, 2009), possibly aided by causal analysis (Gerhard et al., 2011). In practice, to enable visualization of neural sub-circuits, all these approaches must still overcome nontrivial limitations, such as insufficient spectral separation (Brainbow), antibody depth penetration (array tomography), and inadequate signal intensity in the distal branches (voltage-sensitive dyes). Synaptic connectivity may be

revealed by other means (Kim et al., 2012; Zador et al., 2012), but the problem of reconstructing the neuronal arbors of the connected network remains. Another crucial PD0332991 aspect of future emphasis is the temporal dimension. Neuronal reconstruction time-lapse series reflect morphological changes in development, neurodegeneration, or other observable time courses, such as physiological cycles, response to environmental conditions, and learning. During development, dendrites and axons undergo periods of dramatic branch addition, outgrowth,

pruning, or elimination. More subtle, but equally important, structural plasticity continues in many mature networks. Advanced imaging techniques this website allow routine acquisition of in vivo and in vitro time lapse data. However, digital reconstruction of the captured 4D data is still rare. Outstanding challenges include alignment and correspondence identification of the changing morphological components (He and Cline, 2011). New tools for the comparative analysis of (temporally) serial reconstruction of axonal and dendritic arbors in normal and pathological states will glean valuable insight into the mechanisms and implications of change over time (Lee et al., 2013). Whole-circuit reconstructions and temporal series will both necessitate new standardized formats and curation procedure to facilitate data accessibility as well as integration with the continuously evolving analysis, modeling,

and database resources of the digital neuromorphology ecosystem. Elucidating the complex organization of the brain will require synthesis of information about Florfenicol neuron types, the spatial patterns of their dendritic and axonal arborization, cell counts and densities, and synapse number and location (DeFelipe, 2010). Large-scale simulation projects are leveraging the state-of-the art data and tools reviewed here in morphometry, biophysics, and stereology to build realistic network models. Ongoing efforts focus on the organization, connectivity, and function of rat barrel cortex (NeuroDUNE; www.neurodune.org), hippocampus (Ropireddy and Ascoli, 2011), and neocortical columns (Blue Brain Project; Markram, 2006; bluebrain.epfl.ch), with plans aiming at the whole human brain (Abbott and Schiermeier, 2013). The overarching goal to generate virtual functioning nervous systems in silico (Roysam et al.