All Publications

  • Temporal order of signal propagation within and across intrinsic brain networks. Proceedings of the National Academy of Sciences of the United States of America Veit, M. J., Kucyi, A., Hu, W., Zhang, C., Zhao, B., Guo, Z., Yang, B., Sava-Segal, C., Perry, C., Zhang, J., Zhang, K., Parvizi, J. 2021; 118 (48)


    We studied the temporal dynamics of activity within and across functional MRI (fMRI)-derived nodes of intrinsic resting-state networks of the human brain using intracranial electroencephalography (iEEG) and repeated single-pulse electrical stimulation (SPES) in neurosurgical subjects implanted with intracranial electrodes. We stimulated and recorded from 2,133 and 2,372 sites, respectively, in 29 subjects. We found that N1 and N2 segments of the evoked responses are associated with intra- and internetwork communications, respectively. In a separate cognitive experiment, evoked electrophysiological responses to visual target stimuli occurred with less temporal separation across pairs of electrodes that were located within the same fMRI-defined resting-state networks compared with those located across different resting-state networks. Our results suggest intranetwork prior to internetwork information processing at the subsecond timescale.

    View details for DOI 10.1073/pnas.2105031118

    View details for PubMedID 34819365

  • Altered sense of self during seizures in the posteromedial cortex. Proceedings of the National Academy of Sciences of the United States of America Parvizi, J., Braga, R. M., Kucyi, A., Veit, M. J., Pinheiro-Chagas, P., Perry, C., Sava-Segal, C., Zeineh, M., van Staalduinen, E. K., Henderson, J. M., Markert, M. 2021; 118 (29)


    The posteromedial cortex (PMC) is known to be a core node of the default mode network. Given its anatomical location and blood supply pattern, the effects of targeted disruption of this part of the brain are largely unknown. Here, we report a rare case of a patient (S19_137) with confirmed seizures originating within the PMC. Intracranial recordings confirmed the onset of seizures in the right dorsal posterior cingulate cortex, adjacent to the marginal sulcus, likely corresponding to Brodmann area 31. Upon the onset of seizures, the patient reported a reproducible sense of self-dissociation-a condition he described as a distorted awareness of the position of his body in space and feeling as if he had temporarily become an outside observer to his own thoughts, his "me" having become a separate entity that was listening to different parts of his brain speak to each other. Importantly, 50-Hz electrical stimulation of the seizure zone and a homotopical region within the contralateral PMC induced a subjectively similar state, reproducibly. We supplement our clinical findings with the definition of the patient's network anatomy at sites of interest using cortico-cortical-evoked potentials, experimental and resting-state electrophysiological connectivity, and individual-level functional imaging. This rare case of patient S19_137 highlights the potential causal importance of the PMC for integrating self-referential information and provides clues for future mechanistic studies of self-dissociation in neuropsychiatric populations.

    View details for DOI 10.1073/pnas.2100522118

    View details for PubMedID 34272280

  • Metallicity in SrTiO3 substrates induced by pulsed laser deposition APL MATERIALS Balakrishnan, P. P., Veit, M. J., Alaan, U. S., Gray, M. T., Suzuki, Y. 2019; 7 (1)

    View details for DOI 10.1063/1.5080939

    View details for Web of Science ID 000457407500003

  • Commensurate antiferromagnetic excitations as a signature of the pseudogap in the tetragonal high-T-c cuprate HgBa2CuO4+delta NATURE COMMUNICATIONS Chan, M. K., Dorow, C. J., Mangin-Thro, L., Tang, Y., Ge, Y., Veit, M. J., Yu, G., Zhao, X., Christianson, A. D., Park, J. T., Sidis, Y., Steffens, P., Abernathy, D. L., Bourges, P., Greven, M. 2016; 7


    Antiferromagnetic correlations have been argued to be the cause of the d-wave superconductivity and the pseudogap phenomena exhibited by the cuprates. Although the antiferromagnetic response in the pseudogap state has been reported for a number of compounds, there exists no information for structurally simple HgBa2CuO4+δ. Here we report neutron-scattering results for HgBa2CuO4+δ (superconducting transition temperature Tc≈71 K, pseudogap temperature T*≈305 K) that demonstrate the absence of the two most prominent features of the magnetic excitation spectrum of the cuprates: the X-shaped 'hourglass' response and the resonance mode in the superconducting state. Instead, the response is Y-shaped, gapped and significantly enhanced below T*, and hence a prominent signature of the pseudogap state.

    View details for DOI 10.1038/ncomms10819

    View details for Web of Science ID 000371714100001

    View details for PubMedID 26940332

    View details for PubMedCentralID PMC4785222