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Runyon K, Bui T, Mazanek S, Hartle A, Marschalko K, Howe WM. Distinct cholinergic circuits underlie discrete effects of reward on attention. Front Mol Neurosci 2024; 17:1429316. [PMID: 39268248 PMCID: PMC11390659 DOI: 10.3389/fnmol.2024.1429316] [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: 05/07/2024] [Accepted: 08/01/2024] [Indexed: 09/15/2024] Open
Abstract
Attention and reward are functions that are critical for the control of behavior, and massive multi-region neural systems have evolved to support the discrete computations associated with each. Previous research has also identified that attention and reward interact, though our understanding of the neural mechanisms that mediate this interplay is incomplete. Here, we review the basic neuroanatomy of attention, reward, and cholinergic systems. We then examine specific contexts in which attention and reward computations interact. Building on this work, we propose two discrete neural circuits whereby acetylcholine, released from cell groups located in different parts of the brain, mediates the impact of stimulus-reward associations as well as motivation on attentional control. We conclude by examining these circuits as a potential shared loci of dysfunction across diseases states associated with deficits in attention and reward.
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Affiliation(s)
- Kelly Runyon
- School of Neuroscience at Virginia Tech, Blacksburg, VA, United States
| | - Tung Bui
- School of Neuroscience at Virginia Tech, Blacksburg, VA, United States
| | - Sarah Mazanek
- School of Neuroscience at Virginia Tech, Blacksburg, VA, United States
| | - Alec Hartle
- School of Neuroscience at Virginia Tech, Blacksburg, VA, United States
| | - Katie Marschalko
- School of Neuroscience at Virginia Tech, Blacksburg, VA, United States
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Colwell MJ, Tagomori H, Shang F, Cheng HI, Wigg CE, Browning M, Cowen PJ, Murphy SE, Harmer CJ. Direct serotonin release in humans shapes aversive learning and inhibition. Nat Commun 2024; 15:6617. [PMID: 39122687 PMCID: PMC11315928 DOI: 10.1038/s41467-024-50394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 07/09/2024] [Indexed: 08/12/2024] Open
Abstract
The role of serotonin in human behaviour is informed by approaches which allow in vivo modification of synaptic serotonin. However, characterising the effects of increased serotonin signalling in human models of behaviour is challenging given the limitations of available experimental probes, notably selective serotonin reuptake inhibitors. Here we use a now-accessible approach to directly increase synaptic serotonin in humans (a selective serotonin releasing agent) and examine its influence on domains of behaviour historically considered core functions of serotonin. Computational techniques, including reinforcement learning and drift diffusion modelling, explain participant behaviour at baseline and after week-long intervention. Reinforcement learning models reveal that increasing synaptic serotonin reduces sensitivity for outcomes in aversive contexts. Furthermore, increasing synaptic serotonin enhances behavioural inhibition, and shifts bias towards impulse control during exposure to aversive emotional probes. These effects are seen in the context of overall improvements in memory for neutral verbal information. Our findings highlight the direct effects of increasing synaptic serotonin on human behaviour, underlining its role in guiding decision-making within aversive and more neutral contexts, and offering implications for longstanding theories of central serotonin function.
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Affiliation(s)
- Michael J Colwell
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK.
| | - Hosana Tagomori
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Fei Shang
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Hoi Iao Cheng
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Chloe E Wigg
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Michael Browning
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Philip J Cowen
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Susannah E Murphy
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Catherine J Harmer
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK.
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Bastos-Gonçalves R, Coimbra B, Rodrigues AJ. The mesopontine tegmentum in reward and aversion: From cellular heterogeneity to behaviour. Neurosci Biobehav Rev 2024; 162:105702. [PMID: 38718986 DOI: 10.1016/j.neubiorev.2024.105702] [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: 12/29/2023] [Revised: 04/06/2024] [Accepted: 05/01/2024] [Indexed: 05/18/2024]
Abstract
The mesopontine tegmentum, comprising the pedunculopontine tegmentum (PPN) and the laterodorsal tegmentum (LDT), is intricately connected to various regions of the basal ganglia, motor systems, and limbic systems. The PPN and LDT can regulate the activity of different brain regions of these target systems, and in this way are in a privileged position to modulate motivated behaviours. Despite recent findings, the PPN and LDT have been largely overlooked in discussions about the neural circuits associated with reward and aversion. This review aims to provide a timely and comprehensive resource on past and current research, highlighting the PPN and LDT's connectivity and influence on basal ganglia and limbic, and motor systems. Seminal studies, including lesion, pharmacological, and optogenetic/chemogenetic approaches, demonstrate their critical roles in modulating reward/aversive behaviours. The review emphasizes the need for further investigation into the associated cellular mechanisms, in order to clarify their role in behaviour and contribution for different neuropsychiatric disorders.
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Affiliation(s)
- Ricardo Bastos-Gonçalves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Bárbara Coimbra
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Ana João Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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Pickford J, Iosif CI, Bashir ZI, Apps R. Inhibiting cholinergic signalling in the cerebellar interpositus nucleus impairs motor behaviour. Eur J Neurosci 2024; 59:2208-2224. [PMID: 37455360 PMCID: PMC7616440 DOI: 10.1111/ejn.16066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 05/10/2023] [Accepted: 06/04/2023] [Indexed: 07/18/2023]
Abstract
The role of neuromodulators in the cerebellum is not well understood. In particular, the behavioural significance of the cholinergic system in the cerebellum is unknown. To investigate the importance of cerebellar cholinergic signalling in behaviour, we infused acetylcholine receptor antagonists, scopolamine and mecamylamine, bilaterally into the rat cerebellum (centred on interpositus nucleus) and observed the motor effects through a battery of behavioural tests. These tests included unrewarded behaviour during open field exploration and a horizontal ladder walking task and reward-based beam walking and pellet reaching tasks. Infusion of a mix of the antagonists did not impair motor learning in the horizontal ladder walking or the reaching task but reduced spontaneous movement during open field exploration, impaired coordination during beam walking and ladder walking, led to fewer reaches in the pellet reaching task, slowed goal-directed reaching behaviour and reduced reward pellet consumption in a free access to food task. Infusion of the muscarinic antagonist scopolamine on its own resulted in deficits in motor performance and a reduction in the number of reward pellets consumed in the free access to food task. By contrast, infusion of the nicotinic antagonist mecamylamine on its own had no significant effect on any task, except beam walking traversal time, which was reduced. Together, these data suggest that acetylcholine in the cerebellar interpositus nucleus is important for the execution and coordination of voluntary movements mainly via muscarinic receptor signalling, especially in relation to reward-related behaviour.
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Affiliation(s)
- Jasmine Pickford
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Cristiana I Iosif
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Zafar I Bashir
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Richard Apps
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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Zhang S, Mena-Segovia J, Gut NK. Inhibitory Pedunculopontine Neurons Gate Dopamine-Mediated Motor Actions of Unsigned Valence. Curr Neuropharmacol 2024; 22:1540-1550. [PMID: 37702175 PMCID: PMC11097985 DOI: 10.2174/1570159x21666230911103520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/22/2023] [Accepted: 05/28/2023] [Indexed: 09/14/2023] Open
Abstract
BACKGROUND The pedunculopontine nucleus (PPN) maintains a bidirectional connectivity with the basal ganglia that supports their shared roles in the selection and execution of motor actions. Previous studies identified a role for PPN neurons in goal-directed behavior, but the cellular substrates underlying this function have not been elucidated. We recently revealed the existence of a monosynaptic GABAergic input from the PPN that inhibits dopamine neurons of the substantia nigra. Activation of this pathway interferes with the execution of learned motor sequences when the actions are rewarded, even though the inhibition of dopamine neurons did not shift the value of the action, hence suggesting executive control over the gating of behavior. OBJECTIVE To test the attributes of the inhibition of dopamine neurons by the PPN in the context of goal-directed behavior regardless of whether the outcome is positively or negatively reinforced. METHODS We delivered optogenetic stimulation to PPN GABAergic axon terminals in the substantia nigra during a battery of behavioral tasks with positive and negative valence. RESULTS Inhibition of dopamine neurons by PPN optogenetic activation during an appetitive task impaired the initiation and overall execution of the behavioral sequence without affecting the consumption of reward. During an active avoidance task, the same activation impaired the ability of mice to avoid a foot shock, but their escape response was unaffected. In addition, responses to potential threats were significantly attenuated. CONCLUSION Our results show that PPN GABAergic neurons modulate learned, goal-directed behavior of unsigned valence without affecting overall motor behavior.
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Affiliation(s)
- Sirin Zhang
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, USA
| | - Juan Mena-Segovia
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, USA
| | - Nadine K. Gut
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, USA
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Ricciardi L, Apps M, Little S. Uncovering the neurophysiology of mood, motivation and behavioral symptoms in Parkinson's disease through intracranial recordings. NPJ Parkinsons Dis 2023; 9:136. [PMID: 37735477 PMCID: PMC10514046 DOI: 10.1038/s41531-023-00567-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 08/07/2023] [Indexed: 09/23/2023] Open
Abstract
Neuropsychiatric mood and motivation symptoms (depression, anxiety, apathy, impulse control disorders) in Parkinson's disease (PD) are highly disabling, difficult to treat and exacerbated by current medications and deep brain stimulation therapies. High-resolution intracranial recording techniques have the potential to undercover the network dysfunction and cognitive processes that drive these symptoms, towards a principled re-tuning of circuits. We highlight intracranial recording as a valuable tool for mapping and desegregating neural networks and their contribution to mood, motivation and behavioral symptoms, via the ability to dissect multiplexed overlapping spatial and temporal neural components. This technique can be powerfully combined with behavioral paradigms and emerging computational techniques to model underlying latent behavioral states. We review the literature of intracranial recording studies investigating mood, motivation and behavioral symptomatology with reference to 1) emotional processing, 2) executive control 3) subjective valuation (reward & cost evaluation) 4) motor control and 5) learning and updating. This reveals associations between different frequency specific network activities and underlying cognitive processes of reward decision making and action control. If validated, these signals represent potential computational biomarkers of motivational and behavioural states and could lead to principled therapy development for mood, motivation and behavioral symptoms in PD.
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Affiliation(s)
- Lucia Ricciardi
- Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.
| | - Matthew Apps
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham, UK
| | - Simon Little
- Movement Disorders and Neuromodulation Centre, University of California San Francisco, San Francisco, CA, USA
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