摘要：AbstractThe neurophysiological basis of width discrimination has been extensively studied in rodents and has shown that active and passive tactile discrimination engage fundamentally different neural networks. Although previous studies have analyzed active and passive tactile processing in humans, little is known about the neurophysiological basis of width discrimination in humans. Here we present a width discrimination task for humans that reproduces the main features of the width discrimination task previously developed for rodents. The task required subjects to actively or passively sample two movable bars forming a “narrow” or “wide” aperture. Subjects were then required to press one of two buttons to indicate if the bar width was “narrow” or “wide”. Behavioral testing showed that subjects were capable of discriminating between wide or narrow apertures up to distances of 0.1 cm. Electroencephalography (EEG) recordings further suggested distinct topographic maps for active and passive versions of the task during the period associated with the aperture discrimination. These results indicate that the Human Differential Width Discrimination Task is a valuable tool to describe the behavioral characteristics and neurophysiological basis of tactile processing.•Active and passive width discrimination has been extensively studied in rodents but not in humans.•Human subjects were capable of discriminating aperture widths of 0.1 cm.•Electroencephalography recordings showed that active and passive versions of the task were associated with different topographic maps.Graphical abstractRepresentational diagram of the behavioral width discrimination task for active and passive tactile discrimination in humans. (A)The customized Graphical User Interface (GUI) allows the experimenter control over a variety of system management functions, such as, running different versions of the width discrimination task, configuring setups, visualizing finger and saving behavioral data. (B)The Behavioral Apparatus is where the subjects perform the task. It is composed of a box with a small opening that allows the subject to insert the index finger and perform the width discrimination. Inside the small opening is a variable-aperture width determined by two bars. This variable-aperture width is set by a programmable integrated circuit using an Arduino microcontroller. The frontal panel has a central light, two push buttons on the top right corner, and a four-digit LED display on the left corner.C)Steps of Behavioral Protocol: at the start of each trial, the center light is red and the bars are set to a predetermined position, while the subject keeps the finger out of the behavioral apparatus(1).When the center light turns yellow, the subject must insert the finger in the opening and wait for the algorithm to detect the correct finger positioning(2)as the finger reaches the aperture width, the center light turns green. At this point, if the subject is performing the active version of the task, the subject is allowed to move the finger in order to sample the aperture width. Otherwise, if the subject is performing the passive version of the task, the subject is required to remain with the finger in place, and the bars will move towards the finger stopping at the specified aperture width. In active and passive versions the aperture width can be “narrow” or “wide”. This is the Discrimination period(3). After tactile sampling, the light will turn red and the subject is required to remove the finger from the aperture width(4), after which the subject must press one of two buttons, to indicate if the aperture width was narrow (and the subject should press the Blue button) or wide (and the subject should press the Yellow button)(5).Display Omitted
