal the availability of rewarding stimuli. We frequently encounter stimuli—a bowl of candy or an alert from our smartphone—that trigger actions to obtain those rewards, even though there may be positive outcomes associated with not acting. The inability to restrain one's action in the presence of reward-associated cues is one type of impulsive behavior and a component of such maladaptive behaviors as overeating, gambling, and substance abuse. The nucleus accumbens (NAc) is ideally situated to integrate multiple cognitive and affective inputs to bias action via outputs through the basal ganglia. NAc neurons have been shown to respond to cues that predict reward availability, goal-directed behaviors aimed at obtaining them, and delivery of the reward itself. As these processes are typically associated, it is difficult to discern whether signals in the NAc are more closely related to processing reward-predictive aspect...

Research paper thumbnail of Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion

Appetite, 2010

Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over wate... more Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over water across a range of sucralose concentrations, sucralose avoiders prefer water over concentrations of sucralose >0.1 g/L. Previously, we demonstrated that this preferer/avoider profile is influenced by individual differences in sensitivity to a bitter taste quality of sucralose. Because sex and strain can influence responsiveness to bitter/bittersweet compounds, our goal was to determine whether sucralose preference is influenced by sex or strain. Further data in humans suggests that increased sensitivity to bitterness is positively correlated with the number of fungiform papillae on the tongue. Thus, our second goal was to determine whether the number of fungiform papillae differ in sucralose preferers/avoiders. Male and female rats were given access to ascending concentrations of sucralose (0.0001-2.0 g/L) and water in two-bottle, 24-h preference tests. Neither the proportion of preferrers/avoiders nor the preference curves differed as a function of sex. The same experiment was conducted in male Long-Evans (LE) and Sprague-Dawley (SD) rats. LE preferrers, were more accepting of sucralose at all concentrations, relative to SD preferrers. No strain differences were detected among LE/SD avoiders. Examination of the tongues of a subset of LE rats revealed that sucralose avoiders had more fungiform papillae than sucralose preferrers (p < 0.05). We conclude that individual differences in the number of fungiform papillae predict sucralose avoidance/preference profiles in rats.

Research paper thumbnail of Differential encoding of cues in nucleus accumbens predicts behavioral inhibition

Research paper thumbnail of Differential neuronal encoding in the nucleus accumbens is associated with behavioral indices of conditioned taste aversion learning

Appetite, 2011

S27 transgenic drosophila can be a valuable model for future pathogenesis and therapeutic studies... more S27 transgenic drosophila can be a valuable model for future pathogenesis and therapeutic studies. Supported by NIH.

Research paper thumbnail of Nucleus accumbens shell, but not core, tracks motivational value of salt

Journal of Neurophysiology, 2011

To appropriately respond to an affective stimulus, we must be able to track its value across chan... more To appropriately respond to an affective stimulus, we must be able to track its value across changes in both the external and internal environment. The nucleus accumbens (NAc) is a critical component of reward circuitry, but recent work suggests that the NAc encodes aversion as well as reward. It remains unknown whether differential NAc activity reflects flexible changes in stimulus value when it is altered due to a change in physiological state. We measured the activity of individual NAc neurons when rats were given intraoral infusions of a hypertonic salt solution (0.45 M NaCl) across multiple sessions in which motivational state was manipulated. This normally nonpreferred taste was made rewarding via sodium depletion, which resulted in a strong motivation to seek out and consume salt. Recordings were made in three conditions: while sodium replete (REP), during acute sodium depletion (DEP), and following replenishment of salt to normal sodium balance (POST). We found that NAc neur...

Research paper thumbnail of Optogenetic stimulation of accumbens shell or shell projections to lateral hypothalamus produce differential effects on the motivation for cocaine

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 25, 2015

Previous studies suggest that pharmacological or molecular activation of the nucleus accumbens sh... more Previous studies suggest that pharmacological or molecular activation of the nucleus accumbens shell (AcbSh) facilitates extinction of cocaine-seeking behavior. However, overexpression of CREB, which increases excitability of AcbSh neurons, enhances cocaine-seeking behavior while producing depression-like behavior in tests of mood. These discrepancies may reflect activity in differential AcbSh outputs, including those to the lateral hypothalamus (LH), a target region known to influence addictive behavior and mood. Presently, it is unknown whether there is a causal link between altered activity in the AcbSh-LH pathway and changes in the motivation for cocaine. In this study, we used an optogenetics approach to either globally stimulate AcbSh neurons or to selectively stimulate AcbSh terminal projections in the LH, in rats self-administering cocaine. We found that stimulation of the AcbSh-LH pathway enhanced the motivation to self-administer cocaine in progressive ratio testing, and l...

Research paper thumbnail of Reduction of Cocaine Self-Administration and D3 Receptor-Mediated Behavior by Two Novel Dopamine D3 Receptor-Selective Partial Agonists, OS-3-106 and WW-III-55

Journal of Pharmacology and Experimental Therapeutics, 2013

Research paper thumbnail of Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior

Journal of Neurophysiology, 2014

Roitman JD, Loriaux AL. Nucleus accumbens responses differentiate execution and restraint in rewa... more Roitman JD, Loriaux AL. Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior. Our behavior is powerfully driven by environmental cues that signal the availability of rewarding stimuli. We frequently encounter stimuli-a bowl of candy or an alert from our smartphone-that trigger actions to obtain those rewards, even though there may be positive outcomes associated with not acting. The inability to restrain one's action in the presence of rewardassociated cues is one type of impulsive behavior and a component of such maladaptive behaviors as overeating, gambling, and substance abuse. The nucleus accumbens (NAc) is ideally situated to integrate multiple cognitive and affective inputs to bias action via outputs through the basal ganglia. NAc neurons have been shown to respond to cues that predict reward availability, goal-directed behaviors aimed at obtaining them, and delivery of the reward itself. As these processes are typically associated, it is difficult to discern whether signals in the NAc are more closely related to processing reward-predictive aspects of goal-directed behavior or selection of behavioral response. To dissociate these possibilities, we recorded the activity of NAc neurons while rats performed a task in which two different cues both informed rats of reward availability but required them to either press a lever (Go) or withhold pressing (NoGo) to obtain the reward. Individual cue-responsive neurons showed either increases or decreases in activity at cue onset. Increases in activity were larger, and decreases smaller, when rats withheld lever pressing, whether correctly for NoGo trials or in error on Go trials. Thus NAc cue responses correlated with action, regardless of cue type or accuracy.

Research paper thumbnail of Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion

Research paper thumbnail of Differential encoding of cues in nucleus accumbens predicts behavioral inhibition

Research paper thumbnail of Nucleus accumbens shell, but not core, tracks motivational value of salt

Journal of Neurophysiology, 2011

Research paper thumbnail of Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior

Journal of Neurophysiology, 2013

Our behavior is powerfully driven by environmental cues that signal the availability of rewarding... more Our behavior is powerfully driven by environmental cues that signal the availability of rewarding stimuli. We frequently encounter stimuli—a bowl of candy or an alert from our smartphone—that trigger actions to obtain those rewards, even though there may be positive outcomes associated with not acting. The inability to restrain one's action in the presence of reward-associated cues is one type of impulsive behavior and a component of such maladaptive behaviors as overeating, gambling, and substance abuse. The nucleus accumbens (NAc) is ideally situated to integrate multiple cognitive and affective inputs to bias action via outputs through the basal ganglia. NAc neurons have been shown to respond to cues that predict reward availability, goal-directed behaviors aimed at obtaining them, and delivery of the reward itself. As these processes are typically associated, it is difficult to discern whether signals in the NAc are more closely related to processing reward-predictive aspect...

Research paper thumbnail of Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion

Appetite, 2010

Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over wate... more Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over water across a range of sucralose concentrations, sucralose avoiders prefer water over concentrations of sucralose >0.1 g/L. Previously, we demonstrated that this preferer/avoider profile is influenced by individual differences in sensitivity to a bitter taste quality of sucralose. Because sex and strain can influence responsiveness to bitter/bittersweet compounds, our goal was to determine whether sucralose preference is influenced by sex or strain. Further data in humans suggests that increased sensitivity to bitterness is positively correlated with the number of fungiform papillae on the tongue. Thus, our second goal was to determine whether the number of fungiform papillae differ in sucralose preferers/avoiders. Male and female rats were given access to ascending concentrations of sucralose (0.0001-2.0 g/L) and water in two-bottle, 24-h preference tests. Neither the proportion of preferrers/avoiders nor the preference curves differed as a function of sex. The same experiment was conducted in male Long-Evans (LE) and Sprague-Dawley (SD) rats. LE preferrers, were more accepting of sucralose at all concentrations, relative to SD preferrers. No strain differences were detected among LE/SD avoiders. Examination of the tongues of a subset of LE rats revealed that sucralose avoiders had more fungiform papillae than sucralose preferrers (p < 0.05). We conclude that individual differences in the number of fungiform papillae predict sucralose avoidance/preference profiles in rats.

Research paper thumbnail of Differential encoding of cues in nucleus accumbens predicts behavioral inhibition

Research paper thumbnail of Differential neuronal encoding in the nucleus accumbens is associated with behavioral indices of conditioned taste aversion learning

Appetite, 2011

S27 transgenic drosophila can be a valuable model for future pathogenesis and therapeutic studies... more S27 transgenic drosophila can be a valuable model for future pathogenesis and therapeutic studies. Supported by NIH.

Research paper thumbnail of Nucleus accumbens shell, but not core, tracks motivational value of salt

Journal of Neurophysiology, 2011

To appropriately respond to an affective stimulus, we must be able to track its value across chan... more To appropriately respond to an affective stimulus, we must be able to track its value across changes in both the external and internal environment. The nucleus accumbens (NAc) is a critical component of reward circuitry, but recent work suggests that the NAc encodes aversion as well as reward. It remains unknown whether differential NAc activity reflects flexible changes in stimulus value when it is altered due to a change in physiological state. We measured the activity of individual NAc neurons when rats were given intraoral infusions of a hypertonic salt solution (0.45 M NaCl) across multiple sessions in which motivational state was manipulated. This normally nonpreferred taste was made rewarding via sodium depletion, which resulted in a strong motivation to seek out and consume salt. Recordings were made in three conditions: while sodium replete (REP), during acute sodium depletion (DEP), and following replenishment of salt to normal sodium balance (POST). We found that NAc neur...

Research paper thumbnail of Optogenetic stimulation of accumbens shell or shell projections to lateral hypothalamus produce differential effects on the motivation for cocaine

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 25, 2015

Previous studies suggest that pharmacological or molecular activation of the nucleus accumbens sh... more Previous studies suggest that pharmacological or molecular activation of the nucleus accumbens shell (AcbSh) facilitates extinction of cocaine-seeking behavior. However, overexpression of CREB, which increases excitability of AcbSh neurons, enhances cocaine-seeking behavior while producing depression-like behavior in tests of mood. These discrepancies may reflect activity in differential AcbSh outputs, including those to the lateral hypothalamus (LH), a target region known to influence addictive behavior and mood. Presently, it is unknown whether there is a causal link between altered activity in the AcbSh-LH pathway and changes in the motivation for cocaine. In this study, we used an optogenetics approach to either globally stimulate AcbSh neurons or to selectively stimulate AcbSh terminal projections in the LH, in rats self-administering cocaine. We found that stimulation of the AcbSh-LH pathway enhanced the motivation to self-administer cocaine in progressive ratio testing, and l...

Research paper thumbnail of Reduction of Cocaine Self-Administration and D3 Receptor-Mediated Behavior by Two Novel Dopamine D3 Receptor-Selective Partial Agonists, OS-3-106 and WW-III-55

Journal of Pharmacology and Experimental Therapeutics, 2013

Research paper thumbnail of Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior

Journal of Neurophysiology, 2014

Roitman JD, Loriaux AL. Nucleus accumbens responses differentiate execution and restraint in rewa... more Roitman JD, Loriaux AL. Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior. Our behavior is powerfully driven by environmental cues that signal the availability of rewarding stimuli. We frequently encounter stimuli-a bowl of candy or an alert from our smartphone-that trigger actions to obtain those rewards, even though there may be positive outcomes associated with not acting. The inability to restrain one's action in the presence of rewardassociated cues is one type of impulsive behavior and a component of such maladaptive behaviors as overeating, gambling, and substance abuse. The nucleus accumbens (NAc) is ideally situated to integrate multiple cognitive and affective inputs to bias action via outputs through the basal ganglia. NAc neurons have been shown to respond to cues that predict reward availability, goal-directed behaviors aimed at obtaining them, and delivery of the reward itself. As these processes are typically associated, it is difficult to discern whether signals in the NAc are more closely related to processing reward-predictive aspects of goal-directed behavior or selection of behavioral response. To dissociate these possibilities, we recorded the activity of NAc neurons while rats performed a task in which two different cues both informed rats of reward availability but required them to either press a lever (Go) or withhold pressing (NoGo) to obtain the reward. Individual cue-responsive neurons showed either increases or decreases in activity at cue onset. Increases in activity were larger, and decreases smaller, when rats withheld lever pressing, whether correctly for NoGo trials or in error on Go trials. Thus NAc cue responses correlated with action, regardless of cue type or accuracy.

Research paper thumbnail of Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion

Research paper thumbnail of Differential encoding of cues in nucleus accumbens predicts behavioral inhibition

Research paper thumbnail of Nucleus accumbens shell, but not core, tracks motivational value of salt

Journal of Neurophysiology, 2011