Before I even set foot in Paris, I had an agenda to tend to—buy every friend and family member enough chocolate to hold them over until their own trip to France. As (arguably) the biggest dark chocolate fan on the east coast, I have gone out of my way to make sure I try chocolate (in all forms) from all over Paris. I have run the gamut by trying chocolate bars from our favorite local grocery store (shout out to Mono Prix) to inhaling the chocolate pastries sold at Ladurée. Tending to my chocolate cravings in Paris turned out to be much easier than expected…
Chocolate Pastries at Ladurée (yum)
Needless to say, I was beyond excited when I saw that a trip to a chocolate museum was conveniently worked into our syllabus a day-off activity. Probably a bit too excited, the other students and I worked our way through the Parisian Metro and RER systems and arrived at “Choco-Story – Le musée gourmand du chocolat” earlier this week. Walking into the hands-on museum, we were hit with a wave of the sweet scent of chocolate, instantly putting everyone in a better mood. Part of our museum experience involved a chocolate workshop where we actually learned how to make bite-sized chocolates, and we luckily got to package the chocolates to bring back to our dorm.
Chocolate Museum: 28 Boulevard de Bonne Nouvelle, 75010 Paris
After our workshop where we somehow managed to make chocolate without destroying the museum kitchen, we waited for the pieces to cool in the fridge. As soon as our chocolate was cooled and ready to eat, I instantly ate maybe one too many pieces. Regardless, I was completely satisfied with my experience at the museum and our homemade treats. At this point, I’m sure you’re wondering why a chocolate field trip was worked into our neuroscience syllabus. Chocolate, aside from being central to Parisian culture, is responsible for producing pleasurable, hedonic effects and can therefore activate various brain areas (Rolls 2005). It has, for this reason not only been used as an incentive in various animal experiments, but its’ effects on changing activity in different brain areas have also been studied.
The neuroscience student in me wondered why some students were not as excited as I was about our chocolate museum expedition. Doesn’t everyone love chocolate? Why are there some people who don’t have chocolate cravings? Current neuroscience research is exploring the physiological implications behind cravings, emphasizing the brain systems that control our food intake. It turns out that people, like me, who crave chocolate actually show heightened physiological reactivity to images of chocolate. This means that there are measured changes in blood flow in different areas of the brain (such as the orbitofrontal cortex, the insula, ventral striatum and midbrain) in response to chocolate pictures (Small et al., 2001). What does this mean for choco-holics?
Spilling chocolate all over the kitchen floor....
A recent study tested the actual brain activity differences across individuals who craved chocolate and those who didn’t have these characteristic cravings (Asmaro et al., 2012). Researchers recruited undergraduates and asked them to fill out a chocolate-craving questionnaire, which was used to objectively measure “chocolate cravings”. After taking all of the data from these questionnaires, the researchers categorized the participants into one of two groups: chocolate cravers and non-cravers. The behavioral task of this study involved showing three types of images to both groups of participants. Both non-cravers and cravers were shown images falling under the following categories: chocolate, neutral and target. The chocolate stimuli category had pictures of dark or milk chocolate (yum), the neutral category had pictures of bland, uncooked foods (like pasta, for example) and the target stimuli category included random pictures of chairs (Asmaro et al., 2012).
There were two main sessions for this study: before eating chocolate and after eating a delicious piece of chocolate. In each of the two sessions, 220 images (100 chocolate, 100 neutral and 20 chairs) were presented in blocks. The participants (in both groups) were told to keep their eyes fixed on the screen as these images came up, and as soon as a target picture (a chair) appeared, participants had to press a key on a keyboard. After this task, the participants were asked to rate their craving for chocolate on a scale of 1 to 5. While this task was going on, researchers had an electroencephalogram along the patient’s scalp. An electroencephalogram is simply a tool that neuroscientists use to measure and record the electrical activity in the human brain. The reason they used an electroencephalogram in this case was to have a way to measure the brain response to these different, presented images. This actual brain response is commonly referred to as an “event-related potential” (Asmaro et al., 2012).
The researchers found that when the chocolate craving group was presented with a picture of chocolate, their brain activity indicated that they had a greater desire for chocolate overall. The non-craving group, however, had a lesser desire for chocolate after the task (Asmaro et al., 2012). This shows that presenting the chocolate stimuli actually caused different neurological responses across the two groups—cravers and non-cravers. If we take a step back and apply this back to my chocolate obsession, it is probable that I may have had different areas of my brain activated when I walked into the chocolate museum and saw all of the chocolate merchandise and pictures (when compared to some of my not so excited classmates).
Cooling chocolate (the French way...)
Asmaro et al. (2012) also showed that in non-cravers, the early changes in an area of the brain disappeared after eating some chocolate. This suggests that certain brain mechanisms control the otherwise natural urge to continue to eat chocolate in non-cravers (Asmaro et al., 2012). In cravers, however, a similar area of the brain (the orbitofrontal cortex) showed no changes in activity even after eating chocolate. What does this mean for us chocolate lovers, then? Turns out certain areas in our brain, such as the orbitofrontal cortex, are more likely to tell us to stop eating chocolate if we are classified as a “non-craver”. For us cravers, however, chocolate is a “wanted stimulus with a high motivational value” (a value that we subjectively place on it) and so our brains don’t really tell us to stop as readily as the brains of our fellow non-cravers. This is due to the fact that we have grown to appreciate and place immense value on chocolate.
Turns out, studies on the effects of chocolate on the brain are quite popular—mainly because they provide us with insight on consummatory and dietary patterns in humans. The question is now: are you a craver or non-craver, and what are you going to do about it? If you’re anything like me, I’ll see you at the local bakery scoping out the best chocolate pastries.
-Noareen Ahmed
References:
Asmaro D, Fern J, Valery S, Isabel T, Patrick C, Mario L (2012) Spatiotemporal dynamics of the hedonic processing of chocolate imags in individuals with and without trait chocolate craving. Appetite 58: 790-799.
Rolls E, McCabe C (2007). Enhanced affective brain activations of chocolate in cravers vs. non-cravers. European Journal of Neuroscience 26: 1067–1076
Small D, , Zatorre R, Dagher A, Evans A, Jones-Gotman M (2001). Changes in brain activity related to eating chocolate. From pleasure to aversion. Brain, 124: 1720–1733.