It’s For The Birds
HiFiBerry in Academia
By Tim Gentner, Ph.D
Professor, UCSD Department of Psychology
Director, Neurosciences Graduate Program
Credit: Photos by Brad Theilman
In the Gentner lab at UC San Diego, we use songbirds to study auditory perception and understand aspects of how humans process language. Often times this involves training songbirds to recognize patterns that we’ve hidden in their natural songs.
Our work yields important insights into how complex communication signals are learned, remembered and used. This knowledge can lead to better diagnoses and treatments for speech and language processing disorders like dyslexia, development of speech prostheses, and engineering advances in speech recognition and language processing.
The birds live in specialized cages, called operant boxes. These boxes work kind of like a really simple three-button keyboard, and with them we can ask the birds different kinds of questions.
Their answers to these questions tell us what they know about the songs they hear, the kinds of patterns they can attend to, and the properties of the acoustic signals that they use to do things like recognize one another and choose who they’ll mate with.
To control the operant boxes, we designed a custom interface based on the HiFiBerry Amp2 and the Raspberry Pi 3B+. The interface runs a custom Python package called “PyOperant” that uses the GPIOs on the Raspberry Pi to read responses from the peck ports (the buttons on “keyboard”) and dispense food when they answer a question correctly.
It even controls the house lights, turning them on and off in sync with local sunrise and sunset times. The HiFiBerry board is crucial to the whole system, since it serves as both a DAC and amplifier to drive the speakers that play sounds in the operant boxes.
We needed the high fidelity of the AMP2 in order to faithfully reproduce the bird sounds we use in our experiments, which can contain very high frequencies. The compactness of the AMP2 is also crucial so that the entire system can be self-contained.
The audio output of the AMP2 is additionally channeled to an interface with the hardware that we use to actually record the activity of the neurons in the bird’s brain while the bird is listening to the stimuli. That way, we have a simultaneous record of the auditory input the bird is receiving, as well as what is going on in the bird’s brain.
Using that information, we try to understand how patterns of activity in the bird’s brain correspond to the different patterns of sound that the birds hear. Then, we can use these conclusions to make hypotheses about how our brains process the patterns of sounds that we hear, for example, during a conversation.
Our work provides fascinating insights into some hard problems in neuroscience, opens up many possibilities for improving lives and understanding our world, and HiFiBerry gear is at the center of the whole process.