Article Figures & Data
Figures
- Figure 1.
Behavioral task design and associated internal processes. A, Standard Go/NoGo task structure. After the intertrial interval, one of two trials are presented: stimulus present (stimulus trial) or stimulus absent (catch trial). Within this design, stimulus presentation and response windows overlap. Beneath this combined stimulus–response window, we indicate some of the internal processes likely to be deployed. Trial outcomes include response present (Go) and response absent (NoGo). Hit: Stimulus/Go; Miss: Stimulus/NoGo; False alarm (FA): Catch/Go; Correct rejection (CR): Catch/NoGo. B, Same Go/NoGo trial structure as in A, but with the inclusion of a delay between stimulus and response windows. This affords a separation of sensory and decision-making processes during the stimulus window from the task-instructed motor processes and reinforcement signaling during the response window. C, 2AFC trial structure. The same trial types are presented as in A and B, yet subjects are required to report both stimulus present and stimulus absent with different motor actions (e.g., Go Left, Go Right). This trial structure affords a separation between choice encoding (deciding stimulus present vs absent) and generalized motor initiation. How the processes listed in A distribute across task epochs in B and C will depend on the precise details of each task and should be considered for all task designs.
- Figure 2.
Examples of how movement may complicate the evaluation of sensory and cognitive processes. A, Schematic of the active sensing whisker-based spatial discrimination task of O'Connor et al. (2010b). Mice were trained to discriminate posterior (left) from anterior (right) pole locations. Instead of sampling both locations equally, mice developed a strategy of only sampling (pink shade) the posterior (Go) location. B, Schematic of the freely moving 2AFC memory-guided orienting task from Erlich et al. (2011). Rats were trained to report high and low stimulus frequencies at left and right nose ports. During the delay period while still in the central nose port, rats slightly oriented toward the expected reward port, thus using a combination of covert and overt strategies to remember the reward location. C, Top, Schematic of the category assignments before and after rule switch from Reinert et al. (2021). Before the rule switch, mice learned to respond to stimuli according to stimulus feature 1 and ignore stimulus feature 2; after rule switch, mice learned to respond to stimuli according to stimulus feature 2 and ignore stimulus feature 1. Bottom, Illustration of a hypothetical neuron's response to each category on successful Go (green) and NoGo (red) trials, before (left) and after (right) rule switch. Because of the Go/NoGo task design without a delay, neuronal activity following Go stimuli may reflect stimulus category representation and/or response-related movements.
