There is a large variation in the number of neurons needed to form a brain. Animals like sponges don’t have any neurons, so they don’t have a brain at all. The tiny roundworm C. elegans has only 302 neurons, but this is enough for complex behaviors like learning, mating and looking for food. The organization of these neurons are identical in every worm, which is useful for scientists who study them. The number of neurons grows a lot from there—the fruit fly Drosophila melanogaster has about 100,000 neurons, and the human brain has around 85 billion neurons! The overall structure of the brain (like lobes) is the same in most people, but unlike C. elegans, the connections between neurons develop in a completely different way for each individual. This allows us to better adapt to new situations. Interestingly, the African elephant has three times as many neurons as a human, but brain size doesn’t always dictate intelligence-- there are other factors that may affect intelligence, like the number of connections between neurons, brain size as a percentage of body size, the number of supporting cells in the brain, or the complexity of the synapses.
Though the brain works mostly in networks of communicating cells, some research has shown that single cells might recognize specific people’s faces. This idea, known as the “grandmother cell” theory, suggests that one single cell is responsible for recognizing one individual. Using electrodes to record responses from cells, scientists demonstrated that specific images elicit strong responses from one neuron. One study showed a cell responding strongly to pictures of Jennifer Aniston and nothing else. So, a specific type of cell could be involved in recognizing complex visual patterns, rather than just identifying simple shapes. However, if this is really true, losing that cell might mean losing the ability to recognize a person forever! At the very least, this research shows that individual brain cells are capable of more complex “thinking” than previously thought.
The structures remain the same. You will always have 4 brain lobes (frontal, parietal, temporal and occipital), a cerebellum (involved in coordination of movement and balance) and many gyri (bumps of the brain) and sulci (grooves of the brain).
However, everything you do in your life can have an impact at a cellular level (brain cells/ neurons). After you are born, your brain will get larger as it creates new brain cells. Your brain will keep growing until about 18 years of age. Every time you learn something, you create new connections between brain cells. You are also able to re-shape these brain connections through new experiences. This is called brain plasticity and continues throughout life!
No! There are many parts of the brain. We start the BrainReach year by describing the 4 lobes of the brain, as well as the cerebellum and brainstem. However, if we were to slice the brain in half lengthwise, we would see many other structures that are deep inside the brain. For example, you would see the corpus callosum (which connects the left and right hemisphere of the brain), and structures of the limbic system (involved in emotions, learning and memory). Every single part of the brain is connected. For example, injuring a part of the limbic system can impact connections it has with the frontal lobe.
Crowds gathered around the Science Centre at the Old Port on June 8-10, 2018 for the Eureka festival. It was BrainReach’s first time participating, and we had a blast! In the beautiful, sunny weather, our volunteers welcomed people of all ages, from school groups to families to curious individuals. We did some activities on touch perception, taste and smell, and of course our ever-popular brain and microscope activities. The kids may have come for the skittles, but they stayed for the science.
Congratulations to this year's Volunteer of the Year award winners!
High School winner: Lawrie Shahbazian
Lawrie just completed her M.Sc. in Dr. Stefano Stefani's lab at McGill University, and has been volunteering with BrainReach High School for the past 2 years. Not only does Lawrie consistently receive positive feedback from her classroom teachers, but she also volunteers regularly to represent BrainReach for Explore McGill and other one-day events. This year, Lawrie went above and beyond to organize a brain dissection activity on campus for a group of CEGEP students! We'd like to thank Lawrie for all her hard work. Congratulations on being named this year's BrainReach High School - Volunteer of the Year!
Elementary School winner: Edwin Wong
Edwin just completed his M.Sc. in Dr. Tim Kennedy's lab at McGill University, and has been volunteering with BrainReach Elementary for the past 3 years. We are constantly receiving positive feedback about Edwin's amazing teaching skills. Edwin modifies the BrainReach presentation slides to best suit his teaching ability and to improve upon the content delivered to his students. Throughout the school year, Edwin is often the first to volunteer to represent BrainReach at one-day events, including Explore McGill, the Gairdner Event and McGill's Explorations Summer Science Program. Thank you to Edwin for all his efforts and passion for teaching! Congratulations on being named this year's BrainReach Elementary - Volunteer of the Year!
North winner: Reiko
Reiko is working on her Ph.D. in Dr. Robert Zatorre’s lab at McGill University. She has been volunteering with BrainReach North for the past 2 years doing all sorts of jobs that make our teaching materials look great. This year, Reiko almost single-handedly put together our first animated video about brain sizes and shapes, providing a hands-off teaching tool for educators and students in remote communities and giving BrainReach North a model for our content going forward. She also designs our newsletter and prepares it to be sent out to teachers every month. Reiko is a diligent and hard worker, and clearly cares a lot about our goal of making (neuro)science more accessible. We’d like to thank Reiko for her effort and enthusiasm! Congratulations on being named this year's BrainReach North - Volunteer of the Year!
The brain has many layers to protect and suspend it in the skull. Under the skull, there is a layer of leathery tissue called the dura mater that encases the brain. Beneath is another layer called the arachnoid mater, named after its spiderweb-like form. Beneath the arachnoid mater is the arachnoid space, a network of proteins that forms a cushion and contains cerebrospinal fluid that suspends the brain in place. Finally, the pia mater wraps closely around all the sulci and gyri of the brain.
Information about colour is gathered by cells called cones in the eye, which communicate directly with neurons. Each cone responds to a different frequency range of light. In most cases, colourblindness happens when cones that are supposed to capture different ranges of colour have too much overlap. This does not mean that these people see in black and white! It just means that the brain has a hard time telling the difference between two shades, like red and green.
There are now special glasses that eliminate the areas of overlap and allow people with colourblindness to see more normally. The glasses modify the light spectrum in a way that the brain can interpret more easily. Some people have four cones rather than the usual three, which is called tetrachromacy (from “tetra”, meaning four, and “chroma”, meaning colour). They can differentiate colours that we cannot. Some animals naturally have 4 cones as well, and can see colours in the ultraviolet range!
In labs, brains are chemically preserved with a chemical called formaldehyde which “fixes” the tissue and minimizes degradation of the sample. Scientists can then slice parts of the brain and add antibodies, which are other proteins that specifically bind to the proteins of interest in the brain. They can then quantify where and in what quantities specific proteins are expressed in different regions of the brain. Recently some efforts have been made to preserve the brain at very low temperatures in liquid nitrogen. This is called cryonics. Some people hope that we will be able to “revive” brains from these frozen samples, but this is highly debated.
Learn more about the cryonics debate here and here.
Glutamate (or glutamic acid) is an amino acid found in meat, tomatoes, and other foods. It is responsible for the “umami” taste. It is also found in a slightly different form as a neurotransmitter in the brain. The food additive monosodium glutamate (MSG), first used in Japan, is derived from fermented vegetables, and is indistinguishable from glutamate found in naturally-occurring proteins.
The brain maintains a low concentration of glutamate in the fluid surrounding its cells; the level in our bloodstream and in the rest of the body is much higher. This is possible because the brain is separated from the rest of the body by the blood-brain-barrier. For the most part, glutamate cannot cross this barrier unless it is actively transported by cells. So even if you ingest a lot of MSG with your food, it would be difficult for it to find its way into your brain! After some reports of people suffering from neurological symptoms after eating in certain restaurants, there has been a lot of research on the effects of MSG. When studies of MSG consumption are blind, meaning the researchers are unaware of which group ingested MSG while doing their analysis, there seems to be little difference between the two groups. The FDA has therefore classified it “generally considered as safe”.