Synaptic mechanisms of interference in working memory
Information from preceding trials of cognitive tasks can bias performance in the current trial, a phenomenon referred to as interference.聽Subjects performing visual working memory tasks exhibit interference in their responses: the recalled target location is biased in the聽direction of the target presented on the previous trial. We present a recurrent neuronal network model wherein short-term facilitation聽accounts for the observed bias. Short term facilitation dynamically strengthens the synaptic weights emanating from recently active neurons. Network connectivity is thus reshaped dynamically during each trial, generating predictions from prior trial聽observations. Applying timescale separation methods, we obtain a low-dimensional description of the trial-to-trial bias based on the聽history of target locations.聽Furthermore, we demonstrate task protocols for which our model with facilitation performs better than a model with static connectivity:聽repetitively presented targets are better retained in working memory than targets drawn from uncorrelated sequences.