ggplot(df, aes("spikes", "neurons")) +
  geom_linerange(aes(ymin = f{c"neurons" - 1.0},
                     ymax = f{c"neurons" + 1.0})) +
  scale_y_continuous() + # make sure y is considered cont.
  ylim(1, -1) + # at the moment ymin, ymax are not considered for the plot range (that's a bug)
  ggtitle("Spike raster plot") +
  ggsave("spike_raster.pdf")