Reactivation of motor brain areas during explicit memory for actions

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Memory Research

Background:

• Functional brain imaging reveals sensory-specific brain regions activated during perception are also reactivated during memory retrieval.
• The reactivation hypothesis suggests that memory retrieval involves the re-engagement of neural substrates active during initial encoding.

Purpose of the Study:

• To investigate whether verbal retrieval of action phrases reactivates motor brain regions.
• To determine if overt or covert action performance during encoding influences this reactivation during retrieval.

Main Methods:

• Positron Emission Tomography (PET) was employed to scan participants' brains.
• Participants encoded action phrases through verbal recall, overt motor activity, or covert motor imagery.

Main Results:

• Encoding via overt and covert actions, compared to verbal encoding, showed differential activity in contralateral somatosensory and motor cortex.
• Several of these motor regions were reactivated during retrieval.
• Reactivation in left ventral motor cortex and left inferior parietal cortex was common to both overt and covert conditions.
• Activation and reactivation in left dorsal parietal cortex and right cerebellum were specific to the overt condition.

Conclusions:

• The findings support the reactivation hypothesis in the context of action memory.
• Verbal-explicit memory of actions involves neural areas engaged during both overt and covert motor activity.