{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:44:40Z","timestamp":1785422680223,"version":"3.56.0"},"posted":{"date-parts":[[2026,5,5]]},"group-title":"Neuroscience","reference-count":63,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T00:00:00Z","timestamp":1777939200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007049","name":"Evelyn F. McKnight Brain Research Foundation","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100007049","id-type":"DOI","asserted-by":"crossref"}]},{"name":"NIH\/NIA"},{"DOI":"10.13039\/100020220","name":"University of Arizona College of Science","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100020220","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/023drta67","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,5,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>\n                  The Mnemonic Similarity Task (MST) is highly sensitive to age-related cognitive decline in humans and has been adapted for rodents using 3D objects, where aged animals show deficits in discriminating similar lures. To improve translational alignment with human testing and increase automation, we developed a touchscreen-based rat analog using a morphed Object-Cued Spatial Choice (OCSC) task with 2D image stimuli. Young (4-month) and aged (21-month) male and female Fischer 344 \u00d7 Brown Norway hybrid rats were trained in Bussey-Saksida touchscreen chambers and tested on discrimination performance using image pairs that varied parametrically in feature overlap. We also assessed perirhinal cortical engagement in a subset of animals using\n                  <jats:italic>Arc<\/jats:italic>\n                  expression as a readout of activity-related principal cell firing following low-and high-overlap task epochs. Across shaping and procedural training, aged rats required more errors to reach criterion on one stimulus set, but both age groups successfully acquired the task. During morph testing, performance declined systematically as stimulus similarity increased, confirming that the task manipulated discrimination difficulty. However, contrary to expectations, young and aged rats performed similarly across overlap conditions, with no significant age-related impairment. In the\n                  <jats:italic>Arc<\/jats:italic>\n                  experiment, discrimination accuracy was again reduced by greater stimulus overlap, but\n                  <jats:italic>Arc<\/jats:italic>\n                  expression in perirhinal cortex did not differ reliably by age or overlap condition, although expression was associated with behavioral accuracy and deep layers showed higher ensemble similarity than superficial layers. These findings indicate that, while the touchscreen morph OCSC task is sensitive to stimulus similarity, it does not detect the robust age-related mnemonic discrimination deficits previously observed with 3D object-based rodent MST paradigms, underscoring the importance of considering ethological relevance when designing translational cognitive assays.\n                <\/jats:p>","DOI":"10.64898\/2026.04.30.722044","type":"posted-content","created":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T22:30:16Z","timestamp":1778020216000},"source":"Crossref","is-referenced-by-count":0,"title":["An Operant-based Touchscreen Morph Discrimination Task Does Not Detect Age-related Mnemonic Similarity Deficits in Rats"],"prefix":"10.64898","author":[{"given":"Aleyna","family":"Ross","sequence":"first","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"},{"name":"Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carly N.","family":"Logan","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John J.","family":"Thompson","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah A.","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cory","family":"Watson","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Ramirez","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katelyn N.","family":"Lubke","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew P.","family":"Maurer","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"},{"name":"Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida, Gainesville, FL 32611, United States"},{"name":"Department of Neuroscience, College of Science, University of Arizona, Tucson AZ 85719"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara N.","family":"Burke","sequence":"additional","affiliation":[{"name":"Evelyn F. McKnight Brain Institute, Center for Cognitive Aging and Memory, Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States"},{"name":"Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida, Gainesville, FL 32611, United States"},{"name":"Department of Neuroscience, College of Science, University of Arizona, Tucson AZ 85719"},{"name":"BIO5 Institute, The University of Arizona, Tucson, AZ 85719"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026050805250692000_2026.04.30.722044v1.1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.1165-22.2022"},{"key":"2026050805250692000_2026.04.30.722044v1.2","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.3160-14.2015"},{"key":"2026050805250692000_2026.04.30.722044v1.3","doi-asserted-by":"crossref","unstructured":"Ahn JR , Lee I (2017) Neural Correlates of Both Perception and Memory for Objects in the Rodent Perirhinal Cortex. Cereb Cortex:1\u201313.","DOI":"10.1093\/cercor\/bhx093"},{"key":"2026050805250692000_2026.04.30.722044v1.4","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuropsychologia.2007.05.023"},{"key":"2026050805250692000_2026.04.30.722044v1.5","doi-asserted-by":"publisher","DOI":"10.1101\/lm.749207"},{"key":"2026050805250692000_2026.04.30.722044v1.6","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.5171-06.2007"},{"key":"2026050805250692000_2026.04.30.722044v1.7","doi-asserted-by":"publisher","DOI":"10.1046\/j.0953-816x.2001.01491.x"},{"key":"2026050805250692000_2026.04.30.722044v1.8","doi-asserted-by":"publisher","DOI":"10.1016\/j.nlm.2015.06.014"},{"key":"2026050805250692000_2026.04.30.722044v1.9","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/bhu093"},{"key":"2026050805250692000_2026.04.30.722044v1.10","doi-asserted-by":"publisher","DOI":"10.1093\/geronb\/gbx181"},{"key":"2026050805250692000_2026.04.30.722044v1.11","doi-asserted-by":"crossref","unstructured":"Burke SN , Barnes CA (2014) The neural representation of 3-dimensional objects in rodent memory circuits. Behav Brain Res.","DOI":"10.1016\/j.bbr.2014.09.001"},{"key":"2026050805250692000_2026.04.30.722044v1.12","unstructured":"Burke SN , Barnes CA (2024) Aging and the Hippocampus. In: The Hippocampus Book, Second Edition ( Morris RG , Amaral, D. , Bliss, T. , Duff, K. , O\u2019Keefe, J. , ed). New York, NY: Oxford University Press."},{"key":"2026050805250692000_2026.04.30.722044v1.13","doi-asserted-by":"publisher","DOI":"10.1002\/hipo.22066"},{"key":"2026050805250692000_2026.04.30.722044v1.14","doi-asserted-by":"publisher","DOI":"10.3389\/fnsys.2018.00061"},{"key":"2026050805250692000_2026.04.30.722044v1.15","doi-asserted-by":"publisher","DOI":"10.1037\/a0026238"},{"key":"2026050805250692000_2026.04.30.722044v1.16","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuron.2005.01.042"},{"key":"2026050805250692000_2026.04.30.722044v1.17","doi-asserted-by":"crossref","unstructured":"Burke SN , Gaynor LS , Barnes CA , Bauer RM , Bizon JL , Roberson ED , Ryan L (2018b) Shared Functions of Perirhinal and Parahippocampal Cortices: Implications for Cognitive Aging. Trends Neurosci.","DOI":"10.1016\/j.tins.2018.03.001"},{"key":"2026050805250692000_2026.04.30.722044v1.18","doi-asserted-by":"publisher","DOI":"10.1046\/j.0953-816x.2001.01850.x"},{"key":"2026050805250692000_2026.04.30.722044v1.19","doi-asserted-by":"publisher","DOI":"10.1046\/j.0953-816x.2001.01851.x"},{"key":"2026050805250692000_2026.04.30.722044v1.20","doi-asserted-by":"publisher","DOI":"10.1101\/lm.987808"},{"key":"2026050805250692000_2026.04.30.722044v1.21","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuron.2011.03.007"},{"key":"2026050805250692000_2026.04.30.722044v1.22","doi-asserted-by":"crossref","unstructured":"Colon-Perez LM , Turner SM , Lubke KN , Pompilus M , Febo M , Burke SN (2019) Multiscale Imaging Reveals Aberrant Functional Connectome Organization and Elevated Dorsal Striatal. eNeuro 6.","DOI":"10.1523\/ENEURO.0047-19.2019"},{"key":"2026050805250692000_2026.04.30.722044v1.23","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.2818-06.2006"},{"key":"2026050805250692000_2026.04.30.722044v1.24","doi-asserted-by":"publisher","DOI":"10.1016\/0166-4328(88)90157-X"},{"key":"2026050805250692000_2026.04.30.722044v1.25","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuron.2004.11.003"},{"key":"2026050805250692000_2026.04.30.722044v1.26","doi-asserted-by":"publisher","DOI":"10.1038\/16046"},{"key":"2026050805250692000_2026.04.30.722044v1.27","doi-asserted-by":"publisher","DOI":"10.1016\/j.neurobiolaging.2018.06.028"},{"key":"2026050805250692000_2026.04.30.722044v1.28","first-page":"155","article-title":"Use of a body condition score technique to assess health status in a rat model of polycystic kidney disease","volume":"49","year":"2010","journal-title":"Journal of the American Association for Laboratory Animal Science"},{"key":"2026050805250692000_2026.04.30.722044v1.29","doi-asserted-by":"publisher","DOI":"10.1101\/lm.042069.116"},{"key":"2026050805250692000_2026.04.30.722044v1.30","doi-asserted-by":"publisher","DOI":"10.1002\/hipo.22729"},{"key":"2026050805250692000_2026.04.30.722044v1.31","doi-asserted-by":"crossref","first-page":"72","DOI":"10.3389\/fnsys.2018.00072","article-title":"Experience-dependent effects of muscimol-induced hippocampal excitation on mnemonic discrimination","volume":"12","year":"2019","journal-title":"Frontiers in systems neuroscience"},{"key":"2026050805250692000_2026.04.30.722044v1.32","doi-asserted-by":"publisher","DOI":"10.1101\/lm.663507"},{"key":"2026050805250692000_2026.04.30.722044v1.33","doi-asserted-by":"crossref","first-page":"e80648","DOI":"10.1371\/journal.pone.0080648","article-title":"Age-related decline in associative learning in healthy Chinese adults","volume":"8","year":"2013","journal-title":"PloS one"},{"key":"2026050805250692000_2026.04.30.722044v1.34","unstructured":"Logan CN , Ramirez M , Smith SM , Ross A , Hull M , Southern B , Burke SN (2025) Implications for Health Assessments of the Relationship Between Body Fat Percent and Body Condition Scoring in Fisher 344 x Brown Norway Rats Varying by Sex and Age."},{"key":"2026050805250692000_2026.04.30.722044v1.35","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0912955107"},{"key":"2026050805250692000_2026.04.30.722044v1.36","doi-asserted-by":"crossref","unstructured":"Maurer AP , Burke SN , Diba K , Barnes CA (2017) Attenuated Activity Across Multiple Cell Types and Reduced Monosynaptic Connectivity in the Aged Perirhinal Cortex. J Neurosci.","DOI":"10.1523\/JNEUROSCI.0531-17.2017"},{"key":"2026050805250692000_2026.04.30.722044v1.37","doi-asserted-by":"publisher","DOI":"10.1038\/nmeth1006-767"},{"key":"2026050805250692000_2026.04.30.722044v1.38","doi-asserted-by":"publisher","DOI":"10.1016\/S1364-6613(99)01303-0"},{"key":"2026050805250692000_2026.04.30.722044v1.39","doi-asserted-by":"publisher","DOI":"10.1016\/S0959-4388(00)00195-1"},{"key":"2026050805250692000_2026.04.30.722044v1.40","doi-asserted-by":"publisher","DOI":"10.1046\/j.1460-9568.1999.00835.x"},{"key":"2026050805250692000_2026.04.30.722044v1.41","doi-asserted-by":"publisher","DOI":"10.1177\/1545968315584004"},{"key":"2026050805250692000_2026.04.30.722044v1.42","doi-asserted-by":"publisher","DOI":"10.1038\/srep14613"},{"key":"2026050805250692000_2026.04.30.722044v1.43","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuron.2018.01.039"},{"key":"2026050805250692000_2026.04.30.722044v1.44","doi-asserted-by":"publisher","DOI":"10.1159\/000106735"},{"key":"2026050805250692000_2026.04.30.722044v1.45","doi-asserted-by":"publisher","DOI":"10.1002\/hipo.22069"},{"key":"2026050805250692000_2026.04.30.722044v1.46","doi-asserted-by":"publisher","DOI":"10.12982\/VIS.2022.040"},{"key":"2026050805250692000_2026.04.30.722044v1.47","first-page":"176","article-title":"Age-related impairments on the touchscreen paired associates learning (PAL) task in male rats","volume":"109","year":"2021","journal-title":"Neurobiol Aging"},{"key":"2026050805250692000_2026.04.30.722044v1.48","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbr.2022.114106"},{"key":"2026050805250692000_2026.04.30.722044v1.49","doi-asserted-by":"publisher","DOI":"10.3389\/fnbeh.2023.1080366"},{"key":"2026050805250692000_2026.04.30.722044v1.50","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbr.2017.06.049"},{"key":"2026050805250692000_2026.04.30.722044v1.51","doi-asserted-by":"publisher","DOI":"10.1016\/j.tics.2019.08.003"},{"key":"2026050805250692000_2026.04.30.722044v1.52","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuropsychologia.2012.12.014"},{"key":"2026050805250692000_2026.04.30.722044v1.53","doi-asserted-by":"publisher","DOI":"10.1037\/bne0000055"},{"key":"2026050805250692000_2026.04.30.722044v1.54","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/bhs209"},{"key":"2026050805250692000_2026.04.30.722044v1.55","doi-asserted-by":"publisher","DOI":"10.1101\/lm.1315109"},{"key":"2026050805250692000_2026.04.30.722044v1.56","doi-asserted-by":"crossref","first-page":"6935","DOI":"10.1002\/alz.14163","article-title":"Cognitive modeling of the Mnemonic Similarity Task as a digital biomarker for Alzheimer\u2019s disease","volume":"20","year":"2024","journal-title":"Alzheimers Dement"},{"key":"2026050805250692000_2026.04.30.722044v1.57","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.0350-04.2004"},{"key":"2026050805250692000_2026.04.30.722044v1.58","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1101567108"},{"key":"2026050805250692000_2026.04.30.722044v1.59","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuroimage.2010.03.040"},{"key":"2026050805250692000_2026.04.30.722044v1.60","doi-asserted-by":"publisher","DOI":"10.1002\/hipo.20808"},{"key":"2026050805250692000_2026.04.30.722044v1.61","doi-asserted-by":"publisher","DOI":"10.1093\/chemse\/bju001"},{"key":"2026050805250692000_2026.04.30.722044v1.62","doi-asserted-by":"publisher","DOI":"10.1016\/j.neurobiolaging.2017.01.023"},{"key":"2026050805250692000_2026.04.30.722044v1.63","doi-asserted-by":"crossref","first-page":"1789080","DOI":"10.3389\/fncir.2026.1789080","article-title":"The circuitry regulation of associative learning: dissociated and integrated function of the perirhinal cortex and hippocampus","volume":"20","year":"2026","journal-title":"Front Neural Circuits"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.04.30.722044","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T12:25:19Z","timestamp":1778243119000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.04.30.722044"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,5]]},"references-count":63,"URL":"https:\/\/doi.org\/10.64898\/2026.04.30.722044","relation":{},"subject":[],"published":{"date-parts":[[2026,5,5]]},"subtype":"preprint"}}