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Updated: Jul 21, 2026
A Large Lateral Craniotomy Procedure for Mesoscale Wide-field Optical Imaging of Brain Activity
Published on: May 7, 2017
Callosal mediation of cortical inhibition in the lateralized rat brain
Abstract:
This paper tested a brain model for muricide. The model states that, in animals given handling stimulation in infancy, the right hemisphere is dominant for the occurrence of mouse killing and the left hemisphere acts to inhibit this behavior. On the assumption that the inhibition is mediated transcortically, it follows that severing the corpus callosum should result in an increase in muricide. This prediction was confirmed. In addition, prior research has found that animals not given extra stimulation in infancy show no evidence of lateralization for muricide. Therefore, splitting the brains of this group should not have any effect. This prediction was also confirmed. Latency analyses of muricidal rats found that those with only an intact right hemisphere killed much more quickly than those with only an intact left hemisphere. Sham controls had killing latencies similar to animals with only a right hemisphere. This pattern represents a brain model in which the right hemisphere is dominant for latency to kill. Rats exposed to mice in early life killed much more quickly than those without this early social experience, thus indicating that familiarity can reduce killing latency.
Insights
This study reveals the right hemisphere drives mouse killing behavior, while the left hemisphere inhibits it. Severing brain connections confirmed this lateralization, impacting muricide occurrence and latency in rats.
Area of Science:
- Neuroscience
- Animal Behavior
Background:
- Muricide (mouse killing) is a complex predatory behavior.
- Brain lateralization, particularly hemispheric dominance, influences various behaviors.
Purpose of the Study:
- To test a brain model for muricide involving hemispheric dominance and inhibition.
- To investigate the role of the corpus callosum in mediating muricide.
Main Methods:
- Surgical severing of the corpus callosum in rats with and without infant handling stimulation.
- Observation and latency analysis of muricide behavior.
- Sham surgeries as controls.
Main Results:
- Severing the corpus callosum increased muricide in stimulated rats, supporting right hemisphere dominance.
- Brain splitting had no effect in non-stimulated rats, indicating lack of lateralization.
- Rats with only an intact right hemisphere exhibited shorter killing latencies.
- Early life exposure to mice reduced killing latency, suggesting familiarity's role.
Conclusions:
- The right hemisphere is dominant for muricide occurrence and latency.
- The corpus callosum mediates inhibitory control from the left hemisphere.
- Early life experiences can modulate predatory behavior and its neural underpinnings.
