Brain Star Award Feature: Ghazaleh Eskandari-Sedighi, University of Alberta

Ghazaleh Eskandari-Sedighi Ghazaleh Eskandari-Sedighi

Identification of CD33m as a new protective factor in Alzheimer’s Disease development.

Immune cells in the brain, called microglia, are thought to be critical in Alzheimer’s disease (AD) development through numerous functions, including their ability to remove amyloid beta (Aβ), which is protein that accumulates in the brains of AD patients. In this study, Ghazaleh Eskandari-Sedighi, working in Matthew Macauley’s laboratory at the University of Alberta, focused on understanding the mechanism of action of a protein called CD33, which has been identified as one of the top-ranked drivers in the development of AD and that is predominantly found in microglia in the brain. By transferring different versions (called isoforms) of this protein in a mouse model of AD, they were able to show that these different isoforms have opposite effects on microglial cells and AD progression.

CD33 is a receptor that modulates immune response that exists in two forms:  a long isoform CD33M (Major) and a short isoform: CD33m (minor). Understanding how CD33 isoforms differentially impact microglial cell function has been challenging due to functional divergence between CD33 from mouse and humans. In this study, the researchers introduced the human CD33 gene in a mouse model of AD, which accumulates Aβ protein. In these mice, they found that CD33 isoforms have opposing effects on the response of microglia to Aβ accumulation. The larger CD33M increases the total level of Aβ and formation of plaques with a diffuse nature, which correlates with fewer number of microglia as well as higher number of dysfunctional neurons. In contrast, CD33m gives rise to opposite outcomes; beyond decreasing total Aβ levels, CD33m skews formation of compact Aβ deposits, correlating with increased microglia and fewer dysfunctional neurons. Overall, this work reveals how CD33, as a top genetic susceptibility factor for AD, is connected to microglial cell function.

Read the full story here: https://can-acn.org/brain-star-award-winnerghazaleh-eskandari-sedighi/

Scientific publication: Eskandari-Sedighi, G., Crichton, M., Zia, S. et al. Alzheimer’s disease associated isoforms of human CD33 distinctively modulate microglial cell responses in 5XFAD mice. Mol Neurodegeneration 19, 42 (2024).

https://doi.org/10.1186/s13024-024-00734-8

Read CAN’s brief submitted to the 2025 FINA Pre-budget consultations

We are happy to share with you CAN’s pre-budget brief submission for the Consultations launched by the Finance committee of the House of Commons.

https://can-acn.org/wp-content/uploads/2025/07/CAN-FINA-Submission-July-2025_final-1.pdf

Our two main recommendations are an effective doubling of tri-agency budget over the coming years, and increased investment in brain-related programs. 

We believe if multiple organizations submit similar recommendations, including the proposal to double tri-agency funds as a nation-building project, this could have some impact, and therefore wanted to share this with you in advance of the submission deadline, which is August 1st.

In case you missed it, here is the call for briefs:

https://www.ourcommons.ca/DocumentViewer/en/45-1/FINA/news-release/13575827

and here is a link to submit, should your organisation also want to weigh in:

https://www.ourcommons.ca/committees/en/FINA/StudyActivity?studyActivityId=13109197

Also note that individuals can also send in briefs, and that we will be encouraging CAN members to do so. 

It is also possible to send formal submission directly to the Department of Finances here:

https://www.canada.ca/en/department-finance/programs/consultations/2025/pre-budget-consultations-2025.html

The deadline for this second consultation  is Aug 28, and CAN will be sending a similar brief to this consultation also.

Brain Star Award winner feature: Diego B. Piza, Western University

Diego B. Piza

Better understanding the role of vision in the brain’s representation of space by studying freely moving primates

The hippocampus is a structure of the mammalian brain that has been implicated in spatial memory and navigation. Its role has been primarily studied in nocturnal mammals, such as rats, that lack many adaptations for daylight vision. Here, Diego B. Piza, working in the laboratory of Julio Martinez-Trujillo at Western University, demonstrates that during 3D navigation, the common marmoset, a New World primate adapted to daylight, uses different exploration–navigation strategies compared to rats. He further shows that maps of space in the marmoset brain depend on vision-related cues and object relationships used as landmarks for navigation. It is likely that similar encoding mechanisms exist in other diurnal mammals, including humans.

To explore their environment, marmosets predominantly use rapid head-gaze shifts for visual exploration while remaining stationary. During active movement, marmosets stabilize their head, in contrast to rats, who use low-speed head movements to scan the environment as they locomote. This work suggests that spatial memory in primates may rely on anchoring sequences of views to specific places, providing a unique mechanism for encoding spatial experiences.

This publication represents a major technical and conceptual achievement in neuroscience.

Read the full story: https://can-acn.org/brain-star-award-winner-diego-b-piza/

Article citation

Piza, D.B., Corrigan, B.W., Gulli, R.A., Do Carmo, S., Cuello, A.C., Muller, L., Martinez-Trujillo, J. Primacy of vision shapes behavioral strategies and neural substrates of spatial navigation in marmoset hippocampus. Nat Commun 15, 4053 (2024). https://doi.org/10.1038/s41467-024-48374-2

https://doi.org/10.1038/s41467-024-48374-2

Brain Star Award Feature: Andrew Mocle, University of Toronto

Andrew Mocle

Better understanding how ensembles of neurons are recruited in memory formation.

The hippocampus is a critical brain region for encoding and recall of episodic memories. The physical trace left in the brain by memory formation is called an ‘engram’, and the process by which new engrams are formed is still unclear. In this work, Andrew Mocle, working in the laboratory of Sheena Josselyn, used advanced imaging techniques to track neurons and their patterns of activity before, during, and after memory encoding. The resulting data prompted a new engram formation model, whereby small ensembles of neurons (instead of individual cells) are allocated to an engram depending on their average excitability at the time of learning. The demonstration that highly-excitable ensembles are preferentially allocated to encode newly learned information represents a major conceptual advance in the study of how memories are stored in the brain.

Read more: https://can-acn.org/brain-star-award-winner-andrew-mocle/

Featured scientific publication: Mocle, Andrew J., Adam I. Ramsaran, Alexander D. Jacob, Asim J. Rashid, Alessandro Luchetti, Lina M. Tran, Blake A. Richards, Paul W. Frankland, and Sheena A. Josselyn. “Excitability Mediates Allocation of Pre-Configured Ensembles to a Hippocampal Engram Supporting Contextual Conditioned Threat in Mice.” Neuron 112, no. 9 (May 1, 2024): 1487-1497.e6.

https://doi.org/10.1016/j.neuron.2024.02.007

Remembering Leo P. Renaud

It is with great sadness that we learned of the passing of Dr. Leo P. Renaud (1941-2025), distinguished Canadian neuroscientist and Past President of the Canadian Association for Neuroscience on 6th July, 2025. Leo had an iconic status in the field of Neuroendocrinology and indeed Canadian Neuroscience that was founded on his outstanding scientific contributions first at McGill University and later at the University of Ottawa ( https://can-acn.org/leo-renaud-honorary-member/). He trained several generations of scientists and clinicians during his lifetime and was an exemplary teacher, supervisor, colleague, role model and friend. His warmth, disarming sense of humour, and humanism made everyone who came in contact with him feel at ease and special. His loss is profound, but his legacy as a scientist and a model of humanity endure. Leo is survived by his wife, Lillian, and two daughters (Francine and Barbara) and we extend our deepest sympathies to them. 

Charles Bourque & Jack Jhamandas

CAN Connection – Summer 2025

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Brain Star Award feature: Andrea Luppi, McGill University

Andrea Luppi

Understanding how the brain’s network architecture shapes its capacity to transition between different states

To support the diversity of human cognitive functions, such as learning, thinking, reasoning, remembering, problem solving, decision making, and attention, brain regions flexibly form and dissolve connections on the fly. How is the brain’s capacity to transition between different functional configurations shaped by brain network architecture? Andrea Luppi, working in Bratislav Misic’s lab at McGill University and the Montreal Neurological Institute, investigated this question using engineering principles of network control to simulate transitions between behaviourally derived brain states. They identified >100 cognitively relevant brain states in a data-driven manner, corresponding to activation patterns aggregated over 14,000 fMRI studies from a large collaborative database called NeuroSynth, and effectively mapped how brain network organization and chemoarchitecture interact to manifest these brain states. By leveraging large-scale databases of network structure, functional activation and neurotransmitter systems, the present work provides an integrative framework for the systematic exploration of the full range of possible transitions between experimentally defined brain states. This systematic approach allowed the researchers to discover the key role of the brain’s wiring diagram in supporting flexible transitions with high energetic efficiency, and how this efficiency can be disrupted by disease and restored by targeted pharmacology.

Read the full story here: https://can-acn.org/brain-star-award-winner-andrea-luppi/

View the original research article here:

Andrea I. Luppi, S. Parker Singleton, Justine Y. Hansen, Keith W. Jamison, Danilo Bzdok, Amy Kuceyeski, Richard F. Betzel & Bratislav Misic. Contributions of network structure, chemoarchitecture and diagnostic categories to transitions between cognitive topographies. Nature Biomedical Engineering 8, 1142–1161 (2024).

https://doi.org/10.1038/s41551-024-01242-2

Research from University of Ottawa: deciphering what serotonin is saying inside our brains

Richard Naud - image credit University of Ottawa

Richard Naud

The international research team’s ambitious work has implications across multiple fields and sheds compelling new light on the extraordinarily complex serotonin system.

In our day-to-day lives, we’re constantly making a slew of decisions from immediate matters to prospects on the far horizon. But the evolutionary nuts-and-bolts of how our brains weigh these numerous daily decisions and what role is played by the neurotransmitter serotonin has been shrouded in mystery.

Now, a new study led by an interdisciplinary uOttawa Faculty of Medicine team delivers fascinating findings on this big topic and potentially unravels a hidden aspect of what our nervous system’s complex serotonin system is really doing inside the enigmatic organ in our skulls.

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University of Ottawa-led research team forges compelling new insights into dynamics of the brain’s serotonin system

Jean-Claude Béique

Dr. Jean-Claude Béïque (Photo credit: University of Ottawa)

Source of text: David McFadden, Communications Advisor & Research Writer, University of Ottawa

The study’s findings could potentially help develop targeted therapeutics for mood disorders like major depressive disorder.

Our lives are filled with binary decisions – choices between one of two alternatives. But what’s really happening inside our brains when we engage in this kind of decision making?

uOttawa Faculty of Medicine-led study published in Nature Neuroscience sheds new light on these big questions, illuminating a general principle of neural processing in a mysterious region of the midbrain that is the very origin of our central serotonin (5-HT) system, a key part of the nervous system involved in a remarkable range of cognitive and behavioral functions.

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Congratulations to the winners of the 2024 CAN- CIHR-INMHA Brain Star Awards!

The Canadian Association for Neuroscience (CAN) and the Canadian Institutes of Health’s Institute of Neurosciences, Mental Health and Addiction (CIHR-INMHA) are proud to announce the winners of the 2024 Brain Star Awards.

The CIHR-INMHA Brain Star awards, administered by the Canadian Association for Neuroscience, are awarded to students and trainees who have published high impact discoveries in all fields and disciplines covered by CIHR’s Institute of Neurosciences, Mental Health and Addiction in the 2024 calendar year.

The top 3 Brain Star Award winners of the year have been invited to make a presentation at the CAN meeting in May.