Abstract
Being error prone, the consequences of visual behavior must be monitored to achieve goals. In visuo-motor tasks neural signals arise in the supplementary eye field (SEF) when errors are made and when reward is expected. However, how these signals are orchestrated in laminar circuitry is unknown. We report the laminar organization of error and reward processing in neurophysiological data collected with linear electrode arrays (U-probe) sampling all layers of the SEF in two monkeys. From 16 perpendicular penetrations, we isolated 293 neurons across all layers of the SEF. Recordings were conducted while monkeys performed a visual saccade countermanding task. On ~60% of trials they made saccadic eye movement towards a visual stimulus but on a proportion of trials (~20%) made erroneous saccades despite an instruction to stop. After a short delay following the saccade, an auditory tone was presented which indicated the absence or presence of upcoming juice reward. Both monkeys adjusted performance following errors by slowing response time. Neurons that signaled errors before feedback presentation (n = 42) were observed in all layers. The earliest onset latency (< 100ms) was observed in lower L3 and L5 and spread later into L2 and L6. The magnitude of error-related modulation scaled with reward loss value. Neurons with higher discharge rate for positive feedback and/or reward gain (n = 51) were mainly located in lower layers, whereas those that exhibited elevated discharge rate for negative feedback or reward loss (n = 107) were mainly located in superficial layers L2/3 and lower L6. Response suppression (in response to positive outcomes) was commonly found in superficial layers, and scaled with reward magnitude. These results show distinct laminar organization of different functional signals in the SEF which constrain circuit-level models of visual performance control and guide inverse modeling solutions of EEG error- and feedback-related negativity.
Meeting abstract presented at VSS 2018