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The two cortical visual pathways framework has had a profound influence on theories and empirical studies of the visual system for over 40 years. By grounding physiological responses and behavior in neuroanatomy, the framework provided a critical guide for understanding vision. Although the framework has evolved over time, as our understanding of the physiology and neuroanatomy expanded, cortical visual processing is still often conceptualized as two separate pathways emerging from the primary visual cortex that support distinct behaviors ("what" vs. "where/how"). Here, we take a historical perspective and review the continuing evolution of the framework, discussing key and often overlooked insights. Rather than a functional and neuroanatomical bifurcation into two independent serial, hierarchical pathways, the current evidence points to two highly recurrent heterarchies with heterogeneous connections to cortical regions and subcortical structures that flexibly support a wide variety of behaviors. Although many of the simplifying assumptions of the framework are belied by the evidence gathered since its initial proposal, the core insight of grounding function and behavior in neuroanatomy remains fundamental. Given this perspective, we highlight critical open questions and the need for a better understanding of neuroanatomy, particularly in the human., (© 2024 Massachusetts Institute of Technology.)

Importance: The drug overdose crisis is a continuing public health problem and is expected to grow substantially in older adults. Understanding the geographic accessibility to a substance use disorder (SUD) treatment facility that accepts Medicare can inform efforts to address this crisis in older adults., Objective: To assess whether geographic accessibility of services was limited for older adults despite the increasing need for SUD and opioid use disorder treatments in this population., Design, Setting, and Participants: This longitudinal cross-sectional study obtained data on all licensed SUD treatment facilities for all US counties and Census tracts listed in the National Directory of Drug and Alcohol Abuse Treatment Programs from 2010 to 2021., Main Outcomes and Measures: Measures included the national proportion of treatment facilities accepting Medicare, Medicaid, private insurance, or cash as a form of payment; the proportion of counties with a treatment facility accepting each form of payment; and the proportion of the national population with Medicare, Medicaid, private insurance, or cash payment residing within a 15-, 30-, or 60-minute driving time from an SUD treatment facility accepting their form of payment in 2021., Results: A total of 11 709 SUD treatment facilities operated across the US per year between 2010 and 2021 (140 507 facility-year observations). Cash was the most commonly accepted form of payment (increasing slightly from 91.0% in 2010 to 91.6% by 2021), followed by private insurance (increasing from 63.5% to 75.3%), Medicaid (increasing from 54.0% to 71.8%), and Medicare (increasing from 32.1% to 41.9%). The proportion of counties with a treatment facility that accepted Medicare as a form of payment also increased over the same study period from 41.2% to 53.8%, whereas the proportion of counties with a facility that accepted Medicaid as a form of payment increased from 53.5% to 67.1%. The proportion of Medicare beneficiaries with a treatment facility that accepted Medicare as a form of payment within a 15-minute driving time increased from 53.3% to 57.0%. The proportion of individuals with a treatment facility within a 15-minute driving time that accepted their respective form of payment was 73.2% for those with Medicaid, 69.8% for those with private insurance, and 71.4% for those with cash payment in 2021., Conclusions and Relevance: Results of this study suggest that Medicare beneficiaries have less geographic accessibility to SUD treatment facilities given that acceptance of Medicare is low compared with other forms of payment. Policy makers need to consider increasing reimbursement rates and using additional incentives to encourage the acceptance of Medicare.

We use mobile device data to construct empirical interpersonal physical contact networks in the city of Portland, Oregon, both before and after social distancing measures were enacted during the COVID-19 pandemic. These networks reveal how social distancing measures and the public's reaction to the incipient pandemic affected the connectivity patterns within the city. We find that as the pandemic developed there was a substantial decrease in the number of individuals with many contacts. We further study the impact of these different network topologies on the spread of COVID-19 by simulating an SEIR epidemic model over these networks and find that the reduced connectivity greatly suppressed the epidemic. We then investigate how the epidemic responds when part of the population is vaccinated, and we compare two vaccination distribution strategies, both with and without social distancing. Our main result is that the heavy-tailed degree distribution of the contact networks causes a targeted vaccination strategy that prioritizes high-contact individuals to reduce the number of cases far more effectively than a strategy that vaccinates individuals at random. Combining both targeted vaccination and social distancing leads to the greatest reduction in cases, and we also find that the marginal benefit of a targeted strategy as compared to a random strategy exceeds the marginal benefit of social distancing for reducing the number of cases. These results have important implications for ongoing vaccine distribution efforts worldwide., (© The authors 2021. Published by Oxford University Press. All rights reserved.)

Objective: To describe weekly changes in the number of substance use disorder treatment (SUDT) facility visits in 2020 compared to 2019 using cell phone location data., Methods: We calculated the percentage weekly change in visits to SUDT facilities from the week of January 5 through the week of October 11, 2020, relative to the week of January 6 through the week of October 13, 2019. We stratified facilities by county COVID-19 incidence per 10,000 residents in each week and by 2018 fatal drug overdose rate. Finally, we conducted a multivariable linear regression analysis examining percent change in visits per week as a function of county-level COVID-19 tercile, a series of calendar month indicators, and the interaction of county-level COVID-19 tercile and month. We repeated the regression analysis replacing COVID-19 tercile with overdose tercile., Results: Beginning the eleventh week of 2020, the number of visits to SUDT facilities declined substantially, reaching a nadir of 48% of 2019 visits in early July. In contrast to January, there were significantly fewer visits in 2020 compared to 2019 in all subsequent months (p < 0.01 in all months). Multivariable regression results found that facilities in the tercile of counties experiencing the most COVID-19 cases had a significantly greater reduction in the number of SUDT visits in 2020 for the months of June through August than facilities in counties with the fewest COVID-19 rates (p < 0.05). The study found no statistically significant difference in the change in the number of visits by facilities in counties with historically different overdose rates., Discussion: Our findings support the hypothesis that a reduction has occurred in the average weekly number of visits to SUDT facilities. The size of the effect differs based on the number of COVID-19 cases but not on historical overdose rate., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Previous studies demonstrated that a region in the left fusiform gyrus, often referred to as the 'visual word form area' (VWFA), is responsive to written words, but the precise functional role of VWFA remains unclear. In the present study, we investigated the influence of orthographic similarity, and lexical factors on the multivoxel response patterns to written stimuli. Using high-resolution fMRI at 7 T, we compared the organization of visual word representations in VWFA to the organization in early visual cortex and a language region in the superior temporal gyrus. Sets of four letter words and pseudowords were presented, in which orthographic similarity was parametrically manipulated. We found that during a lexical decision task VWFA is responsive to the lexical status of a stimulus, but both real words and pseudowords were further processed in terms of orthographic similarity. In contrast, early visual cortex was only responsive to the visual aspects of the stimuli and in the left superior temporal gyrus there was an interaction between lexical status and orthography such that only real words were processed in terms of orthographic similarity. These findings indicate that VWFA represents the word/non-word status of letter strings as well as their orthographic similarity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Real-world expertise provides a valuable opportunity to understand how experience shapes human behavior and neural function. In the visual domain, the study of expert object recognition, such as in car enthusiasts or bird watchers, has produced a large, growing, and often-controversial literature. Here, we synthesize this literature, focusing primarily on results from functional brain imaging, and propose an interactive framework that incorporates the impact of high-level factors, such as attention and conceptual knowledge, in supporting expertise. This framework contrasts with the perceptual view of object expertise that has concentrated largely on stimulus-driven processing in visual cortex. One prominent version of this perceptual account has almost exclusively focused on the relation of expertise to face processing and, in terms of the neural substrates, has centered on face-selective cortical regions such as the Fusiform Face Area (FFA). We discuss the limitations of this face-centric approach as well as the more general perceptual view, and highlight that expert related activity is: (i) found throughout visual cortex, not just FFA, with a strong relationship between neural response and behavioral expertise even in the earliest stages of visual processing, (ii) found outside visual cortex in areas such as parietal and prefrontal cortices, and (iii) modulated by the attentional engagement of the observer suggesting that it is neither automatic nor driven solely by stimulus properties. These findings strongly support a framework in which object expertise emerges from extensive interactions within and between the visual system and other cognitive systems, resulting in widespread, distributed patterns of expertise-related activity across the entire cortex.