Is the extrastriate body area part of the dorsal visuomotor stream?
Zimmermann M, Mars RB, de Lange FP, Toni I, Verhagen L (2017) Brain Structure and Function; DOI: 10.1007/s00429-017-1469-0
The extrastriate body area (EBA) processes visual information about body parts, and it is considered one among a series of category-specific perceptual modules distributed across the occipito-temporal cortex. However, recent evidence raises the possibility that EBA might also provide an interface between perception and action, linking the ventral and dorsal streams of visual information processing. Here, we assess anatomical evidence supporting this possibility. We localise EBA in individual subjects using a perceptual task and compare the characteristics of its functional and structural connectivity to those of two perceptual areas, the lateral occipital complex (LOC) and the fusiform body area (FBA), separately for each hemisphere. We apply complementary analyses of resting-state fMRI and diffusion-weighted MRI data in a group of healthy right-handed human subjects (N = 31). Functional and structural connectivity profiles indicate that EBA interacts more strongly with dorsal-stream regions compared to other portions of the occipito-temporal cortex involved in processing body parts (FBA) and object identification (LOC). These findings provide anatomical ground for a revision of the functional role of EBA. Building on a number of recent observations, we suggest that EBA contributes to planning goal-directed actions, possibly by specifying a desired postural configuration to parieto-frontal areas involved in computing movement parameters.
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A cortical mechanism for translating action goals into action plans
Zimmermann M (2016) PhD Thesis, Radboud University Nijmegen
Visual information is processed along two cortical pathways in the human brain, a ventral visual stream for perception, and a dorsal visual stream for the generation of actions. It has been assumed that information processed in the two streams remains largely separated and is only combined at a late stage. However, in this thesis, I provide ideas and evidence of early contributions of the ventral visual stream to the generation of goal-directed object manipulating actions. Specifically, using functional and structural neuroimaging, as well as time resolved analyses of the effects of transcranial magnetic stimulation on overt action execution, I show that the extrastriate body area – a ventral stream area involved in the visual perception of human bodies – generates a representation of desired action goal states. This representation is subsequently used by dorsal stream areas during the specification and generation of motor commands. These findings provide a cortical mechanism for the translation of action goals into motor plans, and enhance our understanding of perception and action mechanisms in our brain.
The extrastriate body area computes desired goal states during action planning
Zimmermann M, Verhagen L, de Lange FP, Toni I (2016) eNeuro 3(2); DOI: 10.1523/ENEURO.0020-16.2016
How do object perception and action interact at a neural level? Here we test the hypothesis that perceptual features, processed by the ventral visuo-perceptual stream, are used as priors by the dorsal visuo-motor stream to specify goal-directed grasping actions. We present three main findings, obtained by combining time-resolved transcranial magnetic stimulation (TMS) and kinematic tracking of grasp-and-rotate object manipulations, in a group of healthy human participants (N=22). First, the extrastriate body area (EBA), in the ventral stream, provides an initial structure to motor plans, based on current and desired states of a grasped object and of the grasping hand. Second, EBA’s contributions are earlier in time than those of a caudal intraparietal region known to specify the action plan. Third, EBA’s contributions are particularly important when desired and current object configurations differ, and multiple courses of actions are possible. These findings specify the temporal and functional characteristics for a mechanism that integrates perceptual processing with motor planning.
Body posture modulates action perception
Zimmermann M, Toni I, de Lange FP (2013) Journal of Neuroscience 33(14), 5930-38; DOI: 10.1523/JNEUROSCI.5570-12.2013
Recent studies have highlighted cognitive and neural similarities between planning and perceiving actions. Given that action planning involves a simulation of potential action plans that depends on the actor's body posture, we reasoned that perceiving actions may also be influenced by one's body posture. Here, we test whether and how this influence occurs by measuring behavioral and cerebral (fMRI) responses in human participants predicting goals of observed actions, while manipulating postural congruency between their own body posture and postures of the observed agents. Behaviorally, predicting action goals is facilitated when the body posture of the observer matches the posture achieved by the observed agent at the end of his action (action's goal posture). Cerebrally, this perceptual postural congruency effect modulates activity in a portion of the left intraparietal sulcus that has previously been shown to be involved in updating neural representations of one's own limb posture during action planning. This intraparietal area showed stronger responses when the goal posture of the observed action did not match the current body posture of the observer. These results add two novel elements to the notion that perceiving actions relies on the same predictive mechanism as planning actions. First, the predictions implemented by this mechanism are based on the current physical configuration of the body. Second, during both action planning and action observation, these predictions pertain to the goal state of the action.
Motor planning is facilitated by adopting an action’s goal posture: an fMRI study
Zimmermann M, Meulenbroek RGJ, de Lange FP (2012)
Cerebral Cortex 22, 122-31;
Motor planning is a hierarchical process that is typically organized around an action's goal (e.g., drinking from a cup). However, the motor plan depends not only on the goal but also on the current body state. Here, we investigated how one's own body posture interacts with planning of goal-directed actions. Participants engaged in a grasp selection (GS) task while we manipulated their arm posture. They had to indicate how they would grasp a bar when transporting it from a start to goal position and orientation. We compared situations in which one's body posture was in-congruent with the start posture and/or goal posture of the planned movement. Behavioral results show that GS took longer when one's own body state was incongruent with the goal posture of the planned movement. Correspondingly, neural activity in the intraparietal sulcus (IPS) and extrastriate body area (EBA) was modulated by congruency between the body state and the action plan. IPS was sensitive to overall congruency between body posture and action plan, while the EBA was sensitive specifically to goal posture congruency. Together, our results suggest that IPS maintains an internal state of one's own body posture, while EBA contains a representation of the goal posture of the action plan.
01-01-2019 New postdoc position at SINe Lab at DTU Copenhagen
16-07-2017 Paper accepted in Brain Structure and Function
28-12-2016 Starting as postdoc
23-11-2016 PhD thesis defended
SINe Lab (Social Interaction & Neuroscience)
Section for Cognitive Systems
DTU - Technical University of Denmark
Profile at DTU