Biology subjects

Cash, S. S. S.

Publications and source records attributed to Cash, S. S. S..

2 recordsLinked to original sources

bioRxiv2020

Closed loop enhancement and neural decoding of human cognitive control

Cognitive control is the ability to withhold a default, prepotent response in favor of a more adaptive choice. Control deficits are common across mental disorders, including depression, anxiety, and addiction. Thus, a method for improving cognitive control could be broadly useful in disorders with few effective treatments. Here, we demonstrate closed-loop enhancement of one aspect of cognitive control by direct brain stimulation in humans. We stimulated internal capsule/striatum in participants undergoing intracranial epilepsy monitoring as they performed a cognitive control/conflict task. Stimulation enhanced performance, with the strongest effects from dorsal capsule/striatum stimulation. We then developed a framework to detect control lapses and stimulate in response. This closed-loop approach produced larger behavioral changes than open-loop stimulation, with a slight improvement in performance change per unit of energy delivered. Finally, we decoded task performance directly from activity on a small number of electrodes, using features compatible with existing closed-loop brain implants. Our findings are proof of concept for a new approach to treating severe mental disorders, based on directly remediating underlying cognitive deficits.

bioengineering↗

bioRxiv2019

Improved identification and differentiation from epileptiform activity of human hippocampal sharpwave-ripples during NREM sleep

In rodents, pyramidal cell firing patterns from waking may be replayed in NREM sleep during hippocampal sharpwave-ripples (HC-SWR). In humans, HC-SWR have only been recorded with electrodes implanted to localize epileptogenesis. Here, we characterize human HC-SWR with rigorous rejection of epileptiform activity, requiring multiple oscillations and coordinated sharpwaves. We demonstrated typical SWR in those rare HC recordings which lack interictal epileptiform spikes (IIS), and with no or minimal seizure involvement. These HC-SWR have a similar rate (~12/min) and apparent intra-HC topography (ripple maximum in putative stratum pyramidale, slow wave in radiatum) as rodents, though with lower frequency (~85Hz compared to ~140Hz in rodents). Similar SWR are found in HC with IIS, but no significant seizure involvement. These SWR were modulated by behavior, being largely absent (<2/min) except during NREM sleep in both stage 2 (~9/min) and stage 3 (~15/min), distinguishing them from IIS. This study quantifies the basic characteristics of a strictly selected sample of SWR recorded in relatively healthy human hippocampi.

neuroscience↗