The transcription factor Ebf2 is a marker of somatosensory, motivation and reward system of the developing mouse brain.

The functions of the nervous system depend on the correct connection between neurons and the formation of circuits between them. However, the molecular mechanisms involved in the formation of these circuits are not completely elucidated. In this work, we use the reporter tau-GFP (TGFP) under the control of the promoter of the Ebf2 gene in transgenic mice to trace the formation of neural circuits during mouse brain development. Ebf2 is a transcription factor involved in cell differentiation of the central nervous system, which is abundantly expressed in different areas of the murine brain. Our results show that the Ebf2-TGFP reporter is expressed in somatosensory system circuits connecting the trigeminal nuclei of the brainstem to the Ventral Posteromedial nucleus of the Thalamus, as well as in lamina II of the spinal cord and the Parabrachial nucleus. This distribution of the Ebf2-TGFP signals suggests that these circuits are involved in processing nociceptive signals. Moreover, we can also detect Ebf2-TGFP expression in circuits linking Septal Nuclei of the forebrain and the Bed Nucleus of the Stria Terminalis to the medial Habenula (mHb) via the stria medullaris. Some Ebf2-TGFP fibers link the mHb to the Interpeduncular Nucleus, where numerous Ebf2-TGFP axons that innervate the Dorsal Tegmental (DTg) nucleus originate. Some Ebf2-TGFP axons arising from the DTg and the ventral Periaqueductal Area join the medial forebrain bundle that traverse the hypothalamus and innervate the ventral pallidum region of the forebrain. The location and connectivity of these Ebf2-TGFP circuits suggest that they participate in the processing of motivation and reward signals in the brain. The expression of Ebf2-TGFP in these somatosensory and motivation-reward systems can be detected as early as E14.5 stage of mouse embryo development and is maintained in the adult mouse brain (P56).