Perceptual-Cognitive Training Paradigms for Understanding Cognition and Cortical Visual Impairments

Authors: Ashim Pandey, Dipesh Shrestha and Sujaya Neupane

Abstract

Brain plasticity and behavioral compensation after neurological injury offer promising clinical potential for targeted functional neurorehabilitation. An active area of research in neurorehabilitation is vision restoration via perceptual learning. Despite exciting success stories, vision rehabilitation strategies have faced limitations of achieving longevity and generalization beyond the training parameters. In this chapter, we propose that perceptual learning involves more than just sensory brain regions, suggesting that the search for neural mechanisms of visual learning should expand beyond the visual system. We hypothesize that engaging cognitive circuits with a navigation paradigm that involves visual encoding promotes plasticity in the visual system, a key input to the brain’s navigation networks. Under this hypothesis, we propose an integrated approach for neurorehabilitation where perceptual and cognitive systems are dynamically interacting. Furthermore, we argue that studying cognitive functions in the context of navigation necessitates controlled omission of sensory input in experimental paradigms, and such studies have implications for designing effective rehabilitative training for patients with cortical blindness. We review animal studies on the neural mechanisms of navigation without sensory input, focusing on the hippocampal formation and posterior parietal cortex-brain regions thought to subserve spatial navigation. Finally, we explore potential perceptual-cognitive training tasks for vision restoration and their hypothetical neural mechanisms to address the limitations of existing vision training paradigms. Overall, we identify a promising research direction for developing innovative tools to rehabilitate visual function in individuals with cortical blindness.

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Developing Science Research by Recognizing the Human Capacity for Inquiry

Authors: Sujaya Neupane, Ashim Pandey, Suraj Prasai, Dipesh Shrestha and Sunisha Neupane

Amid the anxiety of evolving coronavirus variants, the discovery of the Omicron variant of COVID-19 in South Africa was interpreted as it having originated there, resulting in immediate travel bans imposed on South African nations, only to be realized soon after that Omicron was already present around the world (Lencucha and Neupane, 2022). Such a policy reaction, one might argue, is the result of epistemic hierarchy in scientific knowledge production. Conversations with scientists, however, reveal their awareness of epistemic injustices and their desire to not only understand the world but also to improve it, often with innovative methodologies (Sinha, 2016; Quirk, 2019). Why is there incoherency in our micro-level thoughts and macro-level policies?

A testament to the growing concern of scientists to build a more just society is apparent in the increasing effort of science departments trying to improve diversity and inclusion in training and recruitment. Yet the places that would most benefit from science still have limited access to research and training. Despite technological progress, with extreme poverty at a steady decline (World Bank, 2022), the freedom to inquire and the means to exercise the richness of human potential remain highly unequal. Why is this the case and how can scientists play an active role in the betterment of the world?

As there is no singular diagnosis or a prescription for society's ills, so complex in nature, multiple approaches and their corresponding stories of successes and failures must be taken into account with an attitude of learning so that we can make collective progress that benefits all. In this spirit, we share our experience of an ongoing effort to develop neuroscience research infrastructure in Kathmandu, Nepal and reflect on our assumptions and outcomes.

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Cortical visual impairment at birth can be improved rapidly by vision training in adulthood: A case study

Authors: Ashim Pandeya, Sujaya Neupane, Srijana Adhikary, Keepa Vaidya, and Christopher C. Pack

Background: Cortical visual impairment (CVI) is a severe loss of visual function caused by damage to the visual cortex or its afferents, often as a consequence of hypoxic insults during birth. It is one of the leading causes of vision loss in children, and it is most often permanent.

Objective: Several studies have demonstrated limited vision restoration in adults who trained on well-controlled psychophysical tasks, after acquiring CVI late in life. Other studies have shown improvements in children who underwent vision training. However, little is known about the prospects for the large number of patients who acquired CVI at birth but received no formal therapy as children.

Methods: We, therefore, conducted a proof-of-principle study in one CVI patient long after the onset of cortical damage (age 18), to test the training speed, efficacy and generalizability of vision rehabilitation using protocols that had previously proven successful in adults. The patient trained at home and in the laboratory, on a psychophysical task that required discrimination of complex motion stimuli presented in the blind field. Visual function was assessed before and after training, using perimetric measures, as well as a battery of psychophysical tests.

Results: The patient showed remarkably rapid improvements on the training task, with performance going from chance to 80% correct over the span of 11 sessions. With further training, improved vision was found for untrained stimuli and for perimetric measures of visual sensitivity. Some, but not all, of these performance gains were retained upon retesting after one year.

Conclusions: These results suggest that existing vision rehabilitation programs can be highly effective in adult patients who acquired CVI at a young age. Validation with a large sample size is critical, and future work should also focus on improving the usability and accessibility of these programs for younger patients.

Keywords: Cortical visual impairment, visual rehabilitation, motion perception training.

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The use, misuse and overuse of the ‘low-income and middle-income countries’ category

Authors: Raphael Lenchucha, Sujaya Neupane

The use of low/middle-income countries (LMIC) has become so pervasive and normalised across disciplines that its use is rarely questioned. The income classification is assigned to countries by the World Bank based on the countries’ Gross National Income. The most recent (2022) categories range from US$1045 or less for low-income countries to an upper range of US$4096–US$12 695 for upper-middle-income countries.1 The latest classification positions 137 countries in the LMIC categories, representing 63% of countries in the world. The use of such a broad classification in global health scholarship requires consideration both in terms of its utility and its implications in perpetuating divisions and separation between countries that are not warranted and fostering ‘otherness’. The latter point is part of the broader project of critically examining how asymmetries are maintained in the domain of global health.2

The ubiquitous use of LMIC as a category across disciplines suggests that this category is seen to represent something meaningful when seeking to understand phenomena. Whether it is agricultural practices, population nutrition, healthcare services or some other domain of concern, this category is often used beyond its narrow association with national income. The use of this category can serve to implicitly reify and naturalise differences across country categories (ie, between high-income countries (HIC) and LMIC). When the category is used in global scholarship without proper justification it can serve to extend legacies of racism, imperialism, colonialism and a general othering or ‘foreign gaze’.3 In this article, we suggest that an unreflexive reliance on income classifications can serve both to obscure and divide. As Memmi wrote, ‘The colonialist stresses those things which keep him separate, rather than emphasizing that which might contribute to the foundation of a joint community’.4

The absence of a critical approach to the use of income categories persists despite findings that suggest income classification is often of limited value when studying phenomena. For example, in an introduction to a journal supplement on health economic evaluation in countries around the world, Briggs and Nugent make the powerful observation that

"what is clear from the collection of papers in this supplement, and the collective experience of authors across many countries, is that the differences between health economic evaluation in LMIC and those in higher income countries (HIC) are chiefly down to the context … the conceptual differences between LMIC and HIC are relatively few."

There are many examples illustrating that the crude usage of LMIC as a lens to understand phenomena often serves to position innovation, knowledge, practices and other important social goods as the products of ‘HIC’, serving to marginalise or silence the contributions of those in LMICs.

Here, we suggest that using the category LMIC to reflect something static, homogenous and ultimately ‘real’ has important (and often negative) implications for research, policy, programming and how we view others. In this paper, we suggest a need to critically examine the pervasive use of this category in global scholarship. We explore the implications of its use and suggest a way forward that emphasises targeted categorisation in global scholarship.

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