An activating light-responsive polypeptide, or a nucleic acid comprising a nucleotide sequence encoding the light-responsive polypeptide, for use in a method of modulating a feature of anxiety in a subject, the method comprising: a) activating a basolateral amygdala pyramidal neuron input to an anterodorsal bed nucleus of stria terminalis (BNST) neuron by: i) expressing the activating light-responsive polypeptide in the BNST neuron, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron to light of an activating wavelength, thereby activating the BLA pyramidal neuron, wherein said activating reduces risk avoidance and reduces respiratory rate; or b) wherein said modulating comprises activating an anterodorsal BNST neuron projection to the lateral hypothalamus by: i) expressing the activating light-responsive polypeptide in the anterodorsal BNST neuron projection, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron projection to light of an activating wavelength, wherein said activating reduces risk avoidance, and has substantially no effect on respiratory rate; or c) wherein said modulating comprises activating an anterodorsal BNST neuron projection to the parabrachial nucleus by: i) expressing the activating light-responsive polypeptide in the anterodorsal BNST neuron projection, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron projection to light of an activating wavelength, thereby activating the anterodorsal BNST neuron projection, wherein said activating reduces respiratory rate, and has substantially no effect on risk avoidance behavior. a) activating a basolateral amygdala pyramidal neuron input to an anterodorsal bed nucleus of stria terminalis (BNST) neuron by: i) expressing the activating light-responsive polypeptide in the BNST neuron, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron to light of an activating wavelength, thereby activating the BLA pyramidal neuron, wherein said activating reduces risk avoidance and reduces respiratory rate; or b) wherein said modulating comprises activating an anterodorsal BNST neuron projection to the lateral hypothalamus by: i) expressing the activating light-responsive polypeptide in the anterodorsal BNST neuron projection, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron projection to light of an activating wavelength, wherein said activating reduces risk avoidance, and has substantially no effect on respiratory rate; or c) wherein said modulating comprises activating an anterodorsal BNST neuron projection to the parabrachial nucleus by: i) expressing the activating light-responsive polypeptide in the anterodorsal BNST neuron projection, wherein the light-responsive polypeptide comprises an amino acid sequence having at least 90% amino acid sequence identity to one of SEQ ID NOs:5-11; and ii) exposing the anterodorsal BNST neuron projection to light of an activating wavelength, thereby activating the anterodorsal BNST neuron projection, wherein said activating reduces respiratory rate, and has substantially no effect on risk avoidance behavior.