The habenula is crucial for experience-dependent modification of fear responses in zebrafish

Agetsuma and colleagues find that the pathway between the lateral subnucleus of the dorsal habenula (dHbL) and the interpeduncular nucleus is involved in mediating experience-dependent fear responses in zebrafish. Genetic inactivation of the dHbL biased fish towards freezing, rather than the typical flight behavior, in response to a conditioned fear stimulus. The zebrafish dorsal habenula (dHb) shows conspicuous asymmetry in its connection with the interpeduncular nucleus (IPN) and is equivalent to the mammalian medial habenula. Genetic inactivation of the lateral subnucleus of dHb (dHb L ) biased fish towards freezing rather than the normal flight response to a conditioned fear stimulus, suggesting that the dHb L -IPN pathway is important for controlling experience-dependent modification of fear responses.