Presynaptic nigral GPR55 receptors stimulate [ H]-GABA release through [ H]-cAMP production and PKA activation and promote motor behavior.

Striatal medium-sized spiny neurons express mRNA and protein of GPR55 receptors that stimulate neurotransmitter release; thus, GPR55 could be sent to nigral striatal projections, where it might modulate GABA release and motor behavior. Here, we study the presence of GPR55 receptors at striato-nigral terminals, their modulation of GABA release, their signaling pathway, and their effect on motor activity. By double immunohistochemistry, we found the colocation of GPR55 protein and substance P in the dorsal striatum.

Cost of mental set reconfiguration between digits and their photisms in synaesthesia.

In this study we present an experiment investigating the reconfiguration process elicited by the task switching paradigm in synaesthesia. We study the time course of the operations involved in the activation of photisms. In the experimental Group, four digit-color synaesthetes alternated between an odd-even task and a color task (to indicate the photism elicited by each digit).