AX-CPT Task

Field	Value
Name	AX-CPT Task
Version	main (1.0)
URL / Repository	https://github.com/TaskBeacon/AX-CPT
Short Description	A task measuring cognitive control, context processing, and goal maintenance.
Created By	Zhipeng Cao (zhipeng30@foxmail.com)
Date Updated	2025/07/25
PsyFlow Version	0.1.0
PsychoPy Version	2025.1.1
Modality	Behavior/EEG
Language	Chinese
Voice Name	zh-CN-YunyangNeural

1. Task Overview

This task is an AX-Continuous Performance Test (AX-CPT) designed to assess cognitive control and context processing. Participants are presented with a series of letter pairs (cue followed by probe). They must make a specific target response only when the cue is an ‘A’ and the probe is an ‘X’ (AX trials). For all other combinations (AY, BX, BY), a different response (or no response) is required.

2. Task Flow

Block-Level Flow

Step	Description
1. Instruction	Instructions are displayed at the beginning of the experiment.
2. Trial Execution	Each block runs for a set number of trials, as defined in config.yaml.
3. Block Break	After each block, a break screen is shown with the accuracy for the current block.
4. Goodbye	After all blocks are complete, a “goodbye” message is displayed.

Trial-Level Flow

Step	Description
1. Fixation	A central fixation cross (+) is displayed.
2. Cue Presentation	The cue letter (A or B) is presented.
3. Inter-Stimulus Interval (ISI) Fixation	A central fixation cross (+) is displayed for a short duration.
4. Probe Presentation & Response	The probe letter (X or Y) is presented, and the participant responds.
4. Feedback	Feedback (Correct, Incorrect, or Too Slow) is displayed.
5. Inter-Trial Interval (ITI)	A blank screen is shown before the next trial.

3. Configuration Summary

a. Subject Info

Field	Meaning
subject_id	Subject Identifier
subname	Subject Name
age	Age
gender	Gender

b. Window Settings

Parameter	Value
size	[1920, 1080]
units	deg
screen	1
bg_color	gray
fullscreen	True
monitor_width_cm	60
monitor_distance_cm	72

c. Stimuli

Name	Type	Description
fixation	text	Central cross +.
cue_A	text	The cue letter ‘A’.
cue_B	text	The cue letter ‘B’.
probe_X	text	The probe letter ‘X’.
probe_Y	text	The probe letter ‘Y’.
correct_feedback	text	“正确” (Correct) in white.
incorrect_feedback	text	“错误” (Incorrect) in white.
no_response_feedback	text	“未反应” (No response) in white.
instruction_text	textbox	Instructions explaining the task.
instruction_text_voice	voice	Voice instructions for the task.
block_break	text	Feedback shown between blocks.
good_bye	text	Final message at the end of the task.

d. Timing

Phase	Duration (s)	Config Variable
fixation	0.5	fixation_duration
cue	0.5	cue_duration
isi	0.5	isi_duration
probe	1.0 (max response time)	probe_duration
feedback	0.5	feedback_duration
iti	random 0.8–1.2	iti_duration

e. Triggers

Event	Code
exp_onset	98
exp_end	99
block_onset	100
block_end	101
cue_onset	10
probe_onset	20
AX_trial_onset	30
AY_trial_onset	31
BX_trial_onset	32
BY_trial_onset	33
key_press	40
no_response	41
feedback_correct_response	51
feedback_incorrect_response	52
feedback_no_response	53
feedback_onset	60

4. Methods

Participants perform an AX-CPT task, a continuous performance paradigm used to measure cognitive control and context processing. Each trial consists of a cue letter (A or B) followed by a probe letter (X or Y). Participants are instructed to press the ‘f’ key if the cue is ‘A’ and the probe is ‘X’ (AX trials). For all other cue-probe combinations (AY, BX, BY), they are instructed to press the ‘j’ key.

The task begins with a fixation cross, displayed for 500ms. The cue letter is then presented for 500ms, followed by a brief inter-stimulus interval (ISI) fixation of 500ms, and then the probe letter for up to 1000ms or until a response is made. Feedback (correct, incorrect, or no response) is provided for 500ms, followed by a randomized inter-trial interval between 800ms and 1200ms.

The task is structured into 4 blocks of 40 trials each (total 160 trials). Trial types (AX, AY, BX, BY) are presented in a randomized order within each block, with a higher proportion of AX trials to establish a strong context. This design allows for the examination of proactive and reactive cognitive control strategies.