Basic linguistic composition recruits the left anterior temporal lobe and left angular gyrus during both listening and reading.

Language is experienced primarily through one of two mediums--spoken words and written text. Although substantially different in form, these two linguistic vehicles possess similar powers of expression. Consequently, one goal for the cognitive neuroscience of language is to determine where, if anywhere, along the neural path from sensory stimulation to ultimate comprehension these two processing streams converge. In the present study, we investigate the relationship between basic combinatorial operations in both reading and listening. Using magnetoencephalography, we measured neural activity elicited by the comprehension of simple adjective-noun phrases (red boat) using the same linguistic materials and tasks in both modalities. The present paradigm deviates from previous cross-modality studies by investigating only basic combinatorial mechanisms--specifically, those evoked by the construction of simple adjective-noun phrases. Our results indicate that both modalities rely upon shared neural mechanisms localized to the left anterior temporal lobe (lATL) and left angular gyrus (lAG) during such processing. Furthermore, we found that combinatorial mechanisms subserved by these regions are deployed in the same temporal order within each modality, with lATL activity preceding lAG activity. Modality-specific combinatorial effects were identified during initial perceptual processing, suggesting top-down modulation of low-level mechanisms even during basic composition.

Number estimation relies on a set of segmented objects.

How do we estimate the number of objects in a set? Two types of visual representations might underlie this ability - an unsegmented visual image or a segmented collection of discrete objects. We manipulated whether individual objects were isolated from each other or grouped into pairs by irrelevant lines. If number estimation operates over an unsegmented image, then this manipulation should not affect estimates. But if number estimation relies on a segmented image, then grouping pairs of objects into single units should lead to lower estimates. In Experiment 1 participants underestimated the number of grouped objects, relative to disconnected objects in which the connecting lines were 'broken'. Experiment 2 presents evidence that this segmentation process occurred broadly across the entire set of objects. In Experiment 3, a staircase procedure provides a quantitative measure of the underestimation effect. Experiment 4 shows that the strength of the grouping effect was equally strong for a single thin line, and the effect can be eliminated by a small break in the line. These results provide direct evidence that number estimation relies on a segmented input.