In the spring of 2016, I collaborated with Cristiana Vagnoni to develop a stall of neuroscience activities for the Oxfordshire Science Festival (OSF). It was part of a larger neuroscience-themed area entitled “Get to Know Your Brain”, with scientists from various Oxford neuro-related departments coming together to present their own activities. The stall was presented at the OSF opening weekend at the Oxford Town Hall on June 25-26, 2016.
We are still waiting to get professional photos and videos from the main OSF organisers. We'll have to make do until then!
I'm also aiming to clean up the Python code for the Eyeball demo and put it online for whoever is curious.
After the success of our previous stall, Brain Power!, we were encouraged to see visitors eager to learn about basic neuroscience principles and research methods. In the current stall, we further explored these themes, using different activities. Of course, people's enthusiasm hinged on the interactivity of our demos, and so we developed new ways to get people engaged!
to make accessible the idea of sensory representations – that information in the external world is captured by the senses, and transformed into a code by neurons in the brain
to make accessible the widely used technique of electroencephalography (EEG) – what it measures, what the data looks like, how sensory input changes the EEG signal (and therefore the brain) in real time
to do the above in the most hands-on way possible, so as to provide an intuition about the concepts, and to keep visitors of all ages engaged
The all-seeing eyeball (sensory circuit demo)
We wanted to put visitors in the middle of the action of the sensory perception circuit, laying bare its key components. The most intuitive system to use (and to study) is vision, so we built a simple eyeball for them to play with.
Our eyeball was made of two hollow, styrofoam half-spheres. On the inside of one of the spheres was our homemade retina – the layer of neurons responsible for capturing visual information from the environment, and sending it on to the brain. Our retina was made of a grid of 9 photocells (cheap light-sensitive electrical resistors). The photocells were embedded into the “retinal” surface of our sphere, and were connected in the back to an Arduino microcontroller, which was itself connected to a laptop + monitor setup (the “brain” of our perceptual circuit).
[Side note: we also built a touch sensory circuit. It was a patch of skin, made out of latex, with an embedded pressure sensor around the same principles and purposes as the eyeball. It unfortunately died within the first hour on the first day due to a probable short circuit :( ]
The photocells would register the local light levels and send them to the laptop, via the Arduino. On the laptop, I had coded in Python an interactive visualisation of a neural network. This visualisation was the “brain” of our perceptual circuit, playing the part of the visual cortex. It constantly received input from the photocells in our eyeball.
The activity of neurons in our visualisation, the “neural firing”, was represented by flashes of orange glow. The neurons would always fire at a low, baseline frequency, producing a hypnotising “old-school screensaver” kind of animation. This mimics the observed activity of neurons at rest, when they are without any input. It also was a neat way to capture visitors' attention when they walked by.
Visitors were able to take a mini flashlight, and shine it at a photocell of their choosing, effectively providing light stimulation to a part of the eye's retina. If the light levels in a given photocell exceeded a threshold, a group of neurons in the visualisation would emit a burst of activity.
(stimulation of the photocells begins at about 10 sec)
With this interactive demo and visualisation we were able to discuss with visitors how sensory information may be represented by the brain. As we prodded their curiosity with questions, they had a chance to test out ideas for themselves.
What happens when you shine light onto a photocell? What about onto a photocell next to it?
Sensory representations in the brain are organised into orderly maps. In the case of vision, these maps are intuitively spatial. Neighbouring photocells in the eye correspond to neighbouring groups of neurons in the brain – together, they form an image of the world around you which is constantly updated as you look around.
What happens when you continously shine light onto a photocell?
The brain loves new information. Stimulating a photocell for a long time does not make the corresponding neurons light up continuously. Rather, they would settle into a lower response rate, similar to real neurons, indicating that they have effectively gotten “bored”.
What happens when you don't shine any light?
The brain is always active at some level, even when it is not getting any external input. The neural network always shows some activity, as in a real brain.
As they finished playing with the demo, we asked them how it would be possible to study the visual system in the human brain – this led them to the our EEG demo.
The alpha selfie (EEG demo)
For this demo we used a small, portable EEG kit from OpenBCI. Visitors were welcome to see their own brain response to visual input. We applied one electrode on the back of their head (on the scalp, near the visual cortex), and one electrode on each earlobe as a reference. As we started up the software, visitors could observe their own brainwaves on the display monitor.
Photo courtesy of Kate Watkins
As visitors were getting set up, we explained that neural activity is naturally organised into rhythmic patterns, or brainwaves. One very prominent pattern often arising from the visual cortex is called alpha. Alpha is simply a wave of activity reoccurring at a rate of ~10 Hz. It is especially strong when the visual cortex is not getting very much visual input from the external world: when people zone out and daydream, or when they close their eyes.
We had visitors test this idea in real time. We asked them to close their eyes for a few seconds, and we observed their brain activity on the monitor (also saving screenshots for them to see, since their eyes were closed). Almost instantaneously, there was a huge increase in alpha activity. As soon as visitors opened their eyes, it was gone. We could do this multiple times with the same person. Their friends and family, and any other visitors taking a peak were surprised to see this so reliably. Once we showed the saved images to the visitors to compare eyes open and closed, they too were very impressed!
After the demo, visitors were usually very curious about what it all means and what it's used for. We used the opportunity to explain how this kind of activity can be used to track and study the focus of attention, and other applications in research.
Visitors also noticed that every time they moved or blinked, the signal became quite noisy. This was a great chance to mention how relatively precise invasive animal recordings are, and how it is important to have both techniques to address research questions.
As a small parting souvenir, we digitally framed the saved image of their alpha activity as an “alpha selfie”, and they could take a picture with their phones to show others (we would have loved to have a photo printer available to us, to let visitors take something tangible home).
The public's feedback
The main OSF organisers did not want stalls to collect individual feedback so as not to inundate visitors with forms (understandable). However, we were assured of our success by the amount of wonderful conversations we were able to have throughout our two days.
One person wondered how the visual snow she sees would affect her alpha activity -- a great question! Cristiana also had a conversation with a person wondering about how optogenetics can be used to manipulate memory. Another person told me about how she's in the art field, with no background in science, but her young daughter is obsessed with science, and these festivals are the highlight of their days. :)
@OxSciFest - had an amazing time, great atmosphere, loved the experiments and seeing brain waves! pic.twitter.com/rbyjl8ktQP— Lucy Crittenden (@LooseyC1) June 25, 2016