Current Biology
Volume 31, Issue 19, 11 October 2021, Pages 4405-4412.e4
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Neurons of rat motor cortex become active during both grasping execution and grasping observation

https://doi.org/10.1016/j.cub.2021.07.054Get rights and content
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Highlights

  • Rat M1 contains “mirror” neurons responding to grasping execution and observation

  • These mirror neurons are highly specific to grasping actions

  • Their matching properties are analogous to those observed in primates

  • Observation and execution matching systems are evolutionary preserved

Summary

In non-human primates, a subset of frontoparietal neurons (mirror neurons) respond both when an individual executes an action and when it observes another individual performing a similar action.1, 2, 3, 4, 5, 6, 7, 8 Mirror neurons constitute an observation and execution matching system likely involved in others’ actions processing3,5,9 and in a large set of complex cognitive functions.10,11 Here, we show that the forelimb motor cortex of rats contains neurons presenting mirror properties analogous to those observed in macaques. We provide this evidence by event-related potentials acquired by microelectrocorticography and intracortical single-neuron activity, recorded from the same cortical region during grasping execution and observation. Mirror responses are highly specific, because grasping-related neurons do not respond to the observation of either grooming actions or graspable food alone. These results demonstrate that mirror neurons are present already in species phylogenetically distant from primates, suggesting for them a fundamental, albeit basic, role not necessarily related to higher cognitive functions. Moreover, because murine models have long been valued for their superior experimental accessibility and rapid life cycle, the present finding opens an avenue to new empirical studies tackling questions such as the innate or acquired origin of sensorimotor representations and the effects of social and environmental deprivation on sensorimotor development and recovery.

Keywords

grasping
mirror neurons
motor cortex
action observation
rat

Data and code availability

The raw data supporting this study is not available in a public repository because of complex custom data formats and the size of the files but are available from the Lead Contact upon request.

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