def is_conductance(target_cell):
    """
    Returns True if the target cell uses conductance-based synapses, False if
    it uses current-based synapses, and None if the synapse-basis cannot be
    determined.
    """
    if hasattr(target_cell, 'local') and target_cell.local and hasattr(
        target_cell, 'celltype'):
        is_conductance = target_cell.celltype.conductance_based
    else:
        is_conductance = None
    return is_conductance
