Abstract
Fixed-ratio (FR) discrimination learning in adult male spontaneously hypertensive rats (SHR), methylazoxymethanol-induced microencephalic Sprague-Dawley (MAM), and Sprague-Dawley control rats was examined. SHR and MAM rats had little problem learning incrementally more difficult FR discriminations (FR1 vs. FR16, FR4 vs. FR16, and FR8 vs. FR16) that resulted in parallel increases in errors in all animals, and displayed only modest learning deficits during a subsequent FR4 vs. FR16 position reversal. When training involved nonincremental changes in difficulty (FR8 vs. FR16, FR4 vs. FR16, FR8 vs. FR16, FR12 vs. FR16, and FR14 vs. FR16), SHR and MAM rats evidenced relatively large learning deficits during the initial FR8 vs. FR16 discrimination but had no difficulty with the last two discriminations. Furthermore, training selectively and significantly elevated hippocampal weight in MAM rats. These findings: a) question prior suggestions that MAM and SHR model separate human developmental disabilities; b) indicate that manifestation of learning deficits in even markedly brain-damaged organisms depends on initial task difficulty and can be overcome by experience; and c) are the first indicating that training-induced antagonism of prenatally induced hippocampal hypoplasia and its consequences is possible.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.