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Weilnhammer V, Stuke H, Standvoss K, Sterzer P. Sensory processing in humans and mice fluctuates between external and internal modes. PLoS Biol 2023; 21:e3002410. [PMID: 38064502 PMCID: PMC10732408 DOI: 10.1371/journal.pbio.3002410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 12/20/2023] [Accepted: 10/30/2023] [Indexed: 12/21/2023] Open
Abstract
Perception is known to cycle through periods of enhanced and reduced sensitivity to external information. Here, we asked whether such slow fluctuations arise as a noise-related epiphenomenon of limited processing capacity or, alternatively, represent a structured mechanism of perceptual inference. Using 2 large-scale datasets, we found that humans and mice alternate between externally and internally oriented modes of sensory analysis. During external mode, perception aligns more closely with the external sensory information, whereas internal mode is characterized by enhanced biases toward perceptual history. Computational modeling indicated that dynamic changes in mode are enabled by 2 interlinked factors: (i) the integration of subsequent inputs over time and (ii) slow antiphase oscillations in the impact of external sensory information versus internal predictions that are provided by perceptual history. We propose that between-mode fluctuations generate unambiguous error signals that enable optimal inference in volatile environments.
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Affiliation(s)
- Veith Weilnhammer
- Department of Psychiatry, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health, Charité-Universitätsmedizin Berlin and Max Delbrück Center, Berlin, Germany
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California, United States of America
| | - Heiner Stuke
- Department of Psychiatry, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health, Charité-Universitätsmedizin Berlin and Max Delbrück Center, Berlin, Germany
| | - Kai Standvoss
- Department of Psychiatry, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Philipp Sterzer
- Department of Psychiatry (UPK), University of Basel, Basel, Switzerland
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Courte J, Le NA, Pan T, Bousset L, Melki R, Villard C, Peyrin JM. Synapses do not facilitate prion-like transfer of alpha-synuclein: a quantitative study in reconstructed unidirectional neural networks. Cell Mol Life Sci 2023; 80:284. [PMID: 37688644 PMCID: PMC10492778 DOI: 10.1007/s00018-023-04915-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 07/11/2023] [Accepted: 08/07/2023] [Indexed: 09/11/2023]
Abstract
Alpha-synuclein (aSyn) aggregation spreads between cells and underlies the progression of neuronal lesions in the brain of patients with synucleinopathies such as Parkinson's diseases. The mechanisms of cell-to-cell propagation of aggregates, which dictate how aggregation progresses at the network level, remain poorly understood. Notably, while prion and prion-like spreading is often simplistically envisioned as a "domino-like" spreading scenario where connected neurons sequentially propagate protein aggregation to each other, the reality is likely to be more nuanced. Here, we demonstrate that the spreading of preformed aSyn aggregates is a limited process that occurs through molecular sieving of large aSyn seeds. We further show that this process is not facilitated by synaptic connections. This was achieved through the development and characterization of a new microfluidic platform that allows reconstruction of binary fully oriented neuronal networks in vitro with no unwanted backward connections, and through the careful quantification of fluorescent aSyn aggregates spreading between neurons. While this allowed us for the first time to extract quantitative data of protein seeds dissemination along neural pathways, our data suggest that prion-like dissemination of proteinopathic seeding aggregates occurs very progressively and leads to highly compartmentalized pattern of protein seeding in neural networks.
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Affiliation(s)
- Josquin Courte
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
- Institut Curie, CNRS UMR 168, Université PSL, Sorbonne Universités, 75005 Paris, France
| | - Ngoc Anh Le
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
| | - Teng Pan
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
| | - Luc Bousset
- Institut François Jacob, (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, 92260 Fontenay-Aux-Roses, France
| | - Ronald Melki
- Institut François Jacob, (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, 92260 Fontenay-Aux-Roses, France
| | - Catherine Villard
- Institut Curie, CNRS UMR 168, Université PSL, Sorbonne Universités, 75005 Paris, France
| | - Jean-Michel Peyrin
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
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