Carl Petersen and Alexei Verkhratsky share their research on homeostatic neuroglia and imaging of neuronal network function. This webinar is brought to you by APS’ new journal, Function, and part of their Physiology in Focus learning series. During this exclusive live webinar, Carl Petersen and Alexei Verkhratsky discuss astrocyte-mediated homeostatic control of the central nervous system, and how optical and 2-photon microscopy can be used for functional neuroimaging. Imaging Neuronal Function Carl Petersen, PhD Highly dynamic and spatially distributed neuronal circuits in the brain control mammalian behavior. Through technological advances, optical measurements of neuronal function can now be carried out in behaving mice at multiple scales. Wide-field imaging allows the dynamic interactions between different brain areas to be studied as sensory information is processed and transformed into behavioral output. Within a brain region, two-photon microscopy can be used to image the neuronal network activity with cellular resolution allowing different types of projection neurons to be distinguished. Together optical methods provide versatile tools for causal mechanistic understanding of neuronal network function in mice. Astrocytes: indispensable neuronal supporters in sickness and in health Alexei Verkhratsky, MD, PhD, DSc The nervous system is composed of two arms: the executive neurons and the homeostatic neuroglia. The neurons require energy, support, and protection, all of which is provided by the neuroglia. Astrocytes, the principal homeostatic cells of the brain and spinal cord, are tightly integrated into the neural networks and act within the context of the neural tissue. As astrocytes control the homeostasis of the central nervous system at all levels of organization, from the molecular to the whole organ level, we can begin to define and understand brain vulnerabilities to aging and diseases.

1. Welcome to the webinar… before we start, explore Function!

2. The Brain as aWhole: Executive Neurons
and Sustaining Homeostatic Glia
Carl Petersen, PhD
Professor of Neuroscience
École Polytechnique Féderale de Lausanne
AlexeiVerkhratsky, MD, PhD, DSc
Professor of Neurophysiology
University of Manchester

3. The Brain as aWhole: Executive Neurons
and Sustaining Homeostatic Glia
Carl Petersen and AlexeiVerkhratsky share
their research on homeostatic neuroglia
and imaging of neuronal network function.
This webinar is brought to you by APS’ new
journal, Function, and part of their
Physiology in Focus learning series.

4. Evidence Reviews
Physiology of Astroglial Excitability
https://doi.org/10.1093/function/zqaa016
Making a Dent in Dent Disease
https://doi.org/10.1093/function/zqaa017
Perspectives
Ion and Water Absorption by the Kidney Proximal Tubule: Computational
Analysis of Isosmotic Transport
https://doi.org/10.1093/function/zqaa014
New Insight into a Classic Stem Cell: the Satellite Cell may Communicate
with the Muscle Fiber via Extracellular Vesicles
https://doi.org/10.1093/function/zqaa015
Research Articles
Adipose Tissue Inflammation Is Directly Linked to Obesity-Induced
Insulin Resistance, while Gut Dysbiosis and Mitochondrial Dysfunction
Are Not Required
https://doi.org/10.1093/function/zqaa013
Impaired Myocardial Energetics Causes Mechanical Dysfunction in
Decompensated Failing Hearts
https://doi.org/10.1093/function/zqaa018
Some of our recently published articles…

5. Copyright 2020 C. Petersen, American Physiological Society and InsideScientific. All Rights Reserved.
Carl Petersen, PhD
Professor of Neuroscience
École Polytechnique Féderale de
Lausanne
Imaging
Neuronal
Function

6. Brain Function
The function of the brain is to govern behavior.
Understanding the physiological mechanisms
of brain function is necessary for developing
rational therapies for the many brain disorders.
As a first step, we aim to discover causal
mechanisms of neural circuit function in mice
carrying out simple sensorimotor tasks.

7. Goal-directed behavior

8. Whisker detection task
Hit
Miss
Lick
Reward
Reward
Lick
C2 whisker stim No stim
No stimC2 whisker stim

9. Sensorimotor transform
X

10. From whisker to cortex

11. Neuronal circuits

12. Optical imaging
To understand how the brain governs behavior,
we need to measure neuronal activity during
quantified behavior. Multiscale optical functional
imaging:
i) Wide field fluorescence imaging of interacting
brain areas
ii) Two-photon imaging of neuronal network
activity with cellular resolution

13. Voltage imaging

14. Fast voltage signals

15. Imaging the brain in action
Ferezou et al. (2007) Neuron 56: 907-923.

16. Cortex-wide signals
Kyriakatos et al. (2017) Neurophotonics 4: 031204.

17. Single-cell electroporation
Pala & Petersen (2015) Neuron 85: 68-75.

18. wS1 -> wM1 neuron
Yamashita et al. (2013) Neuron 80: 1477-1490.

19. wS1 -> wS2 neuron
Yamashita et al. (2013) Neuron 80: 1477-1490.

20. wS1 projection neurons
Yamashita et al. (2013) Neuron 80: 1477-1490.

21. Retrograde labelling
Yamashita et al. (2013) Neuron 80: 1477-1490.

22. GCaMP6f transgenic mice
Vavladeli et al. (2020) FUNCTION 1: zqaa008.
GCaMP6f
S2p
M1p

24. Neuronal network activity

25. Excitation of S2p neurons
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

26. Lick-triggered signals
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

27. Correlated S2p activity
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

28. Synaptic connectivity
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

29. Causal role for wS1 & wS2
Le Merre et al. (2018) Neuron 97: 83-91.

30. Early steps in perception
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

31. Summary - perception
We begin to understand early steps in sensory
perception, but there is much more to learn…
Vavladeli et al. (2020) FUNCTION 1: zqaa008.

32. Summary - imaging
Optical imaging helps understand spatiotemporal
dynamics of cortical sensory processing during
simple perceptual tasks, and reveals distinct
activities of different types of intermingled
projection neurons.
Future technical developments include calcium
sensors with improved sensitivity, and red calcium
indicators for deeper imaging.

33. Thank you!
Isabelle Ferezou
Alexandros
Kyriakatos
Aurelie Pala
Takayuki Yamashita
Angeliki Vavladeli
Pierre Le Merre
Sylvain Crochet
Tanya Daigle
Hongkui Zeng

34. Astrocytes: supporting
neurones in sickness
and in health
AlexeiVerkhratsky, MD, PhD, DSc
Professor of Neurophysiology
University of Manchester
Copyright 2020 A.Verkhratsky, American Physiological Society and InsideScientific. All Rights Reserved.

35. The human brain, is arguably the most complex structure known to
the natural sciences. Evolution packed about 200 billion cells (~100
billions of neurones and another 100 billion supportive cells, which
include neuroglia, endothelial cells, perycites and smooth muscle
cells of blood vessels) into 1.5 litre of volume of the skull.
These cells are connected with ~ 30 - 100 trillion connections and
all this operates at the cost of 300 - 400 Calories (or 12 W/hour) of
power per day.
As a computing machine the brain has an operational memory in a
range of > 2.5 petabites. The brain operates at petaFLOP range,
one of the fastest world supercomputer Tianhe-2 in Guangzhou,
China, has a maximum processing speed of 54.902 petaFLOPS
and does it at the support of 17.6 MW of power, housed in a building
occupying ~ 720 m2.
The Human Brain

36. Brain organ-wide networks
Neuroglial cells support
all these networks

37. The Numbers

38. How we imagine the brain:

39. And this is how it looks in reality:

40. Classification of Neuroglia
Verkhratsky & Butt (2013): Physiology and Pathophysiology of Neuroglia, Wiley, 560 pp.

41. Astrocytes

42. Astrocytes (literally “star-like cells”): the homeostatic cells of the brain
Von Lenhossek M. (1895). Der feinere Bau des Nervensystems
im Lichte neuester Forschung. Berlin: Fischer's Medicinische
Buchhandlung H. Kornfield.
“I would suggest that all supporting cells be named spongiocytes.
And the most common form in vertebrates be named spider cells
or astrocytes, and use the term neuroglia only cum grano salis
(with a grain of salt), at least until we have a clearer view.”
Michael von Lenhossek
(1863 – 1937)
Protoplasmic and Fibrous glia
Andriezen WL. The neuroglia elements of the brain. Br Med J 2: 227-230, 1893.
Kölliker A. Handbuch der Gewebelchre des menschen. Leipzig: 1893
Early images of astrocytes drawn
by Camillo Golgi (1843 – 1926)

43. Definition of astroglia
Astrocytes are neural cells of ectodermal, neuroepithelial origin
that sustain homeostasis and provide for defence of the central nervous system
Verkhratsky & Nedergaard (2018): Physiol Rev, 98, 239-389

44. Astroglia
(20 – 40% of all glial cells in human CNS)
Verkhratsky et al. (2019). Pflugers Arch 471, 1247-1261

45. Visualisation and morphological heterogeneity of astrocytes
GFAP-EC GFAP-PC GFAP-CA1
s100B-EC s100B-Hipp GS-CA1
Rodriguez & Verkhratsky, own observations

46. Visualisation of astrocytic morphology
Verkhratsky & Nedergaard
(2018): Physiol Rev, 98,
239-389

47. Oberheim, Takano, … & Nedergaard (2009): J Neurosci 29: 3276-3287, 2009.
Mammalian astrocytes: evolutionary advance from rodents to humans

48. Interlaminar and varicose astrocytes in the human brain
Andriezen (1893): Br Med J 2, 227-230.
Oberheim, Takano, … & Nedergaard (2009): J Neurosci 29: 3276-3287, 2009.

49. The astroglial synaptic cradle
Physiology of glia: the concept of multipartite synapse
Verkhratsky & Nedergaard (2014). PhylTrans.Ser B, 369: 20130595

50. Franze K, Grosche J, Skatchkov SN, Schinkinger S, Foja C, Schild D, Uckermann O,
Travis K, Reichenbach A, Guck J. 2007. Proc Natl Acad Sci U S A 104(20):8287-92.
Astrocytes: Exotic function
Müller glial cells act as light guides in the retina

51. General
astrogliopathology

52. Neuroglia respond to the insults; neurones succumb to their fate
Verkhratsky & Parpura (2015): 85, Neurobiology of Disease, 85, 254-261

53. Astrogliopathology

54. Reactive astrogliosis
Pekny, Pekna, Messing, Steinhauser, Lee, Parpura, Hol,
Sofroniew & Verkhratsky. Acta Neuropathol 131: 323-345, 2016.
NO A1/A2 divide!

55. Neuroglial paralysis
drives neurodegeneration

56. Alois Alzheimer
(1864-1915)
Augusta Deter
(1849-1906)
Emil Kraepelin
(1856-1926)
Alzheimer’s disease (Alzheimersche Krankheit): rapidly progressive, young onset,
peculiar (“eigenartig”) dementia with pathology, distinct from senile dementia
Kraepelin (1910): Psychiatrie: Ein Lehrbuch fur Studierende und Arzte. 8th edition. Leipzig: Barth
History of Alzheimer’s disease
1st,2nd cases: Alzheimer 1907; 3rd: O Fischer; 4th: F Bonfiglio; 1908; 5th: G Perusini, 1909

57. The weakness of the brain evinces itself in impairment
of memory, in slowness of apprehension, in inability to
fix the thoughts long on one thing, and the tendency,
therefore, to wander from one subject to another, and to
travel to and fro, which may pass on to want of control,
or imbecility, or even to dementia.
This last, saddest state of all, was witnessed only in two
of our centenarians. Indeed, the brain in many held out
as well or better than other organs - which may be
regarded one of the bright rays, if not the brightest, in
the centenarian landscape.
Cumulative occurrence of dementia for 900 patients:
Centenarians: 2 out of 74
Persons between 80 and 100: 826 in total
Intelligence:
"High" intelligence in 15%
"Average" intelligence in 74%
"Low" intelligence" in 11%
Memory:
"Good" in 78%
Dramatic rise in cases of dementia over last 130 years

58. Chen & Fernandez (2001):
Frontiers in Bioscience 6, e30-40,
In the year 2000 88%, of all centenarians, or 15 out
of the 17, living in the Netherlands had dementia
Blansjaar, Thomassen & Van Schaick
(2000): Int. J. Geriatr. 15, 219–225
Dramatic rise in cases of dementia over last 130 years

59. Neurodegeneration is the progressive loss of function
and structure of neurones, including death of neurones
A varied assortment of central nervous system disorders
characterised by gradual and progressive loss of neural tissue
The process in which neurones die
Progressive loss of neurologic functions.
Neurodegeneration – neurone-centric view

60. Animal models of AD
APPS mouse model
Lesion (focal injections)
- Specific regions: Nucleus
basalis magnocelularis
- Neurotoxins: Quinolic ac.
Ibotenic ac.
(© 2008 NeuroScience Associates. Knoxville)
Transgenic models:
Expressing various
combinations of mutant genes
isolated from family AD (APP,
PS, tau)
Triple transgenic model
expresses PS1M146V,
APPSwe, and tauP301L
transgenes Rodriguez-Arellano, Olabarria, Chvatal & Verkhratsky,
(2009): Cell Death & Differentiation, 16, 378 - 385

61. Olabarria, Noristani, Verkhratsky & Rodriguez (2010): Glia 58: 831-838.
Hippocampus in AD: Astroglial atrophy complements astrogliosis
Rodriguez-Arellano, Olabarria, Chvatal & Verkhratsky, (2009): Cell
Death & Differentiation, 16, 378 - 385

62. Amyloidosis in prefrontal cortex is not associated with astrogliosis
Kulijewicz-Nawrot M, Verkhratsky A… Rodriguez JJ. (2012) J Anat, 221: 252-262.

63. Astroglial atrophy
in human pathology

64. Severe atrophy of interlaminar astrocytes in Alzheimer's disease
Healthy male, 73 years AD, Braak VI, male, 73 years
Colombo, Quinn & Puissant (2002): Brain Res Bull 58, 235-242.

65. Astrocyte activation and synaptic localisation peaks
at Braak stage III-IV prior to synapse loss
Martina Hughes
& Wendy Noble
GFAP AT8 DAPI

66. Astroglial atrophy at late stages of family AD
Rodriguez, Gardinal & Verkhratsky (2019): in preparation

67. Failed astrogliosis in severe AD
Carter & Nordberg (2012): J Nucl Med 53, 37-46.
Verkhratsky, Marutle, Rodriguez-Arellano &
Nordberg, (2015): Neuroscientist 21, 552-568

68. Human astrocytes derived from stem cells
Jones, Verkhratsky & Mohamed (2017): CDDis, 8, e2696

69. Human astrocytes derived from stem cells from AD patients are atrophic
Jones, Verkhratsky & Mohamed (2017): CDDis, 8, e2696

70. AD pathology affects astrocytes and does not affect neurones
Jones, Verkhratsky & Mohamed (2017): CDDis, 8, e2696

71. Life style changes can rescue glial
atrophy and improve memory
and cognition
(1) Diet – caloric restriction

72. Caloric restricted diet increases volume fraction of perisynaptic astroglial
processes, which arguably results in an increased synaptic coverage
Popov… Verkhratsky & Semyanov (2020): Cell Death & Disease, in press

73. Caloric restriction instigates outgrowth of astroglial perisynaptic processes,
which increases efficacy of K+ buffering and glutamate uptake,
reduces glutamate spillover and augments LTP
Popov… Verkhratsky & Semyanov (2020): Cell Death & Disease, in press

74. Life style changes can rescue glial
atrophy and improve memory
and cognition
(2) Environmental stimulation

75. Enriched environment and physical activity reverse
atrophy of astrocytes in the hippocampus of AD transgenic mice
Rodríguez, Terzieva, Olabarria & Verkhratsky (2013): Cell Death & Dis, 4, e678

76. HH3 - phosphorylated Histone 3,
proliferation marker
NeuN - neuronal nucleus
marker
Rodriguez JJ ,… & Verkhratsky A. (2011). Curr Alzheimer Res 8, 707-717.
Physical activity and enriched environment stimulates
neurogenesis in 3xTG AD mice

77. Neuroglial hypothesis of neurodegeneration
Verkhratsky et al (2019): Pflugers Arch 471, 1247-1261.
Verkhratsky (2019):. Cold Spring Harb Persp Biol 11, a035188.
Verkhratsky et al (2016): Curr Opinion Pharmacol 26, 74-79.
Verkhratsky et al. (2015): The Neuroscientist 21, 552-568.
Verkhratsky et al (2010): Neurotherapeutics 7, 399 – 412.
AD Progression

78. Stay intellectually engaged
At best, mental activity seems to protect against age-related declines and
progression to Alzheimer’s disease. At worst, it increases an individual’s
baseline level so that age related declines begin to affect everyday
functioning later in life.
Maintain cardiovascular physical activity
Exercise aids executive function, reduces declines in tissue density in
frontal, parietal and temporal cortex, and might have global effects on the
brain.
Minimize chronic stressors
Proneness to distress, measured by the personality trait of neuroticism, is
associated with increased risk of Alzheimer’s disease and a faster rate of
cognitive decline.
Maintain a brain-healthy diet
How to fight brain ageing

79. Astrocytes are central cellular elements of all
neurological diseases; astroglial malfunction defines
disease progression and neurological outcome.
Targeting of astroglia may provide a new principle for
prevention and/or treatment of neurological disorders.
Conclusions: Reassessment of neurocentrism

80. Helmut Kettenmann
Frank Kirchhoff
Uwe Karsten Hanisch
Sergei Kirischuk
Vitaly Matiash
Thomas Möller
Jana Hartmann
Johan Neuhaus
Sebastian Tuschick
Stephen Haas
Johannes Brockhaus
Gabriela von Blankenfeld
Dorothea Hoppe
Jacqueline TrotterHomburg University, Germany
Frank Kirchhoff, Hannah Jahn
Heidelberg University/Max-Delbruck Center
for Molecular Medicine, Berlin, Germany
Manchester University, UK
Bonn University, Germany
Christian Steinhäuser
Portsmouth University, UK
Arthur Butt
Uliana Lalo
Yuri Pankratov
Alan North
Nancy Rothwell
Weihong Ma
Pavel Pakhotin
Ambra Grolla
Special thanks to
David Langslow for
help with researching
ancient Greek texts
Ljubljana University, Slovenia
Robert Zorec
Leipzig University, Germany
Andreas ReichenbachInstitute of Experimental Medicine, Prague
Eva Sykova, Alexandr Chvatal,
Govindan Dayanithi
Kiyshu University, Japan
Mami Noda
Birmingham University, USA
Vlad Parpura, Reno Reyes
Iqerbasque/Basque Research Foundation
Jose Julio Rodriguez, Carlos Matute
Markel Olabarria, Chia-Yu Yeh, Harun Noristani
Liang Peng
University of Shenyang, China
Copenhagen University, Denmark
Maiken Nedergaard

81. Thank you for
participating!
Carl Petersen, PhD
Professor of Neuroscience
École Polytechnique Féderale de Lausanne
AlexeiVerkhratsky, MD, PhD, DSc
Professor of Neurophysiology
University of Manchester
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