Bestaat er een talenknobbel? Over taal in ons brein

Wanneer iemand goed is in het spreken van meerdere talen, wordt wel gezegd dat zo iemand een talenknobbel heeft. Iedereen weet dat dat niet letterlijk bedoeld is: iemand met een talenknobbel herkennen we niet aan een grote bult op zijn hoofd. Toch dacht men vroeger wel degelijk dat mensen een letterlijke talenknobbel konden ontwikkelen. Een goed ontwikkeld taalvermogen zou gepaard gaan met het groeien van het hersengebied dat hiervoor verantwoordelijk was. Dit deel van het brein zou zelfs zo groot kunnen worden dat het van binnenuit tegen de schedel drukte, met name rond de ogen. Nu weten we wel beter. Maar waar in het brein bevindt de taal zich dan wel precies

Taking the listener into account: Computing common ground requires mentalising

In order to communicate efficiently, speakers have to take into account which information they share with their addressee (common ground) and which information they do not share (privileged ground). Two views have emerged about how and when common ground influences language production. In one view, speakers take common ground into account early on during utterance planning (e.g., Brennan & Hanna, 2009). Alternatively, it has been proposed that speakers’ initial utterance plans are egocentric, but that they monitor their plans and revise them if needed (Horton & Keysar, 1996). In an fMRI study, we investigated which neural mechanisms support speakers’ ability to take into account common ground, and at what stage during speech planning these mechanisms come into play. We tested 22 pairs of native Dutch speakers (20 pairs retained in the analysis), who were assigned to the roles of speaker or listener for the course of the experiment. The speaker performed the experiment in the MRI scanner, while the listener sat behind a computer in the MRI control room. The speaker performed a communicative and a noncommunicative task in the scanner. The communicative task was a referential communication game in which the speaker described objects in an array to the listener. The listener could hear the speaker’s descriptions over headphones and tried to select the intended object on her screen using a mouse. We manipulated common ground within the communicative task. In the privileged ground condition, the speaker saw additional competitor objects that were occluded from the listener’s point of view. In order to communicate efficiently, the speaker had to ignore the occluded competitor objects. In the control conditions, all relevant objects were in common ground. The non-communicative task was identical to the communicative task, except that the speaker was instructed to describe the objects without the listener listening. When comparing the BOLD response during speech planning in the communicative and the noncommunicative tasks, we found activations in the right medial prefrontal cortex and bilateral insula, brain areas involved in mentalizing and empathy. These results confirm previous neuroimaging research that found that speaking in a communicative context as compared to a non-communicative context activates brain areas that are involved in mentalizing (Sassa et al., 2007; Willems et al., 2010). We also contrasted brain activity in the privileged ground and control conditions within the communicative task to tap into the neural mechanisms that allow speakers to take common ground into account. We again found activity in brain regions involved in mentalizing and visual perspective-taking (the bilateral temporo-parietal junction and medial prefrontal cortex). In addition, we found a cluster in the dorsolateral prefrontal cortex, a brain area that has previously been proposed to support the inhibition of task-irrelevant perspectives (Ramsey et al., 2013). Interestingly, these clusters are located outside the traditional language network. Our results suggest that speakers engage in mentalizing and visual perspective-taking during speech planning in order to compute common ground rather than monitoring and adjusting their initial egocentric utterance plans

Characterizing the Anti-Apoptotic Dependencies of T-Cell Prolymphocytic Leukemia Identifies HDAC and JAK/STAT Pathway Inhibitors As Promising Combination Partners to Augment Bcl-2 Targeted Killing By Venetoclax

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