2.4. Go/No-Go Task

We hypothesized that the Cm-Pf nuclei of thalamus will be activated by tasks that are involved in the attention of the participants, which are known to elicit responses in animal models (Minamimoto and Kimura, 2002). The modified Go/No-Go task is a complicated task that requires attention of the participants in order to achieve high accuracy. Although there are multiple segments of the task worthy of investigation in the traditional context of Go/No-Go task such as responses to reward, they are beyond the primary goal of the study, which was to use visual attention physiology for targeting the Cm-Pf nuclei region of thalamus. The visual cue phase is the most attention-demanding segment of the task, in which the participants pay attention to the type of stimuli presented and attempt to react accurately. The full Go/No-Go task will be presented in this section, however only the signals evoked by visual cue presentation, regardless of the Go or No-Go cue were considered for the main purpose of the study.

The experiment consists of four 20-second baseline recordings (two before the task and two after the task), two self-paced 10-button pressing recordings (one before the task, and one after the task; data not shown), two reaction time tests (one before the task, and one after the task; data not shown), and a Go/No-Go task. The task portion consisted of 120 trials for postoperative recordings and shortened version of 60 trials for intraoperative recordings to reduce time taken in the operating room. The task setup is outlined in Fig. 1. The participant was presented with a colored rectangle (visual stimulus) with four possible colors (blue, orange, yellow, purple), each corresponding to a unique condition: 1) press to receive an award (blue; Go To Win), 2) do not press to receive an award (orange; No Go To Win), 3) press to avoid losing (yellow; Go To Avoid Loss), 4) do not press to avoid losing (purple; No Go To Avoid Loss). The order of stimuli was random. The stimuli were presented for 1000 ms followed by a 250 ms wait period after participants reacted (by pressing button or not pressing button) to the stimuli (Fig. 1). Based on the participant’s reaction, feedback was then displayed for 500 ms. Win outcomes were +100 points, lose outcomes were −100 points, and avoid-loss outcomes were +0 points. After feedback a cross was displayed on the screen for 500 ms during the inter-trial interval as the pre-trial baseline. The feedback portion of the task was displayed mainly to provide motivational encouragement to complete the task. A pressure-based push button was given to the participants to hold in their dominant hand for responding during the task. The sensor was connected to the external synchronization box (Alcantara et al., 2020), which was connected to the external amplifier’s digital input (see below).

Task overview. A) Overall block design of the experiment. The experiment is divided into 3 sections: pre-task baseline, task, and post-task baseline. Each voluntary button press section is around 10 s based on once per second rate of pressing. Each resting period is 20 s, however, segments of motor activity as identified by video and EMG recording were discarded. The reaction time calibration was used to ensure the participants are able to react within the 1000 ms window. B) The task design and timing. Each trial includes 500 ms inter-trial interval, 1000 ms stimulus presentation, 250 ms wait, and 500 ms feedback. The stimulus presentation timing will be shortened if reaction occurred early. The 4 possible colors (or trial type) are displayed under the task overview.