Enhanced information processing in the human neocortex: cellular mechanisms and translational perspectives

Understanding the sophisticated cognitive abilities of the human brain requires understanding its cellular and synaptic components. While rodent studies provide foundational knowledge, recent research using freshly resected human neocortical and hippocampal tissue has revealed unanticipated distinctive cellular characteristics. These properties, identified through <i>in vitro</i> electrophysiology, anatomical reconstructions, and computational modeling, have profound implications for physiological processes and modulatory responses. Here we highlight and review a selection of key unique features of human neurons. Human layer 2/3 pyramidal cells exhibit exceptionally low specific membrane capacitance and distinctive ion channel kinetics. Moreover, human pyramidal-to-pyramidal connections display species-specific synaptic dynamics, recovering from short-term depression much faster than in rodents. We also highlight that human pyramidal neurons exhibit more elaborate dendritic trees, particularly perisomatic branching, and faster, more stable Action Potentials (AP) dynamics. Interestingly, these features allow higher-bandwidth information transfer, reflecting enhanced computational power. All these cell-level differences directly impact how circuits process information and respond to pharmacological interventions. Increasingly, drugs targeting ion channels or synaptic mechanisms are used but often display different efficacy or kinetics in human neurons compared to rodents, reflecting underlying biophysical disparities. Consequently, leveraging human brain tissue is key as it allows for the identification of human-specific drug targets and a more accurate understanding of disease mechanisms. This review highlights these crucial cellular distinctions and underscores the importance of exploiting resected human brain tissue for advancing central nervous system therapeutics.