Speaking Tips from a Lecture on the Brains of Fruit Flies

Have you ever wondered how a fruit fly thinks? Maybe?not! But chances are that you’ve wondered about your own brain.

I attended a Janelia Farms “Dialogue of Discovery” called Taking Action: How Small Brains Make Big Choices. The scientist, Gwyneth Card, PhD, gave a dynamic presentation describing her research on the thought process of fruit flies: investigating how individual neurons lead to the fly’s specific movements to escape a predator.

Dr. Card said: We are trying to reverse engineer the brain. I liked that phrase. I like big subjects brought down to something small enough to investigate. The?phrase “reverse-engineer” helpfully orients the exploration: even though the fruit fly brain is tiny, the scientist still stands behind/underneath it. To my mind, understanding always comes from “standing under” with an attitude of curiosity and exploration and respect. (In my life, this describes scripture study.)

The numbers tell us why neuroscientists start with fruit flies. Fruit fly brains have 300,000 neurons, compared to the 86 billion neurons in human brains. Dr. Card showed helpful pictures of the difference between these two figures: the population of Anchorage, Alaska vs. the population of 12 earths.

Context is key to signal interpretation. Dr. Card showed a picture of a man holding a cat by the tail, and also a large knife, all of which are covered by a great gush of red liquid, presumably blood. The brain has to determine what just happened. A pot full of a tomato-based dinner and a curious cat may provide an unexpected answer. It is the job of the brain to make these connections and assessments, almost instantly.

Dr. Card backed up to describe the work of Eadweard Muybridge (1830-1904) which sought to answer the question: When a horse is running are all four legs ever off the ground at once? (I remember studying that in high school, did you?) To answer that question, Muybridge invented a way to take a series of photos in quick succession.

Today the standard for fruit fly investigation is 6,000 frames per second. The scientist is able to introduce a shadowy object (to mimic a predator) and film the result. The scientist can then determine the precise actions a fly takes in evasion.

Dr. Card showed a fabulous clip of a man jumping out of the way of an oncoming car. The man’s body followed the same basic sequence as the fruit fly: freeze, adjust posture, shift body weight, jump.

There were some lighthearted moments, such as a “Fly Pez” which dispenses the fruit flies one at a time. Fun to see the contraptions that scientific exploration requires. Can you imagine what ingenuity they take to build? Another sophisticated piece of equipment can head-fix the fly in order to insert an electrode into the brain. This allows neuronal activity to be matched to specific behaviors.

It was enjoyable to watch an energetic speaker, who made excellent use of visuals. As a preacher/speaker, here are a couple observations:

1) The speaker’s sense of curiosity was contagious.

2) The speaker’s fondness for her tiny subjects was evident, proving once again that intimate study inevitably leads to a certain respect for the subject matter.

3) The speaker’s efforts to make immediate applications to her audience’s life kept attention, even as the complex layers of the subject matter multiplied for a full hour.

4) At the end, the speaker went out of her way to laud her research team, not only showing their names but also their faces, which speaks volumes about her leadership.

(Other Dialogues of Discovery notes here and here and here.)


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