scholarly journals Activation of serotonin neurons promotes active exploitation in a probabilistic foraging task

2017 ◽  
Author(s):  
Eran Lottem ◽  
Dhruba Banerjee ◽  
Pietro Vertechi ◽  
Dario Sarra ◽  
Matthijs oude Lohuis ◽  
...  
Keyword(s):  
Behavioral Inhibition ◽  
Impulse Control ◽  
Adequate Description ◽  
Order Function ◽  
Nose Poke ◽  
Serotonin Neurons ◽  
Foraging Site ◽  
Foraging Task ◽  
The Impact ◽  
Motivational Bias

AbstractThe neuromodulator serotonin (5-HT) has been implicated in a variety of functions that involve patience or impulse control. For example, activation of 5-HT neurons promotes waiting for delayed rewards. Many of these effects are consistent with a long-standing theory that 5-HT promotes behavioral inhibition, a motivational bias favoring passive over active behaviors. To further test this idea, we studied the impact of 5-HT in a probabilistic foraging task, in which mice must learn the statistics of the environment and infer when to leave a depleted foraging site for the next. Critically, mice were required to actively nose poke in order to exploit a given site. We found that optogenetic activation of 5-HT neurons in the dorsal raphe nucleus increased the willingness of mice to actively attempt to exploit a reward site before giving up. These results indicate that behavioral inhibition is not an adequate description of 5-HT function and suggest that a unified account must be based on a higher-order function.

scholarly journals The Long and the Short of Serotonergic Stimulation: Optogenetic activation of dorsal raphe serotonergic neurons changes the learning rate for rewards

2017 ◽  
Author(s):  
Kiyohito Iigaya ◽  
Madalena S. Fonseca ◽  
Masayoshi Murakami ◽  
Zachary F. Mainen ◽  
Peter Dayan
Keyword(s):  
Dorsal Raphe ◽  
Optogenetic Stimulation ◽  
Learning Rates ◽  
Serotonin Neurons ◽  
History Of ◽  
Learning And Cognition ◽  
Foraging Task ◽  
The Impact ◽  
Dorsal Raphé ◽  
Stimulation Of

AbstractSerotonin plays an influential, but computationally obscure, modulatory role in many aspects of normal and dysfunctional learning and cognition. Here, we studied the impact of optogenetic stimulation of dorsal raphe serotonin neurons in mice performing a non-stationary, reward-driven, foraging task. We report that activation of serotonin neurons significantly boosted learning rates for choices following long inter-trial-intervals that were driven by the recent history of reinforcement.

scholarly journals Transient inhibition and long-term facilitation of locomotion by phasic optogenetic activation of serotonin neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Patrícia A Correia ◽  
Eran Lottem ◽  
Dhruba Banerjee ◽  
Ana S Machado ◽  
Megan R Carey ◽  
...  
Keyword(s):  
Motor Behavior ◽  
Motor Impairment ◽  
Long Term Effects ◽  
Strong Suppression ◽  
Serotonin Neurons ◽  
Short And Long Term ◽  
Rapid Kinetics ◽  
Long Term Facilitation ◽  
The Impact

Serotonin (5-HT) is associated with mood and motivation but the function of endogenous 5-HT remains controversial. Here, we studied the impact of phasic optogenetic activation of 5-HT neurons in mice over time scales from seconds to weeks. We found that activating dorsal raphe nucleus (DRN) 5-HT neurons induced a strong suppression of spontaneous locomotor behavior in the open field with rapid kinetics (onset ≤1 s). Inhibition of locomotion was independent of measures of anxiety or motor impairment and could be overcome by strong motivational drive. Repetitive place-contingent pairing of activation caused neither place preference nor aversion. However, repeated 15 min daily stimulation caused a persistent increase in spontaneous locomotion to emerge over three weeks. These results show that 5-HT transients have strong and opposing short and long-term effects on motor behavior that appear to arise from effects on the underlying factors that motivate actions.

On the Extent of Dominance of Asymptotic Elastodynamic Crack-Tip Fields: Part II—Numerical Investigation of Three-Dimensional and Transient Effects

1991 ◽  
Vol 58 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Sridhav Krishnaswamy ◽  
Ares J. Rosakis ◽  
G. Ravichandran
Keyword(s):  
Three Dimensional ◽  
Crack Tip ◽  
Experimental Results ◽  
Mode I ◽  
Transient Effects ◽  
Adequate Description ◽  
Crack Tip Field ◽  
Drop Weight ◽  
The Impact ◽  
Laboratory Specimen

In Part I of this paper, the question of the extent of dominance of the mode I asymptotic elastodynamic crack-tip field (the KdI-field) was studied experimentally. Here, the results of two and three-dimensional elastodynamic finite element simulations of the drop-weight experiments are reported. The load records as obtained from the impact hammer and supports of the drop-weight loading device were used as boundary tractions in the numerical simulations. For the laboratory specimen studied, the results of the simulations indicate that the asymptotic elastodynamic field is not an adequate description of the actual fields prevailing over any sizeable region around the crack tip. This confirms the experimental results of Part I which showed that three-dimensional and transient effects necessarily have to be taken into account for valid interpretation of experimental results.

The Discontinuity of Offending Among African American Youth in the Juvenile Justice System

2014 ◽  
Vol 49 (5) ◽  
pp. 610-633 ◽  
Author(s):  
Abigail B. Williams ◽  
Joseph P. Ryan ◽  
Pamela E. Davis-Kean ◽  
Vonnie C. McLoyd ◽  
John E. Schulenberg
Keyword(s):  
African American ◽  
Juvenile Justice ◽  
Protective Factors ◽  
Impulse Control ◽  
Justice System ◽  
Juvenile Justice System ◽  
Developmental Change ◽  
African American Youth ◽  
Parental Supervision ◽  
The Impact

Little is known about what factors contribute to African American youth desisting from offending. Participants were 3,230 moderate- to high-risk adolescents from Washington State who completed a statewide risk assessment to assess the likelihood of recidivism. Participants were screened by juvenile probation officers between 2003 and 2010. Researchers investigated whether youth possessed protective factors and whether developmental change took place after contact with the juvenile justice system. It was hypothesized that having protective factors would decrease the likelihood of recidivism and the impact of each factor would differ by gender. Findings indicate African American youth have protective factors across a range of domains. However, little developmental change occurs after contact with the juvenile justice system. Impulse control, parental supervision, and pro-social peers were important for reducing recidivism. Problem solving was more influential for African American males, while impulse control and parental supervision were more influential for African American females. Implications for practice and policy are discussed.

scholarly journals Temporal cascade of frontal, motor and muscle processes underlying human action-stopping

2019 ◽  
Author(s):  
Sumitash Jana ◽  
Ricci Hannah ◽  
Vignesh Muralidharan ◽  
Adam R. Aron
Keyword(s):  
Basal Ganglia ◽  
Impulse Control ◽  
Motor System ◽  
Inferior Frontal Gyrus ◽  
Human Action ◽  
High Temporal Resolution ◽  
Single Trial ◽  
Top Down ◽  
Detailed Model ◽  
The Impact

AbstractAction-stopping is a canonical executive function thought to involve top-down control over the motor system. Here we aimed to validate this stopping system using high temporal resolution methods in humans. We show that, following the requirement to stop, there was an increase of right frontal beta (∼13 to 30 Hz) at ∼120 ms, likely a proxy of right inferior frontal gyrus; then, at 140 ms, there was a broad skeletomotor suppression, likely reflecting the impact of the subthalamic nucleus on basal ganglia output; then, at ∼160 ms, suppression was detected in the muscle, and, finally, the behavioral time of stopping was ∼220 ms. This temporal cascade confirms a detailed model of action-stopping, and partitions it into subprocesses that are isolable to different nodes and are more precise than the behavioral speed of stopping. Variation in these subprocesses, including at the single-trial level, could better explain individual differences in impulse control.

scholarly journals The effect of comorbid anxiety in youth with ADHD: an ERP analysis of attentional control and impulse control

2021 ◽  
Author(s):  
Deanna F. Klymkiw
Keyword(s):  
Impulse Control ◽  
Event Related Potentials ◽  
Self Report ◽  
Attention Task ◽  
Future Directions ◽  
Attentional Processing ◽  
Comorbid Anxiety ◽  
Related Potentials ◽  
The Impact ◽  
Youth With Adhd

Differences in attentional and impulse control may underlie the increased impairment associated with youth with ADHD and comorbid anxiety (ADHD+ANX) compared to youth with ADHD without anxiety; however, findings from studies using behavioural and self-report measures have been mixed. This study addressed this issue by exploring the impact of the addition of anxiety on attentional and impulse control at a neural level, using event-related potentials (ERPs). Youth aged 11 to 17 with ADHD without anxiety (n = 34) and ADHD+ANX (n = 33) completed a Go/No-Go and Selective Auditory Attention task. Results indicated that the addition of anxiety in youth with ADHD was associated with enhanced early attentional processing, as well as stronger activation of impulse control, as exhibited by greater EFP and N2 amplitudes, respectively. Future directions and clinical implications of these results are discussed.

scholarly journals Feeding behaviour, risk-sensitivity and response control: effects of 5-HT2Creceptor manipulations

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180144 ◽  
Author(s):  
Trevor Humby ◽  
Yateen Patel ◽  
Jenny Carter ◽  
Laura-Jean G. Stokes ◽  
Robert D. Rogers ◽  
...  
Keyword(s):  
Risk Taking ◽  
Impulse Control ◽  
Delay Condition ◽  
Risk Sensitivity ◽  
Variable Delay ◽  
Theme Issue ◽  
The Past ◽  
Theoretical Perspectives ◽  
Developed World ◽  
The Impact

People, like animals, tend to choose the variable option when given the choice between a fixed and variable delay to reward where, in the variable delay condition, some rewards are available immediately (Laura-Jeanet al. 2019Phil. Trans. R. Soc. B374, 20180141. (doi:10.1098/rstb.2018.0141)). This bias has been suggested to reflect evolutionary pressures resulting from food scarcity in the past placing a premium on obtaining food quickly that can win out against the risks of sometimes sustaining longer delays to food. The psychologies mediating this effect may become maladaptive in the developed world where food is readily available contributing, potentially, to overeating and obesity. Here, we report our development of a novel touchscreen task in mice allowing comparisons of the impact of food delay and food magnitude across species. We show that mice exhibit the typical preference, as shown by humans, for variable over fixed delays to rewards but no preference when it comes to fixed versus variable reward amounts and further show that this bias is sensitive to manipulations of the 5-HT2Creceptor, a key mediator of feeding and impulse control. We discuss the data in terms of the utility of the task to model the psychologies and underlying brain mechanisms impacting on feeding behaviours.This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

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