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ABSTRACT In the present study, we examined the role of the medial temporal lobe (MTL) in prospective time estimation at short and long timescales using a novel behavioral paradigm adapted from rodent work. Amnesic patients with MTL damage and healthy control participants estimated the duration of nature-based video clips that were either short (≤90 s) or long (more than 4 min). Consistent with previous work in rodents, we found that amnesic patients were impaired at making estimations for long, but not for short durations. Critically, these effects were observed in patients who had lesions circumscribed to the hippocampus, suggesting that the pattern observed was not attributable to the involvement of extra-hippocampal structures. That the MTL, and more specifically the hippocampus, is critical for prospective temporal estimation only at long intervals suggests that multiple neurobiological mechanisms support prospective time estimation. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The effect of lexical status on the time course of repetition priming was examined in an auditory lexical decision task. Words and nonwords were repeated at lags of 0, 1, 4, and 8 items (Experiment 1A) and 0, 2, 4, and 8 items (Experiment 1B). The pattern of repetition effects differed for words and nonwords in that repetition priming for nonwords at lag 0 was significantly greater than for words. The magnitude of this effect decreased when one or more items intervened. A second experiment, replicating Experiment 1A with visual presentation, clarified that the greater magnitude of repetition priming for nonwords at lag 0 is unique to the auditory modality. This finding suggests that in the course of forming a stable perceptual representation, the details of the acoustic/phonological information of an auditory stimulus are more readily available for nonwords than for words. The capacity to carry this phonological information is limited, however, and can only be maintained until another stimulus is encountered. [ABSTRACT FROM AUTHOR]

The current study sought to examine whether lifetime PTSD symptom severity is associated with a bias toward sampling extreme negative events from memory when making decisions involving uncertainty. To this end, 40 trauma-exposed warzone veterans performed a decision task in which information about outcomes was learned through experience and making choices required sampling memories of past experiences. On each trial, participants made choices between certain and uncertain gains and between certain and uncertain losses. Uncertain outcomes were equally likely to yield a relatively positive or relatively negative outcome. After accounting for overall willingness to take risks, lifetime PTSD symptom severity was associated with less frequent choice of the uncertain option for gains and for losses, a pattern consistent with a memory sampling bias for all negative experiences rather than only extreme negative experiences. The overweighting of negative experiences as a function of lifetime PTSD symptom severity, however, was not observed in a subsequent explicit memory task in which participants estimated the frequency with which different outcomes had occurred during the decision task. These findings suggest that the memory mechanism responsible for the PTSD-associated memory bias in decision making is distinct from that mediating explicit memory performance., Competing Interests: Declaration of Competing Interest We have no known conflicts of interest to disclose., (Published by Elsevier Ltd.)

Background and Objectives: Despite documented alterations in future thinking in posttraumatic stress disorder (PTSD), our understanding of how individuals with PTSD make future-oriented decisions is limited. We tested the hypothesis that increased discounting in association with PTSD reflects failure to spontaneously envision future rewarding situations., Methods: Thirty-seven trauma exposed war-zone veterans completed a standard temporal discounting task as well as a temporal discounting task accompanied by episodic future thinking cues., Results: Severity of PTSD symptoms was associated with preference for sooner, smaller rewards in the standard task. Consistent with our hypothesis, when participants engaged in future thinking, greater PTSD symptom severity was no longer associated with steeper discounting. Moreover, difficulty anticipating future events, as measured contemporaneously in a separate task (Verfaellie et al., 2024), mediated the relationship between PTSD symptom severity and degree of discounting in the standard task. Among PTSD symptom clusters, the severity of avoidance and negative alterations in cognition and mood was related to steeper discounting. Measures of depression and alcohol use were not associated with discounting., Limitations: The sample included mostly male, predominantly White veterans who experienced primarily combat-related trauma., Conclusions: PTSD-associated alterations in temporal discounting reflect failure to spontaneously imagine future positive events. Two common correlates of PTSD, depression and alcohol use, could not account for the observed associations between PTSD and future-oriented decisions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Face recognition is a highly developed and specialised human ability, distinct from other cognitive abilities. Previous studies examining individual differences in face recognition have focused on face perception and specialised perceptual mechanisms such as holistic face processing. However, the contribution of specific face memory processes to face recognition ability remains unclear. In 99 neurotypical individuals, we administered validated face perception assessments, three face memory tasks (old/new task, face-scene task, face-name/occupation task), and the Cambridge Face Memory Test (CFMT) to assess face recognition ability. We found that after accounting for face perception ability (which significantly predicted face recognition ability), face-name recall and recollection of faces in the face-scene task predicted unique variance in face recognition ability, with face-name recall being the strongest predictor. This highlights that associative memory mechanisms contribute to face recognition abilities and suggests that the ability to learn and recall proper names is particularly important to face recognition., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Previous studies have found that face perception deficits do not fully account for the severity of face recognition deficits in developmental prosopagnosia (DP). Researchers have begun identifying deficient memory mechanisms such as impaired face recollection, but these findings require replication, and further characterization of additional memory deficits is necessary. Our goals were to replicate prior findings of face recollection impairment in DP and extend these findings to assess different types of face associative memory. We had 69 DPs and 99 controls perform a face perception battery as well as three face memory tasks: 1) Old/New task with confidence ratings to calculate recollection and familiarity using ROC analysis, 2) Face/Scene task to examine remember-know judgments and contextual memory for faces, and 3) Face-Name/Occupation task to assess the ability to learn semantic associations with faces. Compared to controls, DPs showed poorer recollection and familiarity across both Old/New and Face/Scene tasks as well as reduced scene accuracy for correct faces. Of these differences, only Old/New recollection remained significant after controlling for group differences in face perception abilities. In the Face-Name/Occupation task, after controlling for face perception, DPs showed poorer recall of names than controls but performed similarly in recalling occupations. Finally, we found that DPs with major, mild, and no face perception deficits showed consistent impairments in Old/New recollection and face-naming, and larger perceptual deficits were associated with larger memory deficits. Together, these results provide several mechanistic insights into the nature of memory deficits in DPs and have diagnostic and treatment implications., (Published by Elsevier Ltd.)

When considering future outcomes, humans tend to discount gains more than losses. This phenomenon, referred to as the temporal discounting sign effect, is thought to result from the greater anticipated emotional impact of waiting for a negative outcome (dread) compared to waiting for a positive outcome (mixture of savoring and impatience). The impact of such anticipatory emotions has been proposed to rely on episodic future thinking. We evaluated this proposal by examining the presence and magnitude of a sign effect in the intertemporal decisions of individuals with hippocampal amnesia, who are severely impaired in their ability to engage in episodic mental simulation, and by comparing their patterns of choices to those of healthy controls. We also measured loss aversion, the tendency to assign greater value to losses compared to equivalent gains, to verify that any reduction in the sign effect in the hippocampal lesion group could not be explained by a group difference in loss aversion. Results showed that participants with hippocampal amnesia exhibited a sign effect, with less discounting of monetary losses compared to gains, that was similar in magnitude to that of controls. Loss aversion, albeit greater in the hippocampal compared to the control group, did not account for the sign effect. These results indicate that the sign effect does not depend on the integrity of hippocampally mediated episodic processes. They suggest instead that the impact of anticipatory emotions can be factored into decisions via semantic future thinking, drawing on non-contextual knowledge about oneself., (Published by Elsevier Ltd.)

Research on the role of the hippocampus in memory acquisition has generally focused on active learning. But to understand memory, it is at least as important to understand processes that happen offline, during both wake and sleep. In a study of patients with amnesia, we previously demonstrated that although a functional hippocampus is not necessary for the acquisition of procedural motor memory during training session, it is required for its offline consolidation during sleep. Here, we investigated whether an intact hippocampus is also required for the offline consolidation of procedural motor memory while awake. Patients with amnesia due to hippocampal damage ( n  = 4, all male) and demographically matched controls ( n  = 10, 8 males) trained on the finger tapping motor sequence task. Learning was measured as gains in typing speed and was divided into online (during task execution) and offline (during interleaved 30 s breaks) components. Amnesic patients and controls showed comparable total learning, but differed in the pattern of performance improvement. Unlike younger adults, who gain speed across breaks, both groups gained speed only while typing. Only controls retained these gains over the breaks; amnesic patients slowed down and compensated for these losses during subsequent typing. In summary, unlike their peers, whose motor performance remained stable across brief breaks in typing, amnesic patients showed evidence of impaired access to motor procedural memory. We conclude that in addition to being necessary for the offline consolidation of motor memories during sleep, the hippocampus maintains access to motor memory across brief offline periods during wake., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 the authors.)