A possible role of BA8 in Pre-surgical fMRI   A possible role of BA8 in Pre-surgical fMRI homage to an exceptional scientist Korbinian Brodmann 17-11-1868 → 22-08-1918  In 1909, >100 years ago, Brodmann published his cytoarchitectonal map of brain areas. Although the Brodmann areas have been discussed, debated, refined, and renamed exhaustively during a century, they remain the most widely known and frequently cited cytoarchitectural organization of the human cortex Functions have been attributed to these areas, such as the sensory cortex, the motor homunculus, the visual cortices and the linguistic areas. Korbinian Brodmann: Vergleichende Lokalisationslehre der Grosshirnrinde in Ihren Prinzipien dargestellt auf Grund des Zellenbaues, Johann Ambrosius Barth Verlag, Leipzig, 1909

it is also suggested that activation in BA8 encodes “hope”,  Brodmann area 8, or BA8, is part of the frontal cortex in the human brain. and is situated just anterior to the premotor cortex (BA6) it includes the frontal eye fields (so-named because they are believed to play an important role in the control of eye movements) fMRI demonstrates that BA8 activation occurs when subjects experience uncertainty (Volz et al. Brain Research, 2005, 67: 403-412) it is also suggested that activation in BA8 encodes “hope”, a higher order expectation linked with uncertainty

BA8 Broca

Broca fasciculus arcuatis Wernicke BA8 parieto-temporal-occipital antero-temporal associations area parieto-temporal-occipital associations area

robust paradigms were used to activate eloquent centers of the brain, including motor strip, the visual cortex, areas involved in memory and, perhaps most important, areas governing speech and language; In 100 presurgical patients analysis was made of the linguistic areas

connections in the language domain adapted from: DTI tractography of the Human’s language pathways Glasser MF, Rilling JK, Cerebral Cortex, 18, 2471-2482, 2008

connections in the language domain BA8 adapted from: DTI tractography of the Human’s language pathways Glasser MF, Rilling JK, Cerebral Cortex, 18, 2471-2482, 2008

Aphasia types BA8

typical result in word generation paradigm right-handed male, 38 years, low grade astrocytoma

some activation on the right tumor

BA8 Broca BA8 transverse and sagittal images of normal volunteer: showing activated areas in word generation block design Broca predominantly activated on the left; confirmed by BA8 activation

36 year old patient with tumor in posterior insular area on the left: BA8 Broca displaced upwards Broca 36 year old patient with tumor in posterior insular area on the left: Broca on the left is pushed upwards, now close to the BA8 activation; some Broca activation on the right, but only weak BA8 activation on the right side

wordgeneration female, 22 years lefthanded there is a bilateral activation of Broca; BA 8 is more activated on the right side tumor frontal left parasagittal

bilateral activation of Broca, BA8 mainly on the right side

this paradigm shows bilateral activation of Broca; BA 44 BA 8 this paradigm shows bilateral activation of Broca; some downward displacement on the left side; activation of Brodmann area 8 on the right side is embedded In the tumor area tumor

fasciculus arcuatus on both sides intact Broca Broca WERNICKE Wernicke Wernicke right left no fibers seen connecting to BA8

Connectivity and Synchronicity there are no “wireless” connections in the brain DTI-fiber tracking allows to depict some of the fiber connections: a beautiful example in the linguistic areas is the connection between the Broca executive and Wernicke receptive center: fasciculus arcuatis BA8 44 22

In this right-handed patient the arcuate fibers are well Broca Wernicke fasciculus arcuatis CST left right In this right-handed patient the arcuate fibers are well traceable on the left side, not on the right BA8 Wernicke

FLAIR male 57 years right handed transcortical motor aphasia

wordgeneration wordgeneration activates Broca and BA8

Broca mainly on the left side; BA8 also; close to tumor posterior to anterior BA8 BA8 BA8 Broca tumor Broca mainly on the left side; BA8 also; close to tumor scattered and displaced Broca Broca Broca

Broca activated on both sides, Broca is scattered on the left, BA8 Broca Broca Broca Broca activated on both sides, Broca is scattered on the left, patient suffers from a mild aphasia with the characteristics of a conductive aphasia

Broca Broca scattered on the left side

Broca Wernicke Broca Wernicke tracing started in Wernicke starting in Broca no arcuate fibers can be traced; some fibers encompass the tumor tracing started in Broca Broca Wernicke Broca tracing started in Wernicke Wernicke

tumor Broca Wernicke tracing started in Wernicke tracing started in Broca Wernicke tracing started in Wernicke

? BA8 tumor Broca arcuate fibers tracked from Broca Wernicke corticospinal tracts arcuate fibers tracked from Wernicke tumor ? BA8 Broca Wernicke no fibers tracked linking language areas to BA8

view from above right tumor arcuate fibers corticospinal tracts arcuate fibers tracked from Wernicke

right ↔ anterior tumor bird’s eye stereoscopic view

Paul Broca Korbinian Brodmann Carl Wernicke

Conclusion: Although the connection between Broca and BA8 could not be established in the same way as the Broca-Wernicke connection the synchronicity between the activations makes it useful to confirm the activity of Broca by the activation of BA8, especially in those cases where there is displacement of Broca, where language dominance is important, and in cases with bilateral activation when a quantifiable difference between the two sides exists. This, of course, is important in pre-operative cases, but has also great impact on the study of language development and aphasias.