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Brown EK, Sherry DF, Hampton RR. Cognitive control of memory in a food-storing and a non-storing bird species. Anim Cogn 2025; 28:36. [PMID: 40323538 PMCID: PMC12053294 DOI: 10.1007/s10071-025-01954-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2024] [Revised: 03/25/2025] [Accepted: 04/08/2025] [Indexed: 05/08/2025]
Abstract
Scatter hoarding black-capped chickadees use memory to relocate hidden food, often after delays of hours or days. The ability of these birds to maintain accurate memories of the location and current status of many food caches while engaging in other distracting daily activities suggests that their memory may be especially resistant to competing cognitive load. We measured resistance to competing cognitive load during spatial memory tests in black-capped chickadees (Poecile atricapillus) and a non-caching species, dark-eyed juncos (Junco hyemalis). Birds were presented with two types of task. In the Discrimination task, birds learned by trial-and-error to select a target from among 2 distractors. In the Match-to-Sample task, birds viewed a sample which they had to remember in order to correctly select it from among two distractors at test. On two-thirds of trials, the tasks were presented Stand-Alone: after birds initiated a trial, they completed either a Discrimination or a Match-to-Sample task. The remaining trials were Concurrent causing a competing cognitive load: after birds intiated a trial, they saw the sample for the Match-to-Sample task, then completed a Discrimination during the retention interval, and finally completed a Match-to-Sample test. Competing cognitive load reduced accuracy of juncos significantly more than accuracy of chickadees. The need to encode and retain the locations of multiple food caches may have led to the evolution of enhanced cognitive control of memory in black-capped chickadees.
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Affiliation(s)
| | - David F Sherry
- Advanced Facility for Avian Research and Department of Psychology, Western University, London, ON, Canada
| | - Robert R Hampton
- Department of Psychology, Emory University, Atlanta, GA, USA
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA
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Basile BM, Waters SJ, Murray EA. What does preferential viewing tell us about the neurobiology of recognition memory? Trends Neurosci 2024; 47:326-337. [PMID: 38582659 PMCID: PMC11096050 DOI: 10.1016/j.tins.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/09/2024] [Accepted: 03/14/2024] [Indexed: 04/08/2024]
Abstract
The two tests most widely used in nonhuman primates to assess the neurobiology of recognition memory produce conflicting results. Preferential viewing tests (e.g., visual paired comparison) produce robust impairments following hippocampal lesions, whereas matching tests (e.g., delayed nonmatching-to-sample) often show complete sparing. Here, we review the data, the proposed explanations for this discrepancy, and then critically evaluate those explanations. The most likely explanation is that preferential viewing tests are not a process-pure assessment of recognition memory, but also test elements of novelty-seeking, habituation, and motivation. These confounds likely explain the conflicting results. Thus, we propose that memory researchers should prefer explicit matching tests and readers interested in the neural substrates of recognition memory should give explicit matching tests greater interpretive weight.
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Affiliation(s)
| | - Spencer J Waters
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA; Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, MD, USA
| | - Elisabeth A Murray
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, MD, USA.
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3
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Webster MF, Engelberg JWM, Hampton RR. Rhesus monkeys show greater habituation to repeated computer-generated images than do orangutans. Behav Processes 2024; 216:105011. [PMID: 38417563 PMCID: PMC11019916 DOI: 10.1016/j.beproc.2024.105011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/23/2024] [Accepted: 02/23/2024] [Indexed: 03/01/2024]
Abstract
Humans and several other species of animals have demonstrated the ability to use familiarity to recognize that they have seen images before. In prior experiments, orangutans failed to show use of familiarity in memory tasks, even when other solutions were not available. We tested for evidence of habituation, a decreased response to repeated stimuli, as a behavioral indicator that repeated images were familiar to subjects. Monkeys and orangutans selected the smallest target out of four while computerized images were presented as distractors. Latency to complete the target-finding task was compared between conditions in which the distractor image was a familiar, repeating image, a novel, never-before-seen image, or no distractor was present. Rhesus macaques showed significant habituation, and significantly more habituation than orangutans, in each of four experiments. Orangutans showed statistically reliable habituation in only one of the four experiments. These results are consistent with previous research in which orangutans failed to demonstrate familiarity. Because we expect that familiarity and habituation are evolutionarily ancient memory processes, we struggle to explain these surprising, but consistent findings. Future research is needed to determine why orangutans respond to computerized images in this peculiar way.
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Affiliation(s)
- Mackenzie F Webster
- Emory University Department of Psychology, USA; Emory National Primate Research Center, USA.
| | | | - Robert R Hampton
- Emory University Department of Psychology, USA; Emory National Primate Research Center, USA
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Smulders TV, Douglas LJ, Reza D, Male LH, Prysce A, Alix A, de Guzman Dodd A, Read JCA. Hoarding titmice predominantly use Familiarity, and not Recollection, when remembering cache locations. Anim Cogn 2023; 26:1929-1943. [PMID: 37865619 PMCID: PMC10769918 DOI: 10.1007/s10071-023-01829-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/05/2023] [Accepted: 09/29/2023] [Indexed: 10/23/2023]
Abstract
Scatter-hoarding birds find their caches using spatial memory and have an enlarged hippocampus. Finding a cache site could be achieved using either Recollection (a discrete recalling of previously experienced information) or Familiarity (a feeling of "having encountered something before"). In humans, these two processes can be distinguished using receiver operating characteristic (ROC) curves. ROC curves for olfactory memory in rats have shown the hippocampus is involved in Recollection, but not Familiarity. We test the hypothesis that food-hoarding birds, having a larger hippocampus, primarily use Recollection to find their caches. We validate a novel method of constructing ROC curves in humans and apply this method to cache retrieval by coal tits (Periparus ater). Both humans and birds mainly use Familiarity in finding their caches, with lower contribution of Recollection. This contribution is not significantly different from chance in birds, but a small contribution cannot be ruled out. Memory performance decreases with increasing retention interval in birds. The ecology of food-hoarding Parids makes it plausible that they mainly use Familiarity in the memory for caches. The larger hippocampus could be related to associating cache contents and temporal context with cache locations, rather than Recollection of the spatial information itself.
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Affiliation(s)
- Tom V Smulders
- Centre for Behaviour & Evolution and Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
- School of Psychology, Newcastle University, Newcastle upon Tyne, NE2 4DR, UK.
| | - Laura J Douglas
- Centre for Behaviour & Evolution and Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniel Reza
- School of Psychology, Newcastle University, Newcastle upon Tyne, NE2 4DR, UK
| | - Lucinda H Male
- Centre for Behaviour & Evolution and Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Alexander Prysce
- School of Psychology, Newcastle University, Newcastle upon Tyne, NE2 4DR, UK
| | - Amélie Alix
- Centre for Behaviour & Evolution and Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | | | - Jenny C A Read
- Centre for Behaviour & Evolution and Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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5
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Waters SJ, Basile BM, Murray EA. Reevaluating the role of the hippocampus in memory: A meta-analysis of neurotoxic lesion studies in nonhuman primates. Hippocampus 2023; 33:787-807. [PMID: 36649170 PMCID: PMC10213107 DOI: 10.1002/hipo.23499] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 12/21/2022] [Accepted: 12/28/2022] [Indexed: 01/18/2023]
Abstract
The hippocampus and perirhinal cortex are both broadly implicated in memory; nevertheless, their relative contributions to visual item recognition and location memory remain disputed. Neuropsychological studies in nonhuman primates that examine memory function after selective damage to medial temporal lobe structures report various levels of memory impairment-ranging from minor deficits to profound amnesia. The discrepancies in published findings have complicated efforts to determine the exact magnitude of visual item recognition and location memory impairments following damage to the hippocampus and/or perirhinal cortex. To provide the most accurate estimate to date of the overall effect size, we use meta-analytic techniques on data aggregated from 26 publications that assessed visual item recognition and/or location memory in nonhuman primates with and without selective neurotoxic lesions of the hippocampus or perirhinal cortex. We estimated the overall effect size, evaluated the relation between lesion extent and effect size, and investigated factors that may account for between-study variation. Grouping studies by lesion target and testing method, separate meta-analyses were conducted. One meta-analysis indicated that impairments on tests of visual item recognition were larger after lesions of perirhinal cortex than after lesions of the hippocampus. A separate meta-analysis showed that performance on tests of location memory was severely impaired by lesions of the hippocampus. For the most part, meta-regressions indicated that greater impairment corresponds with greater lesion extent; paradoxically, however, more extensive hippocampal lesions predicted smaller impairments on tests of visual item recognition. We conclude the perirhinal cortex makes a larger contribution than the hippocampus to visual item recognition, and the hippocampus predominately contributes to spatial navigation.
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Affiliation(s)
- Spencer J. Waters
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, NIH, Bethesda MD 20892, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, USA
| | - Benjamin M. Basile
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, NIH, Bethesda MD 20892, USA
- Department of Psychology, Dickinson College, Carlisle PA, USA
| | - Elisabeth A. Murray
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, NIH, Bethesda MD 20892, USA
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Hassett TC, Lord VK, Hampton RR. Rhesus monkeys manipulate mental images. Cognition 2022; 228:105225. [PMID: 35843135 PMCID: PMC9922027 DOI: 10.1016/j.cognition.2022.105225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/02/2022] [Accepted: 07/08/2022] [Indexed: 01/27/2023]
Abstract
Humans form mental images and manipulate them in ways that mirror physical transformations of objects. Studies of nonhuman animals will inform our understanding of the evolution and distribution among species of mental imagery. Across three experiments, we found mostly converging evidence that rhesus monkeys formed and rotated mental images. In Experiment 1, monkeys discriminated rotations of sample images from mirror images, and showed longer response latencies with greater rotation as is characteristic of human mental rotation. In Experiment 2 monkeys used a rotation cue that indicated how far to mentally rotate sample images before tests, indicating a precision of better than 30° in discriminating rotations. Experiment 3 yielded mixed evidence on whether the rotation cue shortened decision times as has been found in humans. These results show that rhesus monkeys manipulate mental images.
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Affiliation(s)
- Thomas C Hassett
- Department of Psychology, Emory University, Atlanta, GA, United States of America; Emory National Primate Research Center, Atlanta, GA, United States of America.
| | - Victoria K Lord
- Department of Psychology, Emory University, Atlanta, GA, United States of America
| | - Robert R Hampton
- Department of Psychology, Emory University, Atlanta, GA, United States of America; Emory National Primate Research Center, Atlanta, GA, United States of America
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Interaction of memory systems is controlled by context in both food-storing and non-storing birds. Learn Behav 2022; 50:140-152. [PMID: 34918201 PMCID: PMC8983471 DOI: 10.3758/s13420-021-00496-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2021] [Indexed: 11/08/2022]
Abstract
Animals and humans have multiple memory systems. While both black-capped chickadees (Poecile atricapillus) and dark-eyed juncos (Junco hyemalis) are under selective pressure to remember reliable long-term spatial locations (habit memory), chickadees must additionally quickly form and rapidly update spatial memory for unique cache sites (one-trial memory). We conducted a series of three experiments in which we assessed the degree to which habit and one-trial memory were expressed in both species as a function of training context. In Experiment 1, birds failed to demonstrate habits on probe trials after being trained in the context of a biased Match-to-Sample task in which the same high-frequency target was always correct. In Experiment 2, habit strongly controlled performance when habits were learned as Discriminations, defining a specific training context. In Experiment 3, context no longer defined when to express habits and habit and one-trial memory competed for control of behavior. Across all experiments, birds preferentially used the memory system at test that was consistent with the context in which it was acquired. Although the memory adaptations that allow chickadees to successfully recover cached food might predispose them to favor one-trial memory, we found no species differences in the weighting of habit and one-trial memory. In the experiments here, context was a powerful factor controlling the interaction of memory systems.
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Endogenous cortisol correlates with performance under pressure on a working memory task in capuchin monkeys. Sci Rep 2022; 12:953. [PMID: 35046477 PMCID: PMC8770687 DOI: 10.1038/s41598-022-04986-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/24/2021] [Indexed: 11/10/2022] Open
Abstract
Humans often experience striking performance deficits when their outcomes are determined by their own performance, colloquially referred to as “choking under pressure.” Physiological stress responses that have been linked to both choking and thriving are well-conserved in primates, but it is unknown whether other primates experience similar effects of pressure. Understanding whether this occurs and, if so, its physiological correlates, will help clarify the evolution and proximate causes of choking in humans. To address this, we trained capuchin monkeys on a computer game that had clearly denoted high- and low-pressure trials, then tested them on trials with the same signals of high pressure, but no difference in task difficulty. Monkeys significantly varied in whether they performed worse or better on high-pressure testing trials and performance improved as monkeys gained experience with performing under pressure. Baseline levels of cortisol were significantly negatively related to performance on high-pressure trials as compared to low-pressure trials. Taken together, this indicates that less experience with pressure may interact with long-term stress to produce choking behavior in early sessions of a task. Our results suggest that performance deficits (or improvements) under pressure are not solely due to human specific factors but are rooted in evolutionarily conserved biological factors.
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Kazemi M, Aliyari H, Tekieh E, Tavakoli H, Golabi S, Sahraei H, Meftahi GH, Salehi M, Saberi M. The Effect of 12 Hz Extremely Low-frequency Electromagnetic Field on Visual Memory of Male Macaque Monkeys. Basic Clin Neurosci 2022; 13:1-14. [PMID: 36589014 PMCID: PMC9790106 DOI: 10.32598/bcn.2021.724.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/23/2020] [Accepted: 08/04/2020] [Indexed: 01/04/2023] Open
Abstract
Introduction Today, humans live in a world surrounded by electromagnetic fields. Numerous studies have been conducted to discover the biological, physiological, and behavioral effects of electromagnetic fields on humans and animals. Given the biological similarities between monkeys and humans, The present research aimed to examine Visual Memory (VM), hormonal, genomic, and anatomic changes, in the male rhesus macaques exposed to an Extremely Low-Frequency Magnetic Field (ELF-MF). Methods Four male rhesus macaques (Macaca mulatta) were used. For the behavioral tests, the animals should be fasting for 17 hours. For the tests such as visual memory, the animal's cooperation was necessary. Using the radiation protocol, we exposed two monkeys to a 12-Hz electromagnetic field with a magnitude of 0.7 μT (electromagnetic radiation) four hours a day for a month. Before and after the exposure, a visual memory test was conducted using a coated device (visible reward) on a movable stand. Ten milliliters of blood was obtained from the femoral artery of each monkey, and half of it was used to examine cortisol serum levels using the MyBioSource kit (made in the USA). The other half of the blood was used to extract lymphocytes for assaying expressions of Glucocorticoid Receptor (GR) genes before and after radiation using the PCR method. Anatomic studies of the amygdala were carried out based on pre- and post-radiation Magnetic Resonance Imaging (MRI). Results Research results indicated that visual memory in male primates increased significantly after exposure to the 12-Hz frequency. Hormonal analysis at the 12-Hz frequency showed a decrease in cortisol serum levels. However, visual memory and serum cortisol levels did not change considerably in male primates in the control group. There was no considerable amygdala volumetric difference after exposure to the 12-Hz frequency. The expression of the GR genes decreased in the 12-Hz group compared to the control group. Conclusion In short, these results indicated that ELF might benefit memory enhancement because exposure to the 12-HZ ELF can enhance visual memory. This outcome may be due to a decrease in plasma cortisol and or expression of GR genes. Moreover, direct amygdala involvement in this regard cannot be recommended. Highlights The effects of Extremely Low-Frequency Electromagnetic Fields (ELF-EMF) of 12 Hz on monkeys were studied.The results showed a reduction in the serum cortisol levels and the expression of GR genes.The amygdala anatomical area changes were not significant in the experimental group.In the experimental group, visual memory (delay of 30- and 60-s evaluation) improved after exposure to a frequency of 12 Hz. Plain Language Summary Extremely low-frequency electromagnetic fields are among the most important factors affecting humans. This study aimed to determine the fields of 12-Hz frequency on the visual memory changes of male monkeys. The importance of research is due to the cognitive similarity of monkeys to humans. The findings of the research can be attributed to humans. Behavioral, hormonal, genetic, and anatomical studies indicated improvement in visual memory (test monkeys versus control monkeys). This study demonstrates the effect of the 12-Hz frequency on the monkey's visual memory. Researchers can study 12-Hz frequency in other cognitive indices.
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Affiliation(s)
- Masoomeh Kazemi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Hamed Aliyari
- Center for Human-Engaged Computing, Kochi University of Technology, Kochi, Japan
| | - Elaheh Tekieh
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Hassan Tavakoli
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Sahar Golabi
- Department of Medical Physiology, School of Medicine, Abadan University of Medical Sciences, Abadan, Iran
| | - Hedayat Sahraei
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | | | - Maryam Salehi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mehdi Saberi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Brady RJ, Mickelberg JM, Hampton RR. Greater dependence on working memory and restricted familiarity in orangutans compared with rhesus monkeys. Learn Mem 2021; 28:260-269. [PMID: 34266991 PMCID: PMC8284315 DOI: 10.1101/lm.053422.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/17/2021] [Indexed: 11/24/2022]
Abstract
The prefrontal cortex is larger than would be predicted by body size or visual cortex volume in great apes compared with monkeys. Because prefrontal cortex is critical for working memory, we hypothesized that recognition memory tests would engage working memory in orangutans more robustly than in rhesus monkeys. In contrast to working memory, the familiarity response that results from repetition of an image is less cognitively taxing and has been associated with nonfrontal brain regions. Across three experiments, we observed a striking species difference in the control of behavior by these two types of memory. First, we found that recognition memory performance in orangutans was controlled by working memory under conditions in which this memory system plays little role in rhesus monkeys. Second, we found that unlike the case in monkeys, familiarity was not involved in recognition memory performance in orangutans, shown by differences with monkeys across three different measures. Memory in orangutans was not improved by use of novel images, was always impaired by a concurrent cognitive load, and orangutans did not accurately identify images seen minutes ago. These results are surprising and puzzling, but do support the view that prefrontal expansion in great apes favored working memory. At least in orangutans, increased dependence on working memory may come at a cost in terms of the availability of familiarity.
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Affiliation(s)
- Ryan J Brady
- Emory University, Atlanta, Georgia 30322, USA
- Yerkes National Primate Research Center, Atlanta, Georgia 30329, USA
| | | | - Robert R Hampton
- Emory University, Atlanta, Georgia 30322, USA
- Yerkes National Primate Research Center, Atlanta, Georgia 30329, USA
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Beran MJ, Parrish AE. Non-human primate token use shows possibilities but also limitations for establishing a form of currency. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190675. [PMID: 33423633 PMCID: PMC7815425 DOI: 10.1098/rstb.2019.0675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2020] [Indexed: 11/12/2022] Open
Abstract
Non-human primates evaluate choices based on quantitative information and subjective valuation of options. Non-human primates can learn to value tokens as placeholders for primary rewards (such as food). With those tokens established as a potential form of 'currency', it is then possible to examine how they respond to opportunities to earn and use tokens in ways such as accumulating tokens or exchanging tokens with each other or with human experimenters to gain primary rewards. Sometimes, individuals make efficient and beneficial choices to obtain tokens and then exchange them at the right moments to gain optimal reward. Sometimes, they even accumulate such rewards through extended delay of gratification, or through other exchange-based interactions. Thus, non-human primates are capable of associating value to arbitrary tokens that may function as currency-like stimuli, but there also are strong limitations on how non-human primates can integrate such tokens into choice situations or use such tokens to fully 'symbolize' economic decision-making. These limitations are important to acknowledge when considering the evolutionary emergence of currency use in our species. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.
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Affiliation(s)
- Michael J. Beran
- Department of Psychology and Language Research Center, Georgia State University, Atlanta, GA 30302, USA
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12
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Brown EK, Hampton RR. Cognitive control of working memory but not familiarity in rhesus monkeys (Macaca mulatta). Learn Behav 2020; 48:444-452. [PMID: 32638291 PMCID: PMC7686054 DOI: 10.3758/s13420-020-00432-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Directed forgetting paradigms assess cognitive control by determining whether memory accuracy is superior in trials on which subjects were instructed to remember compared with accuracy in trials on which they were instructed to forget. We used a directed forgetting paradigm to compare the extent to which working memory and familiarity are subject to rehearsal-like cognitive control in rhesus monkeys. Monkeys studied a sample image, then saw one of two distinctive cues during a retention interval. The remember cue typically predicted a four-choice match to sample test, for which memory of the sample was critical. The forget cue typically predicted one of five perceptual discrimination tests, matched for accuracy to the memory tests, for which memory of the sample was irrelevant. On rare probe trials, the test type other than the type typically predicted by the cue was presented. When cognitive control of memory was possible, accuracy should have been higher on memory tests following the remember cue than on those following the forget cue. We found that accuracy was higher following the remember cue under conditions that favored working memory (small image set) but was not higher under conditions that favored matching on the basis of relative familiarity (large image set). Working memory, but not familiarity, is subject to cognitive control in rhesus monkeys.
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Affiliation(s)
- Emily Kathryn Brown
- Department of Psychology and Yerkes National Primate Research Center, Emory University, 36 Eagle Row, Atlanta, GA, 30322, USA.
| | - Robert R Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, 36 Eagle Row, Atlanta, GA, 30322, USA
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Aliyari H, Sahraei H, Erfani M, Mohammadi M, Kazemi M, Daliri MR, Minaei-Bidgoli B, Agaei H, Sahraei M, Seyed Hosseini SMA, Tekieh E, Salehi M, Farajdokht F. Changes in Cognitive Functions Following Violent and Football Video Games in Young Male Volunteers by Studying Brain Waves. Basic Clin Neurosci 2020; 11:279-288. [PMID: 32963721 PMCID: PMC7502184 DOI: 10.32598/bcn.9.10.335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/10/2018] [Accepted: 12/02/2018] [Indexed: 11/29/2022] Open
Abstract
Introduction: This research investigated the effects of violent and football video games on cognitive functions, cortisol levels, and brain waves. Methods: A total of 64 participants competed in a single-elimination tournament. Saliva samples of all players were obtained before and after the games for the assessment of cortisol levels. The cognitive performances of the players were also assessed by paced auditory serial addition test. Moreover, the electroencephalogram recording was conducted during the games. Results: The results showed that salivary cortisol levels significantly decreased after playing both games. Also, playing the football game increased reaction time, whereas decreased sustained attention and mental fatigue. Conclusion: Conversely, following playing a violent game, the reaction time decreased, and sustained attention and mental fatigue increased. Furthermore, the results of the EEG recording revealed that playing a violent game engaged more brain regions than the football game. In conclusion, playing violent game more effectively improved cognitive performances in the players than the football game.
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Affiliation(s)
- Hamed Aliyari
- Faculty of Electrical, Biomedical and Mechatronics Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
| | - Hedayat Sahraei
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Marjan Erfani
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Mohammadi
- Human Motion Control and Computational Neuroscience Laboratory, School of ECE, College of Engineering, University of Tehran, Tehran, Iran
| | - Masoomeh Kazemi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Daliri
- Department of Electrical Engineering, University of Science and Technology, Tehran, Iran
| | | | - Hassan Agaei
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Sahraei
- Faculty of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Elaheh Tekieh
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Maryam Salehi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Basile BM, Templer VL, Gazes RP, Hampton RR. Preserved visual memory and relational cognition performance in monkeys with selective hippocampal lesions. SCIENCE ADVANCES 2020; 6:eaaz0484. [PMID: 32832615 PMCID: PMC7439495 DOI: 10.1126/sciadv.aaz0484] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
The theory that the hippocampus is critical for visual memory and relational cognition has been challenged by discovery of more spared hippocampal tissue than previously reported in H.M., previously unreported extra-hippocampal damage in developmental amnesiacs, and findings that the hippocampus is unnecessary for object-in-context memory in monkeys. These challenges highlight the need for causal tests of hippocampal function in nonhuman primate models. Here, we tested rhesus monkeys on a battery of cognitive tasks including transitive inference, temporal order memory, shape recall, source memory, and image recognition. Contrary to predictions, we observed no robust impairments in memory or relational cognition either within- or between-groups following hippocampal damage. These results caution against over-generalizing from human correlational studies or rodent experimental studies, compel a new generation of nonhuman primate studies, and indicate that we should reassess the relative contributions of the hippocampus proper compared to other regions in visual memory and relational cognition.
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Affiliation(s)
- Benjamin M. Basile
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, NIH, Bethesda, MD, USA
| | - Victoria L. Templer
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Psychology, Providence College, Providence, RI, USA
| | - Regina Paxton Gazes
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Psychology and Program in Animal Behavior, Bucknell University, Lewisburg, PA, USA
| | - Robert R. Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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15
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Wu Z, Kavanova M, Hickman L, Lin F, Buckley MJ. Similar time course of fast familiarity and slow recollection processes for recognition memory in humans and macaques. ACTA ACUST UNITED AC 2020; 27:258-269. [PMID: 32540915 PMCID: PMC7301754 DOI: 10.1101/lm.051342.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/21/2020] [Indexed: 11/24/2022]
Abstract
According to dual-process theory, recognition memory performance draws upon two processes, familiarity and recollection. The relative contribution to recognition memory are commonly distinguished in humans by analyzing receiver-operating-characteristics (ROC) curves; analogous methods are more complex and very rare in animals but fast familiarity and slow recollective-like processes (FF/SR) have been detected in nonhuman primates (NHPs) based on analyzing recognition error response time profiles. The relative utility of these methods to investigate familiarity and recollection/recollection-like processes across species is uncertain; indeed, even how comparable the FF/SR measures are across humans and NHPs remains unclear. Therefore, in this study a broadly similar recognition memory task was exploited in both humans and a NHP to investigate the time course of the two recognition processes. We first show that the FF/SR dissociation exists in this task in human participants and then we demonstrate a similar profile in the NHP which suggests that FF/SR processes are comparable across species. We then verified, using ROC-derived indices for each time-bin in the FF/SR profile, that the ROC and FF/SR measures are related. Hence, we argue that the FF/SR approach, procedurally easier in nonhuman animals, can be used as a decent proxy to investigate these two recognition processes in future animal studies, important given that scant data exists as to the neural basis underlying recollection yet many of the most informative techniques primarily exist in animal models.
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Affiliation(s)
- Zhemeng Wu
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3SR, United Kingdom
| | - Martina Kavanova
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3SR, United Kingdom
| | - Lydia Hickman
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3SR, United Kingdom
| | - Fiona Lin
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3SR, United Kingdom
| | - Mark J Buckley
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3SR, United Kingdom
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16
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Hampton RR, Engelberg JWM, Brady RJ. Explicit memory and cognition in monkeys. Neuropsychologia 2020; 138:107326. [PMID: 31917205 PMCID: PMC8719341 DOI: 10.1016/j.neuropsychologia.2019.107326] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/16/2019] [Accepted: 12/22/2019] [Indexed: 11/19/2022]
Abstract
Taxonomies of human memory, influenced heavily by Endel Tulving, make a fundamental distinction between explicit and implicit memory. Humans are aware of explicit memories, whereas implicit memories control behavior even though we are not aware of them. Efforts to understand the evolution of memory, and to use nonhuman animals to model human memory, will be facilitated by better understanding the extent to which this critical distinction exists in nonhuman animals. Work with metacognition paradigms in the past 20 years has produced a strong case for the existence of explicit memory in nonhuman primates and possibly other nonhuman animals. Clear dissociations of explicit and implicit memory by metacognition have yet to be demonstrated in nonhumans, although dissociations between memory systems by other behavioral techniques, and by brain manipulations, suggest that the explicit-implicit distinction applies to nonhumans. Neurobehavioral studies of metamemory are beginning to identify neural substrates for memory monitoring in the frontal cortex of monkeys. We have strong evidence that at least some memory systems are explicit in rhesus monkeys, but we need to learn more about the distribution of explicit processes across cognitive systems within monkeys, and across species.
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Affiliation(s)
- Robert R Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.
| | - Jonathan W M Engelberg
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Ryan J Brady
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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17
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Abstract
Monkeys demonstrate metacognition by avoiding memory tests when they forget, seeking information when ignorant, and gambling sensibly after making judgments. Some of this metacognition appears to be based on introspection of private mental states. It is likely that nonhuman cognitive systems, like human systems, differ in accessibility to such introspective metacognition, and the extent to which differences in access map to explicit and implicit cognition will be an important topic for future work. It will be exciting to learn more about the distribution of metacognition among species, and the conditions under which metacognition evolves.
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18
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Völter CJ, Mundry R, Call J, Seed AM. Chimpanzees flexibly update working memory contents and show susceptibility to distraction in the self-ordered search task. Proc Biol Sci 2019; 286:20190715. [PMID: 31337315 PMCID: PMC6661351 DOI: 10.1098/rspb.2019.0715] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/30/2019] [Indexed: 11/12/2022] Open
Abstract
Working memory (WM) is a core executive function that allows individuals to hold, process and manipulate information. WM capacity has been repeatedly nominated as a key factor in human cognitive evolution; nevertheless, little is known about the WM abilities of our closest primate relatives. In this study, we examined signatures of WM ability in chimpanzees (Pan troglodytes). Standard WM tasks for humans (Homo sapiens) often require participants to continuously update their WM. In Experiment 1, we implemented this updating requirement in a foraging situation: zoo-housed chimpanzees (n = 13) searched for food in an array of containers. To avoid redundant searches, they needed to continuously update which containers they had already visited (similar to WM paradigms for human children) with 15 s retention intervals in between each choice. We examined chimpanzees' WM capacity and to what extent they used spatial cues and object features to memorize their previous choices. In Experiment 2, we investigated how susceptible their WM was to attentional interference, an important signature, setting WM in humans apart from long-term memory. We found large individual differences with some individuals remembering at least their last four choices. Chimpanzees used a combination of spatial cues and object features to remember which boxes they had chosen already. Moreover, their performance decreased specifically when competing memory information was introduced. Finally, we found that individual differences in task performance were highly reliable over time. Together, these findings show remarkable similarities between human and chimpanzee WM abilities despite evolutionary and life-history differences.
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Affiliation(s)
- Christoph J. Völter
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
- Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Roger Mundry
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Josep Call
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
- Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Amanda M. Seed
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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19
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Templer VL, Gazes RP, Hampton RR. Co-operation of long-term and working memory representations in simultaneous chaining by rhesus monkeys ( Macaca mulatta). Q J Exp Psychol (Hove) 2019; 72:2208-2224. [PMID: 30827186 DOI: 10.1177/1747021819838432] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We studied the memory representations that control execution of action sequences by training rhesus monkeys (Macaca mulatta) to touch sets of five images in a predetermined arbitrary order (simultaneous chaining). In Experiment 1, we found that this training resulted in mental representations of ordinal position rather than learning associative chains, replicating the work of others. We conducted novel analyses of performance on probe tests consisting of two images "derived" from the full five-image lists (i.e., test B, D from list A→B→C→D→E). We found a "first item effect" such that monkeys responded most quickly to images that occurred early in the list in which they had been learned, indicating that monkeys covertly execute known lists mentally until an image on the screen matches the one stored in memory. Monkeys also made an ordinal comparison of the two images presented at test based on long-term memory of positional information, resulting in a "symbolic distance effect." Experiment 2 indicated that ordinal representations were based on absolute, rather than on relative, positional information because subjects did not link two lists into one large list after linking training, unlike what occurs in transitive inference. We further examined the contents of working memory during list execution in Experiments 3 and 4 and found evidence for a prospective, rather than a retrospective, coding of position in the lists. These results indicate that serial expertise in simultaneous chaining results in robust absolute ordinal coding in long-term memory, with rapidly updating prospective coding of position in working memory during list execution.
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Affiliation(s)
| | - Regina Paxton Gazes
- 2 Department of Psychology and Animal Behavior Program, Bucknell University, Lewisburg, PA, USA
| | - Robert R Hampton
- 3 Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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20
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Dissociation of memory signals for metamemory in rhesus monkeys (Macaca mulatta). Anim Cogn 2019; 22:331-341. [PMID: 30762160 DOI: 10.1007/s10071-019-01246-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 01/28/2019] [Accepted: 01/31/2019] [Indexed: 10/27/2022]
Abstract
Some nonhuman species demonstrate metamemory, the ability to monitor and control memory. Here, we identify memory signals that control metamemory judgments in rhesus monkeys by directly comparing performance in two metamemory paradigms while holding the availability of one memory signal constant and manipulating another. Monkeys performed a four-choice match-to-sample memory task. In Experiment 1, monkeys could decline memory tests on some trials for a small, guaranteed reward. In Experiment 2, monkeys could review the sample on some trials. In both experiments, monkeys improved accuracy by selectively declining tests or reviewing samples when memory was poor. To assess the degree to which different memory signals made independent contributions to the metamemory judgement, we made the decline-test or review-sample response available either prospectively, before the test, or concurrently with test stimuli. Prospective metamemory judgements are likely controlled by the current contents of working memory, whereas concurrent metamemory judgements may also be controlled by additional relative familiarity signals evoked by the sight of the test stimuli. In both paradigms, metacognitive responding enhanced accuracy more on concurrent than on prospective tests, suggesting additive contributions of working memory and stimulus-evoked familiarity. Consistent with the hypothesis that working memory and stimulus-evoked familiarity both control metamemory judgments when available, metacognitive choice latencies were longer in the concurrent condition, when both were available. Together, these data demonstrate that multiple memory signals can additively control metacognitive judgements in monkeys and provide a framework for mapping the interaction of explicit memory signals in primate memory.
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21
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Brady RJ, Hampton RR. Nonverbal Working Memory for Novel Images in Rhesus Monkeys. Curr Biol 2018; 28:3903-3910.e3. [PMID: 30503618 PMCID: PMC6501570 DOI: 10.1016/j.cub.2018.10.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 10/27/2022]
Abstract
Human working memory is greatly facilitated by linguistic representations-for example, by verbal rehearsal and by verbal recoding of novel stimuli. The absence of language in nonhumans raises questions about the extent to which nonhuman working memory includes similar mechanisms. There is strong evidence for rehearsal-like active maintenance in working memory when monkeys are tested with highly familiar stimuli, but not when tested with novel stimuli, suggesting that working memory depends on the existence of previously encoded representations. This difference in working memory for familiar and novel images may exist because, lacking language, monkeys cannot recode novel stimuli in a way that permits active maintenance in working memory. Alternatively, working memory for novel images may have been present, but behaviorally silent, in earlier studies. In tests with novel images, the high familiarity of to-be-remembered stimuli compared to never-before-seen distractors may be such a strong determinant of recognition performance that evidence of working memory is obscured. In the current study, we developed a technique for attenuating the utility of relative familiarity as a mnemonic signal in recognition tests with novel stimuli. In tests with novel images, we observed impairments of memory by concurrent cognitive load and delay interval that indicate actively maintained working memory. This flexibility in monkey working memory suggests that monkeys may recode unfamiliar stimuli to facilitate working memory and establishes new parallels between verbal human working memory and nonverbal nonhuman primate working memory.
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Affiliation(s)
- Ryan J Brady
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, USA; Yerkes National Primate Research Center, 954 Gatewood Road NE, Atlanta, GA 30329, USA.
| | - Robert R Hampton
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, USA; Yerkes National Primate Research Center, 954 Gatewood Road NE, Atlanta, GA 30329, USA.
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22
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Beran MJ. Monkey Memory: Rehearsal Emerges for Novel Images When Familiarity Cues Fade. Curr Biol 2018; 28:R1399-R1400. [PMID: 30562534 DOI: 10.1016/j.cub.2018.10.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It was thought that, when monkeys use familiarity cues to aid recognition memory, they do not engage working memory. A new study shows that, when the value of those familiarity cues is attenuated, monkeys rehearse novel images like familiar ones, a striking parallel with human working memory.
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Affiliation(s)
- Michael J Beran
- Department of Psychology and Language Research Center, Georgia State University, Atlanta, GA 30302, USA.
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23
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Basile BM, Hampton RR. Nonnavigational spatial memory performance is unaffected by hippocampal damage in monkeys. Hippocampus 2018; 29:93-101. [PMID: 30069946 DOI: 10.1002/hipo.23013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/20/2018] [Accepted: 07/13/2018] [Indexed: 11/05/2022]
Abstract
Evidence that the hippocampus is critical for spatial memory in nonnavigational tests is mixed. A recent study reported that temporary hippocampal inactivation impaired spatial memory in the nonnavigational Hamilton Search Task in monkeys. However, several studies have documented no impairment on other nonnavigational spatial memory tests following permanent hippocampal lesions. It was hypothesized that transient, but not permanent, hippocampal disruption produces deficits because monkeys undergoing transient inactivation continue to try to use a hippocampal-dependent strategy, whereas monkeys with permanent lesions use a nonhippocampal-dependent strategy. We evaluated this hypothesis by testing five rhesus monkeys with hippocampal lesions and five controls on a computerized analogue of the Hamilton Search Task. On each trial, monkeys saw an array of squares on a touchscreen, each of which "hid" one reward. Retrieving a reward depleted that location and monkeys continued selecting squares until they found all rewards. The optimal strategy is to remember chosen locations and choose each square once. Unlike the inactivation study, monkeys with hippocampal damage were as accurate as controls regardless of retention interval. Critically, we found no evidence that the groups used different strategies, as measured by learning rates, spatial search biases, perseverative win-stay errors, or inter-choice distance. This discrepancy between the effect of inactivations and lesions may result from off-target effects of inactivations or as-yet-unidentified differences between the physical and computerized tasks. Combined with previous evidence that hippocampal damage impairs navigational memory in monkeys, this evidence constrains the role of the hippocampus in spatial memory as being critical for navigational tests that likely involve allocentric spatial memory but not nonnavigational tests that likely involve egocentric spatial memory.
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Affiliation(s)
- Benjamin M Basile
- Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland
| | - Robert R Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
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24
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Templer VL, Brown EK, Hampton RR. Rhesus monkeys metacognitively monitor memories of the order of events. Sci Rep 2018; 8:11541. [PMID: 30068995 PMCID: PMC6070473 DOI: 10.1038/s41598-018-30001-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/16/2018] [Indexed: 11/16/2022] Open
Abstract
Human working memory is a capacity- and duration-limited system in which retention and manipulation of information is subject to metacognitive monitoring and control. At least some nonhuman animals appear to also monitor and control the contents of working memory, but only relatively simple cases where animals monitor or control the presence or absence of single memories have been studied. Here we combine a comparatively complex order memory task with methodology that assesses the capacity to introspect about memory. Monkeys observed sequential presentations of five images, and at test, reported which of two images from the list had appeared first during study. Concurrently, they chose to complete or avoid these tests on a trial-by-trial basis. Monkeys "knew when they knew" the correct response. They were less accurate discriminating images that had appeared close in time to one another during study and were more likely to avoid these difficult tests than they were to avoid easier tests. These results indicate that monkeys can metacognitively monitor relatively complex properties of the contents of working memory, including the quality of representations of temporal relations among images.
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Affiliation(s)
- Victoria L Templer
- Department of Psychology, Providence College, 1 Cunningham Sq., Providence, RI, 02918, USA.
| | - Emily Kathryn Brown
- Department of Psychology and Yerkes National Primate Research Center, Emory University, 201 Dowman Dr., Atlanta, GA, 30322, USA
| | - Robert R Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, 201 Dowman Dr., Atlanta, GA, 30322, USA
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25
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Comrie AE, Gray DT, Smith AC, Barnes CA. Different macaque models of cognitive aging exhibit task-dependent behavioral disparities. Behav Brain Res 2018; 344:110-119. [PMID: 29432794 PMCID: PMC5890935 DOI: 10.1016/j.bbr.2018.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 02/05/2018] [Accepted: 02/06/2018] [Indexed: 11/17/2022]
Abstract
Deficits in cognitive functions that rely on the integrity of the frontal and temporal lobes are characteristic of normative human aging. Due to similar aging phenotypes and homologous cortical organization between nonhuman primates and humans, several species of macaque monkeys are used as models to explore brain senescence. These macaque species are typically regarded as equivalent models of cognitive aging, yet no direct comparisons have been made to support this assumption. Here we used adult and aged rhesus and bonnet macaques (Macaca mulatta and Macaca radiata) to characterize the effect of age on acquisition and retention of information across delays in a battery of behavioral tasks that rely on prefrontal cortex and medial temporal lobe networks. The cognitive functions that were tested include visuospatial short-term memory, object recognition memory, and object-reward association memory. In general, bonnet macaques at all ages outperformed rhesus macaques on tasks thought to rely primarily on the prefrontal cortex, and were more resilient to age-related deficits in these behaviors. On the other hand, both species were comparably impaired by age on tasks thought to preferentially engage the medial temporal lobe. Together, these results suggest that rhesus and bonnet macaques are not equivalent models of cognitive aging and highlight the value of cross-species comparisons. These observations should enable improved design and interpretation of future experiments aimed at understanding changes in cognition across the lifespan.
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Affiliation(s)
- Alison E Comrie
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, 85724, USA; Division of Neural Systems, Memory & Aging, University of Arizona, Tucson, AZ, 85724, USA
| | - Daniel T Gray
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, 85724, USA; Division of Neural Systems, Memory & Aging, University of Arizona, Tucson, AZ, 85724, USA
| | - Anne C Smith
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, 85724, USA
| | - Carol A Barnes
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, 85724, USA; Division of Neural Systems, Memory & Aging, University of Arizona, Tucson, AZ, 85724, USA; Department of Psychology, Neurology and Neuroscience, University of Arizona, Tucson, AZ, 85724, USA.
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26
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Perdue BM, Evans TA, Beran MJ. Chimpanzees show some evidence of selectively acquiring information by using tools, making inferences, and evaluating possible outcomes. PLoS One 2018; 13:e0193229. [PMID: 29641519 PMCID: PMC5894953 DOI: 10.1371/journal.pone.0193229] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/07/2018] [Indexed: 11/18/2022] Open
Abstract
Metacognition refers to thinking about one's thinking or knowing what one knows. Research suggests that this ability is not unique to humans and may be shared with nonhuman animals. In particular, great apes have shown behaviors on a variety of tasks that are suggestive of metacognitive ability. Here we combine a metacognitive task, the information-seeking task, with tool use and variable forms of initial information provided to chimpanzees to explore how informational states impact behavioral responses in these apes. Three chimpanzees were presented with an apparatus that contained five locations where food could be hidden. If they pointed to the correct location, they received the reward, but otherwise they did not. We first replicated several existing findings using this method, and then tested novel hypotheses. The chimpanzees were given different types of information across the experiments. Sometimes, they were shown the location of the food reward. Other times, they were shown only one empty location, which was not useful information. The chimpanzees also could use a tool to search any of those locations before making a selection. Chimpanzees typically used the tool to search out the location of the reward when they could not already know where it was, but they did not use the tool when they already had been given that information. One chimpanzee made inferences about the location of hidden food, even when that food was never shown in that location. The final experiment involved hiding foods of differing preference values, and then presenting the chimpanzees with different initial knowledge states (i.e., where the best food was located, where the less-preferred food was located, or where no food was located). All chimpanzees used the tool when they needed to use it to find the best possible item on that trial, but responded by choosing a location immediately when they did not need the tool. This finding highlights that their behavior was not the result of a simple rule following such as pointing to where any food had been seen.
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Affiliation(s)
- Bonnie M. Perdue
- Department of Psychology, Agnes Scott College, Decatur, Georgia, United States of America
- * E-mail:
| | - Theodore A. Evans
- Language Research Center, Georgia State University, Decatur, Georgia, United States of America
| | - Michael J. Beran
- Language Research Center, Georgia State University, Decatur, Georgia, United States of America
- Department of Psychology, Georgia State University, Atlanta, Georgia, United States of America
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27
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Dahlhaus R. Of Men and Mice: Modeling the Fragile X Syndrome. Front Mol Neurosci 2018; 11:41. [PMID: 29599705 PMCID: PMC5862809 DOI: 10.3389/fnmol.2018.00041] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/31/2018] [Indexed: 12/26/2022] Open
Abstract
The Fragile X Syndrome (FXS) is one of the most common forms of inherited intellectual disability in all human societies. Caused by the transcriptional silencing of a single gene, the fragile x mental retardation gene FMR1, FXS is characterized by a variety of symptoms, which range from mental disabilities to autism and epilepsy. More than 20 years ago, a first animal model was described, the Fmr1 knock-out mouse. Several other models have been developed since then, including conditional knock-out mice, knock-out rats, a zebrafish and a drosophila model. Using these model systems, various targets for potential pharmaceutical treatments have been identified and many treatments have been shown to be efficient in preclinical studies. However, all attempts to turn these findings into a therapy for patients have failed thus far. In this review, I will discuss underlying difficulties and address potential alternatives for our future research.
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Affiliation(s)
- Regina Dahlhaus
- Institute for Biochemistry, Emil-Fischer Centre, University of Erlangen-Nürnberg, Erlangen, Germany
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28
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Watanabe K, Funahashi S. Toward an understanding of the neural mechanisms underlying dual-task performance: Contribution of comparative approaches using animal models. Neurosci Biobehav Rev 2018; 84:12-28. [DOI: 10.1016/j.neubiorev.2017.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 08/09/2017] [Accepted: 08/11/2017] [Indexed: 10/19/2022]
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29
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Abstract
Source memory, or memory for the context in which a memory was formed, is a defining characteristic of human episodic memory and source memory errors are a debilitating symptom of memory dysfunction. Evidence for source memory in nonhuman primates is sparse despite considerable evidence for other types of sophisticated memory and the practical need for good models of episodic memory in nonhuman primates. A previous study showed that rhesus monkeys confused the identity of a monkey they saw with a monkey they heard, but only after an extended memory delay. This suggests that they initially remembered the source - visual or auditory - of the information but forgot the source as time passed. Here, we present a monkey model of source memory that is based on this previous study. In each trial, monkeys studied two images, one that they simply viewed and touched and the other that they classified as a bird, fish, flower, or person. In a subsequent memory test, they were required to select the image from one source but avoid the other. With training, monkeys learned to suppress responding to images from the to-be-avoided source. After longer memory intervals, monkeys continued to show reliable item memory, discriminating studied images from distractors, but made many source memory errors. Monkeys discriminated source based on study method, not study order, providing preliminary evidence that our manipulation of retention interval caused errors due to source forgetting instead of source confusion. Finally, some monkeys learned to select remembered images from either source on cue, showing that they did indeed remember both items and both sources. This paradigm potentially provides a new model to study a critical aspect of episodic memory in nonhuman primates.
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Affiliation(s)
- Benjamin M Basile
- Emory University and Yerkes National Primate Research Center, Atlanta, GA 30322, USA.
| | - Robert R Hampton
- Emory University and Yerkes National Primate Research Center, Atlanta, GA 30322, USA
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Hassett TC, Hampton RR. Change in the relative contributions of habit and working memory facilitates serial reversal learning expertise in rhesus monkeys. Anim Cogn 2017; 20:485-497. [PMID: 28185097 PMCID: PMC6413322 DOI: 10.1007/s10071-017-1076-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/18/2016] [Accepted: 01/30/2017] [Indexed: 11/27/2022]
Abstract
Functionally distinct memory systems likely evolved in response to incompatible demands placed on learning by distinct environmental conditions. Working memory appears adapted, in part, for conditions that change frequently, making rapid acquisition and brief retention of information appropriate. In contrast, habits form gradually over many experiences, adapting organisms to contingencies of reinforcement that are stable over relatively long intervals. Serial reversal learning provides an opportunity to simultaneously examine the processes involved in adapting to rapidly changing and relatively stable contingencies. In serial reversal learning, selecting one of the two simultaneously presented stimuli is positively reinforced, while selection of the other is not. After a preference for the positive stimulus develops, the contingencies of reinforcement reverse. Naïve subjects adapt to such reversals gradually, perseverating in selection of the previously rewarded stimulus. Experts reverse rapidly according to a win-stay, lose-shift response pattern. We assessed whether a change in the relative control of choice by habit and working memory accounts for the development of serial reversal learning expertise. Across three experiments, we applied manipulations intended to attenuate the contribution of working memory but leave the contribution of habit intact. We contrasted performance following long and short intervals in Experiments 1 and 2, and we interposed a competing cognitive load between trials in Experiment 3. These manipulations slowed the acquisition of reversals in expert subjects, but not naïve subjects, indicating that serial reversal learning expertise is facilitated by a shift in the control of choice from passively acquired habit to actively maintained working memory.
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Affiliation(s)
- Thomas C Hassett
- Department of Psychology, Yerkes National Primate Research Center, Emory University, 36 Eagle Row #270, Atlanta, GA, 30322, USA.
| | - Robert R Hampton
- Department of Psychology, Yerkes National Primate Research Center, Emory University, 36 Eagle Row #270, Atlanta, GA, 30322, USA
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Wittig JH, Morgan B, Masseau E, Richmond BJ. Humans and monkeys use different strategies to solve the same short-term memory tasks. ACTA ACUST UNITED AC 2016; 23:644-647. [PMID: 27918285 PMCID: PMC5066608 DOI: 10.1101/lm.041764.116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 05/08/2016] [Indexed: 12/03/2022]
Abstract
The neural mechanisms underlying human working memory are often inferred from studies using old-world monkeys. Humans use working memory to selectively memorize important information. We recently reported that monkeys do not seem to use selective memorization under experimental conditions that are common in monkey research, but less common in human research. Here we compare the performance of humans and monkeys under the same experimental conditions. Humans selectively remember important images whereas monkeys largely rely on recency information from nonselective memorization. Working memory studies in old-world monkeys must be interpreted cautiously when making inferences about the mechanisms underlying human working memory.
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Affiliation(s)
- John H Wittig
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-4415, USA
| | - Barak Morgan
- Global Risk Governance Program, Department of Public Law, University of Cape Town, Rondebosch 7701, South Africa.,DST-NRF Centre of Excellence in Human Development, DVC Research Office, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Evan Masseau
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-4415, USA
| | - Barry J Richmond
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-4415, USA
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Beran MJ, Menzel CR, Parrish AE, Perdue BM, Sayers K, Smith JD, Washburn DA. Primate cognition: attention, episodic memory, prospective memory, self-control, and metacognition as examples of cognitive control in nonhuman primates. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2016; 7:294-316. [PMID: 27284790 PMCID: PMC5173379 DOI: 10.1002/wcs.1397] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/21/2016] [Accepted: 04/28/2016] [Indexed: 11/09/2022]
Abstract
Primate Cognition is the study of cognitive processes, which represent internal mental processes involved in discriminations, decisions, and behaviors of humans and other primate species. Cognitive control involves executive and regulatory processes that allocate attention, manipulate and evaluate available information (and, when necessary, seek additional information), remember past experiences to plan future behaviors, and deal with distraction and impulsivity when they are threats to goal achievement. Areas of research that relate to cognitive control as it is assessed across species include executive attention, episodic memory, prospective memory, metacognition, and self-control. Executive attention refers to the ability to control what sensory stimuli one attends to and how one regulates responses to those stimuli, especially in cases of conflict. Episodic memory refers to memory for personally experienced, autobiographical events. Prospective memory refers to the formation and implementation of future-intended actions, such as remembering what needs to be done later. Metacognition consists of control and monitoring processes that allow individuals to assess what information they have and what information they still need, and then if necessary to seek information. Self-control is a regulatory process whereby individuals forego more immediate or easier to obtain rewards for more delayed or harder to obtain rewards that are objectively more valuable. The behavioral complexity shown by nonhuman primates when given tests to assess these capacities indicates psychological continuities with human cognitive control capacities. However, more research is needed to clarify the proper interpretation of these behaviors with regard to possible cognitive constructs that may underlie such behaviors. WIREs Cogn Sci 2016, 7:294-316. doi: 10.1002/wcs.1397 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Michael J Beran
- Department of Psychology, Georgia State University, Atlanta, GA, USA
| | - Charles R Menzel
- Language Research Center, Georgia State University, Atlanta, GA, USA
| | - Audrey E Parrish
- Department of Psychology, Georgia State University, Atlanta, GA, USA
| | - Bonnie M Perdue
- Department of Psychology, Agnes Scott College, Decatur, GA, USA
| | - Ken Sayers
- Language Research Center, Georgia State University, Atlanta, GA, USA
| | - J David Smith
- Department of Psychology, Georgia State University, Atlanta, GA, USA
| | - David A Washburn
- Department of Psychology, Georgia State University, Atlanta, GA, USA
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Gray DT, Smith AC, Burke SN, Gazzaley A, Barnes CA. Attentional updating and monitoring and affective shifting are impacted independently by aging in macaque monkeys. Behav Brain Res 2016; 322:329-338. [PMID: 27368416 DOI: 10.1016/j.bbr.2016.06.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/02/2016] [Accepted: 06/27/2016] [Indexed: 11/29/2022]
Abstract
One hallmark of the normal cognitive aging process involves alterations in executive function. Executive function can be divided into at least three separable components, including set shifting, attentional updating and monitoring, and inhibition of prepotent responses. The ability to study the neural basis of cognitive aging has been enriched by the use of animal models such as the macaque monkey. In aged macaques, changes in attentional updating and monitoring systems are poorly understood compared to changes in shifting and inhibition. A partial explanation for this is the fact that the tasks designed to study executive function in aged monkeys, to date, primarily have probed shifting and inhibition processes. Here we examine how aging impacts attentional updating and monitoring processes in monkeys using an interference task designed after a paradigm used to examine multi-tasking in older humans. Young and aged macaque monkeys were tested on this interference task as well as on an object reversal learning task to study these processes in the same animals. Relative to the young monkeys, aged animals were impaired on both tasks. Proactive and retroactive interference did not differ between age groups on an array of 40 object pairs presented each day in the object reversal learning task. The levels of performance on the interference task were not correlated with levels of performance in the object reversal task. These results suggest that attentional updating and monitoring and affective shifting are separable functions in the macaque, and that normal aging affects these mental operations independently.
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Affiliation(s)
- Daniel T Gray
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ 85724, USA; Division of Neural System, Memory & Aging, University of Arizona, Tucson, AZ 85724, USA
| | - Anne C Smith
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ 85724, USA
| | - Sara N Burke
- Evelyn F. McKnight Brain Institute, Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA
| | - Adam Gazzaley
- Department of Neurology and Psychiatry, University of California, San Francisco, CA 94158, USA
| | - Carol A Barnes
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ 85724, USA; Division of Neural System, Memory & Aging, University of Arizona, Tucson, AZ 85724, USA; Department of Psychology, Neurology and Neuroscience, University of Arizona, Tucson, AZ 85724, USA.
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Scott BH, Mishkin M. Auditory short-term memory in the primate auditory cortex. Brain Res 2016; 1640:264-77. [PMID: 26541581 PMCID: PMC4853305 DOI: 10.1016/j.brainres.2015.10.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/17/2015] [Accepted: 10/26/2015] [Indexed: 12/20/2022]
Abstract
Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory.
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Affiliation(s)
- Brian H Scott
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Mortimer Mishkin
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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A dual-task paradigm for behavioral and neurobiological studies in nonhuman primates. J Neurosci Methods 2015; 246:1-12. [PMID: 25769271 DOI: 10.1016/j.jneumeth.2015.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/26/2015] [Accepted: 03/03/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND The dual-task paradigm is a procedure in which subjects are asked to perform two behavioral tasks concurrently, each of which involves a distinct goal with a unique stimulus-response association. Due to the heavy demand on subject's cognitive abilities, human studies using this paradigm have provided detailed insights regarding how the components of cognitive systems are functionally organized and implemented. Although dual-task paradigms are widely used in human studies, they are seldom used in nonhuman animal studies. NEW METHOD We propose a novel dual-task paradigm for monkeys that requires the simultaneous performance of two cognitively demanding component tasks, each of which uses an independent effector for behavioral responses (hand and eyes). We provide a detailed description of an optimal training protocol for this paradigm, which has been lacking in the existing literature. RESULTS An analysis of behavioral performance showed that the proposed dual-task paradigm (1) was quickly learned by monkeys (less than 40 sessions) with step-by-step training protocols, (2) produced specific behavioral effects, known as dual-task interference in human studies, and (3) achieved rigid and independent control of the effectors for behavioral responses throughout the trial. COMPARISON WITH EXISTING METHODS The proposed dual-task paradigm has a scalable task structure, in that each of the two component tasks can be easily replaced by other tasks, while preserving the overall structure of the paradigm. CONCLUSIONS This paradigm should be useful for investigating executive control that underlies dual-task performance at both the behavioral and neuronal levels.
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Abstract
Episodic memories differ from other types of memory because they represent aspects of the past not present in other memories, such as the time, place, or social context in which the memories were formed. Focus on phenomenal experience in human memory, such as the sense of 'having been there', has resulted in conceptualizations of episodic memory that are difficult or impossible to apply to nonhuman species. It is therefore a significant challenge for investigators to agree on objective behavioral criteria that can be applied in nonhuman animals and still capture features of memory thought to be critical in humans. Some investigators have attempted to use neurobiological parallels to bridge this gap; however, defining memory types on the basis of the brain structures involved rather than on identified cognitive mechanisms risks missing crucial functional aspects of episodic memory, which are ultimately behavioral. The most productive way forward is likely a combination of neurobiology and sophisticated cognitive testing that identifies the mental representations present in episodic memory. Investigators that have refined their approach from asking the naïve question "do nonhuman animals have episodic memory" to instead asking "what aspects of episodic memory are shared by humans and nonhumans" are making progress.
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Affiliation(s)
- Victoria L Templer
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, USA.
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Automated cognitive testing of monkeys in social groups yields results comparable to individual laboratory-based testing. Anim Cogn 2012; 16:445-58. [PMID: 23263675 DOI: 10.1007/s10071-012-0585-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 11/26/2012] [Accepted: 11/30/2012] [Indexed: 10/27/2022]
Abstract
Cognitive abilities likely evolved in response to specific environmental and social challenges and are therefore expected to be specialized for the life history of each species. Specialized cognitive abilities may be most readily engaged under conditions that approximate the natural environment of the species being studied. While naturalistic environments might therefore have advantages over laboratory settings for cognitive research, it is difficult to conduct certain types of cognitive tests in these settings. We implemented methods for automated cognitive testing of monkeys (Macaca mulatta) in large social groups (Field station) and compared the performance to that of laboratory-housed monkeys (Laboratory). The Field station animals shared access to four touch-screen computers in a large naturalistic social group. Each Field station subject had an RFID chip implanted in each arm for computerized identification and individualized assignment of cognitive tests. The Laboratory group was housed and tested in a typical laboratory setting, with individual access to testing computers in their home cages. Monkeys in both groups voluntarily participated at their own pace for food rewards. We evaluated performance in two visual psychophysics tests, a perceptual classification test, a transitive inference test, and a delayed matching-to-sample memory test. Despite the differences in housing, social environment, age, and sex, monkeys in the two groups performed similarly in all tests. Semi-free ranging monkeys living in complex social environments are therefore viable subjects for cognitive testing designed to take advantage of the unique affordances of naturalistic testing environments.
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