Differential firing pattern and response to lighting conditions of rat intergeniculate leaflet neurons projecting to suprachiasmatic nucleus or contralateral intergeniculate leaflet

► Different firing and light responses of differently projecting rat intergeniculate leaflet (IGL) neurons. ► Rat IGL neurons innervating the SCN have an irregular pattern of firing. ► Rat IGL neurons innervating the cIGL fire slow bursts of action potentials. ► The majority of the rat IGL neurons innervating the SCN are activated by darkness. ► All of the rat IGL neurons innervating the contralateral IGL are activated by light.