Figure 1. Four different techniques for manipulating neural activity.

Each of the techniques described in this Reader’s Toolbox excite or inhibit neural activity via their effects on membrane-bound proteins, including (A) voltage-gated proteins, (B) ion channels or other receptors (C) opsins, and (D) modified receptors that respond to an exogenous ligand instead of their endogenous ligand. Because of their different molecular mechanisms, these four techniques exhibit varying degrees of spatial range, temporal dynamics, and neuron-type specificity. Researchers use these techniques for manipulating neural activity in order to study the role of neural circuits in a range of physiological, behavioral, and cognitive states.