In their follow-up VNO studies, Moran and Jafek carefully examined the noses of two hundred volunteers. Peering inside with special headlamps and magnification devices, they were able to locate the VNO in every subject. Moran then used an electron microscope to probe even deeper into surgical speci- mens of nasal tissue.
This time, there was no question: Moran and Jafek were looking at the human Vomeronasal organ. The old school of science had stated that the human VNO rarely existed in adults. Moran and Jafek had proved otherwise. “We couldn’t believe it when we saw the VNO in every instance,” says Moran. “We found that there is not only an opening, but an organ behind it. And, we found that there are some very interesting-looking cells in it. And, it looked like a sense organ.”
The human VNO system is made up of two tiny organs that sit deep inside both nostrils. Although in some people you can see the VNO opening, or pit, with the naked eye, in most cases the pit must be magnified to be visible. That may explain why the VNO had previously only been observed on rare occasions.
With the presence of the human VNO confirmed, the task turned toward finding the link between the organ and the brain, the freeway on which pheromonal messages can travel. That freeway is the Vomeronasal nerve.
Larry Stensaas and his colleagues looked again to the fetal brain for answers. Earlier research had concluded that the fetus has a vomeronasal nerve that connects the VNO to the accessory olfactory bulb. However, the nerve was thought to exist only during the early months of gestation. Before moving on to other ventures, Stensaas investigated the probability that the VNO maintains its link to the hypothalamus into adulthood. Subsequent studies have indeed shown this to be the case.
Moran and Jafek also discovered that the VNO lies separate from the olfactory epithelium (the cells that make up the olfactory system, which is responsible for the sense of smell) inside them.
Eventually, they realized that while the two systems are separate and work independently, they run parallel in the following way:
VNO receptor -> vomeronasal nerve —) accessory olfactory bulb of the brain Olfactory receptor —) olfactory nerve to olfactory bulb of the brain.
When Berliner found out about Moran’s micrographs, he contacted him with an irresistible proposal: Come work with me. Moran accepted, joining the team of respected scientists that Berliner had assembled for his journey to the sixth sense.
The pieces of the pheromone puzzle were slowly shifting into place. David Berliner and his fellow scientists now sought to find out if the human VNO which existed beyond a doubt responded to pheromones. Berliner would turn to the contents in his ﬂask, his confidence boosted by David Moran’s elegant micrographs of the VNO.
Pheromones and the VNO: Solving the Puzzle
A neurophysiologist whose accent is ﬂowered with the inﬂuence of his native Uruguay, Dr. Louis Monti-Bloch works in the psychiatry department of the University of Utah in Salt Lake City. Monti-Bloch, whose pioneer investigations into the workings of the human VNO have provided us with much of the framework for our study of the sixth sense, designed and conducted a series of double—blind studies to determine how the VNO reacts to pheromones.
To perform the experiments, Monti-Bloch developed a mini-probe, a device that delivers pheromones and other control substances directly to the VNO and records resulting electrical activity on a computer. The mini-probe detects subtle changes. in the surface voltage of VNO cells and illustrates that activity with the help of an electrovomerogram (EVG). A Monti-Bloch needed to devise a method of delivering the pheromones.
The pheromones that would prevent them from leaking into the adjacent olfactory system; should this happen, the scientists would be unable to obtain accurate VNO test results. He surrounded a hair-thin wire electrode with two concentric plastic coverings that ensured the substances inside would be delivered where they were supposed to, and not wander to nearby olfactory cells.
The device worked beautifully. It delivered test chemicals to the VNO in a micropuff of humidified air mixed with pheromones or non-pheromone control substances. When placed directly on the VNO, the electrode picked up any electrical activity caused by the chemical inputs. It could also be trained on the surrounding respiratory tissue or the olfactory epithelium so that comparisons of electrical activity could be obtained from several other sensory and non-sensory locations inside the nose.
Monti-Bloch could also monitor what the volunteers experienced during the tests. The subjects were awake during all phases of the experiments, so they were able to describe how their feelings and moods changed (or didn’t) when certain substances were delivered into their noses.
Monti-Bloch’s test substances were pheromones synthesized in a lab by Clive Jennings-White, his colleague at the University of Utah. Jennings-White had devised a way to duplicate the molecular structures of pheromones derived from the skin cell extracts in Berliner’s now-famous ﬂask.
One of the keys to the VNO-functionality experiments was differentiating between the sense of smell and the VNO. If the scientists were indeed poised to reveal the presence of a sixth sense, they had to prove that this pheromone-sensing system acted independently of the sense of smell. To do this, they selected a series of strong—smelling olfactory stimulants, including clove oil and cineole. Monti-Bloch then signed up forty-nine volunteers ranging in age from eighteen to fifty-five, all of whom seemed more than willing to ﬂare their nostrils for science. He outfitted them with electrodes for monitoring galvanic skin.
He also performed psychometric tests to explore pheromonal behavior.
While the volunteers reclined comfortably on exam tables, Monti-Bloch delivered tiny puffs of pheromones into their noses. In all cases, the VNO responded immediately, sending a rapid-fire staccato of electrical activity through the mini-probe and into the computer. The olfactory cells, meanwhile, showed no response to the odorless pheromones.
Continuing with his experiments, Monti-Bloch delivered puffs of olfactory stimulants into the noses of the volunteers. The olfactory cells zipped into life . . . and the VNO sat quiet. This was clear evidence that the VNO and the olfactory cells do not react to the same substances. The VNO requires a pheromone to pro- duce electrical activity, while the sense of smell requires a scent‘ molecule to perform its work. What’s remarkable about this experiment is that the VNO responded to picogram quantities of pheromones. A picogram is a millionth of a millionth of a gram – a staggeringly small quantity.
In general, pheromones are sexually powerful—some are more active in males and others are more active in females. Monti-Bloch found this to be the case with his test pheromones; some had a more pronounced effect on women while others had a more pronounced effect on men. Specifically, the synthesized pheromone ER-670 (a version of the naturally occurring human pheromone androstadienone) shows more activity in women and ER-830 (a version of the naturally occurring human ° pheromone estratetraenol) shows more activity in men. To put it more simply, women react strongly to male pheromones and men react strongly to female pheromones. ”
In a later experiment, Monti-Bloch delivered puffs of odorless . human pheromones from Berliner’s ﬂask onto single VNO cells 3’5 that had been harvested from research volunteers and cultivated, in a petri dish. The result stunned him: The single VNO cells fired in reaction to the pheromones but showed no response to odors. This study showed that the VNO contains neurons that matter.