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 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.

scholarly journals Paraventricular hypothalamic nucleus are essential for arousal promotion and maintenance

2021 ◽  
Author(s):  
Zhi-Li Huang ◽  
Chang-Rui Chen ◽  
Yu-Heng Zhong ◽  
Shan Jiang ◽  
Wei Xu ◽  
...  
Keyword(s):  
Nrem Sleep ◽  
Neural Circuitry ◽  
Lateral Septum ◽  
Hypothalamic Nucleus ◽  
Population Activity ◽  
Daytime Functioning ◽  
Paraventricular Hypothalamic Nucleus ◽  
Clinical Observations ◽  
Electrophysiological Recordings

Abstract Adequate wakefulness is fundamental for proper daytime functioning. Clinical observations indicate that the paramedian region of the hypothalamus is a critical node for controlling wakefulness. However, the specific nucleus and neural circuitry for this function remain unknown. Here, we found that inhibition of PVHvglut2 neurons induced 3-h increase of NREM sleep. Chemogenetic activation of PVHvglut2 neurons potently induced 9-h wakefulness, and PVHCRH neuronal activation also exerted wakefulness. Photostimulation of PVHvglut2→parabrachial complex/ventral lateral septum circuits immediately drove transitions from NREM to wakefulness. Furthermore, using in vivo fiber photometry or multichannel electrophysiological recordings in mice, we find arousal-dependent increases in population activity of PVHvglut2 neurons. Most importantly, ablation of PVHvglut2 neurons dramatically led mice to hypersomnia-like behaviors. These results demonstrate that PVHvglut2 neurons are essential for physiologic arousal in the hypothalamus.

Ex Vivo Brain Preparation to Analyze Vocal Pathways of Xenopus Frogs

2021 ◽  
Vol 2021 (9) ◽  
pp. pdb.prot106872
Author(s):  
Ayako Yamaguchi
Keyword(s):  
Neural Activity ◽  
Ex Vivo ◽  
Neural Circuitry ◽  
Neural Basis ◽  
Vocal Production ◽  
Basic Principles ◽  
Electrophysiological Recordings ◽  
The Brain

Understanding the neural basis of behavior is a challenging task for technical reasons. Most methods of recording neural activity require animals to be immobilized, but neural activity associated with most behavior cannot be recorded from an anesthetized, immobilized animal. Using amphibians, however, there has been some success in developing in vitro brain preparations that can be used for electrophysiological and anatomical studies. Here, we describe an ex vivo frog brain preparation from which fictive vocalizations (the neural activity that would have produced vocalizations had the brain been attached to the muscle) can be elicited repeatedly. When serotonin is applied to the isolated brains of male and female African clawed frogs, Xenopus laevis, laryngeal nerve activity that is a facsimile of those that underlie sex-specific vocalizations in vivo can be readily recorded. Recently, this preparation was successfully used in other species within the genus including Xenopus tropicalis and Xenopus victorianus. This preparation allows a variety of techniques to be applied including extracellular and intracellular electrophysiological recordings and calcium imaging during vocal production, surgical and pharmacological manipulation of neurons to evaluate their impact on motor output, and tract tracing of the neural circuitry. Thus, the preparation is a powerful tool with which to understand the basic principles that govern the production of coherent and robust motor programs in vertebrates.

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 contribution of cone photoreceptor subtypes to the mammalian biological clock

2021 ◽  
Vol 118 (22) ◽  
pp. e2024500118
Author(s):  
Hester C. van Diepen ◽  
Robin A. Schoonderwoerd ◽  
Ashna Ramkisoensing ◽  
Jan A. M. Janse ◽  
Samer Hattar ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Uv Light ◽  
Biological Clock ◽  
Green Light ◽  
Sustained Response ◽  
Activity Levels ◽  
Cone Photoreceptors ◽  
Light Levels ◽  
Electrophysiological Recordings

Ambient light detection is important for the synchronization of the circadian clock to the external solar cycle. Light signals are sent to the suprachiasmatic nuclei (SCN), the site of the major circadian pacemaker. It has been assumed that cone photoreceptors contribute minimally to synchronization. Here, however, we find that cone photoreceptors are sufficient for mediating entrainment and transmitting photic information to the SCN, as evaluated in mice that have only cones as functional photoreceptors. Using in vivo electrophysiological recordings in the SCN of freely moving cone-only mice, we observed light responses in SCN neuronal activity in response to 60-s pulses of both ultraviolet (UV) (λmax 365 nm) and green (λmax 505 nm) light. Higher irradiances of UV light led to irradiance-dependent enhancements in SCN neuronal activity, whereas higher irradiances of green light led to a reduction in the sustained response with only the transient response remaining. Responses in SCN neuronal activity decayed with a half-max time of ∼9 min for UV light and less than a minute for green light, indicating differential input between short-wavelength–sensitive and mid-wavelength–sensitive cones for the SCN responsiveness. Furthermore, we show that UV light is more effective for photoentrainment than green light. Based on the lack of a full sustained response in cone-only mice, we confirmed that rapidly alternating light levels, rather than slowly alternating light, caused substantial phase shifts. Together, our data provide strong evidence that cone types contribute to photoentrainment and differentially affect the electrical activity levels of the SCN.

scholarly journals Locomotor suppression by a monosynaptic amygdala to brainstem circuit

2019 ◽  
Author(s):  
Thomas K. Roseberry ◽  
Arnaud L. Lalive ◽  
Benjamin D. Margolin ◽  
Anatol C. Kreitzer
Keyword(s):  
Ex Vivo ◽  
Conditioned Avoidance ◽  
Neural Circuitry ◽  
Glutamatergic Neurons ◽  
Monosynaptic Connection ◽  
Animal Survival ◽  
Defensive Behaviors ◽  
Defensive Action ◽  
Increased Activity

AbstractThe control of locomotion is fundamental to vertebrate animal survival. Defensive situations require an animal to rapidly decide whether to run away or suppress locomotor activity to avoid detection. While much of the neural circuitry involved in defensive action selection has been elucidated, top-down modulation of brainstem locomotor circuitry remains unclear. Here we provide evidence for the existence and functionality of a monosynaptic connection from the central amygdala (CeA) to the mesencephalic locomotor region (MLR) that inhibits locomotion in unconditioned and conditioned defensive behavior in mice. We show that locomotion stimulated by airpuff coincides with increased activity of MLR glutamatergic neurons. Using retrograde tracing and ex vivo electrophysiology, we find that the CeA makes a monosynaptic connection with the MLR. In the open field, in vivo stimulation of this projection suppressed spontaneous locomotion, whereas inhibition of this projection had no effect. However, inhibiting CeA terminals within the MLR increased both neural activity and locomotor responses to airpuff. Finally, using a conditioned avoidance paradigm known to activate CeA neurons, we find that inhibition of the CeA projection increased successful escape, whereas activating the projection reduced escape. Together these results provide evidence for a new circuit substrate influencing locomotion and defensive behaviors.

scholarly journals Activity of the Lateral Hypothalamus during Genetically Determined Absence Seizures

2021 ◽  
Vol 22 (17) ◽  
pp. 9466
Author(s):  
Péter Sere ◽  
Nikolett Zsigri ◽  
Timea Raffai ◽  
Szabina Furdan ◽  
Fanni Győri ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Lateral Hypothalamus ◽  
Brain Area ◽  
State Dependence ◽  
Absence Epilepsy ◽  
Absence Seizures ◽  
Spike Wave Discharges ◽  
Genetically Determined

(1) Background: Absence seizures (ASs) are sudden, transient lapses of consciousness associated with lack of voluntary movements and generalized 2.5–4 Hz spike-wave discharges (SWDs) in the EEG. In addition to the thalamocortical system, where these pathological oscillations are generated, multiple neuronal circuits have been involved in their modulation and associated comorbidities including the serotonergic system. Neuronal activity in one of the major synaptic input structures to the brainstem dorsal raphé nucleus (DRN), the lateral hypothalamus (LH), has not been characterized. (2) Methods: We used viral tract tracing and optogenetics combined with in vitro and in vivo electrophysiology to assess the involvement of the LH in absence epilepsy in a genetic rodent model. (3) Results: We found that a substantial fraction of LH neurons project to the DRN of which a minority is GABAergic. The LH to DRN projection can lead to monosynaptic iGluR mediated excitation in DRN 5-HT neurons. Neuronal activity in the LH is coupled to SWDs. (4) Conclusions: Our results indicate that a brain area involved in the regulation of autonomic functions and heavily innervating the RN is involved in ASs. The decreased activity of LH neurons during SWDs could lead to both a decreased excitation and disinhibition in the DRN. These results support a long-range subcortical regulation of serotonergic neuromodulation during ASs and further our understanding of the state-dependence of these seizures and some of their associated comorbidities.

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