Barrel cortex plasticity after photothrombotic stroke involves potentiating responses of pre-existing circuits but not functional remapping to new circuits

• Published in: Nature communications 2021-06, Vol.12 (1), p.3972-3972, Article 3972
• Main Authors: Zeiger, William A., Marosi, Máté, Saggi, Satvir, Noble, Natalie, Samad, Isa, Portera-Cailliau, Carlos
• Format: Article
• Language: English
• Subjects: 14/35; 14/63; 14/69; 59; 631/378/1687; 631/378/2620/2623; 64/60; 692/617/375/534; 82/51; Anesthesia; Calcium; Calcium imaging; Calcium signalling; Circuits; Cortex (barrel); Cortex (somatosensory); Functional morphology; Humanities and Social Sciences; Imaging; In vivo methods and tests; multidisciplinary; Neuroimaging; Neurons; Plastic properties; Plasticity; Recovery; Recovery of function; Rehabilitation; Science; Science (multidisciplinary); Selectivity; Stroke
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24211-8

Recovery after stroke is thought to be mediated by adaptive circuit plasticity, whereby surviving neurons assume the roles of those that died. However, definitive longitudinal evidence of neurons changing their response selectivity after stroke is lacking. We sought to directly test whether such functional “remapping” occurs within mouse primary somatosensory cortex after a stroke that destroys the C1 barrel. Using in vivo calcium imaging to longitudinally record sensory-evoked activity under light anesthesia, we did not find any increase in the number of C1 whisker-responsive neurons in the adjacent, spared D3 barrel after stroke. To promote plasticity after stroke, we also plucked all whiskers except C1 (forced use therapy). This led to an increase in the reliability of sensory-evoked responses in C1 whisker-responsive neurons but did not increase the number of C1 whisker-responsive neurons in spared surround barrels over baseline levels. Our results argue against remapping of functionality after barrel cortex stroke, but support a circuit-based mechanism for how rehabilitation may improve recovery. Definitive evidence for functional remapping after stroke remains lacking. Here, the authors performed in vivo intrinsic signal imaging and two-photon calcium imaging of sensory-evoked responses before and after photothrombotic stroke and found no evidence of remapping of lost functionalities to new circuits in peri-infarct cortex.