Representative figures for scatter plot analysis of the changes in synaptic plasticity gene expression in HIV infected SK-N-MC neuronal cells with nicotine and in combination with vorinostat. Pair wise comparison of control SK-N-MC cells (No HIV infection) and a) HIV + Nicotine b) HIV + Nicotine + Vorinostat treated SK-N-MC cells by scatter plot analysis. Spots associated with individual human synaptic plasticity gene were collected and converted into log10 scale. The central line indicates unchanged gene expression. The synaptic plasticity genes with expression levels higher or lower in treated neuronal cells than control cells are expected to produce dots that deviate from the centerline. The dots are allocated to positions that are above or below than the +3 fold or -3 fold line when the differences are greater than three folds.