Neural organization of speech production: A lesion-based study of error patterns in connected speech

Brielle C Stark; Alexandra Basilakos; Gregory Hickok; Chris Rorden; Leonardo Bonilha; Julius Fridriksson

4B: Spatial distribution of significant clusters. Here, we demonstrate the spatial distribution of each significant cluster by paraphasia type and task group. As in Figure 4A , variance from lesion volume has been regressed from all analyses, and for the CS task group, we present neologistic and unrelated areas with apraxia of speech variance also regressed. Phonemic paraphasias are not demonstrated here, as there was not a significant cluster for phonemic paraphasia in the PNT task group after lesion volume regression or for the CS task group after both lesion volume and apraxia of speech severity regression. This figure demonstrates the distinction in dorsal and ventral streams associated with sound and verbal paraphasias, respectively. Figure 5 . Conjunction analysis of verbal paraphasias between tasks. As verbal paraphasias in the connected speech and naming tasks significantly associated with lesion damage, we performed a conjunction analysis to identify the region(s) that were significantly associated with semantically related and with unrelated paraphasias in both tasks. A cluster of damage to more anterior, ventral stream areas, comprising superior and middle temporal gyri, was associated with semantically related paraphasias in both tasks (top) while a cluster of damage to more posterior, ventral stream areas was associated with unrelated paraphasias in both tasks (middle). There was an area of overlap in posterior superior and middle temporal gyri significantly associated with both semantically related and unrelated paraphasias in both tasks (bottom).