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Monosov, I. E.

Publications and source records attributed to Monosov, I. E..

11 recordsLinked to original sources

A prefrontal cortex-hypothalamus circuit for heart rate control in non-human primates

Humans exhibit changes in heart rate during cognitive and emotional events, and dysregulation of this brain-heart coupling is a hallmark of many psychiatric disorders. Yet, how circuits that regulate cognition exert direct control over heart physiology remains poorly understood, particularly in primates. Here, we identify a prefrontal-hypothalamic circuit that exerts powerful, bidirectional control over heart rate in monkeys. We show that electrical stimulation of a small ventral subregion within the ventrolateral prefrontal cortex (area 47/12; a12) evokes rapid and robust decreases in heart rate and increases heart rate variability, whereas neighboring prefrontal regions produce weaker or no effects. And a12 neurons are coupled to heart rate on a moment-by-moment basis. Anatomical tracing data reveal projections from a12 to a circumscribed region of lateral hypothalamus (LHA), and stimulation of this LHA target recapitulates the cardiac effects of prefrontal activation. Consistent with a prefrontal-to-hypothalamus system for heart rate control, stimulation of LHA produces faster, stronger, state-independent heart effects, whereas stimulation of a12 produces effects that are sensitive to internal states. Oppositely to its activation, chemogenetic inactivation of a12 or its projections to LHA increases heart rate, demonstrating that this pathway can provide tonic inhibitory control over cardiac function. To make steps towards a more cell-type-specific and minimally invasive causal control of this circuit, we developed a primate sonogenetic approach based on ultrasound activation of CaMKII+ neurons virally transduced with TRPV1. Sonogenetic stimulation of a12 produced increases in heart rate variability, and these effects were attenuated by inactivation of LHA. Finally, we found that sonogenetic and chemogenetic perturbation of the same prefrontal region during a value-based decision-making task bidirectionally alters risky decision making. Together, our work identifies how a12 regulates heart rate and cognition, revealing a mechanistic substrate for brain-body interactions and a potential therapeutic target for disorders of cognitive-autonomic dysregulation.

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A dimensional link between gain-loss economic preferences and psychopathology

Human decision-makers differ in how they value and trade off reward, risk, and information when evaluating future gains and losses, and these preferences are central to well-being. However, how multi-attribute economic valuation relates to psychopathology remains unclear. Here, 1,954 individuals completed a transdiagnostic symptom battery and a multi-attribute decision-making task that independently manipulated expected reward, reward uncertainty, and non-instrumental information under matched gain and loss contexts. On average, when choosing among gains, participants preferred larger rewards, avoided risk, and sought advance information. When choosing among losses, they still preferred better outcomes and advance information, but less strongly. Their risk preference, by contrast, reversed, from risk-averse to risk-seeking. Substantial individual variability accompanied these population-level context effects, and different patterns of variability were associated with separate dimensions of psychopathology. Anxious-depressive and social withdrawal symptoms were associated with increased reward sensitivity across contexts, whereas compulsive-intrusive symptoms were associated with reduced reward sensitivity. Symptom-related differences in risk and information preferences were not fully explained by a uniform scaling of overall economic sensitivity, revealing additional attribute- and context-specific variation. A data-driven analysis summarized these symptom-preference associations in a single latent dimension that contrasted compulsive-intrusive symptoms with anxious-depressive and social withdrawal symptoms. An independently identified subgroup that strongly sought information about gains but avoided it about losses mirrored this profile and was enriched for compulsive-intrusive symptoms. These findings reveal structured, low-dimensional variation linking multi-attribute decision-making to psychopathology and could support a dimensional, task-based approach to psychiatric nosology.

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Why do we seek information about the future? On the origins of subjective value without instrumental value

Why do we want to know the future? Humans and many animals pay for information to predict uncertain rewards, even when they cannot control them. The reason for this conserved yet seemingly paradoxical preference - "subjective value without instrumental value" - remains unknown. Here we develop a normative framework to explain the origins of such preferences, their persistence across species, and their contributions to survival. We formalize and evaluate theories that explain subjective value as originating from an adaptive estimate of advantage for solving core computational problems in naturalistic environments. We show that human and animal subjective values are remarkably well suited to solve these problems, accomplishing the goals of multiple theories simultaneously. We derive novel forms of information to enable existing theories to be dissociated, and show that pooling their subjective values improves performance across diverse environments. Thus, organisms may value information because it pays diverse dividends in nature.

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Ventral striatal astrocytes contribute to reinforcement learning

Astrocytes influence synaptic plasticity and neuronal function through astrocytic calcium dynamics (ACD). However, astrocytes contribution to cognitive operations like reinforcement learning (RL) remains unclear. To examine this, we trained mice on a RL dependent probabilistic decision-making task. We attenuated ACD across distinct striatal regions, and found ACD attenuation specifically in ventral striatum (VS) increased decision noisiness and impaired reward-guided choice performance. This effect was largely due to a reduction in "win-stay" behavior. Using in-vivo calcium imaging, we found that VS ACD correlated with reward prediction errors (RPEs). Furthermore, these trial-by-trial ACD fluctuations predicted trial-by-trial choice variability. In-silico lesions of a biologically constrained circuit model suggest that astrocytes could regulate behavioral variability by sharing RPE signals across populations of striatal neurons. Together, these results suggest that VS astrocytes contribute to cortico-striatal functions to mediate decision noisiness.

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Temporal-orbitofrontal pathway regulates choices across physical reward and visual novelty

Perceptually novel objects have profound impacts on our daily decisions. People often pay to try novel meals over familiar ones, or to see novel visual scenes at art exhibits and travel destinations. This suggests that perceptual novelty and the value of physical rewards, such as food, interact at the level of neural circuits to guide decisions, but where and how is unknown. We designed a behavioral task to study this novelty-reward interaction in animals and to uncover its neural underpinnings. Subjects chose among familiar offers associated with different expectations of novel objects and different expectations of juice rewards. Expectation of novel objects increased the preference for expected rewards. This novelty-reward interaction was reflected by neural activity in the anterior ventral temporal cortex (AVMTC) - a region previously implicated in the detection and prediction of novelty - and in the orbitofrontal cortex (OFC) - an area that receives prominent AVMTC inputs and is known for its capacity to signal subjective value of visual objects. Neural activity patterns suggested that AVMTC was upstream of OFC in the decision process. Chemogenetic disruption of the AVMTC[->]OFC circuit altered the impact of expected novelty on the valuation of physical reward. Hence, the ventral visual system impacts novelty-reward interactions during decisions through direct projections to OFC.

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Dorsal raphe neurons signal integrated value during multi-attribute decision-making

The dorsal raphe nucleus (DRN) is implicated in psychiatric disorders that feature impaired sensitivity to reward amount, impulsivity when facing reward delays, and risk-seeking when grappling with reward uncertainty. However, whether and how DRN neurons signal reward amount, reward delay, and reward uncertainty during multi-attribute value-based decision-making, where subjects consider all these attributes to make a choice, is unclear. We recorded DRN neurons as monkeys chose between offers whose attributes, namely expected reward amount, reward delay, and reward uncertainty, varied independently. Many DRN neurons signaled offer attributes. Remarkably, these neurons commonly integrated offer attributes in a manner that reflected monkeys overall preferences for amount, delay, and uncertainty. After decision-making, in response to post-decision feedback, these same neurons signaled signed reward prediction errors, suggesting a broader role in tracking value across task epochs and behavioral contexts. Our data illustrate how DRN participates in integrated value computations, guiding theories of DRN in decision-making and psychiatric disease.

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A neural mechanism for conserved value computations integrating information and rewards

Behavioral and economic theory dictates that we decide between options based on their values. However, humans and animals eagerly seek information about uncertain future rewards, even when this information does not provide any objective value. This implies that decisions can be made by endowing information with subjective value and integrating it with the value of extrinsic rewards, but the mechanism is unknown. Using a novel multi-attribute decision making task we found that human and monkey value judgements are regulated by strikingly conserved computational principles, including how they compute the value of information and scale it with informations timing and ability to resolve a specific form of uncertainty. We then identified a neural substrate in a highly conserved and ancient structure, the lateral habenula (LHb). LHb neurons signal the subjective value of choice options integrating the value of information with extrinsic rewards, and LHb activity both predicts and causally influences online decisions. Key input regions to LHb provide the necessary ingredients for these computations, but do not themselves signal an integrated value signal to guide multi attribute decisions. Our data thus identifies neural mechanisms of the conserved computations underlying multi-attribute, value-based decisions to seek information about the future.

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Neuronal mechanisms of novelty seeking

Humans and other primates interact with the world by observing and exploring visual objects. In particular, they often seek out the opportunities to view novel objects that they have never seen before, even when they have no extrinsic primary reward value. However, despite the importance of novel visual objects in our daily life, we currently lack an understanding of how primate brain circuits control the motivation to seek out novelty. We found that novelty-seeking is regulated by a small understudied subcortical region, the zona incerta (ZI). In a task in which monkeys made eye movements to familiar objects to obtain the opportunity to view novel objects, many ZI neurons were preferentially activated by predictions of future novel objects and displayed burst excitations before gaze shifts to gain access to novel objects. Low intensity electrical stimulation of ZI facilitated gaze shifts, while inactivations of ZI reduced novelty-seeking. Surprisingly, additional experiments showed that this ZI-dependent novelty seeking behavior is not regulated by canonical neural circuitry for reward seeking. The habenula-dopamine pathway, known to reflect reward predictions that control reward seeking, was relatively inactive during novelty-seeking behavior in which novelty had no extrinsic reward value. Instead, high channel-count electrophysiological experiments and anatomical tracing identified a prominent source of control signals for novelty seeking in the anterior ventral medial temporal cortex (AVMTC), a brain region known to be crucially involved in visual processing and object memory. In addition to their well-known function in signaling the novelty or familiarity of objects in the current environment, AVMTC neurons reflected the predictions of future novel objects, akin to the way neurons in reward-circuitry predict future rewards in order to control reward-seeking. Our data uncover a network of primate brain areas that regulate novelty-seeking. The behavioral and neural distinctions between novelty-seeking and reward-processing highlight how the brain can accomplish behavioral flexibility, providing a mechanism to explore novel objects.

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A neural network for information seeking

Humans and other animals often show a strong desire to know the uncertain rewards their future has in store, even when they cannot use this information to influence the outcome. However, it is unknown how the brain predicts opportunities to gain information and motivates this information seeking behavior. Here we show that neurons in a network of interconnected subregions of primate anterior cingulate cortex and basal ganglia predict the moment of gaining information about uncertain rewards. Spontaneous increases in their information prediction signals are followed by gaze shifts toward objects associated with resolving uncertainty, and pharmacologically disrupting this network reduces the motivation to seek information. These findings demonstrate a cortico-basal ganglia mechanism responsible for motivating actions to resolve uncertainty by seeking knowledge about the future.

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Novelty and surprise-timing are broadcast by the basal forebrain

The basal forebrain (BF) is a principal source of modulation of the neocortex, and is thought to regulate cognitive functions such as attention, motivation, and learning by broadcasting information about the behavioral salience of events. An event can be salient because it is novel, surprising, or associated with reward prediction errors. But to date, the type of salience-related information the BF broadcasts is unclear. Here, we report that many BF neurons display phasic excitatory bursting that rapidly conveys the magnitude, probability, and timing of primary reinforcements. The same BF neurons also discriminate fully expected novel visual objects from familiar objects and respond to object-sequence violations, regardless of their relevance for subsequent behaviors, suggesting that they are not dedicated to signaling information about primary reinforcements. A different group of BF neurons displayed ramping activations that predicted the time of novel and surprising events. Their ramping was highly sensitive to the subjects confidence in event timing. Hence, BF neurons signal statistics about time and salience. Their activity may organize cortical computations to facilitate accurate behavioral responses to a diverse set of expected and ongoing events.

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Anterior cingulate is a source of valence-specificinformation about value and uncertainty

Expectations of rewards and punishments can promote similar behavioral states, such as vigilance, as well as distinct behavioral states, such as approach or avoidance. However, the cortical circuits that underlie this behavioral diversity are poorly understood. In a Pavlovian procedure in which monkeys displayed a diverse repertoire of reward, punishment, and uncertainty related behaviors not mandated by the task, I show that many anterior-cingulate (ACC) neurons represent expected value and uncertainty in a valence-specific manner, for example about either rewards or punishments. This flexibility may facilitate the top-down control of many reward- and punishment-related actions and behavioral states.

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