Minimally invasive electrocorticography (ECoG) recording in common marmosets

Electrocorticography (ECoG) enables high spatio-temporal resolution recordings of brain activity with excellent signal quality, making it essential for pre-surgical mapping in epilepsy patients and increasingly useful in neuroscience research, including the development of brain-machine interfaces. The relatively minimal cortical convolution in non-human primate (NHP) brains facilitates ECoG recordings, in particular in the common marmoset (Callithrix jacchus), whose lissencephalic (unfolded) brain surface provides broad cortical access. One of the key advantages of ECoG recordings is the ability to study interactions between distant brain regions. The standard approach is the usage of large electrode arrays, which, however, require extended trepanations and a trade-off between size and electrode spacing. This study introduces an alternative ECoG approach for examining interactions between multiple distant cortical areas in marmosets, combining the advantages of circumscribed trepanations with high-density electrode arrays at specific sites of interest. Two adult marmosets underwent ECoG implantation across frontal, temporal, and parietal regions of interest, assessed by circumscribed trepanations to position individual high density electrode arrays. Postoperative monitoring showed rapid recovery and no long-term complications. The animals remained healthy, and stable neural recordings were successfully obtained during behavioral tasks, highlighting the method’s effectiveness for long-term cortical monitoring.