Vigliocco, G, Krason, A., Stoll, H., Monte, A., Buxbaum, LJ. Multimodal comprehension in left hemisphere stroke patients. Cortex, 2020; 133:309-327. PMID: 33161278

Communication is multimodal, yet studies of communication typically focus solely on language. This study was perhaps the most thorough evaluation to date of the effect of congruent and incongruent gestures on speech comprehension, and the effects of congruent and incongruent speech on gesture comprehension. The study also delineated the temporal and frontal brain regions critical for benefits of congruent speech and gestures on the other modality, and thus has potential clinical implications for identifying individuals whose comprehension benefits from multimodal cues.

Garcea, F., Buxbaum, LJ. Gesturing tool use and tool transport actions modulates inferior parietal functional connectivity with the dorsal and ventral object processing pathways. Human Brain Mapping, Jul;40(10):2867-288, 2019. PMID: 30900321.

Our laboratory has elucidated two major action systems in the human brain: one specialized for skilled tool use, and the other for interacting with currently-visualized objects. This study extended our prior work by showing that the connectivity of the inferior parietal lobe – which plays a role in both action systems – is dynamically modulated by task demands. Like other studies from our lab, this finding illustrated the importance of goals in determining the regions of the brain that are activated and in communication.

Buxbaum, L.J., Shapiro, A.D., Coslett, H.B. Critical brain regions for tool-related and imitative actions: A componential analysis. Brain, 2014 Jul;137(Pt 7):1971-85. PMID:24776969

Individuals with left hemisphere stroke often exhibit limb apraxia, a disorder affecting tool use pantomime and action imitation. In a large sample of individuals with stroke, this study systematically explored the brain regions that, when lesioned, give rise to tool use and pantomime deficits. Contrary to the wisdom of the time, which argued that apraxia is a parietal lobe disorder, we showed that the posterior temporal lobe makes a surprisingly large contribution to tool use actions.

Binkofski, F, Buxbaum, LJ. Two action systems in the human brain. Brain and Language, 127(2):222-9, 2013, PMID: 22889467

Prior research in the macaque monkey had shown that the brain’s “dorsal visual stream” could be divided into two sub-streams with different functions. This manuscript was the first to outline the functional neuroanatomy of two human brain networks for visually-guided, structure-based actions versus memory-guided, function-based actions. Furthermore, we described how lesions to the former give rise to disorders of visually-guided reaching (optic ataxia) whereas lesions to the latter result in limb apraxia.

Jax, S., and Buxbaum, LJ. Response interference between functional and structural actions linked to the same familiar object. Cognition, 115(2): 350-355, 2010.  PMID: 20156619

The world of manipulable objects presents multiple opportunities for manual actions, yet with a single hand we can only perform one action at a time. To solve this “many to one” problem, a system for selection of actions is required. This study, one of many in our lab focused on response competition, showed that structure-based and function-based actions are associated with single objects and activated in parallel, with resulting competition for selection and slowing of response times.