Person: Perez, David
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Perez
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Perez, David
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Publication Clinical and Neuroimaging Investigations in Neuropsychiatric Disorders(2016-05-18) Perez, David; Dickerson, Bradford; Dworetzky, Barbara; Dougherty, Darin; Chhatwal, JasmeerIn this Master’s Program in Clinical and Translational Investigation Thesis Titled “Clinical and Neuroimaging Investigations in Neuropsychiatric Disorders” by Dr. David L. Perez, research activities related to two studies are summarized. In the first research project, preliminary findings of a retrospective chart review for patients with Functional Neurological Disorder are discussed. Analyses aimed at investigating preliminary markers of adherence to referral, symptom severity and prognosis are highlighted. In the second now published study, neural mechanisms of response to psychotherapy in patients with Borderline Personality Disorder are outlined. Preliminary evidence detailing neural activation patterns predicting response to psychotherapy are also presented.Publication Brain Plasticity in Blind Subjects Centralizes Beyond the Modal Cortices(Frontiers Media S.A., 2016) Ortiz-Teran, Laura; Ortiz, Tomás; Perez, David; Aragón, Jose Ignacio; Diez, Ibai; Pascual-Leone, Alvaro; Sepulcre, JorgeIt is well established that the human brain reorganizes following sensory deprivations. In blind individuals, visual processing regions including the lateral occipital cortex (LOC) are activated by auditory and tactile stimuli as demonstrated by neurophysiological and neuroimaging investigations. The mechanisms for such plasticity remain unclear, but shifts in connectivity across existing neural networks appear to play a critical role. The majority of research efforts to date have focused on neuroplastic changes within visual unimodal regions, however we hypothesized that neuroplastic alterations may also occur in brain networks beyond the visual cortices including involvement of multimodal integration regions and heteromodal cortices. In this study, two recently developed graph-theory based functional connectivity analyses, interconnector analyses and local and distant connectivity, were applied to investigate functional reorganization in regional and distributed neural-systems in late-onset blind (LB) and congenitally blind (CB) cohorts each compared to their own group of sighted controls. While functional network alterations as measured by the degree of differential links (DDL) occurred in sensory cortices, neuroplastic changes were most prominent within multimodal and association cortices. Subjects with LB showed enhanced multimodal integration connections in the parieto-opercular, temporoparietal junction (TPJ) and ventral premotor (vPM) regions, while CB individuals exhibited increased superior parietal cortex (SPC) connections. This study reveals the critical role of recipient multi-sensory integration areas in network reorganization and cross-modal plasticity in blind individuals. These findings suggest that aspects of cross-modal neuroplasticity and adaptive sensory-motor and auditory functions may potentially occur through reorganization in multimodal integration regions.Publication Altered threat and safety neural processing linked to persecutory delusions in schizophrenia: a two-task fMRI study(Elsevier BV, 2015) Perez, David; Pan, Hong; Weisholtz, Daniel; Root, James C.; Tuescher, Oliver; Fischer, David; Butler, Tracy; Vago, David R.; Isenberg, Nancy; Epstein, Jane; Landa, Yulia; Smith, Thomas; Savitz, Adam J.; Silbersweig, David; Stern, EmilyPersecutory delusions are a clinically important symptom in schizophrenia associated with social avoidance and increased violence. Few studies have investigated the neurobiology of persecutory delusions, which is a prerequisite for developing novel treatments. The aim of this two-paradigm functional magnetic resonance imaging (fMRI) study is to characterize social “real world” and linguistic threat brain activations linked to persecutory delusions in schizophrenia (n=26) using instructed-fear/safety and emotional word paradigms. Instructed-fear/safety activations correlated to persecutory delusion severity demonstrated significant increased lateral orbitofrontal cortex and visual association cortex activations for the instructed-fear vs. safety and instructed-fear vs. baseline contrasts; decreased lateral orbitofrontal cortex and ventral occipital-temporal cortex activations were observed for the instructed-safety stimuli vs. baseline contrast. The salience network also showed divergent fear and safety cued activations correlated to persecutory delusions. Emotional word paradigm analyses showed positive correlations between persecutory delusion severity and left-lateralized linguistic and hippocampal–parahippocampal activations for the threat vs. neutral word contrast. Visual word form area activations correlated positively with persecutory delusions for both threat and neutral word vs. baseline contrasts. This study links persecutory delusions to enhanced neural processing of threatening stimuli and decreased processing of safety cues, and helps elucidate systems-level activations associated with persecutory delusions in schizophrenia.