Channelrhodopsins for optical control of cells

A method of producing spikes in a neuron, the method comprising:

• a) introducing into a neuron a nucleic acid comprising a nucleotide sequence encoding an amino acid sequence of a light-activated ion channel polypeptide, the amino acid sequence having at least 90% amino acid identity to amino acids 86-320 as set forth in SEQ ID NO:
• 2 and at least 95% identity to the amino acids 321-350 as set forth as SEQ ID NO:
• 2, to generate a modified neuron that expresses the light-activated ion channel polypeptide;
• and
• b) contacting the light-activated ion channel polypeptide in the modified neuron with a light wherein the contacting activates the light-activated ion channel polypeptide, alters the ion conductivity of the neuron membrane, and induces spikes in the modified neuron.