1
|
Bohraus Y, Merkle H, Logothetis NK, Goense J. Laminar differences in functional oxygen metabolism in monkey visual cortex measured with calibrated fMRI. Cell Rep 2023; 42:113341. [PMID: 37897728 DOI: 10.1016/j.celrep.2023.113341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/23/2023] [Accepted: 10/10/2023] [Indexed: 10/30/2023] Open
Abstract
Blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD fMRI) of cortical layers relies on the hemodynamic response and is biased toward large veins on the cortical surface. Functional changes in the cerebral metabolic rate of oxygen (ΔCMRO2) may reflect neural cortical function better than BOLD fMRI, but it is unknown whether the calibrated BOLD model for functional CMRO2 measurement remains valid at high resolution. Here, we measure laminar ΔCMRO2 elicited by visual stimulation in macaque primary visual cortex (V1) and find that ΔCMRO2 peaks in the middle of the cortex, in agreement with autoradiographic measures of metabolism. ΔCMRO2 values in gray matter are similar as found previously. Reductions in CMRO2 are associated with veins at the cortical surface, suggesting that techniques for vein removal may improve the accuracy of the model at very high resolution. However, our results show feasibility of laminar ΔCMRO2 measurement, providing a physiologically meaningful metric of laminar functional metabolism.
Collapse
Affiliation(s)
- Yvette Bohraus
- Department of Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany
| | | | - Nikos K Logothetis
- Department of Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany; Department of Physiology of Cognitive Processes, International Center for Primate Brain Research, Songjiang District, Shanghai 201602, China; Centre for Imaging Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Jozien Goense
- Department of Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany; Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA; Department of Psychology, University of Illinois, Urbana-Champaign, Champaign, IL 61820, USA; Department of Bioengineering, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
| |
Collapse
|
2
|
Liu X, Irwin DA, Huang C, Gu Y, Chen L, Donohue KD, Chen L, Yu G. A Wearable Fiber-Free Optical Sensor for Continuous Monitoring of Cerebral Blood Flow in Freely Behaving Mice. IEEE Trans Biomed Eng 2023; 70:1838-1848. [PMID: 37015409 PMCID: PMC10542964 DOI: 10.1109/tbme.2022.3229513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Wearable technologies for functional brain monitoring in freely behaving subjects can advance our understanding of cognitive processing and adaptive behavior. Existing technologies are lacking in this capability or need procedures that are invasive and/or otherwise impede brain assessments during social behavioral conditions, exercise, and sleep. METHODS In response a complete system was developed to combine relative cerebral blood flow (rCBF) measurement, O2 and CO2 supplies, and behavior recording for use on conscious, freely behaving mice. An innovative diffuse speckle contrast flowmetry (DSCF) device and associated hardware were miniaturized and optimized for rCBF measurements in small subject applications. The use of this wearable, fiber-free, near-infrared DSCF head-stage/probe allowed no craniotomy, minimally invasive probe implantation, and minimal restraint of the awake animal. RESULTS AND CONCLUSIONS Significant correlations were found between measurements with the new DSCF design and an optical standard. The system successfully detected rCBF responses to CO2-induced hypercapnia in both anesthetized and freely behaving mice. SIGNIFICANCE Collecting rCBF and activity information together during natural behaviors provides realistic physiological results and opens the path to exploring their correlations with pathophysiological conditions.
Collapse
Affiliation(s)
- Xuhui Liu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Daniel A. Irwin
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Chong Huang
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Yutong Gu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - Li Chen
- Biostatistics and Bioinformatics Shared Resource Facility, Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Kevin D. Donohue
- Department of Electrical and Computer Engineering, University of Kentucky, Lexington, KY, USA
| | - Lei Chen
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA
| | - Guoqiang Yu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| |
Collapse
|
3
|
López-Pérez ME, Romero-Arenas S, Giráldez-García MA, Colomer-Poveda D, Márquez G. Acute psychophysiological responses during exercise while using resistive respiratory devices: A systematic review. Physiol Behav 2022; 256:113968. [PMID: 36155205 DOI: 10.1016/j.physbeh.2022.113968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 10/31/2022]
Abstract
Different studies have observed that respiratory muscle training (RMT) improve the endurance and strength of the respiratory muscles, having a positive impact on performance of endurance sports. Nevertheless, it remains to be clarified how to improve the efficiency of such training. The objective of this systematic review was to evaluate the acute physiological responses produced by training the respiratory muscles during exercise with flow resistive devices because such information may support us improve the efficiency of this type of training. A search in the Medline, Science Direct, Web of Science and Scopus databases was conducted, following the PRISMA guidelines. The methodological quality of the articles was assessed using the PEDro scale. Nineteen studies met the inclusion criteria and a total of 212 subjects were included in the studies. The RMT method used in all studies was flow resistive loading, whereas the constant load exercise was the most common type of exercise among the studies. The results obtained seem to indicate that the use of this type of training during exercise reduces the performance, the lactate (La-) values and the ventilation, whereas the end - tidal partial pressure of carbon dioxide (PCO2) is increased.
Collapse
Affiliation(s)
- María E López-Pérez
- Department of Physical Education, IES El Palmeral, Hermano Lázaro s/n, Vera, Almería 04620, Spain.
| | | | - Manuel A Giráldez-García
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - David Colomer-Poveda
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| |
Collapse
|
4
|
Cao R, Tran A, Li J, Xu Z, Sun N, Zuo Z, Hu S. Hemodynamic and oxygen-metabolic responses of the awake mouse brain to hypercapnia revealed by multi-parametric photoacoustic microscopy. J Cereb Blood Flow Metab 2021; 41:2628-2639. [PMID: 33899557 PMCID: PMC8504963 DOI: 10.1177/0271678x211010352] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 11/16/2022]
Abstract
A widely used cerebrovascular stimulus and common pathophysiologic condition, hypercapnia is of great interest in brain research. However, it remains controversial how hypercapnia affects brain hemodynamics and energy metabolism. By using multi-parametric photoacoustic microscopy, the multifaceted responses of the awake mouse brain to different levels of hypercapnia are investigated. Our results show significant and vessel type-dependent increases of the vessel diameter and blood flow in response to the hypercapnic challenges, along with a decrease in oxygen extraction fraction due to elevated venous blood oxygenation. Interestingly, the increased blood flow and decreased oxygen extraction are not commensurate with each other, which leads to reduced cerebral oxygen metabolism. Further, time-lapse imaging over 2-hour chronic hypercapnic challenges reveals that the structural, functional, and metabolic changes induced by severe hypercapnia (10% CO2) are not only more pronounced but more enduring than those induced by mild hypercapnia (5% CO2), indicating that the extent of brain's compensatory response to chronic hypercapnia is inversely related to the severity of the challenge. Offering quantitative, dynamic, and CO2 level-dependent insights into the hemodynamic and metabolic responses of the brain to hypercapnia, these findings might provide useful guidance to the application of hypercapnia in brain research.
Collapse
Affiliation(s)
- Rui Cao
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Angela Tran
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Jun Li
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA
| | - Zhiqiang Xu
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Naidi Sun
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Zhiyi Zuo
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA
| | - Song Hu
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| |
Collapse
|
5
|
Watson AN, Berthiaume AA, Faino AV, McDowell KP, Bhat NR, Hartmann DA, Shih AY. Mild pericyte deficiency is associated with aberrant brain microvascular flow in aged PDGFRβ +/- mice. J Cereb Blood Flow Metab 2020; 40:2387-2400. [PMID: 31987006 PMCID: PMC7820684 DOI: 10.1177/0271678x19900543] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The receptor tyrosine kinase PDGFRβ is essential for pericyte migration to the endothelium. In mice lacking one allele of PDGFRβ (PDGFRβ+/-), previous reports have described an age-dependent loss of pericytes in the brain, leading to cerebrovascular dysfunction and subsequent neurodegeneration reminiscent of that seen in Alzheimer's disease and vascular dementia. We examined 12-20-month-old PDGFRβ+/- mice to better understand how pericyte loss affects brain microvascular structure and perfusion in vivo. We observed a mild reduction of cortical pericyte number in PDGFRβ+/- mice (27% fewer cell bodies) compared to controls, but no decrease in pericyte coverage of the endothelium. This mild degree of pericyte loss caused no discernable change in cortical microvascular density, length, basal diameter or reactivity to hypercapnia. Yet, it was associated with an increase in basal blood cell velocity, primarily in pre-capillary arterioles. Taken together, our results suggest that mild pericyte loss can lead to aberrant cerebral blood flow despite a lack of apparent effect on microvascular structure and reactivity.
Collapse
Affiliation(s)
- Ashley N Watson
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andree-Anne Berthiaume
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Anna V Faino
- Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA
| | - Konnor P McDowell
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Narayan R Bhat
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - David A Hartmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA.,Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA.,Department of Pediatrics, University of Washington, Seattle, WA, USA
| |
Collapse
|
6
|
Hypercapnia Impairs Vasoreactivity to Changes in Blood Pressure and Intraocular Pressure in Rat Retina. Optom Vis Sci 2020; 96:470-476. [PMID: 31274734 DOI: 10.1097/opx.0000000000001400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
SIGNIFICANCE The balance between oxygen and carbon dioxide sets the resting tone (or diameter) of retinal blood vessels. Eyes that are hypercapnic use up their "vasodilatory reserve" and therefore fail to respond adequately to changes in intraocular or blood pressure. PURPOSE Retinal vessels are regulated by both myogenic and metabolic mechanisms. We considered whether alteration of metabolic status would modify the vascular response to ocular perfusion pressure (OPP) lowering in rat retina. METHODS In pentobarbital anesthetized adult Brown-Norway rats, normocapnia or hypercapnia was achieved by artificially ventilating animals with air or 5% carbon dioxide in ~30% oxygen, respectively. Ocular perfusion pressure was gradually reduced to ~20 mmHg by either lowering blood pressure (slowly drawing blood from a femoral artery/vein) or manometrically increasing intraocular pressure under normocapnic or hypercapnic conditions. In all four groups (n = 7 eyes for each), a confocal scanning laser ophthalmoscope was used to acquire image sequences centered on the optic nerve throughout pressure modification. The diameter of arterioles and venules at various OPP levels was measured and expressed as percentage relative to their own baseline. The response of arterioles and venules to OPP lowering was compared between normocapnic and hypercapnic groups. RESULTS Average arterial carbon dioxide partial pressures were 36.9 ± 2.6 mmHg in normocapnic and 64.1 ± 5.9 mmHg in hypercapnic (P < .001) animals. In the normocapnic groups, blood pressure lowering and intraocular pressure elevation resulted in significant vasodilation of both arterioles and venules (P < .0001). In the hypercapnic groups, OPP lowering-induced vasodilation was significantly attenuated compared with the corresponding normocapnic groups (P < .0001 for both, two-way analysis of variance). CONCLUSION Hypercapnia significantly modified myogenic vascular autoregulation in response to OPP reduction.
Collapse
|
7
|
Romero-Arenas S, López-Pérez E, Colomer-Poveda D, Márquez G. Oxygenation Responses While Wearing the Elevation Training Mask During an Incremental Cycling Test. J Strength Cond Res 2019; 35:1897-1904. [DOI: 10.1519/jsc.0000000000003038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|