Research
My research falls under the label of cognitive neuroscience, but I draw on methodologies from electrophysiology and behavioral observations to machine learning, acoustics, and musicology.
Marine Mammal Auditory Perception and Learning
How do dolphins navigate and hunt in murky coastal waters with horrible visibility? How can they interpret sonar information to distinguish a swim bladder in a fish from a kelp float? How do sea lions using hear in air and underwater to navigate their world? These are some of the many questions I work on, with a team made up of engineers, marine biologists, acousticians, and theoretical neuroscientists.
Personally I'm interested in comparative auditory cognition between humans and dolphins and sea lions. We're all well adapted to our environments, and can all make use of sound to navigate and communicate.
Audiomotor Integration
I am interested in how we synchronize movements with sounds. Dancers and musicians remind us of this ability often, but it is a complex task that requires anticipation and tight coordination between auditory, somatosensory, and motor systems.
The motor system likely anticipates when a sound needs to be made, as it initiates movement before that time. For instance, a drummer lifts a hand moments before bringing it down to make noise. In this case the auditory system could act as a feedback mechanism, contributing to mismatch detection between prediction and perception, and constraining variability of motor responses.
Music is useful as a tool to probe brain functioning. Features in auditory waves help us anchor features of brainwaves in time. Strong rhythmic sounds can synchronize brain rhythms in ways to predict responses. We can use information encoded in drum rhythms to help separate hemispheric activity based on tight coordination of differently timed left and right hand movements. I am interested in discovering novel uses of music as a diagnostic probe of brain function, and its potential use in therapy.
Brain-Computer Interfaces
The applied part of my research focuses on the use of brainwaves to control computers. This technology has wide reaching implications, from helping paralyzed people interact with computers, to novel video game controllers, and rehabilitation training via biofeedback (neurofeedback/NFT). I'm interested in the baseline regulation of our brainwaves, and how we can learn to control them. It can take hours for a given person to learn how to use a brainwave based computer interface, and my research focuses on multi-sensory integration to speed up the process.
Signal Processing
I am also interested in signal processing methods. One reason I enjoy coding stimuli in Max and Pd is the ability to build processes from banks of oscillators. As a an electrophysiologist, I make assumptions about pattern generators and oscillators in the brain. In addition to modeling oscillators, I spend time exploring PCA and ICA solutions to blind source separation problems. When you record a signal from an environment with multiple sources that interact and combine, you have an undetermined amount of solutions when separating later. I've applied these methods on datasets collected from over a dozen different EEG systems. I tinker with blind source separation solutions for auditory recordings of multiple instruments.
Psychopharmacology
While I have not worked in pharmacology for a few years, I keep up with literature, particularly as it pertains to cannabinoids and psychomimetics. I approach brain chemistry through perception, decision making, brainwaves, and ethnobotany.
PUBLICATIONS
2022 Kendall-Bar, Mukherji, Nichols, Lopez, Lozano, Pitman, Holser, Beltran, Schalles, field, Johnson, Vysstoski, Costa, Williams. Eavesdropping on the brain at sea: development of a surface-mounted system to detect weak electrophysiological signals from wild animals. Animal Biotelemetry.
2021 Schalles, Mulsow, Houser, Finneran, Tyack, Shinn-Cunningham. Auditory Oddball Responses in Tursiops truncatus. J. Acoustical Society of America - Express Letters.
2021 Schalles, Houser, Finneran, Tyack, Shinn-Cunningham, Mulsow. Measuring auditory cortical responses in Tursiops truncatus.
2018 Schalles & Pineda, Synchronizing Moving & Listening Behavior with Brainwaves via Rhythmic Hand Drumming. Journal of J. of Brain, Behavior & Cognitive Science.
2015 Schalles & Pineda, Musical Sequence Learning and EEG Correlates of Audiomotor Processing, Behavioural Neurology
2014 Pineda, Carrassco, Datko, Pillen & Schalles, Neurofeedback training produces normalization in behavioural and electrophysiological measures of high-functioning autism, Phil. Transactions of the Royal Society of London B
2012 McGarry, Russo, Schalles & Pineda, Audio-visual facilitation of the mu rhythm, Experimental Brain Research