When Is Enough Enough? (image) Scuola Internazionale Superiore di Studi Avanzati Share Print E-Mail Caption The main conclusions of the two studies are illustrated in this cartoon, where the rat must identify the texture as grooved or smooth. The first Current Biology study identified the nature of the tactile evidence: whisker kinematics (bending and motion) differ according to the contacted texture. Once kinematic features are converted to neuronal firing, the brain begins to process texture information, as shown on the left. While the information acquired in a single touch indicates one texture more strongly than the other, the signal is graded: whisker kinematics are consistent with the grooved texture to some degree, but also with the smooth texture to some degree. Thus, there are different quantities of evidence in favor of both textures, shown as the upward steps in the plot. The main finding is that the rat makes its choice when the total quantity of evidence for one texture, summated across touches, reaches a boundary. Here, the total evidence in favor of the grooved texture reaches the boundary on the 4th touch, while the total evidence in favor of the smooth texture remains below. As shown on the right, once the evidence for the grooved texture reaches the boundary, the rat forms a percept - a mental image of the object -- and makes the correct choice. Had the evidence for the smooth texture reached the boundary first, the rat would have made an incorrect choice based on an erroneous percept. That is exactly what happened on 20% of trials. Credit Mathew Diamond, SISSA Usage Restrictions The image use is allowed only if the news covers these pieces of research Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.