EVENT

Functionally specific optogenetic modulation in primate visual cortex

Mykyta M. Chernov, Robert M. Friedman, Gang Chen, Gene R. Stoner, and Anna Wang Roe/ PNAS October 9, 2018 115 (41) 10505-10510; published ahead of print September 26, 2018 https://doi.org/10.1073/pnas.1802018115 

 

Significance

Primate visual cortex is organized into columns that process different features of a visual scene, such as color, orientation preference, and ocular dominance. Until now, their small size has made it difficult to modulate them directly. Here, we report for the first time that focal targeting of light-sensitive ion channels (channelrhodopsins) in macaques using lentiviral vectors allows one to stimulate functional domains. We show that such targeted stimulation leads to selective activation of anatomically connected neighboring domains with similar function. Such a fine-scale optical stimulation approach is capable of mapping functionally specific domain-based neuronal networks. Its potential for linking such networks to optogenetic modulation of perception and behavior opens doors for developing targeted, domain-based neuroprosthetics.

Abstract

In primates, visual perception is mediated by brain circuits composed of submillimeter nodes linked together in specific networks that process different types of information, such as eye specificity and contour orientation. We hypothesized that optogenetic stimulation targeted to cortical nodes could selectively activate such cortical networks. We used viral transfection methods to confer light sensitivity to neurons in monkey primary visual cortex. Using intrinsic signal optical imaging and single-unit electrophysiology to assess effects of targeted optogenetic stimulation, we found that (i) optogenetic stimulation of single ocular dominance columns (eye-specific nodes) revealed preferential activation of nearby same-eye columns but not opposite-eye columns, and (ii) optogenetic stimulation of single orientation domains increased visual response of matching orientation domains and relatively suppressed nonmatching orientation selectivity. These findings demonstrate that optical stimulation of single nodes leads to modulation of functionally specific cortical networks related to underlying neural architecture.

Link: http://www.pnas.org/content/115/41/10505

2018-10-18 READ MORE

Significance

Detection and analyzing visual motion is an important task for the visual system. In the past half a century, research on motion information processing has been focused primarily on the dorsal visual areas (e.g. area MT/V5). Other visual areas (e.g. V2, V4) are virtually unexplored in this aspect, despite the fact that the motion-sensitive neurons in these areas are significantly present and form functional domains. In this study, we combined optical imaging with single-cell recordings to specifically record from direction-selective neurons in the second largest visual area, V2, in macaque monkeys, in order to have a full picture of how motion information is analyzed in the brain.

We found that motion-sensitive neurons in area V2 have characteristic features that are different from those in the well-studied motion areas like area MT. Particularly, these neurons have small receptive field and strong surround suppression, which make them sensitive to “motion contrast”, a key information delineating object boundaries. These features suggest that area V2 detects visual objects based on motion information.

Abstract

In the primate visual system, direction-selective (DS)neurons are critical for visual motion perception. While DS neurons in the dorsal visual pathway have been well characterized, the response properties of DS neurons in other major visual areas are largely unexplored. Recent optical imaging studies in monkey visual cortex area 2 (V2) revealed clusters of DS neurons. This imaging method facilitates targeted recordings from these neurons. Using optical imaging and single-cell recording, we characterized detailed response properties of DS neurons in macaque V2. Compared with DS neurons in the dorsal areas (e.g., middle temporal area [MT]), V2 DS neurons have a smaller receptive field and a stronger antagonistic surround. They do not code speed or plaid motion but are sensitive to motion contrast. Our results suggest that V2 DS neurons play an important role in figure-ground segregation. The clusters of V2 DS neurons are likely specialized functional systems for detecting motion contrast. 

Keywords

Macaque, V2, direction selectivity, RF surround, motion contrast

Online paper: https://www.cell.com/cell-reports/fulltext/S2211-1247(18)31444-X#secsectitle0265pdf.pdf

2018-10-17 READ MORE


Significance

Detection and analyzing visual motion is an important task for the visual system. In the past half a century, research on motion information processing has been focused primarily on the dorsal visual areas (e.g. area MT/V5). Other visual areas (e.g. V2, V4) are virtually unexplored in this aspect, despite the fact that the motion-sensitive neurons in these areas are significantly present and form functional domains. In this study, we combined optical imaging with single-cell recordings to specifically record from direction-selective neurons in the second largest visual area, V2, in macaque monkeys, in order to have a full picture of how motion information is analyzed in the brain.

We found that motion-sensitive neurons in area V2 have characteristic features that are different from those in the well-studied motion areas like area MT. Particularly, these neurons have small receptive field and strong surround suppression, which make them sensitive to “motion contrast”, a key information delineating object boundaries. These features suggest that area V2 detects visual objects based on motion information.

Abstract

In the primate visual system, direction-selective (DS)neurons are critical for visual motion perception. While DS neurons in the dorsal visual pathway have been well characterized, the response properties of DS neurons in other major visual areas are largely unexplored. Recent optical imaging studies in monkey visual cortex area 2 (V2) revealed clusters of DS neurons. This imaging method facilitates targeted recordings from these neurons. Using optical imaging and single-cell recording, we characterized detailed response properties of DS neurons in macaque V2. Compared with DS neurons in the dorsal areas (e.g., middle temporal area [MT]), V2 DS neurons have a smaller receptive field and a stronger antagonistic surround. They do not code speed or plaid motion but are sensitive to motion contrast. Our results suggest that V2 DS neurons play an important role in figure-ground segregation. The clusters of V2 DS neurons are likely specialized functional systems for detecting motion contrast. 

Keywords

Macaque, V2, direction selectivity, RF surround, motion contrast

Online paper: https://www.cell.com/cell-reports/fulltext/S2211-1247(18)31444-X#secsectitle0265pdf.pdf

2018-10-17 READ MORE
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各学院(系),行政各部门,各校区管委会,直属各单位:

根据《国务院办公厅关于2018年部分节假日安排的通知》(国办发明电〔2017〕12号),结合学校校历安排,经学校研究决定,2018年元旦、清明节、劳动节、端午节、中秋节和国庆节放假安排如下:


一、元旦:1月1日放假,与2017年12月30日(星期六)、12月31日(星期日)连休,共3天。


二、清明节:4月5日至7日放假调休,共3天。4月8日(星期日)上班、上课。


三、劳动节:4月29日至5月1日放假调休,4月28日(星期六)上班、上课。


四、端午节:6月18日放假,与6月16日(星期六)、6月17日(星期日)连休,共3天。


五、中秋节:9月24日放假,与9月22日(星期六)、9月23日(星期日)连休,共3天。


六、国庆节:10月1日至7日放假调休,共7天。9月29日(星期六)、9月30(星期日)上班。


节假日具体课程调整安排见本科生院、研究生院通知。

学校在节假日期间安排总值班,请各校区管委会安排好本校区值班,加强安全保卫工作,确保全校师生度过一个平安的节日。请各校区管委会汇总本校区各单位值班联系人及联系方式后于放假日5日前报校长办公室(传真:88981358,电子邮箱:zdlb@zju.edu.cn)。

学校总值班地点:紫金港校区纳米楼511B室;

值班时间:上午8:30—11:30,下午1:30—4:30;

值班电话:88981583(值班时间),88206110(其它时间)。


  


  


                                                                   浙江大学校长办公室


                                                                   2017年12月6日


通知链接:

http://zy.zju.edu.cn/web/detail.doappdomain=zhedasousuo&keyword=%E8%8A%82%E5%81%87%E6%97%A5&docNo=3bz22548

 


2018-09-26 READ MORE

    7月13日至7月16日第十四届亚太视觉会议暨第三届中国视觉科学学术会议,在杭州望湖宾馆成功举办。此次会议是由浙江大学主办,浙江大学心理与行为科学系、浙江大学系统神经与认知科学研究所和中国科学院心理研究所承办。

 

本次会议是亚太地区规格最高、规模最大的视觉学术盛会,是国内外心理学,神经生物学及相关学科专家、学者学术和信息交流的平台。议题涵盖基础视觉认知、临床视觉、视觉过程的神经机制、机器视觉与人工智能、学习与发展、虚拟视觉等主题。会议邀请到了包括来自美国纽约大学神经科学中心的国际著名神经科学家,美国国家科学院院士Anthony Movshon 教授,以及美国洛克菲勒大学神经生物学实验室负责人Charles Gilbert教授在内的8位领域内的顶级专家做主题报告,另设8场大会报告、8场专题讨论、1场女科学家论坛、以及近250张学术海报的展出。共有400余名来自国内外的代表参加,涵盖基础研究的专业人员与从事应用领域的相关人员。他们时刻关注着视觉研究领域的动态,也为视觉科学产业的发展与壮大做出了卓越的贡献。

 图片1.png   Charles Gilbert教授做学术报告

 图片2.png

学者们在学术海报展上的讨论

此次大会旨在扩大亚太地区与中国视觉研究领域专家的学术交流,提升中国心理学与神经生物学的整体学术水平,推动心理学与神经生物学在“一带一路”沿线城市的发展和应用,促进心理学与神经生物学在社会创新实践中的广泛应用,服务于“创新驱动”的国家战略。同时也帮助了解相关领域内不同单位的先进科研技术及方法,不断提高浙江大学的科学研究水平。同时也为领域内的科学家们提供了一个科研进展及成果展示的平台。


2018-07-20 READ MORE

The International Society for Magnetic Resonance in Medicine (ISMRM) is the biggest international conference in the field of medical magnetic resonance imaging (MRI). The 27th ISMRM was held on 16-21 June in Paris, France. Many teachers and students in our institute attended the conference and made oral and poster presentations. On the morning of June 21st, Dr. Guohua Xu (a.k.a Augix) gave a talk titled "A novel method for mesoscale connectome mapping: focal infrared neural stimulation in high-field functional MRI". The talk received the ISMRM Magna Cum Laude Merit Awards. In this talk, Guohua introduced the development of a new technique led by him and Prof. Anna Wang Roe. This technique is a new method for studying brain connectivity. It combines 7T ultra-high field functional MRI and near-infrared laser stimulation. The purpose of developing this technique is to rapidly and systematically study primate connectomes at sub-millimeter resolution.


Dr. Guohua Xu studied the evolution of rice genome in Zhejiang University between 2000 and 2004, and received Bachelor degree in Agronomy. He then moved to France, studied the evolution of mouse genome, and received Master degree in Biomathematics in Bioinformatics from University of Lyon 1. Between 2006 and 2010, he worked in CAS-MPG Partner Institute for Computational Biology, and led a study between human and chimpanzee brain gene expression. In 2010, he started his Ph.D. program in Max Planck Institute for Evolutionary Anthropology in Germany, and studied gene expression evolution in single cells in primate prefrontal cortices. In 2015, he joined Prof. Anna Wang Roe’s laboratory in Zhejiang University Interdisciplinary Institute of Neuroscience and Technology (ZIINT). His current research focus is the development of a new technique for connectome mapping.


2018-07-17 READ MORE
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