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Hamodi, A. S.

Publications and source records attributed to Hamodi, A. S..

2 recordsLinked to original sources

Transverse sinus injections: A novel method for whole-brain vector-driven gene delivery

A major challenge in neuroscience is convenient whole-brain delivery of transgenes, especially early in postnatal development. Recent advances demonstrate whole-brain gene delivery by retro-orbital injection of virus, but slow and sparse expression, and the large injection volumes required, precludes early developmental studies. We developed a novel method for simple, fast and efficient gene delivery across the central nervous system in neonates as early as P4 and persisting into adulthood. The method employs transverse sinus injections of 2-4L of AAV9 at P0. Here, we describe how to use this method to label and/or genetically manipulate cells in the neonatal rat and mouse brain. This protocol is fast, easy, can be readily adopted by any laboratory, and utilizes the widely available AAV9 capsid. The procedure outlined here is adaptable for diverse experimental applications ranging from biochemistry, anatomical and functional mapping, to gene expression, silencing, and editing.

neuroscience

Simultaneous mesoscopic and two-photon imaging of neuronal activity in cortical circuits

Spontaneous and sensory-evoked activity propagates across spatial scales in the mammalian cortex but technical challenges have generally precluded establishing conceptual links between the function of local circuits of neurons and brain-wide network dynamics. To solve this problem, we developed a method for simultaneous cellular-resolution two-photon calcium imaging of a local microcircuit and mesoscopic widefield calcium imaging of the entire cortical mantle in awake, behaving mice. Our method employs an orthogonal axis design whereby the mesoscopic objective is oriented downward directly above the brain and the two-photon objective is oriented horizontally, with imaging performed through a glass right angle microprism implanted in the skull. In support of this method, we introduce a suite of analysis tools for relating the activity of individual cells to distal cortical areas, as well as a viral method for robust and widespread gene delivery in the juvenile mouse brain. We use these methods to characterize the diversity of associations of individual, genetically-defined neurons with cortex-wide network motifs.

neuroscience