Neonatal prefrontal cortex lesion using CO2 laser technique

Abstract

Prefrontal cortex (PFC) is a large area of the brain and its neonatal lesion with ibotenic or kainic acid is used to study the early abnormalities in neurodevelopment that lead to behavioral changes linked to schizophrenia. However, these exitotoxic drugs produce a large and asymmetric damage in the PFC. We produced the bilateral lesions of the dorsal part of the PFC of neonatal Sprague-Dawley rats (postnatal day 7, P7) at the anteroposterior +2.5 mm and mediolateral +/-0.4 coordinates by the new laser technique that employ the confined radiation of the CO2 laser in the pulsed mode. The laser was used because its coherent radiation can be focused in a very small spot and as small as of several tens of micrometers in diameters. The CO, laser radiation is strongly absorbed by water that is present in any soft tissue. Thereafter, the configuration of the heated zone and, consequently, that of the lesion does not depend on the morphological non-homogeneity of particular structures. We obtained the symmetric, conical in shape and small-size bilateral lesions of the PFC. The size of the lesion depended on the beam spot-size and could be as small as several dozens of micrometers in diameter. Our data suggests that the laser technique will be used for the anatomical-functional studies of the PFC in the brain. (C) 2002 Elsevier Science B.V. All rights reserved.