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Wehrman JJ, Chung CC, Sanders R. Anaesthetics and time perception: A review. Q J Exp Psychol (Hove) 2024; 77:1898-1910. [PMID: 36453756 DOI: 10.1177/17470218221144614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Consciousness requires subjective experience in the "now." Establishing "now," however, necessitates temporal processing. In the current article, we review one method of altering consciousness, anaesthetic drug administration, and its effects on perceived duration. We searched PubMed, PsycInfo, and ScienceDirect databases, and article reference sections, for combinations of anaesthetic drugs and time perception tasks, finding a total of 36 articles which met our inclusion criteria. We categorised these articles with regard to whether they altered the felt passage of time, short or long interval timing, or were motor timing tasks. We found that various drugs alter the perceived passage of time; ketamine makes time subjectively slow down while GABAergic drugs make time subjectively speed up. At a short interval there is little established evidence of a shift in time perception, though temporal estimates appear more variable. Similarly, when asked to use time to optimise responses (i.e., in motor timing tasks), various anaesthetic agents make timing more variable. Longer durations are estimated as lasting longer than their objective duration, though there is some variation across articles in this regard. We conclude by proposing further experiments to examine time perception under altered states of consciousness and ask whether it is possible to perceive the passage of time of events which do not necessarily reach the level of conscious perception. The variety of methods used raises the need for more systematic investigations of time perception under anaesthesia. We encourage future investigations into the overlap of consciousness and time perception to advance both fields.
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Affiliation(s)
| | - Clara C Chung
- Royal Prince Alfred Hospital, Sydney, NSW, Australia
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Oriol L, Chao M, Kollman GJ, Dowlat DS, Singhal SM, Steinkellner T, Hnasko TS. Ventral tegmental area interneurons revisited: GABA and glutamate projection neurons make local synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597996. [PMID: 38895464 PMCID: PMC11185768 DOI: 10.1101/2024.06.07.597996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The ventral tegmental area (VTA) contains projection neurons that release the neurotransmitters dopamine, GABA, and/or glutamate from distal synapses. VTA also contains GABA neurons that synapse locally on to VTA dopamine neurons, synapses widely credited to a population of so-called VTA interneurons. Interneurons in cortex, striatum, and elsewhere have well-defined morphological features, physiological properties, and molecular markers, but such features have not been clearly described in VTA. Indeed, there is scant evidence that local and distal synapses originate from separate populations of VTA GABA neurons. In this study we tested whether several markers expressed in non-dopamine VTA neurons are selective markers of interneurons, defined as neurons that synapse locally but not distally. Challenging previous assumptions, we found that VTA neurons genetically defined by expression of parvalbumin, somatostatin, neurotensin, or mu-opioid receptor project to known VTA targets including nucleus accumbens, ventral pallidum, lateral habenula, and prefrontal cortex. Moreover, we provide evidence that VTA GABA and glutamate projection neurons make functional inhibitory or excitatory synapses locally within VTA. These findings suggest that local collaterals of VTA projection neurons could mediate functions prior attributed to VTA interneurons. This study underscores the need for a refined understanding of VTA connectivity to explain how heterogeneous VTA circuits mediate diverse functions related to reward, motivation, or addiction.
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Affiliation(s)
- Lucie Oriol
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Melody Chao
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Grace J Kollman
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Dina S Dowlat
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Sarthak M Singhal
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Thomas Steinkellner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Austria
| | - Thomas S Hnasko
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
- Research Service VA San Diego Healthcare System, San Diego, United States
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Scott A, Palmer D, Newell B, Lin I, Cayton CA, Paulson A, Remde P, Richard JM. Ventral Pallidal GABAergic Neuron Calcium Activity Encodes Cue-Driven Reward Seeking and Persists in the Absence of Reward Delivery. J Neurosci 2023; 43:5191-5203. [PMID: 37339880 PMCID: PMC10342224 DOI: 10.1523/jneurosci.0013-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 06/01/2023] [Accepted: 06/10/2023] [Indexed: 06/22/2023] Open
Abstract
Reward-seeking behavior is often initiated by environmental cues that signal reward availability. This is a necessary behavioral response; however, cue reactivity and reward-seeking behavior can become maladaptive. To better understand how cue-elicited reward seeking becomes maladaptive, it is important to understand the neural circuits involved in assigning appetitive value to rewarding cues and actions. Ventral pallidum (VP) neurons are known to contribute to cue-elicited reward-seeking behavior and have heterogeneous responses in a discriminative stimulus (DS) task. The VP neuronal subtypes and output pathways that encode distinct aspects of the DS task remain unknown. Here, we used an intersectional viral approach with fiber photometry to record bulk calcium activity in VP GABAergic (VP GABA) neurons in male and female rats as they learned and performed the DS task. We found that VP GABA neurons are excited by reward-predictive cues but not neutral cues and that this response develops over time. We also found that this cue-evoked response predicts reward-seeking behavior and that inhibiting this VP GABA activity during cue presentation decreases reward-seeking behavior. Additionally, we found increased VP GABA calcium activity at the time of expected reward delivery, which occurred even on trials when reward was omitted. Together, these findings suggest that VP GABA neurons encode reward expectation, and calcium activity in these neurons encodes the vigor of cue-elicited reward seeking.SIGNIFICANCE STATEMENT VP circuitry is a major driver of cue-evoked behaviors. Previous work has found that VP neurons have heterogenous responses and contributions to reward-seeking behavior. This functional heterogeneity is because of differences of neurochemical subtypes and projections of VP neurons. Understanding the heterogenous responses among and within VP neuronal cell types is a necessary step in further understanding how cue-evoked behavior becomes maladaptive. Our work explores the canonical GABAergic VP neuron and how the calcium activity of these cells encodes components of cue-evoked reward seeking, including the vigor and persistence of reward seeking.
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Affiliation(s)
- Alexandra Scott
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
| | - Dakota Palmer
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
| | - Bailey Newell
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Iris Lin
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Christelle A Cayton
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Anika Paulson
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Paige Remde
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Jocelyn M Richard
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
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Rahaman SM, Chowdhury S, Mukai Y, Ono D, Yamaguchi H, Yamanaka A. Functional Interaction Between GABAergic Neurons in the Ventral Tegmental Area and Serotonergic Neurons in the Dorsal Raphe Nucleus. Front Neurosci 2022; 16:877054. [PMID: 35663550 PMCID: PMC9160575 DOI: 10.3389/fnins.2022.877054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/21/2022] [Indexed: 12/02/2022] Open
Abstract
GABAergic neurons in the ventral tegmental area (VTA) have brain-wide projections and are involved in multiple behavioral and physiological functions. Here, we revealed the responsiveness of Gad67+ neurons in VTA (VTAGad67+) to various neurotransmitters involved in the regulation of sleep/wakefulness by slice patch clamp recording. Among the substances tested, a cholinergic agonist activated, but serotonin, dopamine and histamine inhibited these neurons. Dense VTAGad67+ neuronal projections were observed in brain areas regulating sleep/wakefulness, including the central amygdala (CeA), dorsal raphe nucleus (DRN), and locus coeruleus (LC). Using a combination of electrophysiology and optogenetic studies, we showed that VTAGad67+ neurons inhibited all neurons recorded in the DRN, but did not inhibit randomly recorded neurons in the CeA and LC. Further examination revealed that the serotonergic neurons in the DRN (DRN5–HT) were monosynaptically innervated and inhibited by VTAGad67+ neurons. All recorded DRN5–HT neurons received inhibitory input from VTAGad67+ neurons, while only one quarter of them received inhibitory input from local GABAergic neurons. Gad67+ neurons in the DRN (DRNGad67+) also received monosynaptic inhibitory input from VTAGad67+ neurons. Taken together, we found that VTAGad67+ neurons were integrated in many inputs, and their output inhibits DRN5–HT neurons, which may regulate physiological functions including sleep/wakefulness.
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Affiliation(s)
- Sheikh Mizanur Rahaman
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Srikanta Chowdhury
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, United States
| | - Yasutaka Mukai
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroshi Yamaguchi
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
- *Correspondence: Akihiro Yamanaka,
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