Biology subjects

Toren, I.

Publications and source records attributed to Toren, I..

2 recordsLinked to original sources

bioRxiv2020

Behavioral elements and neural circuits underlying exploratory decisions in normative anxiety

Exploration reduces uncertainty about the environment and improves the quality of future decisions, but at the cost of provisional uncertain and suboptimal outcomes. Although anxiety promotes intolerance to uncertainty, it remains unclear whether and by which mechanisms anxiety modulates exploratory decision-making. We use a dynamic three-armed-bandit task and find that higher trait-anxiety increases exploration, which in turn harms overall performance. We identify two distinct behavioral sources: first, decisions made by anxious individuals were guided towards reduction of uncertainty; and second, decisions were less guided by immediate value gains. Imaging (fMRI) revealed that anxiety correlated negatively with the representation of expected-value in the dorsal-anterior-cingulate-cortex, and in contrast, positively with the representation of uncertainty in the anterior-insula. Moreover, the findings were similar in both loss and gain domains, and demonstrated that affective trait modulates exploration and results in an inverse-U-shaped relationship between anxiety and overall performance. We conclude that a shift in balance towards representation of uncertainty in the insula prevails over reduced value representation in the dACC, and entails maladaptive decision-making in individuals with higher normal-range anxiety.

neuroscience↗

bioRxiv2019

Right on time: prediction-errors bidirectionally bias time perception

The brain updates internal representation of the environment by using the mismatch between the predicted state/outcome and the actual one, termed prediction-error. In parallel, time perception in the sub-second range is crucial for many behaviors such as movement, learning, memory, attention and speech. Both time-perception and prediction-errors are essential for everyday life function of an organism, and interestingly, the striatum was shown to be independently involved in both functions. We therefore hypothesized that the putative shared circuitry might induce behavioral interaction, namely that prediction-errors might bias time perception. To examine this, participants performed a time-duration discrimination task in the presence of positive and negative prediction-errors that were irrelevant and independent of the main task. We find that positive/negative prediction-errors induce a bias in time perception by increasing/decreasing the perceived time, respectively. Using functional imaging, we identify an interaction in Putamen activity between encoding of prediction-error and performance in the discrimination task. A model that accounts for the behavioral and physiological observations confirms that the interaction in regional activations for prediction-errors and time-estimation underlies the observed bias. Our results demonstrate that these two presumably independent roles of the striatum can actually interfere or aid one another in specific scenarios.

neuroscience↗