If Broca's area makes speech, why does a lesion confined to it rarely cause lasting Broca's aphasia? · Grey Matter

Speech production is a network, and Broca's area (left Brodmann areas 44 and 45) is one node in it, beside the insula, the motor and premotor cortex for the mouth, and the white matter that links them to the temporal lobe.

If Broca's area makes speech, why does a lesion confined to it rarely cause lasting Broca's aphasia?

Speech production is a network, and Broca's area (left Brodmann areas 44 and 45) is one node in it, beside the insula, the motor and premotor cortex for the mouth, and the white matter that links them to the temporal lobe. In 1978 Mohr and colleagues found that a stroke limited to Broca's area produced mutism or effortful speech that recovered within weeks, while the full, lasting syndrome followed large lesions of the territory around it. Even the brains of Broca's own patients, scanned in 2007, showed damage reaching well beyond the area that carries his name.