Biology subjects

Sclar, M.

Publications and source records attributed to Sclar, M..

3 recordsLinked to original sources

bioRxiv2025

Uncertainty during visual search: Insights from a computational model and behavioral experiment in natural stimuli

Visual search, driven by bottom-up and top-down processes, offers a unique framework for investigating decision-making. This study examines individuals awareness of their own visual search by combining computational modeling with behavioral experiments. Fifty-seven participants performed a classical visual search task in which the goal was to find an object in a natural scene. Crucially, in some trials, the search was interrupted by clearing the screen before the gaze reached the target object. Participants had to report their best guess of the targets location and the uncertainty on their response. We show that a modified version of the Entropy-Limit Minimization (ELM) model captures scanpaths and perceived target locations, while also revealing that uncertainty is influenced by scanpath length, the distance between the perceived and true target location, and the entropy of decision maps. These findings highlight the models capacity to reflect cognitive processes underlying response selection and uncertainty judgment.

neuroscience↗

bioRxiv2024

Social Isolation During Adolescence Differentially Affects Spatial Learning in Adult Male and Female Mice

Social isolation is a risk factor for cognitive impairment. Adolescents may be particularly vulnerable to these effects, because they are in a critical period of development marked by significant physical, hormonal, and social changes. However, it is unclear if the effects of social isolation on learning and memory are similar in both sexes or if they persist into adulthood after a period of recovery. We socially isolated male and female 129Sv/Ev mice throughout adolescence (post-natal days 29-56), provided a 2-week re-socialization recovery period, and then tested spatial learning and cognitive flexibility in the active place avoidance task. After behavioral testing, mice were injected with 5-bromo-2-deoxyuridine (BrdU) so that lasting effects of social isolation on cell proliferation in the dentate gyrus could be examined. We found that in males, isolation led to a modest impairment in the rate of initial spatial learning, whereas in females, initial learning was unaffected. However, when the location of the shock zone was switched during the conflict variant of the task, cognitive flexibility was impaired in females only. Similarly, social isolation reduced cell proliferation in the ventral dentate gyrus only in females. Together, these findings indicate that social isolation during adolescence differentially impairs spatial processing in males and females, with effects that persist into adulthood.

neuroscience↗

bioRxiv2024

Infralimbic projections to the basal forebrain mediate extinction learning

Fear extinction learning and retrieval are critical for decreasing fear responses to a stimulus that no longer poses a threat. While it is known that the infralimbic region (IL) of the medial prefrontal cortex mediates retrieval of an extinction memory through projections to the basolateral amygdala (BLA), the contribution of the IL to extinction learning is not well-understood. Given the strong projection from the IL to the basal forebrain (BF), a center of attentional processing, we investigated whether this pathway participates in extinction, and compared it to the IL-BLA pathway. Using retrograde tracing, we first demonstrate that projections from the IL to the BF originate from superficial (L2/3) and deep cortical layers (L5), and that they are denser than IL projections to the BLA. Next, combining retrograde tracing with labeling of the immediate early gene cFos, we show increased activity of the L5 IL-BF pathway during extinction learning and increased activity of the L2/3 IL-BLA pathway during extinction retrieval. Our in vitro recordings demonstrate that neurons in the IL-BF pathway become more excitable towards the end of extinction learning, but less excitable during extinction retrieval. Finally, using optogenetics we show that inactivation of the IL-BF pathway impairs extinction learning, leaving retrieval intact. We propose that the IL acts as a switchboard operator during extinction, with increased L5 IL-BF communication during learning and increased L2/3 IL-BLA communication during retrieval. Anxiety and stress-related changes in IL physiology could affect one or multiple lines of communication, impairing different aspects of extinction. Significance StatementExtinction of conditioned fear is a widely used behavioral approach to diminish fear, with projections from infralimbic prefrontal cortex to the amygdala known for mediating extinction memory retrieval. However, less is known about infralimbic pathways involved in extinction learning. We use neuroanatomical tracing, behavior, slice recordings, and circuit manipulation to show that infralimbic output to the basal forebrain, an attention processing center, is denser than to the amygdala, and is active during extinction learning rather than retrieval. Neurons in the infralimbic-basal forebrain pathway become more excitable as extinction learning progresses, and then less excitable during extinction retrieval. Moreover, inhibiting this pathway impairs extinction learning. Our findings identify different lines of communication the infralimbic cortex uses for extinction learning and retrieval.

neuroscience↗