Handling in infancy, taste aversion, and brain laterality in rats

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Animal Behavior

Background:

• Early life experiences can shape adult brain function and behavior.
• Brain lateralization, the specialization of hemispheres, is crucial for complex cognitive processes.

Purpose of the Study:

• To investigate the role of brain lateralization in conditioned emotional responses in rats.
• To determine the impact of early handling on fear conditioning and hemispheric function.

Main Methods:

• Rats were subjected to early life handling or left undisturbed.
• Taste aversion conditioning was induced using lithium chloride.
• Surgical procedures included neocortical lesions (right or left) or sham surgery.
• Postoperative retention of taste aversion was assessed by measuring milk consumption.

Main Results:

• The right hemisphere was preferentially involved in conditioned emotional behavior.
• Early handling reduced the left hemisphere's susceptibility to conditioned fear.
• Rats with intact brains consumed more milk, indicating less aversion, compared to lesioned groups.

Conclusions:

• The rat brain exhibits lateralization, with the right hemisphere playing a primary role in conditioned emotional responses.
• Infant handling confers resilience to conditioned fear, particularly in the left hemisphere.