scholarly journals The Paraventricular Thalamus as a Critical Node of Motivated Behavior via the Hypothalamic-Thalamic-Striatal Circuit

2021 ◽  
Vol 15 ◽  
Author(s):  
Amanda G. Iglesias ◽  
Shelly B. Flagel
Keyword(s):  
Nucleus Accumbens ◽  
Lateral Hypothalamus ◽  
External Environment ◽  
Glutamatergic Neurons ◽  
Efferent Connections ◽  
Motivated Behavior ◽  
Internal States ◽  
Paraventricular Thalamus ◽  
Motivated Behaviors ◽  
Anterior Posterior

In this review, we highlight evidence that supports a role for the paraventricular nucleus of the thalamus (PVT) in motivated behavior. We include a neuroanatomical and neurochemical overview, outlining what is known of the cellular makeup of the region and its most prominent afferent and efferent connections. We discuss how these connections and distinctions across the anterior-posterior axis correspond to the perceived function of the PVT. We then focus on the hypothalamic-thalamic-striatal circuit and the neuroanatomical and functional placement of the PVT within this circuit. In this regard, the PVT is ideally positioned to integrate information regarding internal states and the external environment and translate it into motivated actions. Based on data that has emerged in recent years, including that from our laboratory, we posit that orexinergic (OX) innervation from the lateral hypothalamus (LH) to the PVT encodes the incentive motivational value of reward cues and thereby alters the signaling of the glutamatergic neurons projecting from the PVT to the shell of the nucleus accumbens (NAcSh). The PVT-NAcSh pathway then modulates dopamine activity and resultant cue-motivated behaviors. As we and others apply novel tools and approaches to studying the PVT we will continue to refine the anatomical, cellular, and functional definitions currently ascribed to this nucleus and further elucidate its role in motivated behaviors.

The paraventricular thalamus is a critical thalamic area for wakefulness

Science ◽  
2018 ◽  
Vol 362 (6413) ◽  
pp. 429-434 ◽  
Author(s):  
Shuancheng Ren ◽  
Yaling Wang ◽  
Faguo Yue ◽  
Xiaofang Cheng ◽  
Ruozhi Dang ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Neuronal Activity ◽  
Lateral Hypothalamus ◽  
Neural Circuitry ◽  
Glutamatergic Neurons ◽  
Clinical Observations ◽  
Electrophysiological Recordings ◽  
Paraventricular Thalamus ◽  
Effector Pathways

Clinical observations indicate that the paramedian region of the thalamus is a critical node for controlling wakefulness. However, the specific nucleus and neural circuitry for this function remain unknown. Using in vivo fiber photometry or multichannel electrophysiological recordings in mice, we found that glutamatergic neurons of the paraventricular thalamus (PVT) exhibited high activities during wakefulness. Suppression of PVT neuronal activity caused a reduction in wakefulness, whereas activation of PVT neurons induced a transition from sleep to wakefulness and an acceleration of emergence from general anesthesia. Moreover, our findings indicate that the PVT–nucleus accumbens projections and hypocretin neurons in the lateral hypothalamus to PVT glutamatergic neurons’ projections are the effector pathways for wakefulness control. These results demonstrate that the PVT is a key wakefulness-controlling nucleus in the thalamus.

scholarly journals The tubular striatum and nucleus accumbens distinctly represent reward-taking and seeking

2020 ◽  
Author(s):  
Katherine N. Wright ◽  
Daniel W Wesson
Keyword(s):  
Nucleus Accumbens ◽  
Ventral Striatum ◽  
Neural Representation ◽  
Single Unit Activity ◽  
Self Administration ◽  
Reward Seeking ◽  
Motivated Behavior ◽  
Behavioral Paradigm ◽  
Motivated Behaviors ◽  
Goal Directed Behavior

The ventral striatum regulates motivated behaviors which are essential for survival. The ventral striatum contains both the nucleus accumbens (NAc), which is well established to contribute to motivated behavior, and the adjacent tubular striatum (TuS), which is poorly understood in this context. We reasoned that these ventral striatal subregions may be uniquely specialized in their neural representation of goal-directed behavior. To test this, we simultaneously examined TuS and NAc single-unit activity as male mice engaged in a sucrose self-administration task, which included extinction and cue-induced reinstatement sessions. While background levels of activity were comparable between regions, more TuS neurons were recruited upon reward-taking, and among recruited neurons, TuS neurons displayed greater changes in their firing during reward-taking and extinction than those in the NAc. Conversely, NAc neurons displayed greater changes in their firing during cue-reinstated reward-seeking. Interestingly, at least in the context of this behavioral paradigm, TuS neural activity predicted reward-seeking whereas NAc activity did not. Together, by directly comparing their dynamics in several behavioral contexts, this work reveals that the NAc and TuS ventral striatum subregions distinctly represent reward-taking and seeking.

scholarly journals Input-specific modulation of murine nucleus accumbens differentially regulates hedonic feeding

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Daniel J. Christoffel ◽  
Jessica J. Walsh ◽  
Boris D. Heifets ◽  
Paul Hoerbelt ◽  
Sophie Neuner ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Neural Circuit ◽  
Critical Role ◽  
Synaptic Strength ◽  
Fat Intake ◽  
High Fat ◽  
Cell Type Specific ◽  
Paraventricular Thalamus ◽  
Opposing Effects ◽  
Motivated Behaviors

AbstractHedonic feeding is driven by the “pleasure” derived from consuming palatable food and occurs in the absence of metabolic need. It plays a critical role in the excessive feeding that underlies obesity. Compared to other pathological motivated behaviors, little is known about the neural circuit mechanisms mediating excessive hedonic feeding. Here, we show that modulation of prefrontal cortex (PFC) and anterior paraventricular thalamus (aPVT) excitatory inputs to the nucleus accumbens (NAc), a key node of reward circuitry, has opposing effects on high fat intake in mice. Prolonged high fat intake leads to input- and cell type-specific changes in synaptic strength. Modifying synaptic strength via plasticity protocols, either in an input-specific optogenetic or non-specific electrical manner, causes sustained changes in high fat intake. These results demonstrate that input-specific NAc circuit adaptations occur with repeated exposure to a potent natural reward and suggest that neuromodulatory interventions may be therapeutically useful for individuals with pathologic hedonic feeding.

scholarly journals Thalamo-Nucleus Accumbens Projections in Motivated Behaviors and Addiction

2021 ◽  
Vol 15 ◽  
Author(s):  
Aurélie De Groote ◽  
Alban de Kerchove d’Exaerde
Keyword(s):  
Nucleus Accumbens ◽  
Calcium Imaging ◽  
Ventral Striatum ◽  
Recent Advances ◽  
Neuronal Connections ◽  
Paraventricular Thalamus ◽  
Motivated Behaviors ◽  
Shed Light

The ventral striatum, also called nucleus accumbens (NAc), has long been known to integrate information from cortical, thalamic, midbrain and limbic nuclei to mediate goal-directed behaviors. Until recently thalamic afferents have been overlooked when studying the functions and connectivity of the NAc. However, findings from recent studies have shed light on the importance and roles of precise Thalamus to NAc connections in motivated behaviors and in addiction. In this review, we summarize studies using techniques such as chemo- and optogenetics, electrophysiology and in vivo calcium imaging to elucidate the complex functioning of the thalamo-NAc afferents, with a particular highlight on the projections from the Paraventricular Thalamus (PVT) to the NAc. We will focus on the recent advances in the understanding of the roles of these neuronal connections in motivated behaviors, with a special emphasis on their implications in addiction, from cue-reward association to the mechanisms driving relapse.

scholarly journals Distinct role of nucleus accumbens D2-MSN projections to ventral pallidum in different phases of motivated behavior

2020 ◽  
Author(s):  
Carina Soares-Cunha ◽  
Raquel Correia ◽  
Ana Verónica Domingues ◽  
Bárbara Coimbra ◽  
Nivaldo AP de Vasconcelos ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Behavioral Effect ◽  
Ventral Pallidum ◽  
Medium Spiny Neurons ◽  
Motivated Behavior ◽  
Spiny Neurons ◽  
Reward Delivery ◽  
Instrumental Task ◽  
Motivated Behaviors

AbstractThe nucleus accumbens (NAc) is a key region in motivated behaviors. NAc medium spiny neurons (MSNs) are divided into those expressing dopamine receptor D1 or D2. Classically, D1- and D2-MSNs have been described as having opposing roles in reinforcement but recent evidence suggests a more complex role for D2-MSNs.Here we show that optogenetic modulation of D2-MSN to ventral pallidum (VP) projections during different stages of motivated behavior has contrasting effects in motivation. Activation of D2-MSN-VP projections during a reward-predicting cue results in increased motivational drive, whereas activation at reward delivery results in decreased motivation; optical inhibition has the opposite behavioral effect. In addition, in a free choice instrumental task, animals prefer the lever that originates one pellet in opposition to pellet plus D2-MSN-VP optogenetic activation, and vice versa for optogenetic inhibition.In summary, D2-MSN-VP projections play different (and even opposing) roles in distinct phases of motivated behavior.

scholarly journals Selective filtering of excitatory inputs to nucleus accumbens by dopamine and serotonin

2021 ◽  
Vol 118 (24) ◽  
pp. e2106648118
Author(s):  
Daniel J. Christoffel ◽  
Jessica J. Walsh ◽  
Paul Hoerbelt ◽  
Boris D. Heifets ◽  
Pierre Llorach ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Basolateral Amygdala ◽  
Behavioral Effects ◽  
Medium Spiny Neurons ◽  
Excitatory Postsynaptic Currents ◽  
Spiny Neurons ◽  
Specific Manner ◽  
Paraventricular Thalamus ◽  
Motivated Behaviors ◽  
Synaptic Effects

The detailed mechanisms by which dopamine (DA) and serotonin (5-HT) act in the nucleus accumbens (NAc) to influence motivated behaviors in distinct ways remain largely unknown. Here, we examined whether DA and 5-HT selectively modulate excitatory synaptic transmission in NAc medium spiny neurons in an input-specific manner. DA reduced excitatory postsynaptic currents (EPSCs) generated by paraventricular thalamus (PVT) inputs but not by ventral hippocampus (vHip), basolateral amygdala (BLA), or medial prefrontal cortex (mPFC) inputs. In contrast, 5-HT reduced EPSCs generated by inputs from all areas except the mPFC. Release of endogenous DA and 5-HT by methamphetamine (METH) and (±)3,4-methylenedioxymethamphetamine (MDMA), respectively, recapitulated these input-specific synaptic effects. Optogenetic inhibition of PVT inputs enhanced cocaine-conditioned place preference, whereas mPFC input inhibition reduced the enhancement of sociability elicited by MDMA. These findings suggest that the distinct, input-specific filtering of excitatory inputs in the NAc by DA and 5-HT contribute to their discrete behavioral effects.

scholarly journals Circuit directionality for motivation: lateral accumbens-pallidum, but not pallidum-accumbens, connections regulate motivational attraction to reward cues

2018 ◽  
Author(s):  
Elizabeth B. Smedley ◽  
Alyssa DiLeo ◽  
Kyle S. Smith
Keyword(s):  
Nucleus Accumbens ◽  
Designer Drugs ◽  
Ventral Pallidum ◽  
Incentive Salience ◽  
Delivery Strategy ◽  
Sign Tracking ◽  
Motivated Behavior ◽  
Reciprocal Connections ◽  
Motivated Behaviors ◽  
Tracking Behavior

AbstractSign-tracking behavior, in which animals interact with a cue that predicts reward, provides an example of how incentive salience can be attributed to cues and elicit motivation. The nucleus accumbens (NAc) and ventral pallidum (VP) are two regions involved in cue-driven motivation. The VP, and subregions of the NAc including the medial shell and core, are critical for sign-tracking, and connections between the medial shell and VP are known to participate in sign-tracking and other motivated behaviors. The NAc lateral shell (NAcLSh) is a distinct and understudied subdivision of the NAc, and its contribution to the process by which reward cues acquire value remains unclear. The NAcLSh has been implicated in reward-directed behavior, and has reciprocal connections with the VP, suggesting that NAcLSh and VP interactions could be important mechanisms for incentive salience. Here, we use DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) and an intersectional viral delivery strategy to produce a biased inhibition of NAcLSh neurons projecting to the VP, and vice versa. We find that disruption of connections from NAcLSh to VP reduces sign-tracking behavior while not affecting consumption of food rewards. In contrast, VP to NAcLSh disruption affected neither sign-tracking nor reward consumption, but did produce a greater shift in animals’ behavior more towards the reward source when it was available. These findings indicate that the NAcLSh→VP pathway plays an important role in guiding animals towards reward cues, while VP→NAcLSh back-projections may not and may instead bias motivated behavior towards rewards.

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