All posts by Erik Erhardt

Erik Barry Erhardt, PhD, is an Associate Professor of Statistics at the University of New Mexico Department of Mathematics and Statistics, where he has served as Director of the Statistics Consulting Clinic, and is currently Director of the Biostatistics and NeuroInformatics (BNI) Core for the second phase of the Center for Biomedical Research Excellence (COBRE) in Brain Function and Mental Illness at the Mind Research Network. His research interests include Bayesian and Frequentist statistical methods for stable isotope sourcing and brain imaging. Erik is a Howard Hughes Medical Institute Interfaces Scholar collaborating in interdisciplinary research and offering consulting services in statistics.

Book Published: All Join Hands: Dances and stories

Richard Wilson book page includes purchasing details. Six and a half years ago we called for contributions.  Now we contribute this book back to the FolkMADS community.

Introduction to the first edition

This book is the fruit of an old idea, a long fallow period, and a final burst of enthusiastic commitment. The idea was to provide Richard with a meaningful focus and contribution during his last year of life. He wrote and wrote, filling notebooks; Lauren transcribed what she could. We photocopied all his cards that could be found in October 2010; Katherine provided an initial transcription. This book has taken many forms in its many revisions and reimaginings: experimenting with different paper sizes, interleaving the stories from other people in with his own story, modifying the dance formats, and finally returning to this fairly simple format. The long lull, after much compilation and redrafting, was partly due to my grieving after Richard passed; with Richard gone the urgency of the project had passed, since my primary commitment was to him. Then I allowed other projects to take over, including the trials of earning tenure as faculty at UNM. Finally, after almost six years, it is done. While I may not have been able to realize the book I envisioned, this is it. I’m heartened by a thoughtful and generous community to whom I present this gift and tribute. Five years since Richard’s passing, I still feel his spirit and gentleness as I teach new dancers and callers, just as he taught me, feeling how each foot lifted is as important as how each is set upon. Erik Barry Erhardt Albuquerque, NM October 2016
... more

Albuquerque The Magazine, Thumbs Up for FolkMADS

Albuquerque The Magazine gave me the opportunity to say what I love and don’t about Albuquerque. Thumbs Up: FolkMADS. I love contributing to and connecting to the living traditions of community-centered American and Western European folk music and dance in New Mexico, from the English influences from the late 1600s, to the local Rocky Mountain squares from the 1820s, through to the current Modern Urban Contra dances we enjoy each week. Thumbs Down: Goatheads. I’m optimistic for Albuquerque‘s Parks and Rec department’s strategy to plant native grass along a portion of the city’s 170 miles of trails to squeeze out the goatheads and their spiny little seeds.  Here’s another option:  host-specific, puncturevine eating weevils. [caption id="attachment_2715" align="aligncenter" width="408"]201511_AlbuquerqueTheMagazine_EBErhardt_FolkMADS_TUTD_p35 Albuquerque The Magazine, November 2015, p. 35[/caption]
... more

Paper published: In Vivo Inhibition of miR-155 Promotes Recovery after Experimental Mouse Stroke

In Vivo Inhibition of miR-155 Promotes Recovery after Experimental Mouse Stroke Ernesto Caballero-Garrido, Juan Carlos Pena-Philippides, Tamar Lordkipanidze, Denis Bragin, Yirong Yang, Erik Barry Erhardt, and Tamara Roitbak. The Journal of Neuroscience, 35(36), pdf, 12446-12464 Online: September 9, 2015 DOI: 10.1523/JNEUROSCI.1641-15.2015 Abstract A multifunctional microRNA, miR-155, has been recently recognized as an important modulator of numerous biological processes. In our previous in vitro studies, miR-155 was identified as a potential regulator of the endothelial morphogenesis. The present study demonstrates that in vivo inhibition of miR-155 supports cerebral vasculature after experimental stroke. Intravenous injections of a specific miR-155 inhibitor were initiated at 48 h after mouse distal middle cerebral artery occlusion (dMCAO). Microvasculature in peri-infarct area, infarct size, and animal functional recovery were assessed at 1, 2, and 3 weeks after dMCAO. Using in vivo two-photon microscopy, we detected improved blood flow and microvascular integrity in the peri-infarct area of miR-155 inhibitor-injected mice. Electron microscopy revealed that, in contrast to the control group, these animals demonstrated well preserved capillary tight junctions (TJs). Western blot analysis data indicate that improved TJ integrity in the inhibitor-injected animals could be associated with stabilization of the TJ protein ZO-1 and mediated by the miR-155 target protein Rheb. MRI analysis showed significant (34%) reduction of infarct size in miR-155 inhibitor-injected animals at 21 d after dMCAO. Reduced brain injury was confirmed by electron microscopy demonstrating decreased neuronal damage in the peri-infarct area of stroke. Preservation of brain tissue was reflected in efficient functional recovery of inhibitor-injected animals. Based on our findings, we propose that in vivo miR-155 inhibition after ischemia supports brain microvasculature, reduces brain tissue damage, and improves the animal functional recovery. SIGNIFICANCE STATEMENT In the present study, we investigated an effect of the in vivo inhibition of a microRNA, miR-155, on brain recovery after experimental cerebral ischemia. To our knowledge, this is the first report describing the efficiency of intravenous anti-miRNA injections in a mouse model of ischemic stroke. The role of miRNAs in poststroke revascularization has been unexplored and in vivo regulation of miRNAs during the subacute phase of stroke has not yet been proposed. Our investigation introduces a new and unexplored approach to cerebral regeneration: regulation of poststroke angiogenesis and recovery through direct modulation of specific miRNA activity. We expect that our findings will lead to the development of novel strategies for regulating neurorestorative processes in the postischemic brain.
... more

Paper published: Nasal vaccination of young rainbow trout (Oncorhynchus mykiss) against infectious hematopoietic necrosis and enteric red mouth disease

Nasal vaccination of young rainbow trout (Oncorhynchus mykiss) against infectious hematopoietic necrosis and enteric red mouth disease Salinas, I, EB Erhardt, and S LaPatra. Developmental & Comparative Immunology, 53(1), pdf, pp. 105–111 Online: June 23, 2015 DOI: 10.1016/j.dci.2015.05.015 Abstract Determining the earliest age at which farmed fish can be successfully vaccinated is a very important question for fish farmers. Nasal vaccines are novel mucosal vaccines that prevent aquatic infectious diseases of finfish. The present study investigates the ontogeny of the olfactory organ of rainbow trout by histology and aims to establish the earliest age for vaccination against infectious hematopoietic necrosis (IHN) and enteric red mouth (ERM) disease using the nasal route. Rainbow trout (Oncorhynchus mykiss) were vaccinated intranasally (I.N) at three different ages: 1050° days (DD) (group A); 450 DD (group B); and 360 DD (group C), or 70, 30 and 24 days post-hatch (dph), respectively. The mean weights of groups A, B and C were 4.69 g, 2.9 g and 2.37 g, respectively. Fish received either a live attenuated IHN virus vaccine, ERM formalin killed bacterin or saline (mock vaccinated). Fish were challenged to the corresponding live pathogen 28 days post-vaccination. IHN vaccine delivery at 360 DD resulted in 40% mortality likely due to residual virulence of the vaccine. No mortality was observed in the ERM nasal delivery groups. Following challenge, very high protection rates against IHN virus were recorded in all three age groups with survivals of 95%, 100% and 97.5% in groups A, B and C, respectively. Survival against ERM was 82.5%, 87.5% and 77.5% in groups A, B and C, respectively. Survival rates did not differ among ages for either vaccine. Our results indicate the feasibility and effectiveness of nasal vaccination as early as 360 DD and vaccination-related mortalities when a live attenuated viral vaccine was used in the youngest fish.
... more

Paper published: Multidimensional frequency domain analysis of full-volume fMRI reveals significant effects of age, gender and mental illness on the spatiotemporal organization of resting-state brain activity

Multidimensional frequency domain analysis of full-volume fMRI reveals significant effects of age, gender and mental illness on the spatiotemporal organization of resting-state brain activity Miller, RL, EB Erhardt, EA Allen, AM Michael, JA Turner, J Bustillo, JM Ford, DH Mathalon, TGM van Erp, S Potkin, A Preda, G Pearlson, and VD Calhoun (2015). Frontiers in Neuroscience. 9(203) pdf, 1–19. Online: June 16, 2015 doi: 10.3389/fnins.2015.00203 Abstract Clinical research employing functional magnetic resonance imaging (fMRI) is often conducted within the connectionist paradigm, focusing on patterns of connectivity between voxels, regions of interest (ROIs) or spatially distributed functional networks. Connectivity-based analyses are concerned with pairwise correlations of the temporal activation associated with restrictions of the whole-brain hemodynamic signal to locations of a priori interest. There is a more abstract question however that such spatially granular correlation-based approaches do not elucidate: Are the broad spatiotemporal organizing principles of brains in certain populations distinguishable from those of others? Global patterns (in space and time) of hemodynamic activation are rarely scrutinized for features that might characterize complex psychiatric conditions, aging effects or gender—among other variables of potential interest to researchers. We introduce a canonical, transparent technique for characterizing the role in overall brain activation of spatially scaled periodic patterns with given temporal recurrence rates. A core feature of our technique is the spatiotemporal spectral profile (STSP), a readily interpretable 2D reduction of the native four-dimensional brain × time frequency domain that is still “big enough” to capture important group differences in globally patterned brain activation. Its power to distinguish populations of interest is demonstrated on a large balanced multi-site resting fMRI dataset with nearly equal numbers of schizophrenia patients and healthy controls. Our analysis reveals striking differences in the spatiotemporal organization of brain activity that correlate with the presence of diagnosed schizophrenia, as well as with gender and age. To the best of our knowledge, this is the first demonstration that a 4D frequency domain analysis of full volume fMRI data exposes clinically or demographically relevant differences in resting-state brain function.
... more

Paper published: Family history of cancer and risk of pediatric and adolescent Hodgkin lymphoma: A Children’s Oncology Group study

Family history of cancer and risk of pediatric and adolescent Hodgkin lymphoma: A Children’s Oncology Group study Linabery, AM, EB Erhardt, MM Richardson, RF Ambinder, DL Friedman, SL Glaser, A Monnereau, LG Spector, JA Ross, and S Grufferman International Journal of Cancer 137(9), pdf, pp. 2163–2174 Online: May 19, 2015 DOI: 10.1002/ijc.29589 Abstract Family history of lymphoid neoplasm (LN) is a strong and consistently observed Hodgkin lymphoma (HL) risk factor, although it has been only marginally examined in pediatric/adolescent patients. Here, healthy control children identified by random digit dialing were matched on sex, race/ethnicity and age to HL cases diagnosed at 0–14 years at Children’s Oncology Group institutions in 1989–2003. Detailed histories were captured by structured telephone interviews with parents of 517 cases and 783 controls. Epstein–Barr virus (EBV) RNA detection was performed for 355 available case tumors. Two analytic strategies were applied to estimate associations between family cancer history and pediatric/adolescent HL. In a standard case–control approach, multivariate conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CIs). In a reconstructed cohort approach, each relative was included as a separate observation, and multivariate proportional hazards regression was used to produce hazard ratios (HRs) and 95% CIs. Using the latter, pediatric/adolescent HL was associated with a positive family history (HR = 1.20, 95% CI: 1.06–1.36), particularly early-onset cancers (HR = 1.30, 95% CI: 1.06–1.59) and those in the paternal lineage (HR = 1.38, 95% CI: 1.16–1.65), with a suggested association for LN in first-degree relatives (HR = 3.61, 95% CI: 0.87–15.01). There were no discernable patterns for EBV+ versus EBV– HL. The clustering of LN within pedigrees may signal shared genetic susceptibility or common environmental exposures. Heritable genetic risk variants have only recently begun to be discovered, however. These results are consistent with other studies and provide a compelling rationale for family-based studies to garner information about genetic susceptibility to HL.
... more

Paper published: Family history of cancer and childhood rhabdomyosarcoma: a report from the Children’s Oncology Group and the Utah Population Database

Family history of cancer and childhood rhabdomyosarcoma: a report from the Children’s Oncology Group and the Utah Population Database Lupo, PJ, HE Danysh, SE Plon, K Curtin, D Malkin, S Hettmer, DS Hawkins, SX Skapek, LG Spector, K Papworth, B Melin, EB Erhardt, S Grufferman, and JD Schiffman Cancer Medicine 2015, 4(5), pdf, 781–790 Online: March 23, 2015 DOI: 10.1002/cam4.448 Abstract Relatively little is known about the epidemiology and factors underlying susceptibility to childhood rhabdomyosarcoma (RMS). To better characterize genetic susceptibility to childhood RMS, we evaluated the role of family history of cancer using data from the largest case–control study of RMS and the Utah Population Database (UPDB). RMS cases (n = 322) were obtained from the Children’s Oncology Group (COG). Population-based controls (n = 322) were pair-matched to cases on race, sex, and age. Conditional logistic regression was used to evaluate the association between family history of cancer and childhood RMS. The results were validated using the UPDB, from which 130 RMS cases were identified and matched to controls (n = 1300) on sex and year of birth. The results were combined to generate summary odds ratios (ORs) and 95% confidence intervals (CI). Having a first-degree relative with a cancer history was more common in RMS cases than controls (ORs = 1.39, 95% CI: 0.97–1.98). Notably, this association was stronger among those with embryonal RMS (ORs = 2.44, 95% CI: 1.54–3.86). Moreover, having a first-degree relative who was younger at diagnosis of cancer (<30 years) was associated with a greater risk of RMS (ORs = 2.37, 95% CI: 1.34–4.18). In the largest analysis of its kind, we found that most children diagnosed with RMS did not have a family history of cancer. However, our results indicate an increased risk of RMS (particularly embryonal RMS) in children who have a first-degree relative with cancer, and among those whose relatives were diagnosed with cancer at <30 years of age.
... more

Paper published: Assessing dynamic brain graphs of time-varying connectivity in fMRI data: application to healthy controls and patients with schizophrenia

Assessing dynamic brain graphs of time-varying connectivity in fMRI data: application to healthy controls and patients with schizophrenia Yu, Q, EB Erhardt, J Sui, Y Du, H He, D Hjelm, M Cetin, S Rachakonda, R Miller, G Pearlson, and VD Calhoun NeuroImage 107, pdf supp, pp. 345–355. Online: 15 February 2015 DOI: 10.1016/j.neuroimage.2014.12.020 Abstract Graph theory-based analysis has been widely employed in brain imaging studies, and altered topological properties of brain connectivity have emerged as important features of mental diseases such as schizophrenia. However, most previous studies have focused on graph metrics of stationary brain graphs, ignoring that brain connectivity exhibits fluctuations over time. Here we develop a new framework for accessing dynamic graph properties of time-varying functional brain connectivity in resting-state fMRI data and apply it to healthy controls (HCs) and patients with schizophrenia (SZs). Specifically, nodes of brain graphs are defined by intrinsic connectivity networks (ICNs) identified by group independent component analysis (ICA). Dynamic graph metrics of the time-varying brain connectivity estimated by the correlation of sliding time-windowed ICA time courses of ICNs are calculated. First- and second-level connectivity states are detected based on the correlation of nodal connectivity strength between time-varying brain graphs. Our results indicate that SZs show decreased variance in the dynamic graph metrics. Consistent with prior stationary functional brain connectivity works, graph measures of identified first-level connectivity states show lower values in SZs. In addition, more first-level connectivity states are disassociated with the second-level connectivity state which resembles the stationary connectivity pattern computed by the entire scan. Collectively, the findings provide new evidence about altered dynamic brain graphs in schizophrenia, which may underscore the abnormal brain performance in this mental illness.
... more