In the decorous chambers of the House Energy and Commerce Subcommittee on Wednesday a U.S. bureaucrat launched a tsunami of panic that has spread further worldwide than the real tsunami that devastated much of Japan on March 11.

In testimony to Congress, Nuclear Regulatory Commission Chairman Gregory Jaczko said, "There is no water in the spent fuel pool and we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures."

Moreover, Jaczko insisted, the Japanese government's response to its ongoing radiation problems at the Fukushima-Daiichi power plant has understated the health risks posed by the damage there. The evacuation zone for safe distancing from the plant should be at a 50-mile periphery, he said -- three times the boundary set by the government of Prime Minister Naoto Kan.

Fear followed. From Beijing to Miami, supplies of potassium iodide were snatched off drug store shelves by people convinced that clouds of lethal, cancer-inducing radiation would soon engulf their families. (The iodine pills are appropriately taken by people directly exposed to radiation to protect their thyroid glands from absorbing radioactive forms of the element.)

U.S. manufacturers of the pills quickly sold out, and are now unable to supply the genuinely needy Japanese population. In Beijing, rumors exaggerating Jaczko's comments triggered stampedes at iodide sales points, causing injuries. Authorities in the U.S., Canada and across Europe have been at pains to make people understand -- believe -- that their health is not in danger, and would not be even were a worst case multi-reactor explosion to occur at far off Fukushima.

In Japan, Naota Kan's government is desperately balancing on the fine line between providing an appropriate sense of urgency to propel mass evacuations from designated areas, while heading off mass panic across the nation.

What we are learning in the age of globalization is that frightening and tragic events in any part of the world can trigger amygdala responses in people thousands of miles away. The amygdala, a tiny almond-shaped body inside the human brain, controls fearfulness and, more importantly, anxiety.

When triggered repeatedly by a steady supply of disturbing images, the amygdala can produce a permanently elevated sense of fear. Ultimately this can present most of the features of post-traumatic stress disorder, or PTSD -- especially depression and the drive for excessive alcohol and drug intake, even addiction.

An observer watching, for example, an earthquake on TV, experiences confusion inside the brain between profound empathy for the suffering of others and fearful apprehension that he will himself experience that tragedy. And this can produce extreme anxiety.

We have seen this before. The images of two jets flying into the Twin Towers on 9/11, and victims inside the World Trade Center leaping to their deaths triggered amygdalas on an international scale, rendering some people -- including thousands of New Yorkers, according to the city's health department -- in permanent states of PTSD.

The subsequent anthrax attacks sent people worldwide rushing to buy the antibiotic ciprofloxacin, a drug that can produce dangerous side effects.

When the Chernobyl reactor exploded in Ukraine in April, 1986, radioactive fallout fell on a European land mass of about 200,000 square kilometers, exposing about 5 million people to elevated radiation. At the time, hundreds of millions of people reported fears of developing cancer from the incident, though most of them lived well outside of the affected region. Their amygdala reactions were severe: Collective anxiety rose.

Today, government authorities in Japan and, frankly, Washington, Beijing and capitals across the planet, have the advantage of knowing a great deal more about the dangers of radiation, partly as a result of Chernobyl. But they face the disadvantage of an instantly globalized chain of images, information and misinformation assaulting the amygdala centers of their populations' collective and individual brains.

Good governance means finding a means of walking a minute-by-minute tightrope, informing and calming a frightened public. In the case of Prime Minister Kan's government, this is a monumental challenge because the Japanese people are also reeling from the Old Testament-scale catastrophes of the March 11 earthquakes and tsunamis.

Aftershocks continue to rock the nation, some 1 million people are homeless, either because their homes are gone or they've been evacuated, the nation's economy is in a tailspin and hundreds of thousands of Japanese are trying to find and help their friends and relatives. It seems trivial, given all this,that the H5N1 bird flu virus has broken out in chicken flocks across the country.

This is not a population that will benefit from worst-case scenario radiation speculation.

I do not know what exclusive information Jaczko possesses that leads him to signal to the people of Japan that they cannot trust their prime minister, that their government is lying to them, and that in the nation of Hiroshima and Nagasaki, the citizenry should reject the voice of Tokyo in favor of the cries from Washington.

If the NRC has unique information or scientific analysis that exceeds available Japanese wisdom, it is unfortunate they could not share that urgency in a more discreet fashion with Tokyo. Instead, the NRC has succeeded in further distancing the Japanese people from their own government, raising their amygdala-driven anxiety levels to new highs, and dragging people all over the globalized world into a collective moment of acute fear.

This is most unfortunate. On Thursday President Barack Obama sought to allay fears, saying twice that, "We do not expect harmful levels of radiation to reach the West Coast, Hawaii, Alaska, or U.S. territories in the Pacific. That is the judgment of our Nuclear Regulatory Commission and many other experts."

But the president maintained the differing posture with Japan, set by the NRC, regarding the necessary evacuation distance from Fukushima. While offering no specific reason for the very different assessment of radiation risk, Obama said the 50-mile periphery reflected that, "We know that the damage to the nuclear reactors in Fukushima Daiichi plant poses a substantial risk to people who are nearby. That is why yesterday, we called for an evacuation of American citizens who are within 50 miles of the plant.

"This decision was based upon a careful scientific evaluation and the guidelines that we would use to keep our citizens safe here in the United States, or anywhere in the world."