All Publications

  • Electrophysiology and Structural Connectivity of the Posterior Hypothalamic Region: Much to Learn From a Rare Indication of Deep Brain Stimulation. Frontiers in human neuroscience Kakusa, B. n., Saluja, S. n., Dadey, D. Y., Barbosa, D. A., Gattas, S. n., Miller, K. J., Cowan, R. P., Kouyoumdjian, Z. n., Pouratian, N. n., Halpern, C. H. 2020; 14: 164


    Cluster headache (CH) is among the most common and debilitating autonomic cephalalgias. We characterize clinical outcomes of deep brain stimulation (DBS) to the posterior hypothalamic region through a novel analysis of the electrophysiological topography and tractography-based structural connectivity. The left posterior hypothalamus was targeted ipsilateral to the refractory CH symptoms. Intraoperatively, field potentials were captured in 1 mm depth increments. Whole-brain probabilistic tractography was conducted to assess the structural connectivity of the estimated volume of activated tissue (VAT) associated with therapeutic response. Stimulation of the posterior hypothalamic region led to the resolution of CH symptoms, and this benefit has persisted for 1.5-years post-surgically. Active contacts were within the posterior hypothalamus and dorsoposterior border of the ventral anterior thalamus (VAp). Delta- (3 Hz) and alpha-band (8 Hz) powers increased and peaked with proximity to the posterior hypothalamus. In the posterior hypothalamus, the delta-band phase was coupled to beta-band amplitude, the latter of which has been shown to increase during CH attacks. Finally, we identified that the VAT encompassing these regions had a high proportion of streamlines of pain processing regions, including the insula, anterior cingulate gyrus, inferior parietal lobe, precentral gyrus, and the brainstem. Our unique case study of posterior hypothalamic region DBS supports durable efficacy and provides a platform using electrophysiological topography and structural connectivity, to improve mechanistic understanding of CH and this promising therapy.

    View details for DOI 10.3389/fnhum.2020.00164

    View details for PubMedID 32670034

    View details for PubMedCentralID PMC7326144

  • Deep Brain Stimulation for Chronic Cluster Headache: A Review NEUROMODULATION Vyas, D. B., Ho, A. L., Dadey, D. Y., Pendharkar, A. V., Sussman, E. S., Cowan, R., Halpern, C. H. 2019; 22 (4): 388–97

    View details for DOI 10.1111/ner.12869

    View details for Web of Science ID 000471831000003

  • PERK Regulates Glioblastoma Sensitivity to ER Stress Although Promoting Radiation Resistance MOLECULAR CANCER RESEARCH Dadey, D. A., Kapoor, V., Khudanyan, A., Thotala, D., Hallahan, D. E. 2018; 16 (10): 1447–53


    The aggressive nature and inherent therapeutic resistance of glioblastoma multiforme (GBM) has rendered the median survival of afflicted patients to 14 months. Therefore, it is imperative to understand the molecular biology of GBM to provide new treatment options to overcome this disease. It has been demonstrated that the protein kinase R-like endoplasmic reticulum kinase (PERK) pathway is an important regulator of the endoplasmic reticulum (ER) stress response. PERK signaling has been observed in other model systems after radiation; however, less is known in the context of GBM, which is frequently treated with radiation-based therapies. To investigate the significance of PERK, we studied activation of the PERK-eIF2α-ATF4 pathway in GBM after ionizing radiation (IR). By inhibiting PERK, it was determined that ionizing radiation (IR)-induced PERK activity led to eIF2α phosphorylation. IR enhanced the prodeath component of PERK signaling in cells treated with Sal003, an inhibitor of phospho-eIF2α phosphatase. Mechanistically, ATF4 mediated the prosurvival activity during the radiation response. The data support the notion that induction of ER stress signaling by radiation contributes to adaptive survival mechanisms during radiotherapy. The data also support a potential role for the PERK/eIF2α/ATF4 axis in modulating cell viability in irradiated GBM.Implications: The dual function of PERK as a mediator of survival and death may be exploited to enhance the efficacy of radiation therapy.Visual Overview: Mol Cancer Res; 16(10); 1447-53. ©2018 AACR.

    View details for PubMedID 29991528