Fig. 1

Lack of automation in brain research. The various methods in brain research described below are not automatized or technically interconnected with each other. Two approaches exist in vivo: non-invasive and invasive approaches. Non-invasive technologies, such as positron emission tomography (PET), computed tomography (CT), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), near-infrared spectroscopy (NIRS), and electroencephalography (EEG), measure brain activities via different principals (Rothschild 2010), whereas transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and transcranial alternating current stimulation (tACS), broadly stimulate the brain (Miranda 2013). These non-invasive technologies are not interconnected and cannot evaluate or stimulate individual neuronal activity. Genetically manipulated animals, including knockout, knockdown, or overexpressed mice, and pharmacological approaches are also categorized as in vivo non-invasive brain research. Conversely, electrocorticography (ECoG), an in vivo invasive technology, simultaneously stimulates and records broad areas of the brain cortex (Rothschild 2010). Other in vivo invasive approaches, such as microelectrode arrays (MEA), electrical cortical stimulation (ECS), and deep brain stimulation (DBS), enable the direct stimulation and recording of neuronal activities (Rothschild 2010). Optogenetic manipulation is categorized as in vivo invasive technology that directly stimulates or suppresses neuronal activities, because blue light, which is necessary for optogenetics, must be supplied under the skull incision (Chen et al. 2018). Of note, digital data obtained by ECoG or MEA can be interconnected with data from other animals and robots via the Internet (Lebedev et al. 2005). Furthermore, the brown wireless device (BWD), a wireless broadband intracortical brain-computer interface (iBCI), non-invasively records and decodes broadband field potentials and spiking activity from individuals with tetraplegia (Simeral et al. 2021). Various in vitro brain research methods exist, including constructing the connectome (Winnubst et al 2019), stimulating, suppressing, and detecting the activities of neurons and brain sections via electrodes or pharmacological methods, dissecting signal transduction inside neurons and brain sections, and various biochemical analyses (of DNA, RNA, proteins, and metabolites, including neurotransmitters). (a) 3072 electrodes mimicking MEA are robotically implanted into the rat brain (Musk 2019). (b) NIRS is utilized for functional brain imaging. Near-infrared (NIR) penetrates into human brain tissues through the skull (Rothschild 2010)