MSGID: 1:317/3 63dc8df2   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Human brain organoids respond to visual stimuli when transplanted into   
   adult rats    
      
     Date:   
         February 2, 2023   
     Source:   
         Cell Press   
     Summary:   
         Researchers show that brain organoids -- clumps of lab-grown   
         neurons - - can integrate with rat brains and respond to visual   
         stimulation like flashing lights.   
      
      
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   FULL STORY   
   ==========================================================================   
   In a study publishing in the journal Cell Stem Cell on February 2,   
   researchers show that brain organoids -- clumps of lab-grown neurons --   
   can integrate with rat brains and respond to visual stimulation like   
   flashing lights.   
      
      
   ==========================================================================   
   Decades of research has shown that we can transplant individual human   
   and rodent neurons into rodent brains, and, more recently, it has been   
   demonstrated that human brain organoids can integrate with developing   
   rodent brains.   
      
   However, whether these organoid grafts can functionally integrate with   
   the visual system of injured adult brains has yet to be explored.   
      
   "We focused on not just transplanting individual cells, but   
   actually transplanting tissue," says senior author H. Isaac Chen, a   
   physician and Assistant Professor of Neurosurgery at the University of   
   Pennsylvania. "Brain organoids have architecture; they have structure   
   that resembles the brain. We were able to look at individual neurons   
   within this structure to gain a deeper understanding of the integration   
   of transplanted organoids."  The researchers cultivated human stem   
   cell-derived neurons in the lab for around 80 days before grafting them   
   into the brains of adult rats that had sustained injuries to their visual   
   cortex. Within three months, the grafted organoids had integrated with   
   their host's brain: becoming vascularized, growing in size and number,   
   sending out neuronal projections, and forming synapses with the host's   
   neurons.   
      
   The team made use of fluorescent-tagged viruses that hop along synapses,   
   from neuron to neuron, to detect and trace physical connections between   
   the organoid and brain cells of the host rat. "By injecting one of these   
   viral tracers into the eye of the animal, we were able to trace the   
   neuronal connections downstream from the retina," says Chen. "The tracer   
   got all the way to the organoid."  Next, the researchers used electrode   
   probes to measure the activity of individual neurons within the organoid   
   when the animals were exposed to flashing lights and alternating white   
   and black bars. "We saw that a good number of neurons within the organoid   
   responded to specific orientations of light, which gives us evidence that   
   these organoid neurons were able to not just integrate with the visual   
   system, but they were able to adopt very specific functions of the visual   
   cortex."  The team was surprised by the degree to which the organoids were   
   able to integrate within only three months. "We were not expecting to see   
   this degree of functional integration so early," says Chen. "There have   
   been other studies looking at transplantation of individual cells that   
   show that even 9 or 10 months after you transplant human neurons into   
   a rodent, they're still not completely mature."  "Neural tissues have   
   the potential to rebuild areas of the injured brain," says Chen. "We   
   haven't worked everything out, but this is a very solid first step.   
      
   Now, we want to understand how organoids could be used in other areas   
   of the cortex, not just the visual cortex, and we want to understand   
   the rules that guide how organoid neurons integrate with the brain so   
   that we can better control that process and make it happen faster."   
       * RELATED_TOPICS   
             o Health_&_Medicine   
                   # Nervous_System # Stem_Cells # Brain_Tumor   
             o Mind_&_Brain   
                   # Neuroscience # Brain_Injury # Brain-Computer_Interfaces   
             o Plants_&_Animals   
                   # Mice # Biology # Biotechnology   
       * RELATED_TERMS   
             o Brain o Sensory_neuron o Brown_Rat o Retina o   
             Multiple_sclerosis o Social_cognition o Neural_network o   
             Optic_nerve   
      
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   Story Source: Materials provided by Cell_Press. Note: Content may be   
   edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Dennis Jgamadze, James T. Lim, Zhijian Zhang, Paul M. Harary, James   
         Germi, Kobina Mensah-Brown, Christopher D. Adam, Ehsan Mirzakhalili,   
         Shikha Singh, Jiahe Ben Gu, Rachel Blue, Mehek Dedhia, Marissa Fu,   
         Fadi Jacob, Xuyu Qian, Kimberly Gagnon, Matthew Sergison, Oceane   
         Fruchet, Imon Rahaman, Huadong Wang, Fuqiang Xu, Rui Xiao, Diego   
         Contreras, John A.   
      
         Wolf, Hongjun Song, Guo-li Ming, Han-Chiao Isaac Chen. Structural   
         and functional integration of human forebrain organoids with the   
         injured adult rat visual system. Cell Stem Cell, 2023; 30 (2):   
         137 DOI: 10.1016/ j.stem.2023.01.004   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/02/230202112654.htm   
      
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