1
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Sherman SM, Usrey WM. Transthalamic Pathways for Cortical Function. J Neurosci 2024; 44:e0909242024. [PMID: 39197951 DOI: 10.1523/jneurosci.0909-24.2024] [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: 05/14/2024] [Revised: 07/06/2024] [Accepted: 07/18/2024] [Indexed: 09/01/2024] Open
Abstract
The cerebral cortex contains multiple, distinct areas that individually perform specific computations. A particular strength of the cortex is the communication of signals between cortical areas that allows the outputs of these compartmentalized computations to influence and build on each other, thereby dramatically increasing the processing power of the cortex and its role in sensation, action, and cognition. Determining how the cortex communicates signals between individual areas is, therefore, critical for understanding cortical function. Historically, corticocortical communication was thought to occur exclusively by direct anatomical connections between areas that often sequentially linked cortical areas in a hierarchical fashion. More recently, anatomical, physiological, and behavioral evidence is accumulating indicating a role for the higher-order thalamus in corticocortical communication. Specifically, the transthalamic pathway involves projections from one area of the cortex to neurons in the higher-order thalamus that, in turn, project to another area of the cortex. Here, we consider the evidence for and implications of having two routes for corticocortical communication with an emphasis on unique processing available in the transthalamic pathway and the consequences of disorders and diseases that affect transthalamic communication.
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Affiliation(s)
- S Murray Sherman
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637
| | - W Martin Usrey
- Center for Neuroscience, University of California, Davis, California 95618
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2
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Ma J, O'Malley JJ, Kreiker M, Leng Y, Khan I, Kindel M, Penzo MA. Convergent direct and indirect cortical streams shape avoidance decisions in mice via the midline thalamus. Nat Commun 2024; 15:6598. [PMID: 39097600 PMCID: PMC11297946 DOI: 10.1038/s41467-024-50941-6] [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: 03/04/2024] [Accepted: 07/24/2024] [Indexed: 08/05/2024] Open
Abstract
Current concepts of corticothalamic organization in the mammalian brain are mainly based on sensory systems, with less focus on circuits for higher-order cognitive functions. In sensory systems, first-order thalamic relays are driven by subcortical inputs and modulated by cortical feedback, while higher-order relays receive strong excitatory cortical inputs. The applicability of these principles beyond sensory systems is uncertain. We investigated mouse prefronto-thalamic projections to the midline thalamus, revealing distinct top-down control. Unlike sensory systems, this pathway relies on indirect modulation via the thalamic reticular nucleus (TRN). Specifically, the prelimbic area, which influences emotional and motivated behaviors, impacts instrumental avoidance responses through direct and indirect projections to the paraventricular thalamus. Both pathways promote defensive states, but the indirect pathway via the TRN is essential for organizing avoidance decisions through disinhibition. Our findings highlight intra-thalamic circuit dynamics that integrate cortical cognitive signals and their role in shaping complex behaviors.
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Affiliation(s)
- Jun Ma
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
- Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, 221004, Xuzhou, China
| | - John J O'Malley
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
| | - Malaz Kreiker
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
| | - Yan Leng
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
| | - Isbah Khan
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
| | - Morgan Kindel
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA
| | - Mario A Penzo
- Section on the Neural Circuits of Emotion and Motivation, National Institute of Mental Health, Bethesda, MD, USA.
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3
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Rao RPN. A sensory-motor theory of the neocortex. Nat Neurosci 2024; 27:1221-1235. [PMID: 38937581 DOI: 10.1038/s41593-024-01673-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/26/2024] [Indexed: 06/29/2024]
Abstract
Recent neurophysiological and neuroanatomical studies suggest a close interaction between sensory and motor processes across the neocortex. Here, I propose that the neocortex implements active predictive coding (APC): each cortical area estimates both latent sensory states and actions (including potentially abstract actions internal to the cortex), and the cortex as a whole predicts the consequences of actions at multiple hierarchical levels. Feedback from higher areas modulates the dynamics of state and action networks in lower areas. I show how the same APC architecture can explain (1) how we recognize an object and its parts using eye movements, (2) why perception seems stable despite eye movements, (3) how we learn compositional representations, for example, part-whole hierarchies, (4) how complex actions can be planned using simpler actions, and (5) how we form episodic memories of sensory-motor experiences and learn abstract concepts such as a family tree. I postulate a mapping of the APC model to the laminar architecture of the cortex and suggest possible roles for cortico-cortical and cortico-subcortical pathways.
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Affiliation(s)
- Rajesh P N Rao
- Center for Neurotechnology, University of Washington, Seattle, WA, USA.
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA.
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4
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Koster KP, Sherman SM. Convergence of inputs from the basal ganglia with layer 5 of motor cortex and cerebellum in mouse motor thalamus. eLife 2024; 13:e97489. [PMID: 38856045 PMCID: PMC11208046 DOI: 10.7554/elife.97489] [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: 03/01/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024] Open
Abstract
A key to motor control is the motor thalamus, where several inputs converge. One excitatory input originates from layer 5 of primary motor cortex (M1L5), while another arises from the deep cerebellar nuclei (Cb). M1L5 terminals distribute throughout the motor thalamus and overlap with GABAergic inputs from the basal ganglia output nuclei, the internal segment of the globus pallidus (GPi), and substantia nigra pars reticulata (SNr). In contrast, it is thought that Cb and basal ganglia inputs are segregated. Therefore, we hypothesized that one potential function of the GABAergic inputs from basal ganglia is to selectively inhibit, or gate, excitatory signals from M1L5 in the motor thalamus. Here, we tested this possibility and determined the circuit organization of mouse (both sexes) motor thalamus using an optogenetic strategy in acute slices. First, we demonstrated the presence of a feedforward transthalamic pathway from M1L5 through motor thalamus. Importantly, we discovered that GABAergic inputs from the GPi and SNr converge onto single motor thalamic cells with excitatory synapses from M1L5. Separately, we also demonstrate that, perhaps unexpectedly, GABAergic GPi and SNr inputs converge with those from the Cb. We interpret these results to indicate that a role of the basal ganglia is to gate the thalamic transmission of M1L5 and Cb information to cortex.
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Affiliation(s)
- Kevin P Koster
- Department of Neurobiology, University of ChicagoChicagoUnited States
| | - S Murray Sherman
- Department of Neurobiology, University of ChicagoChicagoUnited States
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5
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Guo F, Lin SD, Du Y, Hu TT, Wang Y, Chen Z, Zhang SH. Secondary somatosensory cortex glutamatergic innervation of the thalamus facilitates pain. Pain 2024; 165:1142-1153. [PMID: 38112733 DOI: 10.1097/j.pain.0000000000003117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 09/27/2023] [Indexed: 12/21/2023]
Abstract
ABSTRACT Although the secondary somatosensory cortex (SII) is known to be involved in pain perception, its role in pain modulation and neuropathic pain is yet unknown. In this study, we found that glutamatergic neurons in deep layers of the SII (SII Glu ) responded to bilateral sensory inputs by changing their firing with most being inhibited by contralateral noxious stimulation. Optical inhibition and activation of unilateral SII Glu reduced and enhanced bilateral nociceptive sensitivity, respectively, without affecting mood status. Tracing experiments revealed that SII Glu sent dense monosynaptic projections to the posterolateral nucleus (VPL) and the posterior nucleus (Po) of the thalamus. Optical inhibition and activation of projection terminals of SII Glu in the unilateral VPL and Po inhibited and facilitated pain on the contralateral side, respectively. After partial sciatic nerve ligation, SII Glu became hyperactive as evidenced by higher frequency of spontaneous firing, but the response patterns to peripheral stimulation remained. Optical inhibition of SII Glu alleviated not only bilateral mechanical allodynia and thermal hyperalgesia but also the negative affect associated with spontaneous pain. Inhibition of SII Glu terminals in the VPL and Po also relieved neuropathic pain. This study revealed that SII Glu and the circuits to the VPL and Po constitute a part of the endogenous pain modulatory network. These corticothalamic circuits became hyperactive after peripheral nerve injury, hence contributes to neuropathic pain. These results justify proper inhibition of SII Glu and associated neural circuits as a potential clinical strategy for neuropathic pain treatment.
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Affiliation(s)
- Fang Guo
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shi-Da Lin
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Du
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Ting-Ting Hu
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shi-Hong Zhang
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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6
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Koster KP, Sherman SM. Convergence of inputs from the basal ganglia with layer 5 of motor cortex and cerebellum in mouse motor thalamus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.14.584958. [PMID: 38559179 PMCID: PMC10979938 DOI: 10.1101/2024.03.14.584958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
A key to motor control is the motor thalamus, where several inputs converge. One excitatory input originates from layer 5 of primary motor cortex (M1L5), while another arises from the deep cerebellar nuclei (Cb). M1L5 terminals distribute throughout the motor thalamus and overlap with GABAergic inputs from the basal ganglia output nuclei, the internal segment of the globus pallidus (GPi) and substantia nigra pars reticulata (SNr). In contrast, it is thought that Cb and basal ganglia inputs are segregated. Therefore, we hypothesized that one potential function of the GABAergic inputs from basal ganglia is to selectively inhibit, or gate, excitatory signals from M1L5 in the motor thalamus. Here, we tested this possibility and determined the circuit organization of mouse (both sexes) motor thalamus using an optogenetic strategy in acute slices. First, we demonstrated the presence of a feedforward transthalamic pathway from M1L5 through motor thalamus. Importantly, we discovered that GABAergic inputs from the GPi and SNr converge onto single motor thalamic cells with excitatory synapses from M1L5 and, unexpectedly, Cb as well. We interpret these results to indicate that a role of the basal ganglia is to gate the thalamic transmission of M1L5 and Cb information to cortex.
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Affiliation(s)
- Kevin P. Koster
- Department of Neurobiology, University of Chicago, Chicago, IL 60637
| | - S. Murray Sherman
- Department of Neurobiology, University of Chicago, Chicago, IL 60637
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7
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Issa LK, Sekaran NVC, Llano DA. Highly branched and complementary distributions of layer 5 and layer 6 auditory corticofugal axons in mouse. Cereb Cortex 2023; 33:9566-9582. [PMID: 37386697 PMCID: PMC10431747 DOI: 10.1093/cercor/bhad227] [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: 01/16/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 07/01/2023] Open
Abstract
The auditory cortex exerts a powerful, yet heterogeneous, effect on subcortical targets. Auditory corticofugal projections emanate from layers 5 and 6 and have complementary physiological properties. While several studies suggested that layer 5 corticofugal projections branch widely, others suggested that multiple independent projections exist. Less is known about layer 6; no studies have examined whether the various layer 6 corticofugal projections are independent. Therefore, we examined branching patterns of layers 5 and 6 auditory corticofugal neurons, using the corticocollicular system as an index, using traditional and novel approaches. We confirmed that dual retrograde injections into the mouse inferior colliculus and auditory thalamus co-labeled subpopulations of layers 5 and 6 auditory cortex neurons. We then used an intersectional approach to relabel layer 5 or 6 corticocollicular somata and found that both layers sent extensive branches to multiple subcortical structures. Using a novel approach to separately label layers 5 and 6 axons in individual mice, we found that layers 5 and 6 terminal distributions partially spatially overlapped and that giant terminals were only found in layer 5-derived axons. Overall, the high degree of branching and complementarity in layers 5 and 6 axonal distributions suggest that corticofugal projections should be considered as 2 widespread systems, rather than collections of individual projections.
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Affiliation(s)
- Lina K Issa
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana—Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Nathiya V C Sekaran
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana—Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Daniel A Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana—Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, Urbana, IL, United States
- Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, IL, United States
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8
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Yazdanbakhsh A, Barbas H, Zikopoulos B. Sleep spindles in primates: Modeling the effects of distinct laminar thalamocortical connectivity in core, matrix, and reticular thalamic circuits. Netw Neurosci 2023; 7:743-768. [PMID: 37397882 PMCID: PMC10312265 DOI: 10.1162/netn_a_00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 03/01/2023] [Indexed: 10/16/2023] Open
Abstract
Sleep spindles are associated with the beginning of deep sleep and memory consolidation and are disrupted in schizophrenia and autism. In primates, distinct core and matrix thalamocortical (TC) circuits regulate sleep spindle activity through communications that are filtered by the inhibitory thalamic reticular nucleus (TRN); however, little is known about typical TC network interactions and the mechanisms that are disrupted in brain disorders. We developed a primate-specific, circuit-based TC computational model with distinct core and matrix loops that can simulate sleep spindles. We implemented novel multilevel cortical and thalamic mixing, and included local thalamic inhibitory interneurons, and direct layer 5 projections of variable density to TRN and thalamus to investigate the functional consequences of different ratios of core and matrix node connectivity contribution to spindle dynamics. Our simulations showed that spindle power in primates can be modulated based on the level of cortical feedback, thalamic inhibition, and engagement of model core versus matrix, with the latter having a greater role in spindle dynamics. The study of the distinct spatial and temporal dynamics of core-, matrix-, and mix-generated sleep spindles establishes a framework to study disruption of TC circuit balance underlying deficits in sleep and attentional gating seen in autism and schizophrenia.
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Affiliation(s)
- Arash Yazdanbakhsh
- Computational Neuroscience and Vision Lab, Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
| | - Helen Barbas
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
- Neural Systems Laboratory, Program in Human Physiology, Department of Health Sciences, College of Health and Rehabilitation Sciences (Sargent College), Boston University, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Basilis Zikopoulos
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston University, Boston, MA, USA
- Human Systems Neuroscience Laboratory, Program in Human Physiology, Department of Health Sciences, College of Health and Rehabilitation Sciences (Sargent College), Boston University, Boston, MA, USA
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9
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Martín-Cortecero J, Isaías-Camacho EU, Boztepe B, Ziegler K, Mease RA, Groh A. Monosynaptic trans-collicular pathways link mouse whisker circuits to integrate somatosensory and motor cortical signals. PLoS Biol 2023; 21:e3002126. [PMID: 37205722 DOI: 10.1371/journal.pbio.3002126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 04/14/2023] [Indexed: 05/21/2023] Open
Abstract
The superior colliculus (SC), a conserved midbrain node with extensive long-range connectivity throughout the brain, is a key structure for innate behaviors. Descending cortical pathways are increasingly recognized as central control points for SC-mediated behaviors, but how cortico-collicular pathways coordinate SC activity at the cellular level is poorly understood. Moreover, despite the known role of the SC as a multisensory integrator, the involvement of the SC in the somatosensory system is largely unexplored in comparison to its involvement in the visual and auditory systems. Here, we mapped the connectivity of the whisker-sensitive region of the SC in mice with trans-synaptic and intersectional tracing tools and in vivo electrophysiology. The results reveal a novel trans-collicular connectivity motif in which neurons in motor- and somatosensory cortices impinge onto the brainstem-SC-brainstem sensory-motor arc and onto SC-midbrain output pathways via only one synapse in the SC. Intersectional approaches and optogenetically assisted connectivity quantifications in vivo reveal convergence of motor and somatosensory cortical input on individual SC neurons, providing a new framework for sensory-motor integration in the SC. More than a third of the cortical recipient neurons in the whisker SC are GABAergic neurons, which include a hitherto unknown population of GABAergic projection neurons targeting thalamic nuclei and the zona incerta. These results pinpoint a whisker region in the SC of mice as a node for the integration of somatosensory and motor cortical signals via parallel excitatory and inhibitory trans-collicular pathways, which link cortical and subcortical whisker circuits for somato-motor integration.
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Affiliation(s)
- Jesús Martín-Cortecero
- Medical Biophysics, Institute for Physiology and Pathophysiology, Heidelberg University, Germany
| | | | - Berin Boztepe
- Medical Biophysics, Institute for Physiology and Pathophysiology, Heidelberg University, Germany
| | - Katharina Ziegler
- Medical Biophysics, Institute for Physiology and Pathophysiology, Heidelberg University, Germany
| | - Rebecca Audrey Mease
- Medical Biophysics, Institute for Physiology and Pathophysiology, Heidelberg University, Germany
| | - Alexander Groh
- Medical Biophysics, Institute for Physiology and Pathophysiology, Heidelberg University, Germany
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10
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Zheng B, Liu DD, Theyel BB, Abdulrazeq H, Kimata AR, Lauro PM, Asaad WF. Thalamic neuromodulation in epilepsy: A primer for emerging circuit-based therapies. Expert Rev Neurother 2023; 23:123-140. [PMID: 36731858 DOI: 10.1080/14737175.2023.2176752] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Epilepsy is a common, often debilitating disease of hyperexcitable neural networks. While medically intractable cases may benefit from surgery, there may be no single, well-localized focus for resection or ablation. In such cases, approaching the disease from a network-based perspective may be beneficial. AREAS COVERED Herein, the authors provide a narrative review of normal thalamic anatomy and physiology and propose general strategies for preventing and/or aborting seizures by modulating this structure. Additionally, they make specific recommendations for targeting the thalamus within different contexts, motivated by a more detailed discussion of its distinct nuclei and their respective connectivity. By describing important principles governing thalamic function and its involvement in seizure networks, the authors aim to provide a primer for those now entering this fast-growing field of thalamic neuromodulation for epilepsy. EXPERT OPINION The thalamus is critically involved with the function of many cortical and subcortical areas, suggesting it may serve as a compelling node for preventing or aborting seizures, and so it has increasingly been targeted for the surgical treatment of epilepsy. As various thalamic neuromodulation strategies for seizure control are developed, there is a need to ground such interventions in a mechanistic, circuit-based framework.
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Affiliation(s)
- Bryan Zheng
- The Warren Alpert Medical School of Brown University, Providence, RI, USA.,Department of Neurosurgery, Rhode Island Hospital, Providence, RI, USA
| | - David D Liu
- The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Brian B Theyel
- Department of Psychiatry, Rhode Island Hospital, Providence, RI, USA.,Department of Neuroscience, Brown University, Providence, RI, USA
| | - Hael Abdulrazeq
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, USA
| | - Anna R Kimata
- The Warren Alpert Medical School of Brown University, Providence, RI, USA.,Department of Neurosurgery, Rhode Island Hospital, Providence, RI, USA
| | - Peter M Lauro
- The Warren Alpert Medical School of Brown University, Providence, RI, USA.,Department of Neuroscience, Brown University, Providence, RI, USA
| | - Wael F Asaad
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, USA.,Department of Neuroscience, Brown University, Providence, RI, USA.,The Carney Institute for Brain Science, Brown University, Providence, RI, USA.,The Norman Prince Neurosciences Institute, Rhode Island Hospital, Providence, RI, USA
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11
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Govindaiah G, Fox MA, Guido W. Pattern of Driver-Like Input onto Neurons of the Mouse Ventral Lateral Geniculate Nucleus. eNeuro 2023; 10:ENEURO.0386-22.2022. [PMID: 36609305 PMCID: PMC9850909 DOI: 10.1523/eneuro.0386-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/06/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
The ventral lateral geniculate nucleus (vLGN) is a retinorecipient region of thalamus that contributes to a number of complex visual behaviors. Retinal axons that target vLGN terminate exclusively in the external subdivision (vLGNe), which is also transcriptionally and cytoarchitectonically distinct from the internal subdivision (vLGNi). While recent studies shed light on the cell types and efferent projections of vLGNe and vLGNi, we have a crude understanding of the source and nature of the excitatory inputs driving postsynaptic activity in these regions. Here, we address this by conducting in vitro whole-cell recordings in acutely prepared thalamic slices and using electrical and optical stimulation techniques to examine the postsynaptic excitatory activity evoked by the activation of retinal or cortical layer V input onto neurons in vLGNe and vLGNi. Activation of retinal afferents by electrical stimulation of optic tract or optical stimulation of retinal terminals resulted in robust driver-like excitatory activity in vLGNe. Optical activation of corticothalamic terminals from layer V resulted in similar driver-like activity in both vLGNe and vLGNi. Using a dual-color optogenetic approach, we found that many vLGNe neurons received convergent input from these two sources. Both individual pathways displayed similar driver-like properties, with corticothalamic stimulation leading to a stronger form of synaptic depression than retinogeniculate stimulation. We found no evidence of convergence in vLGNi, with neurons only responding to corticothalamic stimulation. These data provide insight into the influence of excitatory inputs to vLGN and reveal that only neurons in vLGNe receive convergent input from both sources.
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Affiliation(s)
- Gubbi Govindaiah
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
| | - Michael A. Fox
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia 24016
- School of Neuroscience, Virginia Tech, Blacksburg, Virginia 24061
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
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12
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Hádinger N, Bősz E, Tóth B, Vantomme G, Lüthi A, Acsády L. Region-selective control of the thalamic reticular nucleus via cortical layer 5 pyramidal cells. Nat Neurosci 2023; 26:116-130. [PMID: 36550291 PMCID: PMC9829539 DOI: 10.1038/s41593-022-01217-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 10/26/2022] [Indexed: 12/24/2022]
Abstract
Corticothalamic pathways, responsible for the top-down control of the thalamus, have a canonical organization such that every cortical region sends output from both layer 6 (L6) and layer 5 (L5) to the thalamus. Here we demonstrate a qualitative, region-specific difference in the organization of mouse corticothalamic pathways. Specifically, L5 pyramidal cells of the frontal cortex, but not other cortical regions, establish monosynaptic connections with the inhibitory thalamic reticular nucleus (TRN). The frontal L5-TRN pathway parallels the L6-TRN projection but has distinct morphological and physiological features. The exact spike output of the L5-contacted TRN cells correlated with the level of cortical synchrony. Optogenetic perturbation of the L5-TRN connection disrupted the tight link between cortical and TRN activity. L5-driven TRN cells innervated thalamic nuclei involved in the control of frontal cortex activity. Our data show that frontal cortex functions require a highly specialized cortical control over intrathalamic inhibitory processes.
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Affiliation(s)
- Nóra Hádinger
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Budapest, Hungary.
| | - Emília Bősz
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Boglárka Tóth
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Gil Vantomme
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Anita Lüthi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - László Acsády
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Budapest, Hungary.
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13
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Abstract
Neurons in the thalamic reticular nucleus (TRN) are a primary source of inhibition to the dorsal thalamus and, as they are innervated in part by the cortex, are a means of corticothalamic regulation. Previously, cortical inputs to the TRN were thought to originate solely from layer 6 (L6), but we recently reported the presence of putative synaptic terminals from layer 5 (L5) neurons in multiple cortical areas in the TRN [J. A. Prasad, B. J. Carroll, S. M. Sherman, J. Neurosci. 40, 5785-5796 (2020)]. Here, we demonstrate with electron microscopy that L5 terminals from multiple cortical regions make bona fide synapses in the TRN. We further use light microscopy to localize these synapses relative to recently described TRN subdivisions and show that L5 terminals target the edges of the somatosensory TRN, where neurons reciprocally connect to higher-order thalamus, and that L5 terminals are scarce in the core of the TRN, where neurons reciprocally connect to first-order thalamus. In contrast, L6 terminals densely innervate both edge and core subregions and are smaller than those from L5. These data suggest that a sparse but potent input from L5 neurons of multiple cortical regions to the TRN may yield transreticular inhibition targeted to higher-order thalamus.
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14
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Hummos A, Wang BA, Drammis S, Halassa MM, Pleger B. Thalamic regulation of frontal interactions in human cognitive flexibility. PLoS Comput Biol 2022; 18:e1010500. [PMID: 36094955 PMCID: PMC9499289 DOI: 10.1371/journal.pcbi.1010500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 09/22/2022] [Accepted: 08/19/2022] [Indexed: 11/19/2022] Open
Abstract
Interactions across frontal cortex are critical for cognition. Animal studies suggest a role for mediodorsal thalamus (MD) in these interactions, but the computations performed and direct relevance to human decision making are unclear. Here, inspired by animal work, we extended a neural model of an executive frontal-MD network and trained it on a human decision-making task for which neuroimaging data were collected. Using a biologically-plausible learning rule, we found that the model MD thalamus compressed its cortical inputs (dorsolateral prefrontal cortex, dlPFC) underlying stimulus-response representations. Through direct feedback to dlPFC, this thalamic operation efficiently partitioned cortical activity patterns and enhanced task switching across different contingencies. To account for interactions with other frontal regions, we expanded the model to compute higher-order strategy signals outside dlPFC, and found that the MD offered a more efficient route for such signals to switch dlPFC activity patterns. Human fMRI data provided evidence that the MD engaged in feedback to dlPFC, and had a role in routing orbitofrontal cortex inputs when subjects switched behavioral strategy. Collectively, our findings contribute to the emerging evidence for thalamic regulation of frontal interactions in the human brain. The expansion of frontal cortex during mammalian evolution suggested a prominent role in intelligent and adaptive behavior, overshadowing earlier parts of the brain. However, recent rodent studies have pointed to a role for the cognitive mediodorsal thalamus (MD) in sustaining and flexibly switching representations in the frontal cortex, but direct relevance to human decision-making are unclear. Here, inspired by animal work, we extended a neural model of an executive frontal-MD network and trained it on a human decision-making task for which human neuroimaging data were collected. We found that the model MD thalamus learned an abstract representation of its cortical inputs and provided direct feedback to frontal cortex leading to flexible computations and enhanced task switching. These abstract MD representations and ability to re-organize frontal computations created an efficient mechanism where MD can integrate input from other regions to select behavioral strategy dynamically. The model predicted an efficient route through the MD for frontal region interactions and we found consistent evidence in human neuroimaging data. Collectively, our findings contribute to the emerging evidence for thalamic regulation of frontal interactions in the human brain.
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Affiliation(s)
- Ali Hummos
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Bin A. Wang
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
- Collaborative Research Centre 874 "Integration and Representation of Sensory Processes", Ruhr University Bochum, Bochum, Germany
| | - Sabrina Drammis
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Computer Science & Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Michael M. Halassa
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
| | - Burkhard Pleger
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
- Collaborative Research Centre 874 "Integration and Representation of Sensory Processes", Ruhr University Bochum, Bochum, Germany
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15
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Vertes RP, Linley SB, Rojas AKP. Structural and functional organization of the midline and intralaminar nuclei of the thalamus. Front Behav Neurosci 2022; 16:964644. [PMID: 36082310 PMCID: PMC9445584 DOI: 10.3389/fnbeh.2022.964644] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/07/2022] [Indexed: 12/03/2022] Open
Abstract
The midline and intralaminar nuclei of the thalamus form a major part of the "limbic thalamus;" that is, thalamic structures anatomically and functionally linked with the limbic forebrain. The midline nuclei consist of the paraventricular (PV) and paratenial nuclei, dorsally and the rhomboid and nucleus reuniens (RE), ventrally. The rostral intralaminar nuclei (ILt) consist of the central medial (CM), paracentral (PC) and central lateral (CL) nuclei. We presently concentrate on RE, PV, CM and CL nuclei of the thalamus. The nucleus reuniens receives a diverse array of input from limbic-related sites, and predominantly projects to the hippocampus and to "limbic" cortices. The RE participates in various cognitive functions including spatial working memory, executive functions (attention, behavioral flexibility) and affect/fear behavior. The PV receives significant limbic-related afferents, particularly the hypothalamus, and mainly distributes to "affective" structures of the forebrain including the bed nucleus of stria terminalis, nucleus accumbens and the amygdala. Accordingly, PV serves a critical role in "motivated behaviors" such as arousal, feeding/consummatory behavior and drug addiction. The rostral ILt receives both limbic and sensorimotor-related input and distributes widely over limbic and motor regions of the frontal cortex-and throughout the dorsal striatum. The intralaminar thalamus is critical for maintaining consciousness and directly participates in various sensorimotor functions (visuospatial or reaction time tasks) and cognitive tasks involving striatal-cortical interactions. As discussed herein, while each of the midline and intralaminar nuclei are anatomically and functionally distinct, they collectively serve a vital role in several affective, cognitive and executive behaviors - as major components of a brainstem-diencephalic-thalamocortical circuitry.
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Affiliation(s)
- Robert P. Vertes
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, United States
- Department of Psychology, Florida Atlantic University, Boca Raton, FL, United States
| | - Stephanie B. Linley
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, United States
- Department of Psychology, Florida Atlantic University, Boca Raton, FL, United States
- Department of Psychological Science, University of North Georgia, Dahlonega, GA, United States
| | - Amanda K. P. Rojas
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, United States
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16
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Huang R, Gao Y, Chen J, Duan Q, He P, Zhang J, Huang H, Zhang Q, Ma G, Zhang Y, Nie K, Wang L. TGR5 agonist INT-777 alleviates inflammatory neurodegeneration in parkinson’s disease mouse model by modulating mitochondrial dynamics in microglia. Neuroscience 2022; 490:100-119. [DOI: 10.1016/j.neuroscience.2022.02.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/16/2022] [Accepted: 02/25/2022] [Indexed: 11/24/2022]
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17
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Yamagata T, Kahn MC, Prius-Mengual J, Meijer E, Šabanović M, Guillaumin MCC, van der Vinne V, Huang YG, McKillop LE, Jagannath A, Peirson SN, Mann EO, Foster RG, Vyazovskiy VV. The hypothalamic link between arousal and sleep homeostasis in mice. Proc Natl Acad Sci U S A 2021; 118:e2101580118. [PMID: 34903646 PMCID: PMC8713782 DOI: 10.1073/pnas.2101580118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 02/05/2023] Open
Abstract
Sleep and wakefulness are not simple, homogenous all-or-none states but represent a spectrum of substates, distinguished by behavior, levels of arousal, and brain activity at the local and global levels. Until now, the role of the hypothalamic circuitry in sleep-wake control was studied primarily with respect to its contribution to rapid state transitions. In contrast, whether the hypothalamus modulates within-state dynamics (state "quality") and the functional significance thereof remains unexplored. Here, we show that photoactivation of inhibitory neurons in the lateral preoptic area (LPO) of the hypothalamus of adult male and female laboratory mice does not merely trigger awakening from sleep, but the resulting awake state is also characterized by an activated electroencephalogram (EEG) pattern, suggesting increased levels of arousal. This was associated with a faster build-up of sleep pressure, as reflected in higher EEG slow-wave activity (SWA) during subsequent sleep. In contrast, photoinhibition of inhibitory LPO neurons did not result in changes in vigilance states but was associated with persistently increased EEG SWA during spontaneous sleep. These findings suggest a role of the LPO in regulating arousal levels, which we propose as a key variable shaping the daily architecture of sleep-wake states.
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Affiliation(s)
- Tomoko Yamagata
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Martin C Kahn
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - José Prius-Mengual
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Elise Meijer
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Merima Šabanović
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, United Kingdom
| | - Mathilde C C Guillaumin
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Vincent van der Vinne
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Yi-Ge Huang
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Laura E McKillop
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Aarti Jagannath
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Edward O Mann
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3RE, United Kingdom;
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom;
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18
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Yudintsev G, Asilador AR, Sons S, Vaithiyalingam Chandra Sekaran N, Coppinger M, Nair K, Prasad M, Xiao G, Ibrahim BA, Shinagawa Y, Llano DA. Evidence for Layer-Specific Connectional Heterogeneity in the Mouse Auditory Corticocollicular System. J Neurosci 2021; 41:9906-9918. [PMID: 34670851 PMCID: PMC8638684 DOI: 10.1523/jneurosci.2624-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/07/2021] [Accepted: 10/07/2021] [Indexed: 11/21/2022] Open
Abstract
The auditory cortex (AC) sends long-range projections to virtually all subcortical auditory structures. One of the largest and most complex of these-the projection between AC and inferior colliculus (IC; the corticocollicular pathway)-originates from layer 5 and deep layer 6. Though previous work has shown that these two corticocollicular projection systems have different physiological properties and network connectivities, their functional organization is poorly understood. Here, using a combination of traditional and viral tracers combined with in vivo imaging in both sexes of the mouse, we observed that layer 5 and layer 6 corticocollicular neurons differ in their areas of origin and termination patterns. Layer 5 corticocollicular neurons are concentrated in primary AC, while layer 6 corticocollicular neurons emanate from broad auditory and limbic areas in the temporal cortex. In addition, layer 5 sends dense projections of both small and large (>1 µm2 area) terminals to all regions of nonlemniscal IC, while layer 6 sends small terminals to the most superficial 50-100 µm of the IC. These findings suggest that layer 5 and 6 corticocollicular projections are optimized to play distinct roles in corticofugal modulation. Layer 5 neurons provide strong, rapid, and unimodal feedback to the nonlemniscal IC, while layer 6 neurons provide heteromodal and limbic modulation diffusely to the nonlemniscal IC. Such organizational diversity in the corticocollicular pathway may help to explain the heterogeneous effects of corticocollicular manipulations and, given similar diversity in corticothalamic pathways, may be a general principle in top-down modulation.SIGNIFICANCE STATEMENT We demonstrate that a major descending system in the brain is actually two systems. That is, the auditory corticocollicular projection, which exerts considerable influence over the midbrain, comprises two projections: one from layer 5 and the other from layer 6. The layer 6 projection is diffusely organized, receives multisensory inputs, and ends in small terminals; while the layer 5 projection is derived from a circumscribed auditory cortical area and ends in large terminals. These data suggest that the varied effects of cortical manipulations on the midbrain may be related to effects on two disparate systems. These findings have broader implications because other descending systems derive from two layers. Therefore, a duplex organization may be a common motif in descending control.
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Affiliation(s)
- Georgiy Yudintsev
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Alexander R Asilador
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Stacy Sons
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Nathiya Vaithiyalingam Chandra Sekaran
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Macey Coppinger
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Kavya Nair
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Masumi Prasad
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Gang Xiao
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Baher A Ibrahim
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Yoshitaka Shinagawa
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Daniel A Llano
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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19
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Vaithiyalingam Chandra Sekaran N, Deshpande MS, Ibrahim BA, Xiao G, Shinagawa Y, Llano DA. Patterns of Unilateral and Bilateral Projections From Layers 5 and 6 of the Auditory Cortex to the Inferior Colliculus in Mouse. Front Syst Neurosci 2021; 15:674098. [PMID: 34744644 PMCID: PMC8566350 DOI: 10.3389/fnsys.2021.674098] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/19/2021] [Indexed: 12/04/2022] Open
Abstract
The auditory cortex sends massive projections to the inferior colliculus, but the organization of this pathway is not yet well understood. Previous work has shown that the corticocollicular projection emanates from both layers 5 and 6 of the auditory cortex and that neurons in these layers have different morphological and physiological properties. It is not yet known in the mouse if both layer 5 and layer 6 project bilaterally, nor is it known if the projection patterns differ based on projection location. Using targeted injections of Fluorogold into either the lateral cortex or dorsal cortex of the inferior colliculus, we quantified retrogradely labeled neurons in both the left and right lemniscal regions of the auditory cortex, as delineated using parvalbumin immunostaining. After dorsal cortex injections, we observed that approximately 18-20% of labeled cells were in layer 6 and that this proportion was similar bilaterally. After lateral cortex injections, only ipsilateral cells were observed in the auditory cortex, and they were found in both layer 5 and layer 6. The ratio of layer 5:layer 6 cells after lateral cortex injection was similar to that seen after dorsal cortex injection. Finally, injections of different tracers were made into the two inferior colliculi, and an average of 15-17% of cells in the auditory cortex were double-labeled, and these proportions were similar in layers 5 and 6. These data suggest that (1) only the dorsal cortex of the inferior colliculus receives bilateral projections from the auditory cortex, (2) both the dorsal and lateral cortex of the inferior colliculus receive similar layer 5 and layer 6 auditory cortical input, and (3) a subpopulation of individual neurons in both layers 5 and 6 branch to innervate both dorsal cortices of the inferior colliculus.
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Affiliation(s)
- Nathiya Vaithiyalingam Chandra Sekaran
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Meena S. Deshpande
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Baher A. Ibrahim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Gang Xiao
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Yoshitaka Shinagawa
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Daniel A. Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
- Carle Illinois College of Medicine, Urbana, IL, United States
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20
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Vaasjo LO, Han X, Thurmon AN, Tiemroth AS, Berndt H, Korn M, Figueroa A, Reyes R, Feliciano-Ramos PA, Galazo MJ. Characterization and manipulation of Corticothalamic neurons in associative cortices using Syt6-Cre transgenic mice. J Comp Neurol 2021; 530:1020-1048. [PMID: 34617601 DOI: 10.1002/cne.25256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 09/02/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022]
Abstract
Corticothalamic interactions between associative cortices and higher order thalamic nuclei are involved in high-cognitive functions such as decision-making and working memory. Corticothalamic neurons (CTn) in the prefrontal cortex and other associative areas have been much less studied than their counterparts in the primary sensory areas. The availability of characterized transgenic tools to study CTn in associative areas will facilitate their study and contribute to overcome the scarcity of data about their properties, network dynamics, and contribution to cognitive functions. Here, we characterized the Syt6-Cre (KI148Gsat/Mmud) transgenic mouse line, by tracking expression of a Cre-mediated reporter. In this line, Cre-reporter is strongly expressed in the prefrontal, motor, cingulate, and retrosplenial cortices, as well as in other brain areas including the cerebellum and the olfactory tubercle. Cortical expression starts embryonically and reaches the adult expression pattern by postnatal day 15. In the cortex, Cre-reporter is expressed by layer 6-CTn and by layer 5-CTn to a lesser extent. We quantified Syt6-Cre+ CTn axon varicosities to estimate the distribution and density of putative corticothalamic driver and modulator inputs to thalamic nuclei in the medial, midline, intralaminar, anterior, and motor groups. Also, we characterized the effect of optogenetic stimulation of Syt6-Cre+ neurons in the activity of the prefrontal cortex. CTn stimulation in the prefrontal cortex induces an oscillatory activity in the local field potential that resembles the cortical downstates typically observed during slow-wave sleep or quiet wake.
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Affiliation(s)
- Lee O Vaasjo
- Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Xiao Han
- Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Abbigail N Thurmon
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Alina S Tiemroth
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Hallie Berndt
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Madelyn Korn
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Alexandra Figueroa
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Rosa Reyes
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
| | - Pedro A Feliciano-Ramos
- Department Brain and Cognitive Science, Massachusetts Institute of Technology and Picower Institute for Learning and Memory, Cambridge, Massachusetts, USA
| | - Maria J Galazo
- Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA.,Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
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21
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Dichoptic visual field mapping of suppression in exotropia with homonymous hemianopia. J AAPOS 2021; 25:276.e1-276.e6. [PMID: 34587558 PMCID: PMC8665098 DOI: 10.1016/j.jaapos.2021.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/23/2021] [Accepted: 05/17/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The purpose of this study was to investigate which portions of the visual scene are perceived by each eye in an exotropic subject with acquired hemianopia. The pattern of suppression is predictable from knowledge of how suppression scotomas are organized in exotropic subjects with intact visual fields. METHODS Dichoptic perimetry was performed by having a subject wear red/blue goggles while fixating a cross that was either red or blue. Red, blue, or purple spots were presented briefly at peripheral locations. The subject's identification of the spot color revealed which eye was perceptually engaged at any given location in the visual fields. RESULTS A 17-year-old female with a history of exotropia was evaluated after rupture of a right parietal arteriovenous malformation. Dichoptic perimetry showed a left homonymous hemianopia. All stimuli to the right of the right fovea's projection point were perceived via the right eye. Stimuli between the foveal projection points, which were separated horizontally by the 20° exotropia, were perceived by the left eye. CONCLUSIONS Perception of the visual scene is shared by the eyes in hemianopia and exotropia. Suppression occurs only in the peripheral temporal retina of the eye contralateral to the brain lesion, regardless of which eye is engaged in fixation. Although exotropia expands the binocular field of vision in hemianopia, it is probably not an adaptive response, even when it develops after hemianopia.
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22
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Mease RA, Gonzalez AJ. Corticothalamic Pathways From Layer 5: Emerging Roles in Computation and Pathology. Front Neural Circuits 2021; 15:730211. [PMID: 34566583 PMCID: PMC8458899 DOI: 10.3389/fncir.2021.730211] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/10/2021] [Indexed: 11/29/2022] Open
Abstract
Large portions of the thalamus receive strong driving input from cortical layer 5 (L5) neurons but the role of this important pathway in cortical and thalamic computations is not well understood. L5-recipient "higher-order" thalamic regions participate in cortico-thalamo-cortical (CTC) circuits that are increasingly recognized to be (1) anatomically and functionally distinct from better-studied "first-order" CTC networks, and (2) integral to cortical activity related to learning and perception. Additionally, studies are beginning to elucidate the clinical relevance of these networks, as dysfunction across these pathways have been implicated in several pathological states. In this review, we highlight recent advances in understanding L5 CTC networks across sensory modalities and brain regions, particularly studies leveraging cell-type-specific tools that allow precise experimental access to L5 CTC circuits. We aim to provide a focused and accessible summary of the anatomical, physiological, and computational properties of L5-originating CTC networks, and outline their underappreciated contribution in pathology. We particularly seek to connect single-neuron and synaptic properties to network (dys)function and emerging theories of cortical computation, and highlight information processing in L5 CTC networks as a promising focus for computational studies.
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Affiliation(s)
- Rebecca A. Mease
- Institute of Physiology and Pathophysiology, Medical Biophysics, Heidelberg University, Heidelberg, Germany
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23
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Abstract
Cortical and subcortical circuitry are thought to play distinct roles in the generation of sleep oscillations and global state control, respectively. Here we silenced a subset of neocortical layer 5 pyramidal and archicortical dentate gyrus granule cells in male mice by ablating SNAP25. This markedly increased wakefulness and reduced rebound of electroencephalographic slow-wave activity after sleep deprivation, suggesting a role for the cortex in both vigilance state control and sleep homeostasis.
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24
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Antunes FM, Malmierca MS. Corticothalamic Pathways in Auditory Processing: Recent Advances and Insights From Other Sensory Systems. Front Neural Circuits 2021; 15:721186. [PMID: 34489648 PMCID: PMC8418311 DOI: 10.3389/fncir.2021.721186] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/28/2021] [Indexed: 11/24/2022] Open
Abstract
The corticothalamic (CT) pathways emanate from either Layer 5 (L5) or 6 (L6) of the neocortex and largely outnumber the ascending, thalamocortical pathways. The CT pathways provide the anatomical foundations for an intricate, bidirectional communication between thalamus and cortex. They act as dynamic circuits of information transfer with the ability to modulate or even drive the response properties of target neurons at each synaptic node of the circuit. L6 CT feedback pathways enable the cortex to shape the nature of its driving inputs, by directly modulating the sensory message arriving at the thalamus. L5 CT pathways can drive the postsynaptic neurons and initiate a transthalamic corticocortical circuit by which cortical areas communicate with each other. For this reason, L5 CT pathways place the thalamus at the heart of information transfer through the cortical hierarchy. Recent evidence goes even further to suggest that the thalamus via CT pathways regulates functional connectivity within and across cortical regions, and might be engaged in cognition, behavior, and perceptual inference. As descending pathways that enable reciprocal and context-dependent communication between thalamus and cortex, we venture that CT projections are particularly interesting in the context of hierarchical perceptual inference formulations such as those contemplated in predictive processing schemes, which so far heavily rely on cortical implementations. We discuss recent proposals suggesting that the thalamus, and particularly higher order thalamus via transthalamic pathways, could coordinate and contextualize hierarchical inference in cortical hierarchies. We will explore these ideas with a focus on the auditory system.
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Affiliation(s)
- Flora M. Antunes
- Cognitive and Auditory Neuroscience Laboratory (CANELAB), Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
- Institute for Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain
| | - Manuel S. Malmierca
- Cognitive and Auditory Neuroscience Laboratory (CANELAB), Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
- Institute for Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, School of Medicine, University of Salamanca, Salamanca, Spain
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25
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Sampathkumar V, Miller-Hansen A, Sherman SM, Kasthuri N. Integration of signals from different cortical areas in higher order thalamic neurons. Proc Natl Acad Sci U S A 2021; 118:e2104137118. [PMID: 34282018 PMCID: PMC8325356 DOI: 10.1073/pnas.2104137118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Higher order thalamic neurons receive driving inputs from cortical layer 5 and project back to the cortex, reflecting a transthalamic route for corticocortical communication. To determine whether or not individual neurons integrate signals from different cortical populations, we combined electron microscopy "connectomics" in mice with genetic labeling to disambiguate layer 5 synapses from somatosensory and motor cortices to the higher order thalamic posterior medial nucleus. A significant convergence of these inputs was found on 19 of 33 reconstructed thalamic cells, and as a population, the layer 5 synapses were larger and located more proximally on dendrites than were unlabeled synapses. Thus, many or most of these thalamic neurons do not simply relay afferent information but instead integrate signals as disparate in this case as those emanating from sensory and motor cortices. These findings add further depth and complexity to the role of the higher order thalamus in overall cortical functioning.
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Affiliation(s)
- Vandana Sampathkumar
- Department of Neurobiology, University of Chicago, Chicago, IL 60637
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439
| | | | - S Murray Sherman
- Department of Neurobiology, University of Chicago, Chicago, IL 60637;
| | - Narayanan Kasthuri
- Department of Neurobiology, University of Chicago, Chicago, IL 60637;
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439
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26
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Cortical control of behavior and attention from an evolutionary perspective. Neuron 2021; 109:3048-3054. [PMID: 34297915 DOI: 10.1016/j.neuron.2021.06.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 11/22/2022]
Abstract
For animals to survive, they must interact with their environment, taking in sensory information and making appropriate motor responses. Early on during vertebrate evolution, this was accomplished with neural circuits located mostly within the spinal cord and brainstem. As the cerebral cortex evolved, it provided additional and powerful advantages for assessing environmental cues and guiding appropriate responses. Importantly, the cerebral cortex was added onto an already functional nervous system. Moreover, every cortical area, including areas traditionally considered sensory, provides input to the subcortical motor structures that are bottlenecks for driving action. These facts have important ramifications for cognitive aspects of motor control. Here we consider the evolution of cortical mechanisms for attention from the perspective of having to work through these subcortical bottlenecks. From this perspective, many features of attention can be explained, including the preferential engagement of some cortical areas at the cost of disengagement from others to improve appropriate behavioral responses.
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27
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Saldeitis K, Jeschke M, Budinger E, Ohl FW, Happel MFK. Laser-Induced Apoptosis of Corticothalamic Neurons in Layer VI of Auditory Cortex Impact on Cortical Frequency Processing. Front Neural Circuits 2021; 15:659280. [PMID: 34322001 PMCID: PMC8311662 DOI: 10.3389/fncir.2021.659280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 06/14/2021] [Indexed: 12/20/2022] Open
Abstract
Corticofugal projections outnumber subcortical input projections by far. However, the specific role for signal processing of corticofugal feedback is still less well understood in comparisonto the feedforward projection. Here, we lesioned corticothalamic (CT) neurons in layers V and/or VI of the auditory cortex of Mongolian gerbils by laser-induced photolysis to investigate their contribution to cortical activation patterns. We have used laminar current-source density (CSD) recordings of tone-evoked responses and could show that, particularly, lesion of CT neurons in layer VI affected cortical frequency processing. Specifically, we found a decreased gain of best-frequency input in thalamocortical (TC)-recipient input layers that correlated with the relative lesion of layer VI neurons, but not layer V neurons. Using cortical silencing with the GABA a -agonist muscimol and layer-specific intracortical microstimulation (ICMS), we found that direct activation of infragranular layers recruited a local recurrent cortico-thalamo-cortical loop of synaptic input. This recurrent feedback was also only interrupted when lesioning layer VI neurons, but not cells in layer V. Our study thereby shows distinct roles of these two types of CT neurons suggesting a particular impact of CT feedback from layer VI to affect the local feedforward frequency processing in auditory cortex.
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Affiliation(s)
- Katja Saldeitis
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Auditory Neuroscience and Optogenetics Group, Cognitive Hearing in Primates Lab, German Primate Center, Göttingen, Germany.,Institute for Auditory Neuroscience, University Medical Center Goettingen, Göttingen, Germany
| | - Marcus Jeschke
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Auditory Neuroscience and Optogenetics Group, Cognitive Hearing in Primates Lab, German Primate Center, Göttingen, Germany.,Institute for Auditory Neuroscience, University Medical Center Goettingen, Göttingen, Germany
| | - Eike Budinger
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Frank W Ohl
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Institute for Auditory Neuroscience, University Medical Center Goettingen, Göttingen, Germany.,Institute of Biology (IBIO), University Magdeburg, Magdeburg, Germany
| | - Max F K Happel
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Medical School Berlin, Berlin, Germany
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28
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Cover KK, Mathur BN. Rostral Intralaminar Thalamus Engagement in Cognition and Behavior. Front Behav Neurosci 2021; 15:652764. [PMID: 33935663 PMCID: PMC8082140 DOI: 10.3389/fnbeh.2021.652764] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/22/2021] [Indexed: 11/25/2022] Open
Abstract
The thalamic rostral intralaminar nuclei (rILN) are a contiguous band of neurons that include the central medial, paracentral, and central lateral nuclei. The rILN differ from both thalamic relay nuclei, such as the lateral geniculate nucleus, and caudal intralaminar nuclei, such as the parafascicular nucleus, in afferent and efferent connectivity as well as physiological and synaptic properties. rILN activity is associated with a range of neural functions and behaviors, including arousal, pain, executive function, and action control. Here, we review this evidence supporting a role for the rILN in integrating arousal, executive and motor feedback information. In light of rILN projections out to the striatum, amygdala, and sensory as well as executive cortices, we propose that such a function enables the rILN to modulate cognitive and motor resources to meet task-dependent behavioral engagement demands.
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Affiliation(s)
- Kara K Cover
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Brian N Mathur
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, United States
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29
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Hayashi S, Hoerder-Suabedissen A, Kiyokage E, Maclachlan C, Toida K, Knott G, Molnár Z. Maturation of Complex Synaptic Connections of Layer 5 Cortical Axons in the Posterior Thalamic Nucleus Requires SNAP25. Cereb Cortex 2021; 31:2625-2638. [PMID: 33367517 PMCID: PMC8023812 DOI: 10.1093/cercor/bhaa379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/06/2023] Open
Abstract
Synapses are able to form in the absence of neuronal activity, but how is their subsequent maturation affected in the absence of regulated vesicular release? We explored this question using 3D electron microscopy and immunoelectron microscopy analyses in the large, complex synapses formed between cortical sensory efferent axons and dendrites in the posterior thalamic nucleus. Using a Synaptosome-associated protein 25 conditional knockout (Snap25 cKO), we found that during the first 2 postnatal weeks the axonal boutons emerge and increase in the size similar to the control animals. However, by P18, when an adult-like architecture should normally be established, axons were significantly smaller with 3D reconstructions, showing that each Snap25 cKO bouton only forms a single synapse with the connecting dendritic shaft. No excrescences from the dendrites were formed, and none of the normally large glomerular axon endings were seen. These results show that activity mediated through regulated vesicular release from the presynaptic terminal is not necessary for the formation of synapses, but it is required for the maturation of the specialized synaptic structures between layer 5 corticothalamic projections in the posterior thalamic nucleus.
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Affiliation(s)
- Shuichi Hayashi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Anna Hoerder-Suabedissen
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Emi Kiyokage
- Department of Medical Technology, Kawasaki University of Medical Welfare, Kurashiki, Okayama 701-0193, Japan
| | - Catherine Maclachlan
- BioEM Facility, School of Life Sciences, EPFL, Lausanne 1015, Switzerland
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Kazunori Toida
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Graham Knott
- BioEM Facility, School of Life Sciences, EPFL, Lausanne 1015, Switzerland
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
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30
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Desai NV, Varela C. Distinct burst properties contribute to the functional diversity of thalamic nuclei. J Comp Neurol 2021; 529:3726-3750. [PMID: 33723858 PMCID: PMC8440663 DOI: 10.1002/cne.25141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022]
Abstract
Thalamic neurons fire spikes in two modes, burst and tonic. The function of burst firing is unclear, but the evidence suggests that bursts are more effective at activating cortical cells, and that postinhibition rebound bursting contributes to thalamocortical oscillations during sleep. Bursts are considered stereotyped signals; however, there is limited evidence regarding how burst properties compare across thalamic nuclei of different functional or anatomical organization. Here, we used whole-cell patch clamp recordings and compartmental modeling to investigate the properties of bursts in six sensory thalamic nuclei, to study the mechanisms that can lead to different burst properties, and to assess the implications of different burst properties for thalamocortical transmission and oscillatory functions. We found that bursts in higher-order cells on average had higher number of spikes and longer latency to the first spike. Additionally, burst features in first-order neurons were determined by sensory modality. Shifting the voltage-dependence and density of the T-channel conductance in a compartmental model replicates the burst properties from the intracellular recordings, pointing to molecular mechanisms that can generate burst diversity. Furthermore, the model predicts that bursts with higher number of spikes will drastically reduce the effectiveness of thalamocortical transmission. In addition, the latency to burst limited the rebound oscillatory frequency in modeled cells. These results demonstrate that burst properties vary according to the thalamocortical hierarchy and with sensory modality. The findings imply that, while in burst mode, thalamocortical transmission and firing frequency will be determined by the number of spikes and latency to burst.
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Affiliation(s)
- Nidhi Vasant Desai
- Psychology Department, Jupiter Life Sciences Initiative, Florida Atlantic University, Boca Raton, Florida, USA
| | - Carmen Varela
- Psychology Department, Jupiter Life Sciences Initiative, Florida Atlantic University, Boca Raton, Florida, USA
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31
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Asilador A, Llano DA. Top-Down Inference in the Auditory System: Potential Roles for Corticofugal Projections. Front Neural Circuits 2021; 14:615259. [PMID: 33551756 PMCID: PMC7862336 DOI: 10.3389/fncir.2020.615259] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/17/2020] [Indexed: 01/28/2023] Open
Abstract
It has become widely accepted that humans use contextual information to infer the meaning of ambiguous acoustic signals. In speech, for example, high-level semantic, syntactic, or lexical information shape our understanding of a phoneme buried in noise. Most current theories to explain this phenomenon rely on hierarchical predictive coding models involving a set of Bayesian priors emanating from high-level brain regions (e.g., prefrontal cortex) that are used to influence processing at lower-levels of the cortical sensory hierarchy (e.g., auditory cortex). As such, virtually all proposed models to explain top-down facilitation are focused on intracortical connections, and consequently, subcortical nuclei have scarcely been discussed in this context. However, subcortical auditory nuclei receive massive, heterogeneous, and cascading descending projections at every level of the sensory hierarchy, and activation of these systems has been shown to improve speech recognition. It is not yet clear whether or how top-down modulation to resolve ambiguous sounds calls upon these corticofugal projections. Here, we review the literature on top-down modulation in the auditory system, primarily focused on humans and cortical imaging/recording methods, and attempt to relate these findings to a growing animal literature, which has primarily been focused on corticofugal projections. We argue that corticofugal pathways contain the requisite circuitry to implement predictive coding mechanisms to facilitate perception of complex sounds and that top-down modulation at early (i.e., subcortical) stages of processing complement modulation at later (i.e., cortical) stages of processing. Finally, we suggest experimental approaches for future studies on this topic.
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Affiliation(s)
- Alexander Asilador
- Neuroscience Program, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Daniel A. Llano
- Neuroscience Program, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
- Molecular and Integrative Physiology, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
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32
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Schwab BC, Kase D, Zimnik A, Rosenbaum R, Codianni MG, Rubin JE, Turner RS. Neural activity during a simple reaching task in macaques is counter to gating and rebound in basal ganglia-thalamic communication. PLoS Biol 2020; 18:e3000829. [PMID: 33048920 PMCID: PMC7584254 DOI: 10.1371/journal.pbio.3000829] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 10/23/2020] [Accepted: 09/14/2020] [Indexed: 12/24/2022] Open
Abstract
Task-related activity in the ventral thalamus, a major target of basal ganglia output, is often assumed to be permitted or triggered by changes in basal ganglia activity through gating- or rebound-like mechanisms. To test those hypotheses, we sampled single-unit activity from connected basal ganglia output and thalamic nuclei (globus pallidus-internus [GPi] and ventrolateral anterior nucleus [VLa]) in monkeys performing a reaching task. Rate increases were the most common peri-movement change in both nuclei. Moreover, peri-movement changes generally began earlier in VLa than in GPi. Simultaneously recorded GPi-VLa pairs rarely showed short-time-scale spike-to-spike correlations or slow across-trials covariations, and both were equally positive and negative. Finally, spontaneous GPi bursts and pauses were both followed by small, slow reductions in VLa rate. These results appear incompatible with standard gating and rebound models. Still, gating or rebound may be possible in other physiological situations: simulations show how GPi-VLa communication can scale with GPi synchrony and GPi-to-VLa convergence, illuminating how synchrony of basal ganglia output during motor learning or in pathological conditions may render this pathway effective. Thus, in the healthy state, basal ganglia-thalamic communication during learned movement is more subtle than expected, with changes in firing rates possibly being dominated by a common external source.
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Affiliation(s)
- Bettina C. Schwab
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Technical Medical Center, University of Twente, Enschede, the Netherlands
| | - Daisuke Kase
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Andrew Zimnik
- Department of Neuroscience, Columbia University Medical Center, New York, New York, United States of America
| | - Robert Rosenbaum
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, South Bend, Indiana, United States of America
| | - Marcello G. Codianni
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jonathan E. Rubin
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Robert S. Turner
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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