In a Binghamton University laboratory, behavioral neuroscience professor Patricia Di Lorenzo has taken a first step toward understanding how we make decisions about food by studying how the brain encodes information about taste.
Her research focuses on how nerve cells in the brainstem convey information about what tastes are present on the tongue. These cells receive information directly from the nerves that stimulate taste buds and represent the earliest stage of central processing of taste information.
To understand these cells, Di Lorenzo pursues two related research strategies.
The first records and analyzes neuronal responses to taste stimuli bathed over the tongue. The second plays these recorded responses back to the brainstem.
From her experiments, she has found that individual neurons in the brainstem can discriminate among different taste qualities (sweet, sour, salty and bitter) by using spike timing, known as temporal coding. Much like a Morse code communicates the alphabet, temporal coding works when taste nerves send a certain number of electrical spikes in a certain pattern to the brainstem, where neurons interpret taste qualities based on that pattern.
Interestingly, when two taste stimuli evoke the same taste quality, such as two sugars or two salts, neurons use temporal coding to differentiate between them. And when mixtures of two taste qualities are presented, the resulting temporal code is a combination of the temporal codes for each of the components.
However, Di Lorenzo’s most intriguing finding is that when playing a recorded temporal spike pattern back to the brainstem, the brain will interpret the pattern of electrical pulses as having a taste. So, even though a subject might be licking water, the brain will perceive the taste of sugar, salt, sour or bitter.
This ability to influence the central processing of taste has major implications for how we treat common diseases like obesity, diabetes, bulimia and anorexia
Last Updated: 2/3/10