In an uncertain world, adaptive control of voluntary behaviors (such as of our everyday decisions) requires us to estimate our uncertainty about what the future may hold and utilize this information to guide many aspects of our behavior. For example, should you make a risky decision or avoid risk? Is the outcome of that decision trustworthy enough to learn from and adjust future behavior? Should you make decisions that prioritize information-gain to reduce your uncertainty?
Our lab studies the neuronal mechanisms of uncertainty-estimation, risk-seeking, uncertainty reduction (e.g., information-seeking), and reinforcement learning. Thus far, investigations led by members of the Monosov lab resulted in several important findings.
First, we discovered that the primate basal forebrain (BF) contains functionally distinct subregions for processing risky decisions. The ventral pallidum, an area that controls dopaminergic release, located in the dorsal lateral BF, predicts risky vs safe choices. After the choices are made, ventral regions of the BF, that provide cholinergic input to the neocortex, display crucial signals for learning from decision-outcomes: ventral BF neurons anticipate outcome timing and signal the magnitude of outcome-related surprise (Ledbetter et al, Journal of Neuroscience, 2016; Zhang et al., Current Biology, in press). Ventral BF neurons also signal sensory surprises, such as those that arise due to novelty. We are now investigating how the ventral BF mediates surprise- and novelty- related processing in the neocortex to guide attention and learning (Zhang et al., Current Biology, in press). Second, the lab has shown that the graded level of reward uncertainty associated with complex visual objects is encoded in a region of the anterior dorsal striatum (White and Monosov, Nature Communications, 2016). The data indicate that neurons in this area signal uncertainty when it arises either due to a lack of knowledge (ambiguity) or due to statistical uncertainty (economic risk), and that they rapidly adjust their representation of uncertainty as uncertainty is resolved during learning. This signal may arise in the anterior cingulate (ACC), a key excitatory input structure to the uncertainty-sensitive regions of the striatum (Monosov, Nature Communications, 2017). Third, we showed that this ACC-basal ganglia network actively contributes to uncertainty reduction by promoting information seeking behaviors (White* and Bromberg-Martin* et al, in review; * equal contribution).
We are now following up on these discoveries with novel techniques, such as high channel chronic array recording, computational modelling, optogenetics, and pharmacology.
- Monosov IE, Anterior cingulate is a source of valence specific information about value and uncertainty. Nat Commun. 2017 In Press.
- White JK, Monosov IE. Neurons in the primate dorsal striatum signal the uncertainty of object-reward associations. Nat Commun. 2016 Sep 14.
- Ledbetter NM, Chen CD, Monosov IE. Multiple mechanisms for processing reward uncertainty in the primate basal forebrain. J Neurosci. 2016 Jul 27.
- Monosov IE, Hikosaka O. Selective and graded coding of reward uncertainty by neurons in the primate anterodorsal septal region. Nat Neurosci. 2013 Jun;16(6):756-62.
- Cavanaugh J*, Monosov IE*, McAlonan K, Berman R, Smith MK, Cao V, Wang KH, Boyden ES, Wurtz RH (*authors contributed equally). Optogenetic inactivation modifies monkey visuomotor behavior. Neuron. 2012 Dec 6;76(5):901-7.
- Monosov IE, Hikosaka O. Regionally distinct processing of rewards and punishments by the primate ventromedial prefrontal cortex. J Neurosci. 2012 Jul 25;32(30):10318-30.
For a complete list of Dr. Monosov's publications, click here.