TY - JOUR

T1 - The functional characterization of callosal connections

AU - Innocenti, Giorgio M.

AU - Schmidt, Kerstin

AU - Milleret, Chantal

AU - Fabri, Mara

AU - Knyazeva, Maria G.

AU - Battaglia-Mayer, Alexandra

AU - Aboitiz, Francisco

AU - Ptito, Maurice

AU - Caleo, Matteo

AU - Marzi, Carlo A.

AU - Barakovic, Muhamed

AU - Lepore, Franco

AU - Caminiti, Roberto

N1 - Publisher Copyright: © 2021

PY - 2022

Y1 - 2022

N2 - The brain operates through the synaptic interaction of distant neurons within flexible, often heterogeneous, distributed systems. Histological studies have detailed the connections between distant neurons, but their functional characterization deserves further exploration. Studies performed on the corpus callosum in animals and humans are unique in that they capitalize on results obtained from several neuroscience disciplines. Such data inspire a new interpretation of the function of callosal connections and delineate a novel road map, thus paving the way toward a general theory of cortico-cortical connectivity. Here we suggest that callosal axons can drive their post-synaptic targets preferentially when coupled to other inputs endowing the cortical network with a high degree of conditionality. This might depend on several factors, such as their pattern of convergence-divergence, the excitatory and inhibitory operation mode, the range of conduction velocities, the variety of homotopic and heterotopic projections and, finally, the state-dependency of their firing. We propose that, in addition to direct stimulation of post-synaptic targets, callosal axons often play a conditional driving or modulatory role, which depends on task contingencies, as documented by several recent studies.

AB - The brain operates through the synaptic interaction of distant neurons within flexible, often heterogeneous, distributed systems. Histological studies have detailed the connections between distant neurons, but their functional characterization deserves further exploration. Studies performed on the corpus callosum in animals and humans are unique in that they capitalize on results obtained from several neuroscience disciplines. Such data inspire a new interpretation of the function of callosal connections and delineate a novel road map, thus paving the way toward a general theory of cortico-cortical connectivity. Here we suggest that callosal axons can drive their post-synaptic targets preferentially when coupled to other inputs endowing the cortical network with a high degree of conditionality. This might depend on several factors, such as their pattern of convergence-divergence, the excitatory and inhibitory operation mode, the range of conduction velocities, the variety of homotopic and heterotopic projections and, finally, the state-dependency of their firing. We propose that, in addition to direct stimulation of post-synaptic targets, callosal axons often play a conditional driving or modulatory role, which depends on task contingencies, as documented by several recent studies.

KW - Callosal axon diameter

KW - Callosal conduction velocity

KW - Callosal connections flexibility

KW - Callosal disconnection syndromes

KW - Callosal interhemispheric transfer

KW - Corpus callosum

U2 - 10.1016/j.pneurobio.2021.102186

DO - 10.1016/j.pneurobio.2021.102186

M3 - Review

C2 - 34780864

AN - SCOPUS:85119601605

VL - 208

JO - Progress in Neurobiology

JF - Progress in Neurobiology

SN - 0301-0082

M1 - 102186

ER -