Two action systems in the human brain

Abstract

The distinction between dorsal and ventral visual processing streams, first proposed by Ungerleider and Mishkin (1982) and later refined by Milner and Goodale (1995) has been elaborated substantially in recent years, spurred by two developments. The first was proposed in large part by Rizzolatti and Matelli (2003) and is a more detailed description of the multiple neural circuits connecting the frontal, temporal, and parietal cortices. Secondly, there are a number of behavioral observations that the classic “two visual systems” hypothesis is unable to accommodate without additional assumptions. The notion that the Dorsal stream is specialized for “where” or “how” actions and the Ventral stream for “What” knowledge cannot account for two prominent disorders of action, limb apraxia and optic ataxia, that represent a double dissociation in terms of the types of actions that are preserved and impaired. A growing body of evidence, instead, suggests that there are at least two distinct Dorsal routes in the human brain, referred to as the “Grasp” and “Use” systems. Both of these may be differentiated from the Ventral route in terms of neuroanatomic localization, representational specificity, and time course of information processing.

Hand-independent representation of tool-use pantomimes in the left anterior intraparietal cortex

“…However, with a conventional subtraction method based on mass univariate analysis, it cannot be decided whether there is left IPL, which is consistent with the lesion cases of IMA (Buxbaum et al 2007;Binkofski and Buxbaum 2013). Notably, the observed accuracy for the cross-classification (43.1%) is significantly higher than chance (33%) but is still relatively low.…”

“…Recent studies using anodal transcranial direct current stimulation (tDCS) showed that electrical stimulation of the left PPC improves the processing of gesture or imitation in healthy participants (Weiss et al 2013) and also in IMA patients (Bianchi et al 2015;Bolognini et al 2015), which further suggest the importance of left PPC for gesture processing. 15 Among the dorsal visual stream within the PPC, the dorso-dorsal pathway comprising the superior parietal lobule (SPL) and ventro-dorsal pathway, including the IPL, are distinct pathways (Rizzolatti and Matelli 2003;Binkofski and Buxbaum 2013). Online sensorimotor control with objects based on their perceptual attributes ("acting on") is mainly related to the SPL, whereas the stored knowledge of tool-use ("acting with") is 20 subserved by the IPL (Johnson and Grafton 2003;Brandi et al 2014).…”

The role of the basolateral amygdala in the perception of faces in natural contexts

“…Our proposal of a dual route of affective perception [39], and related perspectives [50,[78][79][80], suggest that relatively independent detection and recognition routes underlie affective signal processing. These routes correspond to a dorsal and ventral division, respectively [69,81,82]. The first route comprises subcortical regions, such as the pulvinar and AMG as well as the dorsal stream and orbitofrontal cortex, and sustains early emotion processing, automatic action preparation and reflexive reactions.…”

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

“…Recent evidence suggests that integration of known and visible properties of an object is carried out by a purported 'ventro-dorsal' sub-stream within the visual pathways model, with the left inferior parietal lobe (IPL) being the critical juncture where these object properties are combined (Rizzolatti & Matteli, 2003;Binkofski & Buxbaum, 2013;Vingerhoets, 2014).…”