1. The functional characterization of callosal connections
- Author
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Maurice Ptito, Franco Lepore, Francisco Aboitiz, Chantal Milleret, Roberto Caminiti, Alexandra Battaglia-Mayer, Kerstin E. Schmidt, Maria G. Knyazeva, Matteo Caleo, Muhamed Barakovic, Mara Fabri, Giorgio M. Innocenti, and Carlo Alberto Marzi
- Subjects
callosal conduction velocity ,callosal disconnection syndromes ,Computer science ,VM, vertical meridian of the visual field ,receptive-field properties ,Callosal axon diameter ,Callosal conduction velocity ,Callosal connections flexibility ,Callosal disconnection syndromes ,Callosal interhemispheric transfer ,Corpus callosum ,Review Article ,primary auditory-cortex ,corpus callosum ,AAF, anterior auditory field ,EP, evoked potential ,Operation mode ,EPSP, excitatory post-synaptic potential ,Neural Pathways ,posterior corpus-callosum ,Direct stimulation ,Neurons ,CPN, callosal projection neuron ,callosal connections flexibility ,Synaptic interaction ,GI, primary gustatory area ,General Neuroscience ,SC, split-chiasm ,Brain ,A1, primary auditory cortex ,ICoh, interhemispheric EEG coherence ,BOLD, blood oxygen level dependent ,General theory ,Cortical network ,DW-MRI, diffusion-weighted magnetic resonance imaging tractography ,Excitatory postsynaptic potential ,parietal lobule projections ,callosal axon diameter ,callosal interhemispheric transfer ,body midline representation ,RF, receptive field ,CC, corpus callosum ,Inhibitory postsynaptic potential ,EEG, electroencephalogram ,V1, (primary visual cortex, area 17) ,LFPs, local field potentials ,Animals ,Humans ,interhemispheric eeg coherence ,SI, primary somatosensory cortex ,primary visual-cortex ,EM, electron microscopy ,M1, primary motor cortex ,TMS, transcranial magnetic stimulation ,BDA, biotinylated dextran amine ,axon diameter distribution ,Axons ,DCM, dynamic causal modeling ,SCC, split corpus callosum ,V2, (secondary visual cortex, area 18) ,nervous system ,SII, secondary somatosensory cortex ,2nd somatosensory cortex ,Neuroscience ,stimulus-dependent changes - Abstract
Highlights • The functional characterization of callosal connections is informed by anatomical data. • Callosal connections play a conditional driving role depending on the brain state and behavioral demands. • Callosal connections play a modulatory function, in addition to a driving role. • The corpus callosum participates in learning and interhemispheric transfer of sensorimotor habits. • The corpus callosum contributes to language processing and cognitive functions., 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.
- Published
- 2022
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