Biology subjects

Saunders, B.

Publications and source records attributed to Saunders, B..

3 recordsLinked to original sources

bioRxiv2017

Instantiation of incentive value and movement invigoration by distinct midbrain dopamine circuits

Environmental cues, through Pavlovian learning, become conditioned stimuli that guide animals towards the acquisition of \"rewards\" (i.e., food) that are necessary for survival. Here, we test the fundamental role of midbrain dopamine neurons in conferring predictive or motivational properties to cues, independent of external rewards. We demonstrate that phasic optogenetic excitation of dopamine neurons throughout the midbrain, when presented in temporal association with discrete sensory cues, is sufficient to instantiate those cues as conditioned stimuli that subsequently both evoke dopamine neuron activity on their own, and elicit cue-locked conditioned behaviors. Critically, we identify highly parcellated behavioral functions for dopamine neuron subpopulations projecting to discrete regions of striatum, revealing dissociable mesostriatal systems for the generation of incentive value and movement invigoration. These results show that dopamine neurons orchestrate Pavlovian conditioning via functionally heterogeneous, circuit-specific motivational signals to shape cue-controlled behavior.

neuroscience↗

bioRxiv2017

The conflict negativity: Neural correlate of value conflict and indecision during financial decision making

Individuals struggle when making financial decisions, sometimes preferring to avoid difficult decisions and receive lower future rewards over actively deliberating between options of similar value. Here, we examine how conflict deriving from objective and subjective value characteristics of stocks, as well as the behavioural and phenomenological correlates of decision conflict, are accompanied by variation in a thus far understudied ERP component, the conflict negativity (CN). In a novel EEG paradigm (N = 53), we simulated a financial decision situation in which participants made incentivized choices between different, sometimes conflicting, stock options. Our results indicate that participants become slower, more undecided, and less pleased, when choosing between similar options compared to choices in which one option clearly outweighs the other. This effect even held when participants chose between two objectively good alternatives. We further provide preliminary evidence that the CN, a negative-going ERP recorded over the medial prefrontal cortex, is not only sensitive to decision conflict, but also predicts behavioural indecision. What is more, subjective value characteristics of stocks, impressions based on brand perception of the stock options, modestly influenced affective and behavioural reactions over and above objective stock characteristics. While our results are at odds with assumptions made by classic economic theory, they may serve as one out of several indicators as to why private investors seem to avoid financial decisions.

neuroscience↗

bioRxiv2017

Midfrontal theta and pupil dilation parametrically track subjective conflict (but also surprise) during intertemporal choice

Many everyday choices are based on personal, subjective preferences. When choosing between two options, we often feel conflicted, especially when trading off costs and benefits occurring at different times (e.g., saving for later versus spending now). Although previous work has investigated the neurophysiological basis of conflict during inhibitory control tasks, less is known about subjective conflict resulting from competing subjective preferences. In this pre-registered study, we investigated subjective conflict during intertemporal choice, whereby participants chose between smaller immediate versus larger delayed rewards (e.g., $15 today vs. $22 in 30 days). We used economic modeling to parametrically vary eleven different levels of conflict, and recorded EEG data and pupil dilation. Midfrontal theta power, derived from EEG, correlated with pupil responses, and our results suggest that these signals track different gradations of subjective conflict. Unexpectedly, both signals were also maximally enhanced when decisions were surprisingly easy. Therefore, these signals may track events requiring increased attention and adaptive shifts in behavioral responses, with subjective conflict being only one type of such event. Our results suggest that the neural systems underlying midfrontal theta and pupil responses interact when weighing costs and benefits during intertemporal choice. Thus, understanding these interactions might elucidate how individuals resolve self-control conflicts.\n\nHighlightsO_LIModeled conflict during intertemporal choice and measured EEG and pupil responses.\nC_LIO_LIMidfrontal theta and pupil responses parametrically tracked subjective conflict.\nC_LIO_LIBut theta and pupil responses were also large when decisions were surprisingly easy.\nC_LIO_LIThese signals may implement adaptive control during value-guided choice.\nC_LI

neuroscience↗