Wide-field Functional Imaging Research Articles

Diverse and asymmetric patterns of single-neuron projectome in regulating interhemispheric connectivity

The corpus callosum, historically considered primarily for homotopic connections, supports many heterotopic connections, indicating complex interhemispheric connectivity. Understanding this complexity is crucial yet challenging due to diverse cell-specific wiring patterns. Here, we utilized public AAV bulk tracing and single-neuron tracing data to delineate the anatomical connection patterns of mouse brains and conducted wide-field calcium imaging to assess functional connectivity across various brain states in male mice. The single-neuron data uncovered complex and dense interconnected patterns, particularly for interhemispheric-heterotopic connections. We proposed a metric “heterogeneity” to quantify the complexity of the connection patterns. Computational modeling of these patterns suggested that the heterogeneity of upstream projections impacted downstream homotopic functional connectivity. Furthermore, higher heterogeneity observed in interhemispheric-heterotopic projections would cause lower strength but higher stability in functional connectivity than their intrahemispheric counterparts. These findings were corroborated by our wide-field functional imaging data, underscoring the important role of heterotopic-projection heterogeneity in interhemispheric communication.

Comparison between transgenic and AAV-PHP.eB-mediated expression of GCaMP6s using in vivo wide-field functional imaging of brain activity.

.We employ transcranial wide-field single-photon imaging to compare genetically encoded calcium sensors under transgenic or viral vector expression strategies. Awake, head-fixed animals and brief visual flash stimuli are used to assess function. The use of awake transcranial imaging may reduce confounds attributed to cranial window implantation or anesthesia states. We report differences in wide-field epifluorescence brightness and peak response to visual stimulation between expression strategies. Other metrics for indicator performance include fluctuation analysis (standard deviation) and regional correlation maps made from spontaneous activity. We suggest that multiple measures, such as stimulus-evoked signal-to-noise ratio, brightness, and averaged visual response, may be necessary to characterize indicator sensitivity and methods of expression. Furthermore, we show that strategies using blood brain barrier-permeable viruses, such as PHP.eB, yield comparable expression and function as those derived from transgenic mice. We suggest that testing of new genetically engineered activity sensors could employ a single-photon, wide-field imaging pipeline involving visual stimulation in awake mice that have been intravenously injected with PHP.eB.

Correction to 'Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches'.

Open AccessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Ma Ying, Shaik Mohammed A., Kim Sharon H., Kozberg Mariel G., Thibodeaux David N., Zhao Hanzhi T., Yu Hang and Hillman Elizabeth M. C. 2017Correction to ‘Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches’Phil. Trans. R. Soc. B3722016053920160539http://doi.org/10.1098/rstb.2016.0539SectionOpen AccessCorrectionCorrection to ‘Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches’ Ying Ma Ying Ma Google Scholar Find this author on PubMed Search for more papers by this author , Mohammed A. Shaik Mohammed A. Shaik Google Scholar Find this author on PubMed Search for more papers by this author , Sharon H. Kim Sharon H. Kim Google Scholar Find this author on PubMed Search for more papers by this author , Mariel G. Kozberg Mariel G. Kozberg Google Scholar Find this author on PubMed Search for more papers by this author , David N. Thibodeaux David N. Thibodeaux Google Scholar Find this author on PubMed Search for more papers by this author , Hanzhi T. Zhao Hanzhi T. Zhao Google Scholar Find this author on PubMed Search for more papers by this author , Hang Yu Hang Yu Google Scholar Find this author on PubMed Search for more papers by this author and Elizabeth M. C. Hillman Elizabeth M. C. Hillman http://orcid.org/0000-0001-5511-1451 Google Scholar Find this author on PubMed Search for more papers by this author Ying Ma Ying Ma Google Scholar Find this author on PubMed Search for more papers by this author , Mohammed A. Shaik Mohammed A. Shaik Google Scholar Find this author on PubMed Search for more papers by this author , Sharon H. Kim Sharon H. Kim Google Scholar Find this author on PubMed Search for more papers by this author , Mariel G. Kozberg Mariel G. Kozberg Google Scholar Find this author on PubMed Search for more papers by this author , David N. Thibodeaux David N. Thibodeaux Google Scholar Find this author on PubMed Search for more papers by this author , Hanzhi T. Zhao Hanzhi T. Zhao Google Scholar Find this author on PubMed Search for more papers by this author , Hang Yu Hang Yu Google Scholar Find this author on PubMed Search for more papers by this author and Elizabeth M. C. Hillman Elizabeth M. C. Hillman http://orcid.org/0000-0001-5511-1451 Google Scholar Find this author on PubMed Search for more papers by this author Published:19 February 2017https://doi.org/10.1098/rstb.2016.0539This article corrects the followingReview ArticleWide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approacheshttps://doi.org/10.1098/rstb.2015.0360 Ying Ma, Mohammed A. Shaik, Sharon H. Kim, Mariel G. Kozberg, David N. Thibodeaux, Hanzhi T. Zhao, Hang Yu and Elizabeth M. C. Hillman volume 371issue 1705Philosophical Transactions of the Royal Society B: Biological Sciences05 October 2016Phil. Trans. R. Soc. B371, 20150360 (2016; Published 29 August 2016) (doi:10.1098/rstb.2015.0360)After publication, a mistake was identified in equation (2.7); the denominators in the equation should have a minus sign rather than a plus. The corrected equation is provided here. 2.7 Previous Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Michelson N, Vanni M and Murphy T Comparison between transgenic and AAV-PHP.eB-mediated expression of GCaMP6s using in vivo wide-field functional imaging of brain activity, Neurophotonics, 10.1117/1.NPh.6.2.025014, 6:02, (1) Murphy T, Michelson N, Boyd J, Fong T, Bolanos L, Bierbrauer D, Siu T, Balbi M, Bolanos F, Vanni M and LeDue J (2020) Automated task training and longitudinal monitoring of mouse mesoscale cortical circuits using home cages, eLife, 10.7554/eLife.55964, 9 Related articlesWide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches05 October 2016Philosophical Transactions of the Royal Society B: Biological Sciences This Issue19 February 2017Volume 372Issue 1714Theme issue ‘Auditory and visual scene analysis’ compiled and edited by Hirohito M. Kondo, Jun-Ichiro Kawahara, Anouk M. van Loon and Brian C.J. Moore Article InformationDOI:https://doi.org/10.1098/rstb.2016.0539PubMed:28044026Published by:Royal SocietyPrint ISSN:0962-8436Online ISSN:1471-2970History: Published online19/02/2017Published in print19/02/2017 License:© 2017 The Authors.Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Citations and impact

Noninvasive evaluation of the vascular response to transplantation of alginate encapsulated islets using the dorsal skin-fold model

Alginate encapsulation reduces the risk of transplant rejection by evading immune-mediated cell injury and rejection; however, poor vascular perfusion results in graft failure. Since existing imaging models are incapable of quantifying the vascular response to biomaterial implants after transplantation, in this study, we demonstrate the use of in vivo laser speckle imaging (LSI) and wide-field functional imaging (WiFI) to monitor the microvascular environment surrounding biomaterial implants. The vascular response to two islet-containing biomaterial encapsulation devices, alginate microcapsules and a high-guluronate alginate sheet, was studied and compared after implantation into the mouse dorsal window chamber (N = 4 per implant group). Images obtained over a 14-day period using LSI and WiFI were analyzed using algorithms to quantify blood flow, hemoglobin oxygen saturation and vascular density. Using our method, we were able to monitor the changes in the peri-implant microvasculature noninvasively without the use of fluorescent dyes. Significant changes in blood flow, hemoglobin oxygen saturation and vascular density were noted as early as the first week post-transplant. The dorsal window chamber model enables comparison of host responses to transplanted biomaterials. Future experiments will study the effect of changes in alginate composition on the vascular and immune responses.

Abstract P4-02-04: Tissue oxyhemoglobin dynamics measured with functional optical imaging immediately after starting chemotherapy correlates with markers of cellular proliferation and inflammation in a rat breast tumor model.

Abstract We have reported that a transient increase of oxyhemoglobin level measured 24 hours after the start of neoadjuvant chemotherapy using noninvasive Diffuse Optical Spectroscopic Imaging (DOSI) may be useful in discriminating nonresponding from reponding breast cancer patients (PNAS. 2011 Aug 30;108(35):14626–31). To elucidate the underlying biological mechanism, we compared optical measured hemoglobin levels to tissue biomarkers in a rat tumor model. Method: An orthotopic mammary tumor model using Fischer 344 rats and MAT3B cells was used for this experiment. 16 mg of cyclophosphamide was administered (i.p.) in 15 rats after tumors had grown to a significant size. A wide-field functional imaging device that utilizes structured near-infrared light was used to measure superficial absolute concentrations of oxyhemoglobin (ctO2Hb) and deoxyhemoglobin (ctHHb) of the tumors. Rats were imaged and sacrificed (two per timepoint) at each of the following timepoints: baseline, 2, 6, 12, 24, 48, 96 hours, and day 8 following the injection. Resected tumors were sectioned after paraffin-embedding and representative slides were used for immunohistochemistry. Cellular markers of proliferation (measured by Ki67), apoptosis (Caspase3), NK cells (ANK61), and macrophages (MAC387) were counted in each slide using Image J software. Result: Average tumors baseline values of ctO2Hb and ctHHb were 81.4 µM (±9.2 SD) and 22.4 µM (±4.1 SD) respectively. In most rats, both levels gradually increased from baseline to 24 hours after the injection and reached a maximum at 48 hours and then declined until Day 8. At 24 hours, ctO2Hb was significantly higher than baseline [96.8 µM (±8.8 SD) vs. 81.4µM (±9.2 SD), p = 0.003 using Student's t-test]. This trend was mimicked in the tissue markers of cellular proliferation and apoptosis, which peaked at 24 through 48 hours and then dropped. The average NK cell count was also found to rise consistently through the course of monitoring and reached the highest at day 8, while macrophage counts reached a peak at 48 hours and then declined. The differences between baseline and 24 hours for these were statistically significant: Ki67 [294 (±107 SD) vs. 115 (±68 SD), p = 0.0002], Caspase3 [2916 (±1383 SD) vs. 136 (±150 SD), p < 0.0001], NK cells [635 (±329 SD) vs. 159 (±110 SD), p = 0.0001], and macrophage markers [281 (±260 SD) vs. 39 (±31 SD), p = 0.01]. Conclusion: We observed an increase in oxyhemoglobin early after chemotherapy, closely linked to changes in cellular proliferation, apoptosis, NK cells and macrophage accumulation. Early optical changes may be linked to chemotherapy-induced tumor metabolic and acute inflammatory responses. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-02-04.

Longitudinal, multimodal functional imaging of microvascular response to photothermal therapy

Although studies have shown that photothermal therapy can coagulate selectively abnormal vasculature, the ability of this method to achieve consistent, complete removal of the vasculature is questionable. We present the use of multimodal, wide-field functional imaging to study, in greater detail, the biological response to selective laser injury. Specifically, a single-platform instrument capable of coregistered fluorescence imaging and laser speckle imaging was utilized to monitor vascular endothelial growth factor gene expression and blood flow, respectively, in a transgenic rodent model. Collectively, the longitudinal, in vivo data collected with our instrument suggest that the biological response to selective laser injury involves early-stage redistribution of blood flow, followed by increased vascular endothelial growth factor promoter activity to stimulate pro-angiogenic events.