[Interhemispheric asymmetry in rats differentiating figures by size]

Area of Science:

• Neuroscience
• Behavioral Psychology
• Animal Cognition

Background:

• Conditioned reflexes are fundamental to understanding learning and memory.
• The role of specific brain hemispheres in complex cognitive tasks remains an active area of research.
• Investigating visual discrimination in rats provides insights into neural processing.

Purpose of the Study:

• To investigate the role of the left and right cerebral hemispheres in the elaboration of a motor alimentary conditioned reflex in rats.
• To determine how unilateral hemispheric inactivation affects the analysis of visual stimuli and the performance of conditioned reactions.
• To elucidate the specific contributions of each hemisphere to abstract and concrete visual processing.

Main Methods:

• Elaboration of a motor alimentary conditioned reflex in Wistar rats using visual stimuli (figures of varying areas).
• Testing animals with intact brains and following unilateral cortical inactivation (left and right hemispheres).
• Analysis of the level of discrimination, reaction time, and behavioral signs (frustration, aftereffect) post-inactivation.

Main Results:

• Left hemisphere inactivation led to a significant decrease in the level of analysis (36.4%), prolonged reaction time, and induced frustration.
• Right hemisphere inactivation resulted in a 16.4% decrease in analysis, with discrimination depending on stimulus properties and presentation side.
• Intact brains showed a minimal decrease (5.6%) in analysis compared to inactivated hemispheres.

Conclusions:

• The left hemisphere plays a dominant role in analyzing abstract and concrete visual characteristics.
• The left hemisphere is critical for controlling temporal, spatial, and emotional aspects of conditioned reactions.
• Effective conditioned reflex elaboration, particularly involving abstraction (e.g., 'more-less' discrimination), relies heavily on left hemisphere function.