Optic Ataxia: From Balint’s Syndrome to the Parietal Reach Region

Abstract

Optic ataxia is a high order deficit in reaching to visual goals that occurs with posterior parietal cortex (PPC) lesions. It is a component of Balint’s syndrome that also includes attentional and gaze disorders. Aspects of optic ataxia are misreaching in the contralesional visual field, difficulty preshaping the hand for grasping, and an inability to correct reaches online. Recent research in non-human primates (NHPs) suggests that many aspects of Balint’s syndrome and optic ataxia are a result of damage to specific functional modules for reaching, saccades, grasp, attention, and state estimation. The deficits from large lesions in humans are likely composite effects from damage to combinations of these functional modules. Interactions between these modules, either within posterior parietal cortex or downstream within frontal cortex, may account for more complex behaviors such as hand-eye coordination and reach-to-grasp.

Synchronization patterns suggest different functional organization in parietal reach region and dorsal premotor cortex

“…PRR lesions (Padberg et al 2010;Rushworth et al 1997aRushworth et al , 1997b and inactivation (Hwang et al 2012;Yttri et al 2014) have repeatedly shown that reach trajectories and end points are severely affected by a compromised parietal cortex, although the ability to select between two different types of movement ("push" vs. "pull") that were instructed by different cognitive rules (colors) remained unaffected (Rushworth et al 1997a). Human patients with parietal lesions have long been known to suffer from optic ataxia and the inability to reach precisely to specific targets, part of Balint's syndrome (for review see Andersen et al 2014). Furthermore, although affecting spatial selection, parietal lesions did not compromise the ability of these patients to learn associations between abstract cues and specific movements (Halsband and Freund 1990).…”

Through the forest of motor representations

“…This visuomotor transformation relies on a well defined parietal-premotor network lying in between the posterior parietal cortex and the ventral premotor cortex, that is, a precise portion of the V-D, whose main components for these tasks are the anterior intraparietal (AIP) area (related to the anterior intraparietal sulcus) and area F5, in the most rostral part of the ventral premotor cortex (for a review of the leading role of AIP-F5 in the detection of action possibilities and the related visuomotor transformation of object properties into action properties and then of action properties into motor acts see Baumann, Fluet, & Scherberger, 2009;Borghi & Riggio, 2015;Castiello, 2005;Castiello & Begliomini, 2008;Chinellato & del Pobil, 2016;Ferretti, 2016;Fluet, Baumann, & Scherberger, 2010;Grafton, 2010;Janssen & Scherberger, 2015;Kandel, Schwartz, Jessell, Siegelbaum, & Hudspeth, 2013: chap. 19;Murata et al, 1997;Murata, Gallese, Luppino, Kaseda, & Sakata, 2000;Raos et al, 2006;Romero, Pani, & Janssen, 2014;Sakata, Taira, Murata, & Mine, 1995;Shikata et al, 2003;Srivastava, Orban, De Mazière, & Janssen, 2009;Theys, Pani, van Loon, Goffin, & Janssen, 2012Theys, Srivastava, van Loon, Goffin, & Janssen, 2012;Theys, Romero, van Loon, & Janssen, 2015 concerning lesion studies see Andersen, Andersen, Hwang, & Hauschild, 2014;Graziano, 2009;Turella & Lignau, 2014) -see footnote 19.…”

Sensory and semantic activations evoked by action attributes of manipulable objects: Evidence from ERPs

“…It has been shown that impairment in these two action types doubly dissociates in patients (impairment in grasping but not using objects in patients with optic ataxia: Andersen et al, 2014; Buxbaum and Coslett, 1998; Jakobson et al, 1991; deficits for using but not grasping objects in patients with ideomotor apraxia (IMA): Buxbaum et al, 2003; Haaland et al, 1999; Sirigu et al, 1995). These lesion studies and other converging neuroimaging data (Buxbaum et al, 2006; Culham and Valyear, 2006; Johnson-Frey, 2004) have given rise to the Two Action System Plus (2ASþ) theoretical model, postulating that “grasp-to-move” actions are subserved by the dorso-dorsal visual processing stream (including bilateral intraparietal sulci and dorsolateral fronto-parietal regions) specialized for online sensory-motor control; by contrast, “skilled use” actions are linked to the ventral-dorsal stream in the left hemisphere, including the left posterior temporal/inferior parietal regions that are postulated to store relationships between objects and skilled actions in semantic memory (Fridman et al, 2006; Johnson-Frey, 2004; Pisella et al, 2006; see Buxbaum, 2017 for a review).…”