Suche

zur Hauptseite

Institut für Neurowissenschaften und Medizin
(leer)

Navigation und Service


Delta activity encodes taste information in the human brain

The categorization of food via sensing nutrients or toxins is crucial to the survival of any organism. On ingestion, rapid responses within the gustatory system are required to identify the oral stimulus to guide immediate behavior (swallowing or expulsion). The way in which the human brain accomplishes this task has so far remained unclear.
Using multivariate analysis of 64-channel scalp EEG recordings obtained from 16 volunteers during tasting salty, sweet, sour, or bitter solutions, we found that activity in the delta-frequency range (1–4 Hz; delta power and phase) has information about taste identity in the human brain, with discriminable response patterns at the single-trial level within 130 ms of tasting. Importantly, the latencies of these response patterns predicted the point in time at which participants indicated detection of a taste by pressing a button. Furthermore, taste pattern discrimination was independent of motor-related activation and encoded taste identity rather than other taste features such as intensity and valence. On comparison with our previous findings from a delayed taste-discrimination
task (Crouzet et al., 2015), taste-specific neural representations emerged earlier during this speeded taste-detection task, suggesting a goal-dependent flexibility in gustatory response coding.
Together, these findings provide the first evidence of a role of delta activity in taste-information coding in humans. Crucially, these neuronal response patterns can be linked to the speed of simple gustatory perceptual decisions – a vital performance index of nutrient sensing.
 
 


Wallroth 2018


Figure. Taste information is encoded by delta oscillations.
A) Spectral power estimates obtained via continuous wavelet transformation of the EEG recordings for frequencies from 1 to 100 Hz and averaged across 64 electrodes and 16 participants. B) SVM classifiers were trained at each time point and frequency step to decode the four tastes given the (non-normalized) spectral power in the 64-electrode space. C) Phase-locking value or inter-trial coherence (ITC) is calculated from phase estimates obtained via continuous wavelet transformation for frequencies from 1 to 100 Hz. The ITC expresses the extent of phase synchronization across trials. D) SVM classifiers were trained at each time point and frequency step to decode the four tastes given the phases in radians in the 64-electrode space. E) Comparison of taste response-pattern decoding between the broad-band and delta signal (1-4 Hz). SVM classifiers were trained at each time point to decode the four tastes, given the unfiltered (black) or FIR filtered (blue) electrophysiological recordings from 64 electrodes. F) Comparison between the speeded task of the current study and a delayed task (Crouzet et al., 2015). G) Motor-control task. Successful classification demonstrates that motor-related activity is irrelevant to the multi-taste discrimination.

 
Publication:

Wallroth, R., Höchenberger, R., & Ohla, K. (2018). Delta activity encodes taste information in the human brain. NeuroImage, 181, 471-479.


Servicemenü

Homepage