Spontaneous exploratory preferential decisions after transient inactivation of the nucleus accumbens neurons in the rat.

SOLER MP; RATTI S.G.,; ALVAREZ EO

Mendoza, Argentina

Congreso; Sociedad de Biología de Cuyo; 2009

Sociedad de Biología de Cuyo

Spontaneous exploratory preferential decisions after transient inactivation of the nucleus accumbens neurons in the rat. Soler MP1, Ratti SG1,2, Alvarez EO1,2. (1) Laboratorio de Neuropsicofarmacología Experimental, Área de Farmacología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo e IMBECU-CONICET. (2) Instituto de Ciencias Ambientales (ICA), Universidad Nacional de Cuyo, Mendoza. E-mail: ealvarez@fcm.uncu.edu.ar Evidence from our laboratory has shown that during exploration of novel environments, rats display preferential decisions regarding two mutually excluding ways to spatial exploratory activity. It is not known if the nucleus accumbens (ACC) known to participate in motivated exploratory activity might have a role in the lateralized expression of exploratory behavior. The objective of the present work was to evaluate if the ACC is lateralized to modulate exploratory activity of unknown environments. Adult male rats (90 day-old) were implanted bilaterally with guide cannulae into the ACC for in situ microinjections. 48 h later, groups of animals were injected with saline (Control, n=14); lidocaine (Lid, 2 μg/µl) into the right ACC (n=19) or left ACC (n=12). 5 min afterwards, all groups of animals were tested in the Double Lateral Holeboard (DLHB) during 5 min as previously described. Results show that only the inactivation with lidocaine of the left-ACC modified total exploratory activity of the DLHB corridor (141±13.8 Counts/5 min Vs 97±9.2 Counts/5 min; Lid-left ACC Vs Control, p<0.01). Also the same lidocaine treatment decreased the proportion of animals exploring more left than the right corridor (58.8% left exploration Vs 78.6% left exploration; Lid-left-ACC Vs Control, p<0.027). In conclusion, results suggest that ACC neurons are modulating the lateralized exploration of novel environments in the rat.