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Najafian S, Koch E, Teh KL, Jin J, Rahimi-Nasrabadi H, Zaidi Q, Kremkow J, Alonso JM. A theory of cortical map formation in the visual brain. Nat Commun 2022; 13:2303. [PMID: 35484133 PMCID: PMC9050665 DOI: 10.1038/s41467-022-29433-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 03/16/2022] [Indexed: 11/11/2022] Open
Abstract
The cerebral cortex receives multiple afferents from the thalamus that segregate by stimulus modality forming cortical maps for each sense. In vision, the primary visual cortex maps the multiple dimensions of the visual stimulus in patterns that vary across species for reasons unknown. Here we introduce a general theory of cortical map formation, which proposes that map diversity emerges from species variations in the thalamic afferent density sampling sensory space. In the theory, increasing afferent sampling density enlarges the cortical domains representing the same visual point, allowing the segregation of afferents and cortical targets by multiple stimulus dimensions. We illustrate the theory with an afferent-density model that accurately replicates the maps of different species through afferent segregation followed by thalamocortical convergence pruned by visual experience. Because thalamocortical pathways use similar mechanisms for axon segregation and pruning, the theory may extend to other sensory areas of the mammalian brain. Najafian et al. introduce a developmental theory of map formation in the cerebral cortex. The theory proposes that increases in the density of thalamic afferents sampling sensory space make cortical maps to segregate more stimulus dimensions.
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Affiliation(s)
- Sohrab Najafian
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States
| | - Erin Koch
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States.,Division of Biology and Biological Engineering, Caltech, Pasadena, CA, 91125, United States
| | - Kai Lun Teh
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Philippstraße 13, 10115, Berlin, Germany
| | - Jianzhong Jin
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States
| | - Hamed Rahimi-Nasrabadi
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States
| | - Qasim Zaidi
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States
| | - Jens Kremkow
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Philippstraße 13, 10115, Berlin, Germany
| | - Jose-Manuel Alonso
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, 10036, United States.
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Domijan D, Marić M. A multi-scale neurodynamic implementation of incremental grouping. Vision Res 2022; 197:108057. [PMID: 35487147 DOI: 10.1016/j.visres.2022.108057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 11/17/2022]
Abstract
Incremental grouping is a process entailing serial binding of distal image elements into a unified object representation. At the neural level, incremental grouping involves propagation of the enhanced firing rate among feature-tuned neurons in the early visual cortex. Here, we developed a multi-resolution neural model of incremental grouping. In the model, propagation of the enhanced firing rate is achieved by computing the activity difference between two sets of units: attentional or A-units, whose firing rate is modulated by their horizontal collaterals, and non-attentional or N-units that receive only feedforward input. The activity difference is computed on dendrites that act as independent computational subunits. The proposed model employs multiple spatial scales to account for a variable speed of incremental grouping. In addition, the model incorporates the L-junction detection network that enables incremental grouping over L-junctions. Computer simulations show that the timing of attentional modulations in the model is comparable with neurophysiological measurements in monkey primary visual cortex.
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Yamamori T. Functional visualization and manipulation in the marmoset brain using viral vectors. Curr Opin Pharmacol 2021; 60:11-16. [PMID: 34280704 DOI: 10.1016/j.coph.2021.06.004] [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: 03/30/2021] [Revised: 05/30/2021] [Accepted: 06/14/2021] [Indexed: 02/08/2023]
Abstract
The common marmoset, a New World monkey, has a primate-specific cortex with approximately 40 Brodmann areas. Genetically encoded calcium indicator (GECI) techniques have been applied to study the functional organization of the marmoset cortex. The success of GCaMP (a green fluorescent of GECI) imaging and other advances, including optogenetic approaches, provide an interesting and exciting opportunity to study the primate brain at the molecular and cellular levels, leading to an understanding of primate neural circuits. These approaches will help advance our knowledge on cognition in primates, including humans, and therapy for human neurological and psychiatric disorders.
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Affiliation(s)
- Tetsuo Yamamori
- Center for Brain Science, Laboratory for Molecular Analysis of Higher Brain Function, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan.
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