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Horrocks M, Mohn JL, Jaramillo S. The serotonergic psychedelic DOI impairs deviance detection in the auditory cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.06.611733. [PMID: 39314372 PMCID: PMC11418932 DOI: 10.1101/2024.09.06.611733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Psychedelics are known to induce profound perceptual distortions, yet the neural mechanisms underlying these effects, particularly within the auditory system, remain poorly understood. In this study, we investigated the effects of the psychedelic compound 2,5-Dimethoxy-4-iodoamphetamine (DOI), a serotonin 2A receptor agonist, on the activity of neurons in the auditory cortex of awake mice. We examined whether DOI administration alters sound-frequency tuning, variability in neural responses, and deviance detection (a neural process reflecting the balance between top-down and bottom-up processing). Our results show that while DOI does not alter the frequency selectivity of auditory cortical neurons in a consistent manner, it increases trial-by-trial variability in responses and consistently diminishes the neural distinction between expected (standard) and unexpected (oddball) stimuli. This reduction in deviance detection was primarily driven by a decrease in the response to oddball sounds, suggesting that DOI dampens the auditory cortex's sensitivity to unexpected events. These findings provide insights into how psychedelics disrupt sensory processing and shed light on the neural mechanisms underlying the altered perception of auditory stimuli observed in the psychedelic state.
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Affiliation(s)
- Max Horrocks
- Institute of Neuroscience, University of Oregon. Eugene, OR 97403
| | - Jennifer L Mohn
- Institute of Neuroscience, University of Oregon. Eugene, OR 97403
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2
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Shine JM. Neuromodulatory control of complex adaptive dynamics in the brain. Interface Focus 2023; 13:20220079. [PMID: 37065268 PMCID: PMC10102735 DOI: 10.1098/rsfs.2022.0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/23/2023] [Indexed: 04/18/2023] Open
Abstract
How is the massive dimensionality and complexity of the microscopic constituents of the nervous system brought under sufficiently tight control so as to coordinate adaptive behaviour? A powerful means for striking this balance is to poise neurons close to the critical point of a phase transition, at which a small change in neuronal excitability can manifest a nonlinear augmentation in neuronal activity. How the brain could mediate this critical transition is a key open question in neuroscience. Here, I propose that the different arms of the ascending arousal system provide the brain with a diverse set of heterogeneous control parameters that can be used to modulate the excitability and receptivity of target neurons-in other words, to act as control parameters for mediating critical neuronal order. Through a series of worked examples, I demonstrate how the neuromodulatory arousal system can interact with the inherent topological complexity of neuronal subsystems in the brain to mediate complex adaptive behaviour.
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Affiliation(s)
- James M. Shine
- Brain and Mind Center, The University of Sydney, Sydney, Australia
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3
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Reggiani JDS, Jiang Q, Barbini M, Lutas A, Liang L, Fernando J, Deng F, Wan J, Li Y, Chen C, Andermann ML. Brainstem serotonin neurons selectively gate retinal information flow to thalamus. Neuron 2023; 111:711-726.e11. [PMID: 36584680 PMCID: PMC10131437 DOI: 10.1016/j.neuron.2022.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 10/10/2022] [Accepted: 12/05/2022] [Indexed: 12/30/2022]
Abstract
Retinal ganglion cell (RGC) types relay parallel streams of visual feature information. We hypothesized that neuromodulators might efficiently control which visual information streams reach the cortex by selectively gating transmission from specific RGC axons in the thalamus. Using fiber photometry recordings, we found that optogenetic stimulation of serotonergic axons in primary visual thalamus of awake mice suppressed ongoing and visually evoked calcium activity and glutamate release from RGC boutons. Two-photon calcium imaging revealed that serotonin axon stimulation suppressed RGC boutons that responded strongly to global changes in luminance more than those responding only to local visual stimuli, while the converse was true for suppression induced by increases in arousal. Converging evidence suggests that differential expression of the 5-HT1B receptor on RGC presynaptic terminals, but not differential density of nearby serotonin axons, may contribute to the selective serotonergic gating of specific visual information streams before they can activate thalamocortical neurons.
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Affiliation(s)
- Jasmine D S Reggiani
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Qiufen Jiang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Melanie Barbini
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew Lutas
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Liang Liang
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jesseba Fernando
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Fei Deng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Jinxia Wan
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Chinfei Chen
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| | - Mark L Andermann
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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4
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Gacoin M, Ben Hamed S. Fluoxetine degrades luminance perceptual thresholds while enhancing motivation and reward sensitivity. Front Pharmacol 2023; 14:1103999. [PMID: 37153796 PMCID: PMC10157648 DOI: 10.3389/fphar.2023.1103999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/30/2023] [Indexed: 05/10/2023] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) increase serotonin activity in the brain. While they are mostly known for their antidepressant properties, they have been shown to improve visual functions in amblyopia and impact cognitive functions ranging from attention to motivation and sensitivity to reward. Yet, a clear understanding of the specific action of serotonin to each of bottom-up sensory and top-down cognitive control components and their interaction is still missing. To address this question, we characterize, in two adult male macaques, the behavioral effects of fluoxetine, a specific SSRI, on visual perception under varying bottom-up (luminosity, distractors) and top-down (uncertainty, reward biases) constraints while they are performing three different visual tasks. We first manipulate target luminosity in a visual detection task, and we show that fluoxetine degrades luminance perceptual thresholds. We then use a target detection task in the presence of spatial distractors, and we show that under fluoxetine, monkeys display both more liberal responses as well as a degraded perceptual spatial resolution. In a last target selection task, involving free choice in the presence of reward biases, we show that monkeys display an increased sensitivity to reward outcome under fluoxetine. In addition, we report that monkeys produce, under fluoxetine, more trials and less aborts, increased pupil size, shorter blink durations, as well as task-dependent changes in reaction times. Overall, while low level vision appears to be degraded by fluoxetine, performances in the visual tasks are maintained under fluoxetine due to enhanced top-down control based on task outcome and reward maximization.
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Affiliation(s)
- Maëva Gacoin
- *Correspondence: Maëva Gacoin, ; Suliann Ben Hamed,
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5
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Rodenkirch C, Carmel JB, Wang Q. Rapid Effects of Vagus Nerve Stimulation on Sensory Processing Through Activation of Neuromodulatory Systems. Front Neurosci 2022; 16:922424. [PMID: 35864985 PMCID: PMC9294458 DOI: 10.3389/fnins.2022.922424] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/15/2022] [Indexed: 12/13/2022] Open
Abstract
After sensory information is encoded into neural signals at the periphery, it is processed through multiple brain regions before perception occurs (i.e., sensory processing). Recent work has begun to tease apart how neuromodulatory systems influence sensory processing. Vagus nerve stimulation (VNS) is well-known as an effective and safe method of activating neuromodulatory systems. There is a growing body of studies confirming VNS has immediate effects on sensory processing across multiple sensory modalities. These immediate effects of VNS on sensory processing are distinct from the more well-documented method of inducing lasting neuroplastic changes to the sensory pathways through repeatedly delivering a brief VNS burst paired with a sensory stimulus. Immediate effects occur upon VNS onset, often disappear upon VNS offset, and the modulation is present for all sensory stimuli. Conversely, the neuroplastic effect of pairing sub-second bursts of VNS with a sensory stimulus alters sensory processing only after multiple pairing sessions, this alteration remains after cessation of pairing sessions, and the alteration selectively affects the response properties of neurons encoding the specific paired sensory stimulus. Here, we call attention to the immediate effects VNS has on sensory processing. This review discusses existing studies on this topic, provides an overview of the underlying neuromodulatory systems that likely play a role, and briefly explores the potential translational applications of using VNS to rapidly regulate sensory processing.
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Affiliation(s)
- Charles Rodenkirch
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
- Jacobs Technion-Cornell Institute, Cornell Tech, New York, NY, United States
- *Correspondence: Charles Rodenkirch,
| | - Jason B. Carmel
- Department of Neurology and Orthopedics, Columbia University Medical Center, New York, NY, United States
| | - Qi Wang
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
- Qi Wang,
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Barrientos R, Alatorre A, Oviedo-Chávez A, Delgado A, Nielsen N, Querejeta E. Tonic serotonergic input increases the burst firing mode and diminishes the firing rate of reticular thalamic nucleus neurons through 5-HT1A receptors activation in anesthetized rats. Exp Brain Res 2022; 240:1341-1356. [PMID: 35234992 DOI: 10.1007/s00221-022-06328-4] [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] [Received: 01/04/2022] [Accepted: 02/07/2022] [Indexed: 11/30/2022]
Abstract
The reticular thalamic nucleus (RTn) is a thin shell of GABAergic neurons that covers the dorsal thalamus that regulate the global activity of all thalamic nuclei. RTn controls the flow of information between thalamus and cerebral cortex since it receives glutamatergic information from collaterals of thalamo-cortical (TCs) and cortico-thalamic neurons. It also receives aminergic information from several brain stem nuclei, including serotonergic fibers originated in the dorsal raphe nucleus. RTn neurons express serotonergic receptors including the 5-HT1A subtype, however, the role of this receptor in the RTn electrical activity has been scarcely analyzed. In this work, we recorded in vivo the unitary spontaneous electrical activity of RTn neurons in anesthetized rats; our study aimed to obtain information about the effects of 5-HT1A receptors in RTn neurons. Local application of fluoxetine (a serotonin reuptake inhibitor) increases burst firing index accompanied by a decrease in the basal spiking rate. Local application of different doses of serotonin and 8-OH-DPAT (a specific 5-HT1A receptor agonist) causes a similar response to fluoxetine effects. Local 5-HT1A receptors blockade produces opposite effects and suppresses the effect by 8-OH-DPAT. Our findings indicate the presence of a serotonergic tonic discharge in the RTn that increases the burst firing index and simultaneously decreases the basal spiking frequency through 5-HT1A receptors activation.
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Affiliation(s)
- Rafael Barrientos
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Alberto Alatorre
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Aldo Oviedo-Chávez
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Alfonso Delgado
- Departamento de Fisiología Experimental, Facultad de Medicina y Ciencias Biomédicas, Universidad Autónoma de Chihuahua, Circuito Universitario Campus II, 31127, Chihuahua, Mexico
| | - Nielsine Nielsen
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Enrique Querejeta
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico.
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico.
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Fauss GNK, Hudson KE, Grau JW. Role of Descending Serotonergic Fibers in the Development of Pathophysiology after Spinal Cord Injury (SCI): Contribution to Chronic Pain, Spasticity, and Autonomic Dysreflexia. BIOLOGY 2022; 11:234. [PMID: 35205100 PMCID: PMC8869318 DOI: 10.3390/biology11020234] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/12/2022]
Abstract
As the nervous system develops, nerve fibers from the brain form descending tracts that regulate the execution of motor behavior within the spinal cord, incoming sensory signals, and capacity to change (plasticity). How these fibers affect function depends upon the transmitter released, the receptor system engaged, and the pattern of neural innervation. The current review focuses upon the neurotransmitter serotonin (5-HT) and its capacity to dampen (inhibit) neural excitation. A brief review of key anatomical details, receptor types, and pharmacology is provided. The paper then considers how damage to descending serotonergic fibers contributes to pathophysiology after spinal cord injury (SCI). The loss of serotonergic fibers removes an inhibitory brake that enables plasticity and neural excitation. In this state, noxious stimulation can induce a form of over-excitation that sensitizes pain (nociceptive) circuits, a modification that can contribute to the development of chronic pain. Over time, the loss of serotonergic fibers allows prolonged motor drive (spasticity) to develop and removes a regulatory brake on autonomic function, which enables bouts of unregulated sympathetic activity (autonomic dysreflexia). Recent research has shown that the loss of descending serotonergic activity is accompanied by a shift in how the neurotransmitter GABA affects neural activity, reducing its inhibitory effect. Treatments that target the loss of inhibition could have therapeutic benefit.
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Affiliation(s)
| | | | - James W. Grau
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX 77843, USA; (G.N.K.F.); (K.E.H.)
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8
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Vortioxetine increases absence-like seizures in WAG/Rij rats but decreases penicillin- and pentylenetetrazole-induced seizures in Wistar rats. Epilepsy Behav 2021; 116:107797. [PMID: 33561766 DOI: 10.1016/j.yebeh.2021.107797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/20/2022]
Abstract
AIM Depression is the major psychiatric disorder in patients with epilepsy. Vortioxetine is a novel antidepressant drug for the treatment of major depressive disorders. In the present study, effects of vortioxetine were evaluated in different experimental epilepsy models of rats. MATERIALS AND METHODS Fifty-six adult male Wistar rats and 28 WAG/Rij rats were divided into 12 groups of 7 rats each. Experiments were conducted with penicillin (500 IU, i.c.) and pentylenetetrazole models (50 mg/kg, intraperitoneally (i.p.)) in Wistar rats and genetic absence epileptic WAG/Rij rats. The vortioxetine (1, 5, or 10 mg/kg, i.p.) was evaluated in these three models. All groups were compared with their control groups. RESULTS In the penicillin-induced seizure model, 1, 5, or 10 mg/kg vortioxetine administration significantly decreased mean spike frequency. In the pentylenetetrazole-induced seizure model, 1, 5, or 10 mg/kg vortioxetine demonstrated a significant dose-dependent decrease in mean spike frequency, an increase in the latency to minor and major seizures, and a decrease in total duration of major seizure and convulsion stage. In genetic absence epileptic WAG/Rij rats, 1 mg/kg vortioxetine caused no significant alteration in the number and duration of SWDs compared to the controls, while 5 and 10 mg/kg doses of vortioxetine increased the number and duration of SWDs. Amplitude of the epileptiform activity did not change in any of the experimental epilepsy models. CONCLUSION The results of this study suggested that vortioxetine has anticonvulsant activity in penicillin- and pentylenetetrazole-induced seizure models. However, it exhibited proconvulsant activity in the absence epileptic WAG/Rij rats.
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Pillay S, Bhagwandin A, Bertelsen MF, Patzke N, Engler G, Engel AK, Manger PR. The diencephalon of two carnivore species: The feliform banded mongoose and the caniform domestic ferret. J Comp Neurol 2020; 529:52-86. [PMID: 32964417 DOI: 10.1002/cne.25036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/29/2022]
Abstract
This study provides an analysis of the cytoarchitecture, myeloarchitecture, and chemoarchitecture of the diencephalon (dorsal thalamus, ventral thalamus, and epithalamus) of the banded mongoose (Mungos mungo) and domestic ferret (Mustela putorius furo). Using architectural and immunohistochemical stains, we observe that the nuclear organization of the diencephalon is very similar in the two species, and similar to that reported in other carnivores, such as the domestic cat and dog. The same complement of putatively homologous nuclei were identified in both species, with only one variance, that being the presence of the perireticular nucleus in the domestic ferret, that was not observed in the banded mongoose. The chemoarchitecture was also mostly consistent between species, although there were a number of minor variations across a range of nuclei in the density of structures expressing the calcium-binding proteins parvalbumin, calbindin, and calretinin. Thus, despite almost 53 million years since these two species of carnivores shared a common ancestor, strong phylogenetic constraints appear to limit the potential for adaptive evolutionary plasticity within the carnivore order. Apart from the presence of the perireticular nucleus, the most notable difference between the species studied was the physical inversion of the dorsal lateral geniculate nucleus, as well as the lateral posterior and pulvinar nuclei in the domestic ferret compared to the banded mongoose and other carnivores, although this inversion appears to be a feature of the Mustelidae family. While no functional sequelae are suggested, this inversion is likely to result from the altricial birth of Mustelidae species.
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Affiliation(s)
- Sashrika Pillay
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Nina Patzke
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gerhard Engler
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Okada M, Fukuyama K, Ueda Y. Lurasidone inhibits NMDA receptor antagonist-induced functional abnormality of thalamocortical glutamatergic transmission via 5-HT 7 receptor blockade. Br J Pharmacol 2019; 176:4002-4018. [PMID: 31347694 PMCID: PMC6811777 DOI: 10.1111/bph.14804] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/22/2019] [Accepted: 07/09/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND AND PURPOSE Lurasidone is an atypical mood-stabilizing antipsychotic with a unique receptor-binding profile, including 5-HT7 receptor antagonism; however, the detailed effects of 5-HT7 receptor antagonism on various transmitter systems relevant to schizophrenia, particularly the thalamo-insular glutamatergic system and the underlying mechanisms, are yet to be clarified. EXPERIMENTAL APPROACH We examined the mechanisms underlying the clinical effects of lurasidone by measuring the release of l-glutamate, GABA, dopamine, and noradrenaline in the reticular thalamic nucleus (RTN), mediodorsal thalamic nucleus (MDTN) and insula of freely moving rats in response to systemic injection or local infusion of lurasidone or MK-801 using multiprobe microdialysis with ultra-HPLC. KEY RESULTS Systemic MK-801 (0.5 mg·kg-1 ) administration increased insular release of l-glutamate, dopamine, and noradrenaline but decreased GABA release. Systemic lurasidone (1 mg·kg-1 ) administration also increased insular release of l-glutamate, dopamine, and noradrenaline but without affecting GABA. Local lurasidone administration into the insula (3 μM) did not affect MK-801-induced insular release of l-glutamate or catecholamine, whereas local lurasidone administration into the MDTN (1 μM) inhibited MK-801-induced insular release of l-glutamate and catecholamine, similar to the 5-HT7 receptor antagonist SB269970. CONCLUSIONS AND IMPLICATIONS The present results indicate that MK-801-induced insular l-glutamate release is generated by activation of thalamo-insular glutamatergic transmission via MDTN GABAergic disinhibition resulting from NMDA receptor inhibition in the MDTN and RTN. Lurasidone inhibited this MK-801-evoked insular l-glutamate release through inhibition of excitatory 5-HT7 receptor in the MDTN. These effects on thalamo-insular glutamatergic transmission may contribute to the antipsychotic and mood-stabilizing actions of lurasidone.
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Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of MedicineMie UniversityTsuJapan
| | - Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of MedicineMie UniversityTsuJapan
| | - Yuto Ueda
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of MedicineMie UniversityTsuJapan
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11
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Esmaeeli S, Murphy K, Swords GM, Ibrahim BA, Brown JW, Llano DA. Visual hallucinations, thalamocortical physiology and Lewy body disease: A review. Neurosci Biobehav Rev 2019; 103:337-351. [PMID: 31195000 DOI: 10.1016/j.neubiorev.2019.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 06/03/2019] [Accepted: 06/08/2019] [Indexed: 12/22/2022]
Abstract
One of the core diagnostic criteria for Dementia with Lewy Bodies (DLB) is the presence of visual hallucinations. The presence of hallucinations, along with fluctuations in the level of arousal and sleep disturbance, point to potential pathological mechanisms at the level of the thalamus. However, the potential role of thalamic dysfunction in DLB, particularly as it relates to the presence of formed visual hallucinations is not known. Here, we review the literature on the pathophysiology of DLB with respect to modern theories of thalamocortical function and attempt to derive an understanding of how such hallucinations arise. Based on the available literature, we propose that combined thalamic-thalamic reticular nucleus and thalamocortical pathology may explain the phenomenology of visual hallucinations in DLB. In particular, diminished α7 cholinergic activity in the thalamic reticular nucleus may critically disinhibit thalamocortical activity. Further, concentrated pathological changes within the posterior regions of the thalamus may explain the predilection for the hallucinations to be visual in nature.
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Affiliation(s)
- Shooka Esmaeeli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Kathleen Murphy
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Gabriel M Swords
- University of Illinois at Chicago College of Medicine, Chicago, IL, United States
| | - Baher A Ibrahim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jeffrey W Brown
- University of Illinois at Chicago College of Medicine, Chicago, IL, United States
| | - Daniel A Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Carle Neuroscience Institute, Urbana, IL, United States.
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12
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Three weeks of SSRI administration enhances the visual perceptual threshold - a randomized placebo-controlled study. Psychopharmacology (Berl) 2019; 236:1759-1769. [PMID: 30623228 DOI: 10.1007/s00213-018-5158-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/21/2018] [Indexed: 01/02/2023]
Abstract
RATIONALE The serotonergic system has been repeatedly linked to visual attention in general, but the effects of selective serotonin reuptake inhibitor (SSRI) on specific components of visual attention remain unknown. Changes in distinct perceptual and cognitive processes are not readily evident in most attention paradigms. OBJECTIVE In this study, we isolate basic components of visual attention to investigate potential effects of longer-term SSRI administration on non-emotional aspects of visual attention in healthy males. METHODS In a randomized double-blind placebo-controlled design, 32 young healthy males were tested on multiple attentional parameters, before and after a 3-week SSRI intervention with fluoxetine (40 mg daily) or placebo. Data were modeled with a computational theory of visual attention to derive independent estimates of five distinct components of visual attention. RESULTS The SSRI intervention selectively and significantly lowered the threshold for conscious visual perception. Specifically, we demonstrate that this improvement does not stem from a general increase in the speed of visual processing, as previously suggested, but specifically from a change in the perceptual threshold. CONCLUSIONS The study provides a novel description of the attentional dynamics affected by SSRI, while supporting previous findings on attentional effects of SSRI. Furthermore, it accentuates the utility of employing accuracy-based measures of attentional performance when conducting psychopharmacological research.
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13
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Taskiran M, Tasdemir A, Ayyildiz N, Ayyildiz M, Agar E. The effect of serotonin on penicillin-induced epileptiform activity. Int J Neurosci 2019; 129:687-697. [DOI: 10.1080/00207454.2018.1557166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Mehmet Taskiran
- Department of Biology, Faculty of Science, Erciyes University, Kayseri, Turkey
| | - Abdulkadir Tasdemir
- Graduate School of Natural and Applied Sciences, Erciyes University, Kayseri, Turkey
| | - Nusret Ayyildiz
- Department of Biology, Faculty of Science, Erciyes University, Kayseri, Turkey
| | - Mustafa Ayyildiz
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Erdal Agar
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
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14
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Dougherty DD, Brennan BP, Stewart SE, Wilhelm S, Widge AS, Rauch SL. Neuroscientifically Informed Formulation and Treatment Planning for Patients With Obsessive-Compulsive Disorder: A Review. JAMA Psychiatry 2018; 75:1081-1087. [PMID: 30140845 DOI: 10.1001/jamapsychiatry.2018.0930] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IMPORTANCE Obsessive-compulsive disorder (OCD) is a common and often debilitating psychiatric illness. Recent advances in the understanding of the neuroscience of OCD have provided valuable insights that have begun to transform the way we think about the management of this disorder. This educational review provides an integrated neuroscience perspective on formulation and treatment planning for patients with OCD. The article is organized around key neuroscience themes most relevant for OCD. OBSERVATIONS An integrated neuroscience formulation of OCD is predicated on a fundamental understanding of phenomenology and symptom dimensions, fear conditioning and extinction, neurochemistry, genetics and animal models, as well as neurocircuitry and neurotherapeutics. Symptom dimensions provide a means to better understand the phenotypic heterogeneity within OCD with an eye toward more personalized treatments. The concept of abnormal fear extinction is central to OCD and to the underlying therapeutic mechanism of exposure and response prevention. A framework for understanding the neurochemistry of OCD focuses on both traditional monoaminergic systems and more recent evidence of glutamatergic and γ-aminobutyric acid-ergic dysfunction. Obsessive-compulsive disorder is highly heritable, and future work is needed to understand the contribution of genes to underlying pathophysiology. A circuit dysregulation framework focuses on cortico-striato-thalamo-cortical circuit dysfunction and the development of neurotherapeutic approaches targeting this circuit. The impact of these concepts on how we think about OCD diagnosis and treatment is discussed. Suggestions for future investigations that have the potential to further enhance the clinical management of OCD are presented. CONCLUSIONS AND RELEVANCE These key neuroscience themes collectively inform formulation and treatment planning for patients with OCD. The ultimate goal is to increase crosstalk between clinicians and researchers in an effort to facilitate translation of advances in neuroscience research to improved care for patients with OCD.
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Affiliation(s)
- Darin D Dougherty
- Division of Neurotherapeutics, Massachusetts General Hospital, Boston.,Obsessive-Compulsive Disorder Institute, McLean Hospital, Belmont, Massachusetts.,Obsessive-Compulsive and Related Disorders Program, Massachusetts General Hospital, Boston.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Brian P Brennan
- Obsessive-Compulsive Disorder Institute, McLean Hospital, Belmont, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.,Biological Psychiatry Laboratory, McLean Hospital, Belmont, Massachusetts
| | - S Evelyn Stewart
- BC Mental Health & Addictions Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sabine Wilhelm
- Obsessive-Compulsive and Related Disorders Program, Massachusetts General Hospital, Boston.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Alik S Widge
- Division of Neurotherapeutics, Massachusetts General Hospital, Boston.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.,Picower Institute for Learning and Memory, Massachusetts Institute for Technology, Cambridge
| | - Scott L Rauch
- Obsessive-Compulsive Disorder Institute, McLean Hospital, Belmont, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
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15
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Di Giovanni G, Chagraoui A, Puginier E, Galati S, De Deurwaerdère P. Reciprocal interaction between monoaminergic systems and the pedunculopontine nucleus: Implication in the mechanism of L-DOPA. Neurobiol Dis 2018; 128:9-18. [PMID: 30149181 DOI: 10.1016/j.nbd.2018.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/19/2018] [Accepted: 08/23/2018] [Indexed: 01/31/2023] Open
Abstract
The pedunculopontine nucleus (PPN) is part of the mesencephalic locomotor region (MLR) and has been involved in the control of gait, posture, locomotion, sleep, and arousal. It likely participates in some motor and non-motor symptoms of Parkinson's disease and is regularly proposed as a surgical target to ameliorate gait, posture and sleep disorders in Parkinsonian patients. The PPN overlaps with the monoaminergic systems including dopamine, serotonin and noradrenaline in the modulation of the above-mentioned functions. All these systems are involved in Parkinson's disease and the mechanism of the anti-Parkinsonian agents, mostly L-DOPA. This suggests that PPN interacts with monoaminergic neurons and vice versa. Some evidence indicates that the PPN sends cholinergic, glutamatergic and even gabaergic inputs to mesencephalic dopaminergic cells, with the data regarding serotonergic or noradrenergic cells being less well known. Similarly, the control exerted by the PPN on dopaminergic neurons, is multiple and complex, and more extensively explored than the other monoaminergic systems. The data on the influence of monoaminergic systems on PPN neuron activity are rather scarce. While there is evidence that the PPN influences the therapeutic response of L-DOPA, it is still difficult to discerne the reciprocal action of the PPN and monoaminergic systems in this action. Additional data are required to better understand the functional organization of monoaminergic inputs to the MLR including the PPN to get a clearer picture of their interaction.
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Affiliation(s)
- Giuseppe Di Giovanni
- Department of Physiology & Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK.
| | - Abdeslam Chagraoui
- Normandie Univ, UNIROUEN, INSERM, U1239, CHU Rouen, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Emilie Puginier
- Normandie Univ, UNIROUEN, INSERM, U1239, CHU Rouen, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Salvatore Galati
- Parkinson and movement Disorders Center Neurocenter of Southern Switzerland, Ospedale Civico di Lugano, Lugano, Switzerland
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5287), 146 rue Léo Saignat, B.P.281, F-33000 Bordeaux Cedex, France.
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16
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Abstract
Comparative studies have greatly contributed to our understanding of the organization and function of visual pathways of the brain, including that of humans. This comparative approach is a particularly useful tactic for studying the pulvinar nucleus, an enigmatic structure which comprises the largest territory of the human thalamus. This review focuses on the regions of the mouse pulvinar that receive input from the superior colliculus, and highlights similarities of the tectorecipient pulvinar identified across species. Open questions are discussed, as well as the potential contributions of the mouse model for endeavors to elucidate the function of the pulvinar nucleus.
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17
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Joling M, van den Heuvel OA, Berendse HW, Booij J, Vriend C. Serotonin transporter binding and anxiety symptoms in Parkinson's disease. J Neurol Neurosurg Psychiatry 2018; 89:89-94. [PMID: 28899958 DOI: 10.1136/jnnp-2017-316193] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/09/2017] [Accepted: 08/23/2017] [Indexed: 11/04/2022]
Abstract
BACKGROUND Anxiety is a common neuropsychiatric symptom in Parkinson's disease (PD), yet the neural mechanisms have been scarcely investigated. Disturbances in dopaminergic and serotonergic signalling may play a role in its pathophysiology. 123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (123I-FP-CIT) is a single-photon emission CT radiotracer, and its binding in striatal and extrastriatal subcortical brain areas represents predominant binding to the presynaptic dopamine transporter (DAT) and the serotonin transporter (SERT), respectively. Availability of DAT and SERT may thus provide an in vivo measure for the integrity of both dopamine and serotonin neurons. METHODS We studied the association between anxiety symptoms, measured with an affective subscale of the Beck Anxiety Inventory, and (extra)striatal 123I-FP-CIT binding in 127 non-demented patients with PD with a median disease duration of 2.55 (IQR 2.90) years. We conducted the analyses on patients currently on or not on dopamine replacement therapy (DRT). RESULTS Severity of anxiety symptoms showed a significant negative association with 123I-FP-CIT binding ratios in the right thalamus (β=-0.203, p=0.019; ΔR2=0.040) (multiple testing pcorr <0.020). In the subgroup of patients not on DRT (n=81), we found a significant negative association between anxiety and thalamic 123I-FP-CIT binding ratios bilaterally (right: β=-0.349, p=0.001, ΔR2=0.119; left: β=-0.269, p=0.017, ΔR2=0.071) (pcorr <0.020). CONCLUSION This study shows that higher levels of anxiety in patients with PD are associated with lower thalamic 123I-FP-CIT binding, pointing towards a contribution of serotonergic degeneration to anxiety symptoms in PD.
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Affiliation(s)
- Merijn Joling
- Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.,Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.,Research Program Neurodegeneration, Amsterdam Neuroscience, Amsterdam, The Netherlands.,Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Odile A van den Heuvel
- Research Program Neurodegeneration, Amsterdam Neuroscience, Amsterdam, The Netherlands.,Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.,Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands
| | - Henk W Berendse
- Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.,Research Program Neurodegeneration, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Jan Booij
- Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.,Research Program Neurodegeneration, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Chris Vriend
- Research Program Neurodegeneration, Amsterdam Neuroscience, Amsterdam, The Netherlands.,Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.,Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands
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18
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Fogerson PM, Huguenard JR. Tapping the Brakes: Cellular and Synaptic Mechanisms that Regulate Thalamic Oscillations. Neuron 2017; 92:687-704. [PMID: 27883901 DOI: 10.1016/j.neuron.2016.10.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/03/2016] [Accepted: 10/10/2016] [Indexed: 12/26/2022]
Abstract
Thalamic oscillators contribute to both normal rhythms associated with sleep and anesthesia and abnormal, hypersynchronous oscillations that manifest behaviorally as absence seizures. In this review, we highlight new findings that refine thalamic contributions to cortical rhythms and suggest that thalamic oscillators may be subject to both local and global control. We describe endogenous thalamic mechanisms that limit network synchrony and discuss how these protective brakes might be restored to prevent absence seizures. Finally, we describe how intrinsic and circuit-level specializations among thalamocortical loops may determine their involvement in widespread oscillations and render subsets of thalamic nuclei especially vulnerable to pathological synchrony.
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Affiliation(s)
- P Michelle Fogerson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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19
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Venzi M, David F, Bellet J, Cavaccini A, Bombardi C, Crunelli V, Di Giovanni G. Role for serotonin2A (5-HT2A) and 2C (5-HT2C) receptors in experimental absence seizures. Neuropharmacology 2016; 108:292-304. [PMID: 27085605 PMCID: PMC4920646 DOI: 10.1016/j.neuropharm.2016.04.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/10/2016] [Accepted: 04/12/2016] [Indexed: 01/25/2023]
Abstract
Absence seizures (ASs) are the hallmark of childhood/juvenile absence epilepsy. Monotherapy with first-line anti-absence drugs only controls ASs in 50% of patients, indicating the need for novel therapeutic targets. Since serotonin family-2 receptors (5-HT2Rs) are known to modulate neuronal activity in the cortico-thalamo-cortical loop, the main network involved in AS generation, we investigated the effect of selective 5-HT2AR and 5-HT2CR ligands on ASs in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a well established polygenic rat model of these non-convulsive seizures. GAERS rats were implanted with fronto-parietal EEG electrodes under general anesthesia, and their ASs were later recorded under freely moving conditions before and after intraperitoneal administration of various 5-HT2AR and 5-HT2CR ligands. The 5-HT2A agonist TCB-2 dose-dependently decreased the total time spent in ASs, an effect that was blocked by the selective 5-HT2A antagonist MDL11,939. Both MDL11,939 and another selective 5-HT2A antagonist (M100,907) increased the length of individual seizures when injected alone. The 5-HT2C agonists lorcaserin and CP-809,101 dose-dependently suppressed ASs, an effect blocked by the selective 5-HT2C antagonist SB 242984. In summary, 5-HT2ARs and 5-HT2CRs negatively control the expression of experimental ASs, indicating that selective agonists at these 5-HT2R subtypes might be potential novel anti-absence drugs. 5-HT2AR activation decreases absence seizures in GAERS. 5-HT2CR activation decreases absence seizures in GAERS. 5-HT2AR blockade increases absence seizures in GAERS. 5-HT2CR blockade does not affect absence seizures in GAERS.
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Affiliation(s)
- Marcello Venzi
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - François David
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Joachim Bellet
- Werner Reichardt Centre for Integrative Neuroscience, Tuebingen University, Tuebingen, Germany
| | - Anna Cavaccini
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Cristiano Bombardi
- University of Bologna, Department of Veterinary Medical Sciences, Bologna, Italy
| | - Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Physiology and Biochemistry, University of Malta, Malta.
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Physiology and Biochemistry, University of Malta, Malta.
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20
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Neske GT. The Slow Oscillation in Cortical and Thalamic Networks: Mechanisms and Functions. Front Neural Circuits 2016; 9:88. [PMID: 26834569 PMCID: PMC4712264 DOI: 10.3389/fncir.2015.00088] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 12/21/2015] [Indexed: 12/03/2022] Open
Abstract
During even the most quiescent behavioral periods, the cortex and thalamus express rich spontaneous activity in the form of slow (<1 Hz), synchronous network state transitions. Throughout this so-called slow oscillation, cortical and thalamic neurons fluctuate between periods of intense synaptic activity (Up states) and almost complete silence (Down states). The two decades since the original characterization of the slow oscillation in the cortex and thalamus have seen considerable advances in deciphering the cellular and network mechanisms associated with this pervasive phenomenon. There are, nevertheless, many questions regarding the slow oscillation that await more thorough illumination, particularly the mechanisms by which Up states initiate and terminate, the functional role of the rhythmic activity cycles in unconscious or minimally conscious states, and the precise relation between Up states and the activated states associated with waking behavior. Given the substantial advances in multineuronal recording and imaging methods in both in vivo and in vitro preparations, the time is ripe to take stock of our current understanding of the slow oscillation and pave the way for future investigations of its mechanisms and functions. My aim in this Review is to provide a comprehensive account of the mechanisms and functions of the slow oscillation, and to suggest avenues for further exploration.
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Affiliation(s)
- Garrett T Neske
- Department of Neuroscience, Division of Biology and Medicine, Brown UniversityProvidence, RI, USA; Department of Neurobiology, Yale UniversityNew Haven, CT, USA
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21
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Brill J, Shao Z, Puche AC, Wachowiak M, Shipley MT. Serotonin increases synaptic activity in olfactory bulb glomeruli. J Neurophysiol 2015; 115:1208-19. [PMID: 26655822 DOI: 10.1152/jn.00847.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/09/2015] [Indexed: 11/22/2022] Open
Abstract
Serotoninergic fibers densely innervate olfactory bulb glomeruli, the first sites of synaptic integration in the olfactory system. Acting through 5HT2A receptors, serotonin (5HT) directly excites external tufted cells (ETCs), key excitatory glomerular neurons, and depolarizes some mitral cells (MCs), the olfactory bulb's main output neurons. We further investigated 5HT action on MCs and determined its effects on the two major classes of glomerular interneurons: GABAergic/dopaminergic short axon cells (SACs) and GABAergic periglomerular cells (PGCs). In SACs, 5HT evoked a depolarizing current mediated by 5HT2C receptors but did not significantly impact spike rate. 5HT had no measurable direct effect in PGCs. Serotonin increased spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) in PGCs and SACs. Increased sEPSCs were mediated by 5HT2A receptors, suggesting that they are primarily due to enhanced excitatory drive from ETCs. Increased sIPSCs resulted from elevated excitatory drive onto GABAergic interneurons and augmented GABA release from SACs. Serotonin-mediated GABA release from SACs was action potential independent and significantly increased miniature IPSC frequency in glomerular neurons. When focally applied to a glomerulus, 5HT increased MC spontaneous firing greater than twofold but did not increase olfactory nerve-evoked responses. Taken together, 5HT modulates glomerular network activity in several ways: 1) it increases ETC-mediated feed-forward excitation onto MCs, SACs, and PGCs; 2) it increases inhibition of glomerular interneurons; 3) it directly triggers action potential-independent GABA release from SACs; and 4) these network actions increase spontaneous MC firing without enhancing responses to suprathreshold sensory input. This may enhance MC sensitivity while maintaining dynamic range.
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Affiliation(s)
- Julia Brill
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Zuoyi Shao
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Adam C Puche
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Matt Wachowiak
- Department of Neurobiology and Anatomy, and Brain Institute, University of Utah, Salt Lake City, Utah
| | - Michael T Shipley
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
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22
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Puzerey PA, Kodama NX, Galán RF. Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice. J Neurophysiol 2015; 115:813-25. [PMID: 26609119 DOI: 10.1152/jn.00996.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 11/24/2015] [Indexed: 12/18/2022] Open
Abstract
Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1(-/-)) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1(-/-) mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1.
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Affiliation(s)
- Pavel A Puzerey
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Nathan X Kodama
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Roberto F Galán
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
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23
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Goitia B, Rivero-Echeto MC, Weisstaub NV, Gingrich JA, Garcia-Rill E, Bisagno V, Urbano FJ. Modulation of GABA release from the thalamic reticular nucleus by cocaine and caffeine: role of serotonin receptors. J Neurochem 2015; 136:526-35. [PMID: 26484945 DOI: 10.1111/jnc.13398] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/23/2015] [Accepted: 10/02/2015] [Indexed: 11/30/2022]
Abstract
Serotonin receptors are targets of drug therapies for a variety of neuropsychiatric and neurodegenerative disorders. Cocaine inhibits the re-uptake of serotonin (5-HT), dopamine, and noradrenaline, whereas caffeine blocks adenosine receptors and opens ryanodine receptors in the endoplasmic reticulum. We studied how 5-HT and adenosine affected spontaneous GABAergic transmission from thalamic reticular nucleus. We combined whole-cell patch clamp recordings of miniature inhibitory post-synaptic currents (mIPSCs) in ventrobasal thalamic neurons during local (puff) application of 5-HT in wild type (WT) or knockout mice lacking 5-HT2A receptors (5-HT2A -/-). Inhibition of mIPSCs frequency by low (10 μM) and high (100 μM) 5-HT concentrations was observed in ventrobasal neurons from 5-HT2A -/- mice. In WT mice, only 100 μM 5-HT significantly reduced mIPSCs frequency. In 5-HT2A -/- mice, NAN-190, a specific 5-HT1A antagonist, prevented the 100 μM 5-HT inhibition while blocking H-currents that prolonged inhibition during post-puff periods. The inhibitory effects of 100 μM 5-HT were enhanced in cocaine binge-treated 5-HT2A -/- mice. Caffeine binge treatment did not affect 5-HT-mediated inhibition. Our findings suggest that both 5-HT1A and 5-HT2A receptors are present in pre-synaptic thalamic reticular nucleus terminals. Serotonergic-mediated inhibition of GABA release could underlie aberrant thalamocortical physiology described after repetitive consumption of cocaine. Our findings suggest that both 5-HT1A , 5-HT2A and A1 receptors are present in pre-synaptic TRN terminals. 5-HT1A and A1 receptors would down-regulate adenylate cyclase, whereas 5-HT1A would also increase the probability of the opening of G-protein-activated inwardly rectifying K(+) channels (GIRK). Sustained opening of GIRK channels would hyperpolarize pre-synaptic terminals activating H-currents, resulting in less GABA release. 5-HT2A -would activate PLC and IP3 , increasing intracellular [Ca(2+) ] and thus facilitating GABA release.
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Affiliation(s)
- Belén Goitia
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina.,Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - María Celeste Rivero-Echeto
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina.,Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Noelia V Weisstaub
- Grupo de Neurociencia de Sistemas, Departamento de Fisiología, Facultad de Medicina, Instituto de Fisiología y Biofísica (IFIBIO), UBA, Ciudad de Buenos Aires, Argentina
| | - Jay A Gingrich
- Division of Developmental Neuroscience, Columbia University and the NYSPI, Sackler Institute for Developmental Psychobiology, New York City, New York, USA
| | - Edgar Garcia-Rill
- Department of Neurobiology and Developmental Sciences, Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Verónica Bisagno
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Francisco J Urbano
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina
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24
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Crunelli V, Di Giovanni G. Differential Control by 5-HT and 5-HT1A, 2A, 2C Receptors of Phasic and Tonic GABAA Inhibition in the Visual Thalamus. CNS Neurosci Ther 2015; 21:967-70. [PMID: 26555767 PMCID: PMC4973707 DOI: 10.1111/cns.12480] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 11/29/2022] Open
Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK.,Department of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK.,Department of Physiology and Biochemistry, University of Malta, Msida, Malta
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25
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Leuchter AF, Hunter AM, Krantz DE, Cook IA. Intermediate phenotypes and biomarkers of treatment outcome in major depressive disorder. DIALOGUES IN CLINICAL NEUROSCIENCE 2015. [PMID: 25733956 PMCID: PMC4336921 DOI: 10.31887/dcns.2014.16.4/aleuchter] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Major depressive disorder (MDD) is a pleomorphic illness originating from gene x environment interactions. Patients with differing symptom phenotypes receive the same diagnosis and similar treatment recommendations without regard to genomics, brain structure or function, or other physiologic or psychosocial factors. Using this present approach, only one third of patients enter remission with the first medication prescribed, and patients may take longer than 1 year to enter remission with repeated trials. Research to improve treatment effectiveness recently has focused on identification of intermediate phenotypes (IPs) that could parse the heterogeneous population of patients with MDD into subgroups with more homogeneous responses to treatment. Such IPs could be used to develop biomarkers that could be applied clinically to match patients with the treatment that would be most likely to lead to remission. Putative biomarkers include genetic polymorphisms, RNA and protein expression (transcriptome and proteome), neurotransmitter levels (metabolome), additional measures of signaling cascades, oscillatory synchrony, neuronal circuits and neural pathways (connectome), along with other possible physiologic measures. All of these measures represent components of a continuum that extends from proximity to the genome to proximity to the clinical phenotype of depression, and there are many levels along this continuum at which useful IPs may be defined. Because of the highly integrative nature of brain systems and the complex neurobiology of depression, the most useful biomarkers are likely to be those with intermediate proximity both to the genome and the clinical phenotype of MDD. Translation of findings across the spectrum from genotype to phenotype promises to better characterize the complex disruptions in signaling and neuroplasticity that accompany MDD, and ultimately to lead to greater understanding of the causes of depressive illness.
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Affiliation(s)
- Andrew F Leuchter
- Laboratory of Brain, Behavior, and Pharmacology, and the Depression Research and Clinical Program, Semel Institute for Neuroscience and Human Behavior, UCLA; the Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Aimee M Hunter
- Laboratory of Brain, Behavior, and Pharmacology, and the Depression Research and Clinical Program, Semel Institute for Neuroscience and Human Behavior, UCLA; the Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - David E Krantz
- Laboratory of Brain, Behavior, and Pharmacology, and the Depression Research and Clinical Program, Semel Institute for Neuroscience and Human Behavior, UCLA; the Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Ian A Cook
- Laboratory of Brain, Behavior, and Pharmacology, and the Depression Research and Clinical Program, Semel Institute for Neuroscience and Human Behavior, UCLA; the Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, UCLA; the Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, UCLA, Los Angeles, California, USA
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Pickard GE, So KF, Pu M. Dorsal raphe nucleus projecting retinal ganglion cells: Why Y cells? Neurosci Biobehav Rev 2015; 57:118-31. [PMID: 26363667 PMCID: PMC4646079 DOI: 10.1016/j.neubiorev.2015.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 06/30/2015] [Accepted: 08/01/2015] [Indexed: 10/23/2022]
Abstract
Retinal ganglion Y (alpha) cells are found in retinas ranging from frogs to mice to primates. The highly conserved nature of the large, fast conducting retinal Y cell is a testament to its fundamental task, although precisely what this task is remained ill-defined. The recent discovery that Y-alpha retinal ganglion cells send axon collaterals to the serotonergic dorsal raphe nucleus (DRN) in addition to the lateral geniculate nucleus (LGN), medial interlaminar nucleus (MIN), pretectum and the superior colliculus (SC) has offered new insights into the important survival tasks performed by these cells with highly branched axons. We propose that in addition to its role in visual perception, the Y-alpha retinal ganglion cell provides concurrent signals via axon collaterals to the DRN, the major source of serotonergic afferents to the forebrain, to dramatically inhibit 5-HT activity during orientation or alerting/escape responses, which dis-facilitates ongoing tonic motor activity while dis-inhibiting sensory information processing throughout the visual system. The new data provide a fresh view of these evolutionarily old retinal ganglion cells.
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Affiliation(s)
- Gary E Pickard
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE, 68583, United States; Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, United States; GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Kwok-Fai So
- Department of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; Department of Ophthalmology, The University of Hong Kong, Hong Kong, China; GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China; State Key Laboratory for Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China.
| | - Mingliang Pu
- Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University, Beijing, China; Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, China; Key Laboratory for Visual Impairment and Restoration (Ministry of Education), Peking University, Beijing, China.
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Deviance detection in auditory subcortical structures: what can we learn from neurochemistry and neural connectivity? Cell Tissue Res 2015; 361:215-32. [DOI: 10.1007/s00441-015-2134-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/22/2015] [Indexed: 12/18/2022]
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Dale E, Zhang H, Leiser SC, Xiao Y, Lu D, Yang CR, Plath N, Sanchez C. Vortioxetine disinhibits pyramidal cell function and enhances synaptic plasticity in the rat hippocampus. J Psychopharmacol 2014; 28:891-902. [PMID: 25122043 PMCID: PMC4230848 DOI: 10.1177/0269881114543719] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Vortioxetine, a novel antidepressant with multimodal action, is a serotonin (5-HT)3, 5-HT7 and 5-HT1D receptor antagonist, a 5-HT1B receptor partial agonist, a 5-HT1A receptor agonist and a 5-HT transporter (SERT) inhibitor. Vortioxetine has been shown to improve cognitive performance in several preclinical rat models and in patients with major depressive disorder. Here we investigated the mechanistic basis for these effects by studying the effect of vortioxetine on synaptic transmission, long-term potentiation (LTP), a cellular correlate of learning and memory, and theta oscillations in the rat hippocampus and frontal cortex. Vortioxetine was found to prevent the 5-HT-induced increase in inhibitory post-synaptic potentials recorded from CA1 pyramidal cells, most likely by 5-HT3 receptor antagonism. Vortioxetine also enhanced LTP in the CA1 region of the hippocampus. Finally, vortioxetine increased fronto-cortical theta power during active wake in whole animal electroencephalographic recordings. In comparison, the selective SERT inhibitor escitalopram showed no effect on any of these measures. Taken together, our results indicate that vortioxetine can increase pyramidal cell output, which leads to enhanced synaptic plasticity in the hippocampus. Given the central role of the hippocampus in cognition, these findings may provide a cellular correlate to the observed preclinical and clinical cognition-enhancing effects of vortioxetine.
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Affiliation(s)
| | | | | | - Yixin Xiao
- Shanghai Chempartner Co. Ltd., Shanghai, China
| | - Dunguo Lu
- Shanghai Chempartner Co. Ltd., Shanghai, China
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de Medeiros Silva A, de Santana MAD, de Góis Morais PLA, de Sousa TB, Januário Engelberth RCG, de Souza Lucena EE, Campêlo CLDC, Sousa Cavalcante J, Cavalcante JC, de Oliveira Costa MSM, Nascimento ESD. Serotonergic fibers distribution in the midline and intralaminar thalamic nuclei in the rock cavy (Kerodon rupestris). Brain Res 2014; 1586:99-108. [DOI: 10.1016/j.brainres.2014.08.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/14/2014] [Accepted: 08/16/2014] [Indexed: 12/19/2022]
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Schulson M, Liu A, Björkman T, Quinton A, Mann KP, Benzie R, Peek M, Nanan R. Mid-Gestational Enlargement of Fetal Thalami in Women Exposed to Methadone during Pregnancy. Front Surg 2014; 1:28. [PMID: 25593952 PMCID: PMC4286970 DOI: 10.3389/fsurg.2014.00028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/08/2014] [Indexed: 11/13/2022] Open
Abstract
Methadone maintenance therapy is the standard of care in many countries for opioid-dependent women who become pregnant. Despite recent evidence showing significant neurodevelopmental changes in children and adults exposed to both licit and illicit substances in utero, data on the effects of opioids in particular remains scarce. The purpose of this study was to examine the effects of opiate use, in particular methadone, on various fetal cortical and biometric growth parameters in utero using ultrasound measurements done at 18-22 weeks gestation. Head circumference (HC), bi-parietal diameter, lateral ventricle diameter, transcerebellar diameter, thalamic diameter, cisterna magna diameter, and femur length were compared between fetuses born to methadone-maintained mothers and non-substance using controls. A significantly larger thalamic diameter (0.05 cm, p = 0.01) was observed in the opiate-exposed group. Thalamic diameter/HC ratio was also significantly raised (0.03 mm, p = 0.01). We hypothesize here that the increase in thalamic diameter in opiate-exposed fetuses could potentially be explained by regional differences in opioid and serotonin receptor densities, an alteration in monoamine neurotransmitter systems, and an enhancement of the normal growth increase that occurs in the thalamus during mid-gestation.
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Affiliation(s)
- Meredith Schulson
- Discipline of Paediatrics, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia
| | - Anthony Liu
- Discipline of Paediatrics, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia ; Charles Perkins Centre - Nepean, The University of Sydney , Penrith, NSW , Australia
| | - Tracey Björkman
- Perinatal Research Centre, UQ Centre for Clinical Research, The University of Queensland , Herston, QLD , Australia
| | - Ann Quinton
- Charles Perkins Centre - Nepean, The University of Sydney , Penrith, NSW , Australia ; Discipline of Obstetrics and Gynaecology, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia
| | - Kristy P Mann
- NHMRC Clinical Trials Centre, The University of Sydney , Camperdown, NSW , Australia
| | - Ron Benzie
- Discipline of Obstetrics and Gynaecology, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia
| | - Michael Peek
- Charles Perkins Centre - Nepean, The University of Sydney , Penrith, NSW , Australia ; Discipline of Obstetrics and Gynaecology, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia
| | - Ralph Nanan
- Discipline of Paediatrics, Sydney Medical School - Nepean, The University of Sydney , Penrith, NSW , Australia ; Charles Perkins Centre - Nepean, The University of Sydney , Penrith, NSW , Australia
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Varela C. Thalamic neuromodulation and its implications for executive networks. Front Neural Circuits 2014; 8:69. [PMID: 25009467 PMCID: PMC4068295 DOI: 10.3389/fncir.2014.00069] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 06/07/2014] [Indexed: 01/25/2023] Open
Abstract
The thalamus is a key structure that controls the routing of information in the brain. Understanding modulation at the thalamic level is critical to understanding the flow of information to brain regions involved in cognitive functions, such as the neocortex, the hippocampus, and the basal ganglia. Modulators contribute the majority of synapses that thalamic cells receive, and the highest fraction of modulator synapses is found in thalamic nuclei interconnected with higher order cortical regions. In addition, disruption of modulators often translates into disabling disorders of executive behavior. However, modulation in thalamic nuclei such as the midline and intralaminar groups, which are interconnected with forebrain executive regions, has received little attention compared to sensory nuclei. Thalamic modulators are heterogeneous in regards to their origin, the neurotransmitter they use, and the effect on thalamic cells. Modulators also share some features, such as having small terminal boutons and activating metabotropic receptors on the cells they contact. I will review anatomical and physiological data on thalamic modulators with these goals: first, determine to what extent the evidence supports similar modulator functions across thalamic nuclei; and second, discuss the current evidence on modulation in the midline and intralaminar nuclei in relation to their role in executive function.
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Affiliation(s)
- Carmen Varela
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology Cambridge, MA, USA
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Shukla R, Watakabe A, Yamamori T. mRNA expression profile of serotonin receptor subtypes and distribution of serotonergic terminations in marmoset brain. Front Neural Circuits 2014; 8:52. [PMID: 24904298 PMCID: PMC4032978 DOI: 10.3389/fncir.2014.00052] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 04/25/2014] [Indexed: 01/06/2023] Open
Abstract
To better understand serotonin function in the primate brain, we examined the mRNA expression patterns of all the 13 members of the serotonin receptor (5HTR) family, by in situ hybridization (ISH) and the distribution of serotonergic terminations by serotonin transporter (SERT) protein immunohistochemical analysis. Ten of the 13 5HTRs showed significant mRNA expressions in the marmoset brain. Our study shows several new features of the organization of serotonergic systems in the marmoset brain. (1) The thalamus expressed only a limited number of receptor subtypes compared with the cortex, hippocampus, and other subcortical regions. (2) In the cortex, there are layer-selective and area-selective mRNA expressions of 5HTRs. (3) Highly localized mRNA expressions of 5HT1F and 5HT3A were observed. (4) There was a conspicuous overlap of the mRNA expressions of receptor subtypes known to have somatodendritic localization of receptor proteins with dense serotonergic terminations in the visual cortex, the central lateral (CL) nucleus of the thalamus, the presubiculum, and the medial mammillary nucleus of the hypothalamus. This suggests a high correlation between serotonin availability and receptor expression at these locations. (5) The 5HTRs show differences in mRNA expression pattern between the marmoset and mouse cortices whereas the patterns of both the species were much similar in the hippocampus. We discuss the possible roles of 5HTRs in the marmoset brain revealed by the analysis of their overall mRNA expression patterns.
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Affiliation(s)
- Rammohan Shukla
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI) Okazaki, Japan
| | - Akiya Watakabe
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI) Okazaki, Japan
| | - Tetsuo Yamamori
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI) Okazaki, Japan
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Teran FA, Massey CA, Richerson GB. Serotonin neurons and central respiratory chemoreception: where are we now? PROGRESS IN BRAIN RESEARCH 2014; 209:207-33. [PMID: 24746050 DOI: 10.1016/b978-0-444-63274-6.00011-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) neurons are widely considered to play an important role in central respiratory chemoreception. Although many studies in the past decades have supported this hypothesis, there had been concerns about its validity until recently. One recurring claim had been that 5-HT neurons are not consistently sensitive to hypercapnia in vivo. Another belief was that 5-HT neurons do not stimulate breathing; instead, they inhibit or modulate respiratory output. It was also believed by some that 5-HT neuron chemosensitivity is dependent on TASK channels, but mice with genetic deletion of TASK-1 and TASK-3 have a normal hypercapnic ventilatory response. This review explains why these principal arguments against the hypothesis are not supported by existing data. Despite repeated challenges, a large body of evidence now supports the conclusion that at least a subset of 5-HT neurons are central chemoreceptors.
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Affiliation(s)
- Frida A Teran
- St. Mary's University, One Camino Santa Maria, San Antonio, TX, USA
| | - Cory A Massey
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - George B Richerson
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; VAMC, Iowa City, IA, USA.
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Karthikeyan K, Kumar RS, Dheenkumar P, Perumal PT. Solvent and catalyst free route to 3-indolyl glycoconjugates: synthesis of sugar tethered isoxazolines and isoxazoles from 3-indolyl nitroalkanes. RSC Adv 2014. [DOI: 10.1039/c4ra02825b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
An expedient, solvent and catalyst free strategy for the synthesis of sugar based bis(indolyl)methanes and indolyl nitroalkanes has been developed. Further, the nitroalkanes were converted to novel isoxazolines and isoxazoles by nitrile oxides cycloaddition.
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Affiliation(s)
- K. Karthikeyan
- Organic Chemistry Division
- CSIR-Central Leather Research Institute
- Chennai, India
- Department of Chemistry
- B. S. Abdur Rahman University
| | - R. Senthil Kumar
- Organic Chemistry Division
- CSIR-Central Leather Research Institute
- Chennai, India
| | - P. Dheenkumar
- Organic Chemistry Division
- CSIR-Central Leather Research Institute
- Chennai, India
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Abstract
During waking behavior, animals adapt their state of arousal in response to environmental pressures. Sensory processing is regulated in aroused states, and several lines of evidence imply that this is mediated at least partly by the serotonergic system. However, there is little information directly showing that serotonergic function is required for state-dependent modulation of sensory processing. Here we find that zebrafish larvae can maintain a short-term state of arousal during which neurons in the dorsal raphe modulate sensory responsiveness to behaviorally relevant visual cues. After a brief exposure to water flow, larvae show elevated activity and heightened sensitivity to perceived motion. Calcium imaging of neuronal activity after flow revealed increased activity in serotonergic neurons of the dorsal raphe. Genetic ablation of these neurons abolished the increase in visual sensitivity during arousal without affecting baseline visual function or locomotor activity. We traced projections from the dorsal raphe to a major visual area, the optic tectum. Laser ablation of the tectum demonstrated that this structure, like the dorsal raphe, is required for improved visual sensitivity during arousal. These findings reveal that serotonergic neurons of the dorsal raphe have a state-dependent role in matching sensory responsiveness to behavioral context.
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Abstract
This review summarizes the brain mechanisms controlling sleep and wakefulness. Wakefulness promoting systems cause low-voltage, fast activity in the electroencephalogram (EEG). Multiple interacting neurotransmitter systems in the brain stem, hypothalamus, and basal forebrain converge onto common effector systems in the thalamus and cortex. Sleep results from the inhibition of wake-promoting systems by homeostatic sleep factors such as adenosine and nitric oxide and GABAergic neurons in the preoptic area of the hypothalamus, resulting in large-amplitude, slow EEG oscillations. Local, activity-dependent factors modulate the amplitude and frequency of cortical slow oscillations. Non-rapid-eye-movement (NREM) sleep results in conservation of brain energy and facilitates memory consolidation through the modulation of synaptic weights. Rapid-eye-movement (REM) sleep results from the interaction of brain stem cholinergic, aminergic, and GABAergic neurons which control the activity of glutamatergic reticular formation neurons leading to REM sleep phenomena such as muscle atonia, REMs, dreaming, and cortical activation. Strong activation of limbic regions during REM sleep suggests a role in regulation of emotion. Genetic studies suggest that brain mechanisms controlling waking and NREM sleep are strongly conserved throughout evolution, underscoring their enormous importance for brain function. Sleep disruption interferes with the normal restorative functions of NREM and REM sleep, resulting in disruptions of breathing and cardiovascular function, changes in emotional reactivity, and cognitive impairments in attention, memory, and decision making.
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Affiliation(s)
- Ritchie E Brown
- Laboratory of Neuroscience, VA Boston Healthcare System and Harvard Medical School, Brockton, Massachusetts 02301, USA
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Thalamic burst firing propensity: a comparison of the dorsal lateral geniculate and pulvinar nuclei in the tree shrew. J Neurosci 2012; 31:17287-99. [PMID: 22114295 DOI: 10.1523/jneurosci.6431-10.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Relay neurons in dorsal thalamic nuclei can fire high-frequency bursts of action potentials that ride the crest of voltage-dependent transient (T-type) calcium currents [low-threshold spike (LTS)]. To explore potential nucleus-specific burst features, we compared the membrane properties of dorsal lateral geniculate nucleus (dLGN) and pulvinar nucleus relay neurons using in vitro whole-cell recording in juvenile and adult tree shrew (Tupaia) tissue slices. We injected current ramps of variable slope into neurons that were sufficiently hyperpolarized to de-inactivate T-type calcium channels. In a small percentage of juvenile pulvinar and dLGN neurons, an LTS could not be evoked. In the remaining juvenile neurons and in all adult dLGN neurons, a single LTS could be evoked by current ramps. However, in the adult pulvinar, current ramps evoked multiple LTSs in >70% of recorded neurons. Using immunohistochemistry, Western blot techniques, unbiased stereology, and confocal and electron microscopy, we found that pulvinar neurons expressed more T-type calcium channels (Ca(v) 3.2) and more small conductance potassium channels (SK2) than dLGN neurons and that the pulvinar nucleus contained a higher glia-to-neuron ratio than the dLGN. Hodgkin-Huxley-type compartmental models revealed that the distinct firing modes could be replicated by manipulating T-type calcium and SK2 channel density, distribution, and kinetics. The intrinsic properties of pulvinar neurons that promote burst firing in the adult may be relevant to the treatment of conditions that involve the adult onset of aberrant thalamocortical interactions.
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Trakhtenberg EF, Goldberg JL. The role of serotonin in axon and dendrite growth. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012; 106:105-26. [PMID: 23211461 DOI: 10.1016/b978-0-12-407178-0.00005-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) plays multiple roles in the enteric, peripheral, and central nervous systems (CNS). Although its most prominent biological function is as a signal transmission messenger from pre- to postsynaptic neurons, other roles such as shaping brain development and regulating neurite growth have also been described. Here, we review the less well-studied role of 5-HT as a modulator of neurite growth. 5-HT has been shown to regulate neurite growth in multiple systems and species, including in the mammalian CNS. 5-HT predominantly appears to suppress neurite growth, but depending on the model system and 5-HT receptor subtype, in rare cases, it may promote neurite outgrowth and elongation. Failure of axon regeneration in the adult mammalian CNS is a major problem in multiple diseases, and understanding how 5-HT receptors signal opposing effects on neurite growth may lead to novel neuroregenerative therapies, by targeting either 5-HT receptors or their downstream signaling pathways.
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Affiliation(s)
- Ephraim F Trakhtenberg
- Bascom Palmer Eye Institute, Interdisciplinary Stem Cell Institute, Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Mapping patterns of depression-related brain regions with cytochrome oxidase histochemistry: Relevance of animal affective systems to human disorders, with a focus on resilience to adverse events. Neurosci Biobehav Rev 2011; 35:1876-89. [DOI: 10.1016/j.neubiorev.2011.02.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 12/28/2022]
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Perceptual illusions provide clues to excitatory–inhibitory balance in migraine neocortex. Cephalalgia 2011; 31:1155-7. [DOI: 10.1177/0333102411411205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Liimatainen S, Lehtimäki K, Raitala A, Peltola M, Oja SS, Peltola J, Hurme MA. Increased indoleamine 2,3-dioxygenase (IDO) activity in idiopathic generalized epilepsy. Epilepsy Res 2011; 94:206-12. [PMID: 21377330 DOI: 10.1016/j.eplepsyres.2011.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 01/25/2011] [Accepted: 02/06/2011] [Indexed: 11/17/2022]
Abstract
PURPOSE Indoleamine 2,3-dioxygenase (IDO) is a cytokine-inducible enzyme that participates in tryptophan (trp) and serotonin metabolism with an ability to modulate neuroinflammation. Several recent studies have shown associations between cytokines and epilepsy. In this study we investigated whether activation of IDO is associated with epilepsy. METHODS Kynurenine (kyn)/trp serum ratio, as an indicator of IDO activity was analyzed in 271 carefully classified epilepsy patients, and 309 healthy adults. RESULTS IDO activity was increased in patients with unclassified idiopathic generalized epilepsy (IGE) (n=11; p=0.05), in juvenile myoclonic epilepsy (JME) (n=25; p=0.04) and in patients those with temporal lobe epilepsy but no hippocampal sclerosis (TLE-HS) (n=103; p=0.05) compared to the control subjects. In patients with idiopathic (but not cryptogenic or symptomatic) etiology of epilepsy, IDO activity was increased compared to the control subjects (p<0.05). Patients with extra-TLE or TLE+HS had IDO activity comparable to the control subjects. Patients who were one-month seizure-free prior to sampling had increased IDO activity compared to the control subjects (p=0.03). CONCLUSIONS Increased IDO activity appeared to be associated with idiopathic generalized epilepsies such as unclassified IGE and JME, two of the most common types of primary generalized epilepsy. We also found a trend of increased IDO activity in patients with TLE-HS. Our results suggest that increased IDO activity may represent an adaptive metabolic phenomenon in epilepsy, which may also have a neuroprotective or anticonvulsive role by downregulating neuroinflammation in the brain.
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Affiliation(s)
- Suvi Liimatainen
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland; Emergency Department Acuta, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Kai Lehtimäki
- Department of Neurosurgery, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Annika Raitala
- Department of Microbiology and Immunology, University of Tampere, Medical School, 33014 Tampere, Finland
| | - Maria Peltola
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Simo S Oja
- Department of Paediatrics, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Jukka Peltola
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Mikko A Hurme
- Department of Microbiology and Immunology, University of Tampere, Medical School, 33014 Tampere, Finland; The Laboratory Centre, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
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Sub-threshold cross-modal sensory interaction in the thalamus: lemniscal auditory response in the medial geniculate nucleus is modulated by somatosensory stimulation. Neuroscience 2011; 174:200-15. [DOI: 10.1016/j.neuroscience.2010.11.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 11/19/2010] [Accepted: 11/19/2010] [Indexed: 11/19/2022]
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Hurley LM, Hall IC. Context-dependent modulation of auditory processing by serotonin. Hear Res 2010; 279:74-84. [PMID: 21187135 DOI: 10.1016/j.heares.2010.12.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 12/13/2010] [Accepted: 12/20/2010] [Indexed: 10/18/2022]
Abstract
Context-dependent plasticity in auditory processing is achieved in part by physiological mechanisms that link behavioral state to neural responses to sound. The neuromodulator serotonin has many characteristics suitable for such a role. Serotonergic neurons are extrinsic to the auditory system but send projections to most auditory regions. These projections release serotonin during particular behavioral contexts. Heightened levels of behavioral arousal and specific extrinsic events, including stressful or social events, increase serotonin availability in the auditory system. Although the release of serotonin is likely to be relatively diffuse, highly specific effects of serotonin on auditory neural circuitry are achieved through the localization of serotonergic projections, and through a large array of receptor types that are expressed by specific subsets of auditory neurons. Through this array, serotonin enacts plasticity in auditory processing in multiple ways. Serotonin changes the responses of auditory neurons to input through the alteration of intrinsic and synaptic properties, and alters both short- and long-term forms of plasticity. The infrastructure of the serotonergic system itself is also plastic, responding to age and cochlear trauma. These diverse findings support a view of serotonin as a widespread mechanism for behaviorally relevant plasticity in the regulation of auditory processing. This view also accommodates models of how the same regulatory mechanism can have pathological consequences for auditory processing.
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Affiliation(s)
- L M Hurley
- Indiana University, Jordan Hall/Biology, 1001 E. Third St, Bloomington, IN 47405, USA.
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Effects of T-type calcium channel blockers on cocaine-induced hyperlocomotion and thalamocortical GABAergic abnormalities in mice. Psychopharmacology (Berl) 2010; 212:205-14. [PMID: 20652540 DOI: 10.1007/s00213-010-1947-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/27/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Repetitive cocaine exposure has been shown to induce GABAergic thalamic alterations. Given the key role of T-type (Ca(V)3) calcium channels in thalamocortical physiology, the direct involvement of these calcium channels in cocaine-mediated effects needs to be further explored. OBJECTIVE The objective of this study was to investigate the effect of T-type calcium channel blockers on acute and repetitive cocaine administration that mediates thalamocortical alterations in mice using three different T-type blockers: 2-octanol, nickel, and mibefradil. METHODS During in vitro experiments, whole-cell patch-clamp recordings were conducted in ventrobasal (VB) thalamic neurons from mice treated with acute repetitive cocaine administration (3 x 15 mg/kg, i.p., 1 h apart), under bath application of mibefradil (10 μM), 2-octanol (50 μM), or nickel (200 μM). After systemic administration of T-type calcium channel blockers, we evaluated locomotor activity and also recorded GABAergic neurotransmission onto VB neurons in vitro. RESULTS Bath-applied mibefradil, 2-octanol, or nickel significantly reduced both GABAergic neurotransmission and T-type currents of VB neurons in cocaine-treated mice. In vivo i.p. pre-administration of either mibefradil (20 mg/kg and 5 mg/kg) or 2-octanol (0.5 mg/kg and 0.07 mg/kg) significantly reduced GABAergic mini frequencies onto VB neurons. Moreover, both mibefradil and 2-octanol were able to decrease cocaine-induced hyperlocomotion. CONCLUSION The results shown in this study strongly suggest that T-type calcium channels play a key role in cocaine-mediated GABAergic thalamocortical alterations, and further propose T-type channel blockers as potential targets for future pharmacological strategies aimed at treating cocaine's deleterious effects on physiology and behavior.
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Abstract
There is a long-standing controversy about the role of serotonin in sleep/wake control, with competing theories that it either promotes sleep or causes arousal. Here, we show that there is a marked increase in wakefulness when all serotonin neurons are genetically deleted in mice hemizygous for ePet1-Cre and homozygous for floxed Lmx1b (Lmx1b(f/f/p)). However, this only occurs at cool ambient temperatures and can be explained by a thermoregulatory defect that leads to an increase in motor activity to generate heat. Because some serotonin neurons are stimulated by CO(2), and serotonin activates thalamocortical networks, we hypothesized that serotonin neurons cause arousal in response to hypercapnia. We found that Lmx1b(f/f/p) mice completely lacked any arousal response to inhalation of 10% CO(2) (with 21% O(2) in balance N(2)) but had normal arousal responses to hypoxia, sound, and air puff. We propose that serotonin neurons mediate the potentially life-saving arousal response to hypercapnia. Impairment of this response may contribute to sudden unexpected death in epilepsy, sudden infant death syndrome, and sleep apnea.
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Govindaiah G, Wang Y, Cox CL. Dopamine enhances the excitability of somatosensory thalamocortical neurons. Neuroscience 2010; 170:981-91. [PMID: 20801197 DOI: 10.1016/j.neuroscience.2010.08.043] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/17/2010] [Accepted: 08/20/2010] [Indexed: 11/18/2022]
Abstract
The thalamus conveys sensory information from peripheral and subcortical regions to the neocortex in a dynamic manner that can be influenced by several neuromodulators. Alterations in dopamine (DA) receptor function in thalami of Schizophrenic patients have recently been reported. In addition, schizophrenia is associated with sensory gating abnormalities and sleep-wake disturbances, thus we examined the role of DA on neuronal excitability in somatosensory thalamus. The ventrobasal (VB) thalamus receives dopaminergic innervation and expresses DA receptors; however, the action of DA on VB neurons is unknown. In the present study, we performed whole cell current- and voltage-clamp recordings in rat brain slices to investigate the role of DA on excitability of VB neurons. We found that DA increased action potential discharge and elicited membrane depolarization via activation of different receptor subtypes. Activation of D2-like receptors (D(2R)) leads to enhanced action potential discharge, whereas the membrane depolarization was mediated by D1-like receptors (D(1R)). The D(2R-mediated) increase in spike discharge was mimicked and occluded by α-dendrotoxin (α-DTX), indicating the involvement of a slowly inactivating K(+) channels. The D1R-mediated membrane depolarization was occluded by barium, suggesting the involvement of a G protein-coupled K(+) channel or an inwardly rectifying K(+) channel. Our results indicate that DA produces dual modulatory effects acting on subtypes of DA receptors in thalamocortical relay neurons, and likely plays a significant role in the modulation of sensory information.
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Affiliation(s)
- G Govindaiah
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Ramsey LCB, Sinha SR, Hurley LM. 5-HT1A and 5-HT1B receptors differentially modulate rate and timing of auditory responses in the mouse inferior colliculus. Eur J Neurosci 2010; 32:368-79. [PMID: 20646059 DOI: 10.1111/j.1460-9568.2010.07299.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) is a physiological signal that translates both internal and external information about behavioral context into changes in sensory processing through a diverse array of receptors. The details of this process, particularly how receptors interact to shape sensory encoding, are poorly understood. In the inferior colliculus, a midbrain auditory nucleus, 5-HT1A receptors have suppressive and 5-HT1B receptors have facilitatory effects on evoked responses of neurons. We explored how these two receptor classes interact by testing three hypotheses: that they (i) affect separate neuron populations; (ii) affect different response properties; or (iii) have different endogenous patterns of activation. The first two hypotheses were tested by iontophoretic application of 5-HT1A and 5-HT1B receptor agonists individually and together to neurons in vivo. 5-HT1A and 5-HT1B agonists affected overlapping populations of neurons. During co-application, 5-HT1A and 5-HT1B agonists influenced spike rate and frequency bandwidth additively, with each moderating the effect of the other. In contrast, although both agonists individually influenced latencies and interspike intervals, the 5-HT1A agonist dominated these measurements during co-application. The third hypothesis was tested by applying antagonists of the 5-HT1A and 5-HT1B receptors. Blocking 5-HT1B receptors was complementary to activation of the receptor, but blocking 5-HT1A receptors was not, suggesting the endogenous activation of additional receptor types. These results suggest that cooperative interactions between 5-HT1A and 5-HT1B receptors shape auditory encoding in the inferior colliculus, and that the effects of neuromodulators within sensory systems may depend nonlinearly on the specific profile of receptors that are activated.
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Genetic, Epigenetic and Environmental Factors in Serotonin Associated Disease Condition. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1569-7339(10)70108-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Tassone A, Madeo G, Sciamanna G, Pisani A, Bonsi P. Electrophysiology of 5-HT6 Receptors. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2010; 94:111-28. [DOI: 10.1016/b978-0-12-384976-2.00005-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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