Deficits in Long-Term Recognition Memory Reveal Dissociated Subtypes in Congenital Prosopagnosia

The study investigates long-term recognition memory in congenital prosopagnosia (CP), a lifelong impairment in face identification that is present from birth. Previous investigations of processing deficits in CP have mostly relied on short-term recognition tests to estimate the scope and severity of individual deficits. We firstly report on a controlled test of long-term (one year) recognition memory for faces and objects conducted with a large group of participants with CP. Long-term recognition memory is significantly impaired in eight CP participants (CPs). In all but one case, this deficit was selective to faces and didn't extend to intra-class recognition of object stimuli. In a test of famous face recognition, long-term recognition deficits were less pronounced, even after accounting for differences in media consumption between controls and CPs. Secondly, we combined test results on long-term and short-term recognition of faces and objects, and found a large heterogeneity in severity and scope of individual deficits. Analysis of the observed heterogeneity revealed a dissociation of CP into subtypes with a homogeneous phenotypical profile. Thirdly, we found that among CPs self-assessment of real-life difficulties, based on a standardized questionnaire, and experimentally assessed face recognition deficits are strongly correlated. Our results demonstrate that controlled tests of long-term recognition memory are needed to fully assess face recognition deficits in CP. Based on controlled and comprehensive experimental testing, CP can be dissociated into subtypes with a homogeneous phenotypical profile. The CP subtypes identified align with those found in prosopagnosia caused by cortical lesions; they can be interpreted with respect to a hierarchical neural system for face perception

Keep it real: rethinking the primacy of experimental control in cognitive neuroscience

Naturalistic experimental paradigms in neuroimaging arose from a pressure to test the validity of models we derive from highly-controlled experiments in real-world contexts. In many cases, however, such efforts led to the realization that models developed under particular experimental manipulations failed to capture much variance outside the context of that manipulation. The critique of non-naturalistic experiments is not a recent development; it echoes a persistent and subversive thread in the history of modern psychology. The brain has evolved to guide behavior in a multidimensional world with many interacting variables. The assumption that artificially decoupling and manipulating these variables will lead to a satisfactory understanding of the brain may be untenable. We develop an argument for the primacy of naturalistic paradigms, and point to recent developments in machine learning as an example of the transformative power of relinquishing control. Naturalistic paradigms should not be deployed as an afterthought if we hope to build models of brain and behavior that extend beyond the laboratory into the real world

Topical photodynamic therapy with methylaminolevulinate for the treatment of actinic keratosis and reduction of photodamage in organ transplant recipients: A case-series of 16 patients

Background: Organ transplant recipients (OTR) are at high risk of developing cutaneous neoplasms. Topical photodynamic therapy (PDT) has been used for the treatment of actinic keratosis (AK) in OTR. Aims: The objective was to evaluate the efficacy of PDT with methylaminolevulinate (MAL) in the treatment of facial AK in OTR. As a secondary objective, we wanted to evaluate the usefulness of topical PDT in the reduction of photodamage in OTR. Methods: A prospective, single center, single arm study was made. 16 OTR were included. Topical PDT was applied for 1 or 2 cycles depending on the patient′s characteristics. An evaluation of AK was made at visits pre-treatment, at 12 weeks and at 24 weeks. Photodamage was measured with multispectral image technique (SkinCare®). Results: A complete response rate of 100% was achieved for AK in all patients; it persisted without change at 12 and 24 weeks of follow-up. 62.5% of patients improved their photodamage as measured by SkinCare®, but this result was not statistically significant (P = 0.12). All patients had high level of satisfaction at the end of the therapy. Conclusions: MAL-PDT is an effective therapy for the treatment of AK in OTRs. It can reduce photodamage in this group of patients, but these results were not statistically significant

Event Segmentation In Story Listening Using Deep Language Models

Event segmentation theory posits that we segment continuous experience into discrete events and event boundaries occur at large transient increases in prediction error, often related to context changes. Identifying event boundaries a priori has been difficult in naturalistic settings. To overcome this challenge for story listening, we used a deep learning language model (GPT2) to compute the predicted probability distributions of the next word, at each point in the story. For 3 stories, we computed the surprise, the entropy, and the Kullback-Leibler divergence (KLD). We then asked participants to listen to these stories while marking event boundaries. We used regression models to compare the GPT2 measures and the human segmentation data. Preliminary results indicate that event boundaries are associated with transient increases in KLD. This supports the hypothesis that prediction error serves as a control mechanism governing event segmentation, and points to important differences between operational definitions of prediction error