Operant conditioning reveals task-specific responses of single neurons in a brain–machine interface

Abstract

Objective. Volitional modulation of single cortical neurons holds great potential for the implementation of brain–machine interfaces (BMIs) because it can induce a rapid acquisition of arbitrary associations between machines and neural activity. It can also be used as a framework to study the limits of single-neuron control in BMIs. Approach. We tested the control of a one-dimensional actuator in two BMI tasks which differed only in the neural contingency that determined when a reward was dispensed. A thresholded activity task, commonly implemented in single-neuron BMI control, consisted of reaching or exceeding a neuron activity level, while the second task consisted of reaching and maintaining a narrow neuron activity level (i.e. windowed activity task). Main findings. Single neurons in layer V of the motor cortex of rats improved performance during both the thresholded activity and windowed activity BMI tasks. However, correct performance during the windowed activity task was accompanied by activation of neighboring neurons, not in direct control of the BMI. In contrast, only neurons in direct control of the BMI were active at the time of reward during the thresholded activity task. Significance. These results suggest that thresholded activity single-neuron BMI implementations are more appropriate compared to windowed activity BMI tasks to capitalize on the adaptability of cortical circuits to acquire novel arbitrary skills.

Volitional modulation of neuronal activity in the external globus pallidus by engagement of the cortical–basal ganglia circuit

“…The tremendous diversity among billions of neurons in the mammalian brain, stemming from variations in gene activity, location, innervation patterns and functions, underscores the complexity of their membrane characteristics and their capacity for generating neuronal activities (Nagaeva et al., 2021). The volitional modulation of cortical neurons is influenced by various factors, including neuron type, inherent characteristics and pre‐determined criteria (Garcia‐Garcia et al., 2020; Garcia‐Garcia et al., 2021; Mitani et al., 2018; Vendrell‐Llopis et al., 2022).…”