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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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2
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Frezel N, Ranucci M, Foster E, Wende H, Pelczar P, Mendes R, Ganley RP, Werynska K, d'Aquin S, Beccarini C, Birchmeier C, Zeilhofer HU, Wildner H. c-Maf-positive spinal cord neurons are critical elements of a dorsal horn circuit for mechanical hypersensitivity in neuropathy. Cell Rep 2023; 42:112295. [PMID: 36947543 PMCID: PMC10157139 DOI: 10.1016/j.celrep.2023.112295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/02/2023] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Corticospinal tract (CST) neurons innervate the deep spinal dorsal horn to sustain chronic neuropathic pain. The majority of neurons targeted by the CST are interneurons expressing the transcription factor c-Maf. Here, we used intersectional genetics to decipher the function of these neurons in dorsal horn sensory circuits. We find that excitatory c-Maf (c-MafEX) neurons receive sensory input mainly from myelinated fibers and target deep dorsal horn parabrachial projection neurons and superficial dorsal horn neurons, thereby connecting non-nociceptive input to nociceptive output structures. Silencing c-MafEX neurons has little effect in healthy mice but alleviates mechanical hypersensitivity in neuropathic mice. c-MafEX neurons also receive input from inhibitory c-Maf and parvalbumin neurons, and compromising inhibition by these neurons caused mechanical hypersensitivity and spontaneous aversive behaviors reminiscent of c-MafEX neuron activation. Our study identifies c-MafEX neurons as normally silent second-order nociceptors that become engaged in pathological pain signaling upon loss of inhibitory control.
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Affiliation(s)
- Noémie Frezel
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Matteo Ranucci
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Edmund Foster
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Pawel Pelczar
- Center for Transgenic Models (CTM), University of Basel, 4001 Basel, Switzerland
| | - Raquel Mendes
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Robert P Ganley
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Karolina Werynska
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Simon d'Aquin
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Camilla Beccarini
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, 8092 Zürich, Switzerland.
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland.
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Wang Z, Romanski A, Mehra V, Wang Y, Brannigan M, Campbell BC, Petsko GA, Tsoulfas P, Blackmore MG. Brain-wide analysis of the supraspinal connectome reveals anatomical correlates to functional recovery after spinal injury. eLife 2022; 11:76254. [PMID: 35838234 PMCID: PMC9345604 DOI: 10.7554/elife.76254] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
The supraspinal connectome is essential for normal behavior and homeostasis and consists of numerous sensory, motor, and autonomic projections from brain to spinal cord. Study of supraspinal control and its restoration after damage has focused mostly on a handful of major populations that carry motor commands, with only limited consideration of dozens more that provide autonomic or crucial motor modulation. Here, we assemble an experimental workflow to rapidly profile the entire supraspinal mesoconnectome in adult mice and disseminate the output in a web-based resource. Optimized viral labeling, 3D imaging, and registration to a mouse digital neuroanatomical atlas assigned tens of thousands of supraspinal neurons to 69 identified regions. We demonstrate the ability of this approach to clarify essential points of topographic mapping between spinal levels, measure population-specific sensitivity to spinal injury, and test the relationships between region-specific neuronal sparing and variability in functional recovery. This work will spur progress by broadening understanding of essential but understudied supraspinal populations.
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Affiliation(s)
- Zimei Wang
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Adam Romanski
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Vatsal Mehra
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Yunfang Wang
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Matthew Brannigan
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Benjamin C Campbell
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Gregory A Petsko
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Pantelis Tsoulfas
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Murray G Blackmore
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
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Lu T, Shinozaki M, Nagoshi N, Nakamura M, Okano H. 3D imaging of supraspinal inputs to the thoracic and lumbar spinal cord mapped by retrograde tracing and light-sheet microscopy. J Neurochem 2022; 162:352-370. [PMID: 35674500 DOI: 10.1111/jnc.15653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 12/15/2022]
Abstract
The supraspinal inputs play a major role in tuning the hindlimb locomotion function. While most research on spinal cord injury (SCI) with rodents is based on thoracic segments, the difference in connectivity of the supraspinal centers to the thoracic and lumbar cord is still unknown. Here, we combined retrograde tracing and 3D imaging to map the connectivity of supraspinal neurons projecting to thoracic (T9-vertebral) and lumbar (T13-vertebral) spinal levels in adult female mice. We dissected the difference in connections of corticospinal neurons (CSNs), rubrospinal neurons, and reticulospinal neurons projecting to thoracic and lumbar cords. The ratio of double-labeled neurons is higher in T13-vertebral projection CSNs and parvocellular part of the red nucleus (RPC) than in T9-vertebral projection. Using the Cre-DIO system, we precisely targeted CSNs projecting to T9-vertebral or T13-vertebral. We found that abundant axon branches communicated with the red nucleus and reticular formation and distributed from cervical gray matter to the lumbar cord. Their collateral branches showed a distinct innervation pattern in thoracic and lumbar gray matters and a similar distribution pattern in the cervical spinal cord. These results revealed the difference in connectivity between the thoracic and lumbar projection supraspinal centers and clarified the collateralization of thoracic/lumbar projection CSNs throughout the brain and spinal cord. This study highlights brain-spinal cord neural networks and the complexity of the axon terminals of spinal projection CSNs, which could contribute to the development of targeted therapeutic strategies connecting CST fibers and hindlimb function recovery.
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Affiliation(s)
- Tao Lu
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Munehisa Shinozaki
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Narihito Nagoshi
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Masaya Nakamura
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
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Ganley RP, Werder K, Wildner H, Zeilhofer HU. Spinally projecting noradrenergic neurons of the locus coeruleus display resistance to AAV2retro-mediated transduction. Mol Pain 2021; 17:17448069211037887. [PMID: 34344259 PMCID: PMC8351027 DOI: 10.1177/17448069211037887] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The locus coeruleus (LC) is the principal source of noradrenaline (NA) in the central nervous system. Projection neurons in the ventral portion of the LC project to the spinal cord and are considered the main source of spinal NA. To understand the precise physiology of this pathway, it is important to have tools that allow specific genetic access to these descending projections. AAV2retro serotype vectors are a potential tool to transduce these neurons via their axon terminals in the spinal cord, and thereby limit the expression of genetic material to the spinal projections from the LC. Here, we assess the suitability of AAV2retro to target these neurons and investigate strategies to increase their labelling efficiency. RESULTS We show that the neurons in the LC that project to the spinal dorsal horn are largely resistant to transduction with AAV2retro serotype vectors. Compared to Cholera toxin B (CTb) tracing, AAV2retro.eGFP labelled far fewer neurons within the LC and surrounding regions, particularly within neurons that express tyrosine hydroxylase (TH), the rate-limiting enzyme for NA synthesis. We also show that the sensitivity for transduction of this projection can be increased using AAV2retro.eGFP.cre in ROSA26tdTom reporter mice (23% increase), with a higher proportion of the newly revealed neurons expressing TH compared to those directly labelled with AAV2retro containing an eGFP expression sequence. CONCLUSION These tracing studies identify limitations in AAV2retro-mediated retrograde transduction of a subset of projection neurons, specifically those that express NA and project to the spinal cord. This is likely to have implications for the study of NA-containing projections as well as other types of projection neuron in the central nervous system.
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Affiliation(s)
- Robert P Ganley
- Institute for Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - Kira Werder
- Institute for Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - Hendrik Wildner
- Institute for Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute for Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland.,Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland.,Neuroscience Center Zurich, Zürich, Switzerland
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Yamawaki N, Raineri Tapies MG, Stults A, Smith GA, Shepherd GMG. Circuit organization of the excitatory sensorimotor loop through hand/forelimb S1 and M1. eLife 2021; 10:e66836. [PMID: 33851917 PMCID: PMC8046433 DOI: 10.7554/elife.66836] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/03/2021] [Indexed: 12/16/2022] Open
Abstract
Sensory-guided limb control relies on communication across sensorimotor loops. For active touch with the hand, the longest loop is the transcortical continuation of ascending pathways, particularly the lemnisco-cortical and corticocortical pathways carrying tactile signals via the cuneate nucleus, ventral posterior lateral (VPL) thalamus, and primary somatosensory (S1) and motor (M1) cortices to reach corticospinal neurons and influence descending activity. We characterized excitatory connectivity along this pathway in the mouse. In the lemnisco-cortical leg, disynaptic cuneate→VPL→S1 connections excited mainly layer (L) 4 neurons. In the corticocortical leg, S1→M1 connections from L2/3 and L5A neurons mainly excited downstream L2/3 neurons, which excite corticospinal neurons. The findings provide a detailed new wiring diagram for the hand/forelimb-related transcortical circuit, delineating a basic but complex set of cell-type-specific feedforward excitatory connections that selectively and extensively engage diverse intratelencephalic projection neurons, thereby polysynaptically linking subcortical somatosensory input to cortical motor output to spinal cord.
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Affiliation(s)
- Naoki Yamawaki
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
| | | | - Austin Stults
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
| | - Gregory A Smith
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
| | - Gordon MG Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
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