Vision for action: thalamic and cortical inputs to the macaque superior parietal lobule

The dorsal visual stream, the cortical circuit that in the primate brain is mainly dedicated to the visual control of actions, is split into two routes, a lateral and a medial one, both involved in coding different aspects of sensorimotor control of actions. The lateral route, named “lateral grasping network”, is mainly involved in the control of the distal part of prehension, namely grasping and manipulation. The medial route, named “reach-to-grasp network”, is involved in the control of the full deployment of prehension act, from the direction of arm movement to the shaping of the hand according to the object to be grasped. In macaque monkeys, the reach-to-grasp network (the target of this review) includes areas of the superior parietal lobule (SPL) that hosts visual and somatosensory neurons well suited to control goal-directed limb movements toward stationary as well as moving objects. After a brief summary of the neuronal functional properties of these areas, we will analyze their cortical and thalamic inputs thanks to retrograde neuronal tracers separately injected into the SPL areas V6, V6A, PEc, and PE. These areas receive visual and somatosensory information distributed in a caudorostral, visuosomatic trend, and some of them are directly connected with the dorsal premotor cortex. This review is particularly focused on the origin and type of visual information reaching the SPL, and on the functional role this information can play in guiding limb interaction with objects in structured and dynamic environments.

Transformation: Toward a People’s Democracy

Transformation: Toward a People’s Democracy is a movement book for anyone working for an expansive vision of social justice. Here Suzanne Pharr offers a clear and compelling vision for action amid social and political turmoil. Drawing on decades of work on the frontlines of social movements, Pharr’s writings create a real-time chronicle of on-the-ground organizing and the historical significance of struggles for freedom and democracy. Pharr, a Southern queer feminist and anti-racist organizer, explores the pitfalls and the strengths within social justice movements. Her writings reflect the interchange of ideas and the collective work of thinkers and organizers who led activists to lift up the liberation of gender and sexuality, to fight both domestic and state violence, to advance anti-racist strategies and the leadership of people of color, to work against the advancement of rapacious capitalism, and to confront the rise of the Right in all of its forms. Transformation examines not just what happened but how it happened in the battles against numerous forms of oppression including economic injustice, racism, sexism, heterosexism, transphobia, and nationalism. Taken together, Pharr’s writings give activists and scholars a way to understand decades of attacks on civil rights while offering a roadmap that shows the way toward a people’s democracy where everyone has full participation, voice, a fair share of the benefits, justice, and dignity. Suzanne Pharr is an organizer and political strategist who has spent her adult life working to build a broad-based, multi-racial, multi-issued movement for social and economic justice in the United States. She founded the Women’s Project in Arkansas in 1981, was a co-founder of Southerners on New Ground in 1984, and was director of the Highlander Center from 1999 to 2004. After six decades of working across movements, Pharr now thinks of herself as a political handywoman, engaging with activists of diverse races, genders, sexual identities, classes, ages, abilities, and cultures to develop strategies for justice and equality.

Unconscious perception and central coordinating agency

One necessary condition on any adequate account of perception is clarity regarding whether unconscious perception exists. The issue is complicated, and the debate is growing in both philosophy and science. In this paper we consider the case for unconscious perception, offering three primary achievements. First, we offer a discussion of the underspecified notion of central coordinating agency, a notion that is critical for arguments that purportedly perceptual states are not attributable to the individual, and thus not genuinely perceptual. We develop an explication of what it is for a representational state to be available to central coordinating agency for guidance of behavior. Second, drawing on this explication, we place a more careful understanding of the attributability of a state to the individual in the context of a range of empirical work on vision-for-action, saccades, and skilled typing. The results place pressure on the skeptic about unconscious perception. Third, reflecting upon broader philosophical themes running through debates about unconscious perception, we highlight how our discussion places pressure on the view that perception is a manifest kind, rather than a natural kind. In doing so, we resist the tempting complaint that the debate about unconscious perception is merely verbal.

Accident Vulnerability and Vision for Action: A Pilot Investigation

Many accidents, such as those involving collisions or trips, appear to involve failures of vision, but the association between accident risk and vision as conventionally assessed is weak or absent. We addressed this conundrum by embracing the distinction inspired by neuroscientific research, between vision for perception and vision for action. A dual-process perspective predicts that accident vulnerability will be associated more strongly with vision for action than vision for perception. In this preliminary investigation, older and younger adults, with relatively high and relatively low self-reported accident vulnerability (Accident Proneness Questionnaire), completed three behavioural assessments targeting vision for perception (Freiburg Visual Acuity Test); vision for action (Vision for Action Test—VAT); and the ability to perform physical actions involving balance, walking and standing (Short Physical Performance Battery). Accident vulnerability was not associated with visual acuity or with performance of physical actions but was associated with VAT performance. VAT assesses the ability to link visual input with a specific action—launching a saccadic eye movement as rapidly as possible, in response to shapes presented in peripheral vision. The predictive relationship between VAT performance and accident vulnerability was independent of age, visual acuity and physical performance scores. Applied implications of these findings are considered.

Is Vision for Action Unconscious?

Empirical work and philosophical analysis have led to widespread acceptance that vision for action, served by the cortical dorsal stream, is unconscious. I argue that the empirical argument for this claim is unsound. That argument relies on subjects’ introspective reports. Yet on biological grounds, in light of the theory of primate cortical vision, introspection has no access to dorsal stream mediated visual states. It is wrongly assumed that introspective reports speak to absent phenomenology in the dorsal stream. In light of this, I consider a different conception of consciousness’s relation to agency in terms of access. While theoretical reasons suggest that the inaccessibility of the dorsal stream to conceptual report is evidence that it is unconscious, this position begs important questions about agency and consciousness. I propose a broader notion of access in respect of the guidance of intentional agency as the crucial link connecting agency to consciousness.

Accident Vulnerability and Vision for Action

Many accidents, such as those involving collisions or trips, appear to involve failures of vision; but the association between accident risk and vision as conventionally assessed, is weak or absent. We addressed this conundrum by embracing the distinction inspired by neuroscientific research, between vision for perception and vision for action. A dual-process perspective predicts that accident vulnerability will be associated more strongly with vision for action than vision for perception. Older and younger adults, with relatively high and relatively low self-reported accident vulnerability (Accident Proneness Questionnaire), completed three behavioural assessments targeting: vision for perception (Freiburg Visual Acuity Test); vision for action (Vision for Action Test - VAT); and the ability to perform physical actions involving balance, walking and standing (Short Physical Performance Battery). Accident vulnerability was not associated with visual acuity or with performance of physical actions; but was associated with VAT performance. VAT assesses the ability to link visual input with a specific action –launching a saccadic eye movement as rapidly as possible, in response to shapes presented in peripheral vision. The predictive relationship between VAT performance and accident vulnerability was independent of age, visual acuity and physical performance scores. Applied implications of these findings are considered.

Four reflections on the new global mental health priorities

The discussion of the achievements and limitations of the strategies prioritised in global mental health that has taken place in recent years contributed to a unified vision for action that addresses the gaps still existing on prevention, treatment, quality of care and human rights protection. This editorial presents four reflections on the impact of this vision on the definition of future priorities, particularly in the areas of policy implementation, services reconfiguration and organisation, human rights and research. It concludes that further debate is needed to redefine the balance between priorities and strategies that can better promote an effective response to the needs of low and middle income countries, and to ensure an efficient coordination of efforts in the future.