Vol.:(0123456789) 1 3 Brain Structure and Function https://doi.org/10.1007/s00429-020-02101-x ORIGINAL ARTICLE Aging impairs perceptual decision‑making in mice: integrating computational and neurobiological approaches Ezgi Gür 1,2  · Yalçın Akın Duyan 1,2  · Esin Türkakın 1,2  · Sertan Arkan 1,2,3  · Ayşe Karson 3  · Fuat Balcı 1,2 Received: 24 December 2019 / Accepted: 12 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Decision-making is one of the cognitive domains which has been under-investigated in animal models of cognitive aging along with its neurobiological correlates. This study investigated the latent variables of the decision process using the hierarchical drift–difusion model (HDDM). Neurobiological correlates of these processes were examined via immunohis- tochemistry. Young (n = 11, 4 months old), adult (n = 10, 10 months old), and old (n = 10, 18 months old) mice were tested in a perceptual decision-making task (i.e. two-alternative forced-choice; 2AFC). Observed data showed that there was an age-dependent decrease in the accuracy rate of old mice while response times were comparable between age groups. HDDM results revealed that age-dependent accuracy diference was a result of a decrease in the quality of evidence integration during decision-making. Signifcant positive correlations observed between evidence integration rate and the number of tyrosine hydroxylase positive (TH+) neurons in the ventral tegmental area (VTA) and axon terminals in dorsomedial striatum (DMS) suggest that decrease in the quality of evidence integration in aging is related to decreased function of mesocortical and nigrostriatal dopamine. Keywords Decision-making · Cognitive aging · Two-alternative forced-choice task · Hierarchical drift–difusion model · Dopamine · Mice Introduction Cognitive aging is associated with the impairment of various cognitive functions such as learning, memory, and atten- tion. One of the least studied domains in animal models of (and arguably human) cognitive aging is the health of simple perceptual decision-making. This appears as a prominent translational gap particularly given that perceptual decisions determine the adaptiveness of individuals in many aspects of life including motor, trafc and consumer behaviors. The current study convergently flls this gap by investigating how decision processes are altered in the mouse model of aging, based on the analytical treatment of behavioral data in the light of a computational decision theoretical approach and the investigation of the neurobiological correlates of the age- related alterations in the corresponding components of the decision process. Decision-making is a cognitive function that leads to the choice of an option or action from multiple alternatives based on the processing and assessment of the informa- tion available to the decision-maker (e.g., picking the rip- est berries from a bunch by processing color information). Importantly, research shows that the decision processes that are successfully applied to account for relatively simple perceptual decisions (Ratclif and McKoon 2008) can also account for more complex decisions such as value-based judgments (Mormann et al. 2010). The tradeof between the accuracy and speed of such decisions (i.e., speed-accuracy tradeof; SAT) determines their adaptiveness (e.g., reward rate; Bogacz et al. 2006). Speed accuracy tradeof emerges This study is a part of Ezgi Gür’s Ph.D. thesis. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00429-020-02101-x) contains supplementary material, which is available to authorized users. * Fuat Balcı fbalci@ku.edu.tr 1 Timing and Decision-Making Laboratory, Department of Psychology, Koç University, 34450 Istanbul, Turkey 2 Koç University Research Center for Translational Medicine, 34450 Istanbul, Turkey 3 Physiology Department, Kocaeli University, Umuttepe Campus, 41380 Kocaeli, Turkey