Healthy Brain Development: Protective and Risk Factors

Transcription

1 Healthy Brain Development: Protective and Risk Factors Bryce Geeraert PhD Candidate Developmental Neuroimaging Lab January 31, 2018 About me BSc Psychology, Biomedical Engineering PhD candidate Interest in the brain and psychology was sparked by books Questions I m excited to investigate: How does the brain change and reorganize during childhood? How does the human brain acquire language skills? What s happening in the brain when things go wrong developmentally? The developmental neuroimaging lab Research team led by Dr. Catherine Lebel We aim to investigate: Healthy brain development during childhood and adolescence The biological effects of protective and risk factors Effects on how the brain is formed (Structural) Differences in how the brain activates (Functional) Many different studies on going in our lab 1

2 PRESENTATION goals MAIN GOALS: What does healthy brain development look like? What happens when brain development is disrupted? How do environmental factors affect brain development? How do we answer these questions using the scientific method? Why should we study the brain? Our brain is part of everything that we do: School skills like reading, writing, math, memory Drives our passions, helps us laugh at jokes Every brain is unique and affected by their life experiences Violinist vs a comedian Why should we study the brain? The brain requires very precise environmental conditions Maintained by the blood brain barrier Events that may seem small could cause major changes to our brain 2

3 Why should we study the brain? The better we understand the system, the better our solutions can be Example: Major depressive disorder Why should we study the brain? The better we understand the system, the better our solutions can be Example: Spina bifida HOW DO we study the brain? 3

4 HOW DO we study the brain? ANIMAL MODELS (Rats, mice, fish, etc.) Can achieve a high level of control and detail Can t directly translate results Not the whole picture Human brain is similar, but different! HOW DO we study the brain? NEUROIMAGING (MRI) Non invasive, but definitely not cheap! Good spatial resolution Can collect a lot of different types of information Still an average over an area NEUROIMAGING (MRI) 4

5 HOW DO we study the brain? NEUROIMAGING (MRI) The information we collect isn t as specific as we would like Bush, grass, or tree? Amount of life? Man made or natural? So many other techniques EEG MEG TMS Behavioral Tasks CT Palm Reading (probably not ) TDCS What is our brain Made of? CENTRAL NERVOUS SYSTEM Includes the brain and spinal cord Notable components of the brain: Neurons Glia Neural stem cells Blood vessels 5

6 What is our brain made of? NEURONS V1 M1 45 days Basic unit of the nervous system ~100 billion Primary component of gray and white matter Cortical neurons organized into distinct layers Macrostructure varies by region and time in development What is our brain made of? GLIA Perform various support roles in the brain: Production of cerebrospinal fluid Myelination Structural support Maintenance of the blood brain barrier Immune functions ~100 billion as well! May also be involved in signaling pathways What is our brain made of? NEURAL STEM CELLS Small populations in the subventricular zone and the hippocampus Responsible for adult neurogenesis BLOOD VESSELS Three major arteries supplying the brain Occlusion can lead to stroke Kolb, Whishaw,

7 The Government of Alberta. (2012).Prevention Conversation Manual. PRENATAL DEVELOPMENT: Formation of major brain structures Brain folds into gyri and sulci Differentiation of neurons and migration to their correct location, then axonal sprouting MAJOR TRENDS AFTER BIRTH: Increases in brain volume Changes in gray matter and white matter Reorganization of functional networks 7

8 INCREASES IN BRAIN VOLUME: Rapid increases until 3 4 years old 80% adult volume at 2 years, 90% at 5 years Knickmeyer RC, et al J Neurosci. 28(47): INCREASES IN BRAIN VOLUME: Rapid increases until 3 4 years old 80% adult volume at 2 years, 90% at 5 years Relatively stable brain volume throughout adulthood Lebel C, Beaulieu C J Neurosci. 31(30): MAJOR TRENDS AFTER BIRTH: Increases in brain volume Changes in gray matter and white matter Reorganization of functional networks 8

9 GRAY MATTER VS WHITE MATTER: CHANGES IN GRAY MATTER: Synaptic arborisation and pruning Changes in cortical thickness and surface area Rima.,1997. Walhovd KB, et al Cereb Cortex. 27(2): CHANGES IN GRAY MATTER: Gogtay N, Thompson PM Brain Cogn. 72(1):

10 CHANGES IN WHITE MATTER: Increases in volume and maturity during childhood Unnecessary connections are pruned, useful connections are reinforced Major development in early years, more gradual change continues into adolescence and adulthood 10