Ready For Your Close-up, Mr. Chocolate Iced Kreme Filled

Your brain on Krispy Kremes

CHICAGO--What makes you suddenly dart into the bakery when you spy chocolate- frosted donuts in the window, though you certainly hadn't planned on indulging? As you lick the frosting off your fingers, don't blame a lack of self-control.

New research from Northwestern University's Feinberg School of Medicine reveals how hunger works in the brain and the way neurons pull your strings to lunge for the sweet fried dough.

Krispy Kremes, in perhaps their first starring role in neurological research, helped lead to the discovery.

Wow, this one seems like a parody of itself. "Perhaps" their first starring role? You mean there might be another Krispy Kreme neuroimaging publication out there? The press release continues:

In the study, subjects were tested twice -- once after gorging on up to eight Krispy Kreme donuts until they couldn't eat anymore, and on another day after fasting for eight hours.

In both sessions, people were shown pictures of donuts and screwdrivers, while researchers examined their brains in fMRI's.

When the subjects saw pictures of donuts after the eating binge [NOTE: eight doughnuts!!], their brains didn't register much interest. But after the fast, two areas of the brain leaped into action upon seeing the donuts. First, the limbic brain -- an ancestral part of the brain present in all animals from snakes to frogs to humans -- lit up like fireworks.

You don't say?? Or as Jane Wells puts it:

More earth-shattering research news from our nation’s universities! Northwestern U has come out with a study which reveals that -- hold your breath! -- we are more attracted to food when we are hungry than when we are not. What. A. Breakthrough.

. . .

Specifically, the researchers tested people on two different days. The first day, each person ate eight Krispy Kreme [...] doughnuts. On the second day, they fasted for eight hours. Each day they were shown pictures of Krispy Kremes, and their brains reacted differently.

Lo and behold, when they hadn’t eaten for eight hours they reacted MORE STRONGLY TO PICTURES OF FOOD.

Let that sink in for a moment. When you are hungry, you react more strongly to images of food than when you are not hungry. Who knew?

Now, we at The Neurocritic never engage in such sheer ridicule, so we'll report one interesting result of the study (Mohanty et al., 2008) and expand upon it after access to the full article is obtained. The investigators reported greater activity in the substantia nigra (chock full 'o dopamine) and the locus coeruleus (chock full 'o norepinephrine) while viewing doughnuts (but not tools) during the hungry state. While a number of neuroimaging studies have looked at activity in the human substantia nigra, few have do so in locus coeruleus...

Reference

Mohanty A, Gitelman DR, Small DM, Mesulam MM. (2008). The Spatial Attention Network Interacts with Limbic and Monoaminergic Systems to Modulate Motivation-Induced Attention Shifts. Cereb Cortex Feb 27; [Epub ahead of print].

How does the human brain integrate information from multiple domains to guide spatial attention according to motivational needs? To address this question, we measured hemodynamic responses to central cues predicting locations of peripheral attentional targets (food or tool images) in a novel covert spatial attention paradigm. The motivational relevance of food-related attentional targets was experimentally manipulated via hunger and satiety. Amygdala, posterior cingulate, locus coeruleus, and substantia nigra showed selective sensitivity to food-related cues when hungry but not when satiated, an effect that did not generalize to tools. Posterior parietal cortex (PPC), including intraparietal sulcus, posterior cingulate, and the orbitofrontal cortex displayed correlations with the speed of attentional shifts that were sensitive not just to motivational state but also to the motivational value of the target. Stronger functional coupling between PPC and posterior cingulate occurred during attentional biasing toward motivationally relevant food targets. These results reveal conjoint limbic and monoaminergic encoding of motivational salience in spatial attention. They emphasize the interactive role of posterior parietal and cingulate cortices in integrating motivational information with spatial attention, a process that is critical for selective allocation of attentional resources in an environment where target position and relevance can change rapidly.

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