FIGURE 1.

Pain anatomical pathways and CB1R expression. Ascending pain pathways (in red) are carried from the body periphery through sensory neurons of dorsal root ganglia (DRG) that synapse mainly with laminaes I to III in the dorsal spinal cord. Projection neurons make connections with brain areas such as thalamus and cortex. The descending pathways (in blue), responsible for pain modulation, involve areas such as the periaqueductal gray matter and amygdala, ending in the dorsal spinal cord. The CB1R distribution is heterogeneous in pain pathway areas, being more concentrated in regions such as cortex and Central Amygdala (CeA). LA, lateral amygdala; CeA, central amygdala; BlA, basolateral amigdala.