By CARL ZIMMER
Published: July 12, 2005
Seven years ago Reginald King was lying in a hospital bed recovering from bypass surgery when he first heard the music.

It began with a pop tune, and others followed. Mr. King heard everything from cabaret songs to Christmas carols. “I asked the nurses if they could hear the music, and they said no,” said Mr. King, a retired sales manager in Cardiff, Wales.

“I got so frustrated,” he said. “They didn’t know what I was talking about and said it must be something wrong with my head. And it’s been like that ever since.”

Each day, the music returns. “They’re all songs I’ve heard during my lifetime,” said Mr. King, 83. “One would come on, and then it would run into another one, and that’s how it goes on in my head. It’s driving me bonkers, to be quite honest.”

Last year, Mr. King was referred to Dr. Victor Aziz, a psychiatrist at St. Cadoc’s Hospital in Wales. Dr. Aziz explained to him that there was a name for his experience: musical hallucinations.

Dr. Aziz belongs to a small circle of psychiatrists and neurologists who are investigating this condition. They suspect that the hallucinations experienced by Mr. King and others are a result of malfunctioning brain networks that normally allow us to perceive music.

They also suspect that many cases of musical hallucinations go undiagnosed.

“You just need to look for it,” Dr. Aziz said. And based on his studies of the hallucinations, he suspects that in the next few decades, they will be far more common.

Musical hallucinations were invading people’s minds long before they were recognized as a medical condition. “Plenty of musical composers have had musical hallucinations,” Dr. Aziz said.

Toward the end of his life, for instance, Robert Schumann wrote down the music he hallucinated; legend has it that he said he was taking dictation from Schubert’s ghost.

While doctors have known about musical hallucinations for over a century, they have rarely studied it systematically. That has changed in recent years. In the July issue of the journal Psychopathology, Dr. Aziz and his colleague Dr. Nick Warner will publish an analysis of 30 cases of musical hallucination they have seen over 15 years in South Wales. It is the largest case-series ever published for musical hallucinations.

“We were trying to collect as much information about their day-to-day lives as we could,” Dr. Aziz said. “We were asking a lot of the questions that weren’t answered in previous research. What do they hear, for example? Is it nearby or is it at a long distance?”

Dr. Aziz and Dr. Warner found that in two-thirds of the cases, musical hallucinations were the only mental disturbance experienced by the patients. A third were deaf or hard of hearing. Women tended to suffer musical hallucinations more than men, and the average patient was 78 years old.

Mr. King’s experience was typical for people experiencing musical hallucinations. Patients reported hearing a wide variety of songs, among them “Don’t Cry for Me Argentina” and “Three Blind Mice.”

In two-thirds of the cases, the music was religious; six people reporting hearing the hymn “Abide With Me.”

Dr. Aziz believes that people tend to hear songs they have heard repeatedly or that are emotionally significant to them. “There is a meaning behind these things,” he said.

His study also shows that these hallucinations are different from the auditory hallucinations of people with schizophrenia. Such people often hear inner voices. Patients like Mr. King hear only music.

The results support recent work by neuroscientists indicating that our brains use special networks of neurons to perceive music. When sounds first enter the brain, they activate a region near the ears called the primary auditory cortex that starts processing sounds at their most basic level. The auditory cortex then passes on signals of its own to other regions, which can recognize more complex features of music, like rhythm, key changes and melody.

Neuroscientists have been able to identify some of these regions with brain scans, and to compare the way people respond to musical and nonmusical sounds.

Only a handful of brain scans have been made of people with musical hallucinations. Dr. Tim Griffiths, a neurologist at the University of Newcastle Upon Tyne in England, performed one of these studies on six elderly patients who developed musical hallucinations after becoming partly deaf.

Dr. Griffiths used a scanning technique known as PET, which involves injecting radioactive markers into the bloodstream. Each time he scanned his subjects’ brains, he asked them whether they had experienced musical hallucinations. If they had, he asked them to rate the intensity on a scale from one to seven.

Dr. Griffiths discovered a network of regions in the brain that became more active as the hallucinations became more intense. “What strikes me is that you see a very similar pattern in normal people who are listening to music,” he said.

The main difference is that musical hallucinations don’t activate the primary auditory cortex, the first stop for sound in the brain. When Dr. Griffith’s subjects hallucinated, they used only the parts of the brain that are responsible for turning simple sounds into complex music.

These music-processing regions may be continually looking for signals in the brain that they can interpret, Dr. Griffiths suggested. When no sound is coming from the ears, the brain may still generate occasional, random impulses that the music-processing regions interpret as sound. They then try to match these impulses to memories of music, turning a few notes into a familiar melody.

For most people, these spontaneous signals may produce nothing more than a song that is hard to get out of the head. But the constant stream of information coming in from the ears suppresses the false music.

Dr. Griffith proposes that deafness cuts off this information stream. And in a few deaf people the music-seeking circuits go into overdrive. They hear music all the time, and not just the vague murmurs of a stuck tune. It becomes as real as any normal perception.

“What we’re seeing is an amplification of a normal mechanism that’s in everyone,” Dr. Griffiths said.

It is also possible for people who are not deaf to experience musical hallucinations. Epileptic seizures, certain medications and Lyme disease are a few of the factors that may set them off.

Dr. Aziz also noted that two-thirds of his subjects were living alone, and thus were not getting much stimulation. One patient experienced fewer musical hallucinations when Dr. Aziz had her put in a nursing home, he said, “because then she was talking to people, she was active.”

There is no standard procedure for treating musical hallucinations. Some doctors try antipsychotic drugs, and some use cognitive behavioral therapy to help patients understand what’s going on in their brains. “Sometimes simple things can be the cure,” Dr. Aziz said. “Turning on the radio may be more important than giving medication.”

Despite these treatments, many people with musical hallucinations find little relief. “I’m just living with it,” Mr. King said. “I wish there was something I could do.

“I do silly things like talking to myself, hoping that when I stop talking, the tune will stop. But it doesn’t work that way.”

More studies may help researchers find new treatments. Prof. Diana Deutsch, a psychologist at the University of California, San Diego, is planning a new scanning study of musical hallucination on people who are not deaf, using functional M.R.I. Unlike the PET scanning used by Dr. Griffiths, functional M.R.I. is powerful enough to catch second-by-second changes in brain activity.

“It might be awhile before we have results, but it’s certainly something I’m very excited about,” Dr. Deutsch said. “We’ll see where it takes us.”

Dr. Aziz also believes that it is necessary to get a better sense of how many people hear musical hallucinations. Like Mr. King, many people have had their experiences dismissed by doctors.

Dr. Aziz said that ever since he began presenting his results at medical conferences last year, a growing number of patients have been referred to him.

“In 15 years I got 30 patients,” he said, “and in less than a year I’ve had 5. It just tells you people are more aware of it.”

Dr. Aziz suspects that musical hallucinations will become more common in the future. People today are awash in music from radios, televisions, elevators and supermarkets. It is possible that the pervasiveness of music may lead to more hallucinations. The types of hallucinations may also change as people experience different kinds of songs.

“We have speculated that people will hear more pop and classical music than they do now,” said Dr. Aziz. “I hope I live long enough to find out myself in 20 years’ time.”

서울대 기계항공공학부 ‘김종원’교수님께서 학생들에게 하는 말씀을 게시판에서 퍼왔습니다.

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또다시 한 학기가 끝났다. 이제 곧 자네들은 나름대로의 여름을 보내기 위해서 학교를 떠날 것이다. 그런 자네들에게 이번 여름에는 필히 자신들의 꿈과 비전을 만들고 돌아 오라고 외치고 싶다.

자네들은 곧 이 교정을 떠나서 사회로 나갈 것이다. 대학원을 진학하든 산업체에 취직을 하든 그것은 당장 눈 앞의 진로일 뿐이다. 제일 중요한 것은 자네들이 과연 20년 뒤에 자기가 어떤 곳에서 어떤 모습으로 일과 연구를 할 것인지에 대해서 확실한 꿈과 비전을 가지고 있느냐 하는 것이다.

아마 대부분의 학부생들이 그러한 꿈과 비전이 없이 이 순간 그저 학기말 고사나 준비하고 있을 것이다. 그런데 자네들은 과연 학기말 고사 공부를 하는 정도의 시간과 노력만이라도 자네들의 꿈과 비전을 굳히기 위해서 투자를 해보았는지 잘 모르겠다. 한번만이라도 대기업을 성공적으로 경영하고 있는 엔지니어 출신의 CEO가 쓴 책을 읽고 나도 20년 뒤에는 바로 이런 모습이 되고 싶다고 꿈꾸는 노력을 했는지 모르겠다는 말이다.

그저 이공계 기피 현상이라는 현실에 좌절하면서 20년 뒤에는 없어지겠지 하는 멍청한 생각을 하고 있지나 않은지 모르겠다. 점점 더 포화 상태로 치닫는 경제 현실에서 아무런 꿈과 비전 없이 그저 친구들이 하는 말이나 신문에서 떠드는 피상적인 기사에 자네들의 소중한 미래를 맡기고 있지나 않은지 걱정이 된다.

서울공대에 와서도 여전히 평균적인 위치의 엔지니어의 모습을 자네들의 미래의 소박한 꿈으로 삼고 나도 20년 뒤에는 혹시 회사에서 짤려나는 것은 아니지 하는 막연한 불안감으로 졸업을 기다리지나 않는지 걱정이 된다.

왜 자네들은 서울공대생으로서 20년 뒤에 top 1% 이내에 드는 CEO, 전문 연구직, 교수, 창업가 등을 꿈꾸지 않는가? 왜 자네들은 지금 이 순간 자네들 나름대로의 큰바위 얼굴을 그리지 않는가? 왜 사회 현상만 탓하고 있는가? 과연 자네들은 얼마나 자기 자신의 꿈과 비전을 확실히 세우기 위해서 시간과 노력을 투입했던가?

20년 뒤의 자기 자신의 모습, 즉, 꿈과 비전이 가슴 속에 확실하게 없는 상태에서 지금 죽을 힘을 다 할 수는 없다. 그러면, 결국 평균적인 위치의 엔지니어가 되고 마는 것이다. 아무리 서울대를 없앤다고 난리를 쳐도 자네들은 top 1% 엔지니어가 되어 리더그룹에 들어야 한다고 생각한다. 우리가 사는 세상은 리더가 필요하다. 나는 자네들이 바로 이런 리더가 되기를 원하며, 그런 리더가 될 권리와 의무를 동시에 가지고 있다고 굳게 믿는다.

여러 번 이야기 하지만, 엔지니어로서 20년 뒤의 자네 모습으로서 결국 다음과 같이 크게 다섯 종류의 모습을 꿈꿀 수 있다:

– [대기업 CEO] Global top class 대기업의 CEO 또는 핵심 중역이 되어 활동한다.

– [창업가] 기술 기반의 top class의 세계적인 벤처기업을 창업하여 사회에 커다란 영향을 주면서 엄청난 돈을 번다.

– [전문연구직] 세계적인 연구소에서 프로젝트 팀장으로서 도전적인 프로젝트를 수행한다.

– [교수] 세계적인 대학교에서 훌륭한 교수가 되어 교육과 연구에 몰두한다.

– [전문행정직] 공학적 소양을 바탕으로 top class의 변호사가 되거나 정부 관료가 되어 기술문제가 개입된 법적 소송을 처리하거나 중요한 국가 정책을 수립해서 시행한다.

여기서 제발 내가 과연 그런 모습이 될 수 있나 하는 멍청한 소리를 좀 하지 말기 바란다. 큰바위얼굴 소년은 자기가 큰바위얼굴이 될 것이라고 생각도 하지 않았다. 그리고, 그렇다면 도대체 자네들은 20년 뒤에 무엇이 될 것이냐고 묻고 싶다. 축구 선수는 골대가 있기 때문에 90분 동안 죽을 힘을 다해서 공을 찬다. 자네들은 A학점을 꿈꾸기 때문에 죽을 힘을 다해서 시험 공부를 한다. 고등학생들은 서울대 합격하기 위해서 죽을 힘을 다한다.

내가 과연 그런 모습이 될 수 있나 하는 생각은 결국 모두 다 공을 넣는 것은 아니고, 시험도 다 잘 보는 것은 아니며, 서울대말고도 다른 대학도 많은데 왜 내가 죽을 힘을 다 할 필요가 없다고 생각하는 것과 같다. 그렇다, 실패를 두려워 하면 가지 않으면 된다.

그러나, 우리는 인생을 사는 것이기 때문에 누구나 다 가야 하며, 결국 아무런 목표가 없이 살아가도 결국 20년 뒤에 어떠한 모습으로 되어 있을 것이기 때문에 큰 문제인 것이다. 그리고, 이 놈의 인생은 단 한 번의 기회 밖에 주지 않는다. 자네는 이런 이유로 그냥 그렇게 살다가 20년 뒤에 그냥 되는대로 살면서 그 때도 여전히 이 놈의 사회가 이래서 안 된다고 푸념할 것이냐? 그 때가서도 여전히 사회보고 책임을 지라고 할 것이냐?

위의 다섯 가지의 모습 중에서 어떠한 것도 자기 가슴에 공진과 같이 와 닿는 모습이 없으면 하루 속히 엔지니어가 아닌 다른 길로 가야 한다. 그래 다 좋다. 그런데 한 가지 정말로 묻고 싶은 것은, 학기말 고사 준비하는 정도의 시간과 노력을 투입해서 위의 다섯 가지 길을 간 사람이 쓴 책도 읽고 인터넷도 검색하고 하면서 엔지니어로서의 자네의 꿈과 비전을 만들기 위해서 손톱만큼의 노력은 해보았는지 하는 것이다.

혹시나 부모나 친구들이나 선배들이 그저 지나가면서 던지는 그 한마디에 엔지니어로서는 나는 이런 모습이 될 것이야 하고 있지나 않은지 모르겠다. 그저 언론에서 걱정하는 이공계 기피 현상에 대해서 자네도 같이 걱정하며 주저앉고 있지나 않은지 모르겠다. 이공계 기피 현상보다도 더 걱정스러운 것은 자네들의 꿈과 비전이 없음이 더 걱정이다.

도대체 자네 인생은 누가 살아 주는가? 친구가, 부모가, 신문이? 도대체 자네의 꿈과 비전을 누가 만들어 주는가? 친구가, 부모가, 언론이? 꿈과 비전은 참으로 만들기 어려운 것이다. 역학 문제 풀듯이 unique한 정답이 있는 것이 절대로 아니다.

이번 여름방학에는 제발 좀 시간과 노력을 투입해서 위의 다섯 가지 길을 가고 있는 현재의 선배들이 쓴 책들을 위인전처럼 읽거나, 인터넷을 뒤지거나, 직접 인터뷰를 해서라도 그 사람들이 어떻게 각각 그 길로 갔으며, 지금 과연 무슨 일을 하고 있는지 알아보기를 바란다 (첨부 목록 참조).

대기업 CEO, 창업가, 전문연구직, 교수, 전문행정가 등의 다섯 가지 모습에 대해서 적어도 각각 세 사람 정도를 정해서 철저하게 그 사람에 대해서 탐구를 해보라는 말이다. 스티브 잡스를 모르고 어떻게 창업가가 되겠다고 할 것이며, 화성 탐사선 프로젝트 팀장이 어떤 인생을 살고 있는지 모르고서 어떻게 전문연구직이 되겠다고 할 것이냐? 성공한 창업가가 돈을 과연 얼마나 버는지 자세히 알고는 있느냐? 빌 게이츠가 돈 많이 버는 것은 대충은 알고 있겠지만, 그 밖의 창업가는 과연 얼마나 많은 돈을 버는지 알고는 있느냐?

다섯 가지 길을 간 사람들의 모습을 알면 알수록 점점 더 자네들 나름대로의 20년 뒤의 모습이 그래도 더 확실하게 잡힐 것이다. 이것은 마치 5명의 여자 또는 남자 친구 후보들 중에서 누구를 마지막에 선택할 것인가 결정하는 것과 같다. 각 5명을 만나보고 이야기 해보고 해서 점점 더 잘 알수록 이 여자 또는 남자야 말로 정말로 내 친구로 삼고 싶다 하는 마음이 확실해 진다. 그런 노력도 없이 피상적인 모습만 보고 어떻게 결정을 하겠느냐? 자기 나름대로의 꿈과 비전을 정하는 것도 마찬가지다. 이것은 절대로 이성적이고 논리적으로 결정되는 것이 아니다. 그것은 고도의 감정적이고 주관적인 결정이다..

그 꿈과 비전은 가슴 벅찬 그런 것이다. 그러나, 실현하기에는 지금은 거의 불가능해 보이는 그런 것이다. 그렇지만, 아 정말로 나는 이런 굉장한 모습이 되고 싶다 하는 그런 것을 찾아야 한다. 술 먹고 방 구석에 쳐 박혀서 천장만 쳐다보면 꿈과 비전이 가슴 속에 저절로 새겨지는 것이 아니다.

그리고, 이러한 벅찬 꿈과 비전을 생각하면 바로 1ms 정도나 되겠나하는 찰라의 순간 후에 자기 자신이 자기에게 단칼을 내리치게 된다. “니가 무슨 그게 되겠냐? 너는 이러 이러한 성격이고, 돈도 없고, 경쟁이 심한데 그게 되겠냐구. 그 사람은 천재이어서 그렇게 되었지, 네가 무슨..” 이런 식의 단칼이 자네의 꿈과 비전을 무자비하게 박살낸다. 그것은 일종의 열등감이라고도 할 수 있다.

그러나, 아마도 서울대생이면 말은 안하고 있지만 열등감은 더 강할 것이다. 내가 바로 그랬으니까. 명문고와 서울공대에 박사까지 했지만 오히려 우수한 놈들이 모여 있는 집단에서 기가 죽을 때가 더 많았으니까. 심지어 잘 노는 놈에게도 열등감을 느낀다. 자네들도 다 그럴 것이다. 그러나 그것이 바로 서울대에 들어 온 이유이다. 모두 다 결국 자네를 도와 줄 인적 자원이다. 그래서 그런 단칼을 바로 하나 “아직 해보지도 않았지 않았냐. 해 보고나서.. 죽을 힘을 다 해서 해보고 나서, 그 때 가서 결과를 보자” 이렇게 생각하고 꿈과 비전을 세우는 것을 박살내는 그 단칼을 바로 박살을 내야 한다.

세상에 가장 멍청한 것은 해보지도 않고 포기하는 일이다. 해보지도 않고 이 꿈 저 꿈 잘라버리다가는 남는 것이 없다. 결국 그럭 저럭 살다가 아무리 서울대 나와도 평균치기 something이 되어 있는 내 자신을 발견하게 된다. 꿈과 비전을 미리 잡고 그러면 죽을 힘을 다하게 되며 그러면 실현 불가능하게만 보여 졌던 꿈과 비전을 결국 실현하게 된다. 죽을 힘을 다했으니까..

이번 여름방학 동안에 영어 회화 공부나 해야 하겠다고 하는 계획보다도 더 중요한 것이 바로 여름 방학 끝나고 학교로 돌아 올 때에는 이 가슴 속에 절대로 지워지지 않게 각인된 그런 꿈과 비전을 새기고 돌아오기를 바란다.

그런 꿈과 비전이 확실하면 2학기에는 무슨 과목을 수강할 지부터 시작해서, 군대는 언제 어떻게 가고, 대학원을 갈 것인지, 유학을 갈 것인지, 회사는 어떤 회사에 취직을 할 것인지 등등의 모든 결정이 쉬워질 것이며, 그 보다도 더 지금 이 순간 자네가 하고 있는 모든 공부와 사회활동에 대한 의미가 생기며, 비로소 고등학교 3학년 때처럼 또다시 미래을 위해서 죽을 힘을 다 해야 하겠다고 하는 동기가 생길 것이다.

예를 들어서, 도대체 영어 회화 공부는 왜 하려고 하는가? 토플 토익 성적 높이려고? 이런 동기로 영어 공부하는 친구도 있을 것이지만, 20년 뒤에 Global top class 대기업의 CEO로서 세계 각국에서 집결된 임원급 회의를 할 때를 위해서 영어 공부한다고 생각하면 모골이 송연할 정도로 죽을 힘을 다해서라도 잘 해야 하겠다는 생각이 들 것이다.

자네의 미래를 꿈꾸는 것은 자네의 특권이다. 그런데, 서울공대생인 이상 그러한 찬란한 미래를 만드는 것은 하나의 의무 사항이기도 하다. 그것은 군대 가는 것은 비교할 수 없을 정도로 중요하게 자네들에게 지워지는 무거운 짐이기도 한 것이다.

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Picture1: SCOTT GARDNER / AP, 1999
Dr. Sandra Witelson, a neuroscientist at McMaster University in Hamilton, Canada, has spent decades studying how the brain’s structure affects intelligence.

Close-up
Revealing thoughts on gender and brains

By Robert Lee Hotz
Los Angeles Times

HAMILTON, Ontario — For 40 years, Thomas Harvey, a retired pathologist from Princeton, N.J., had been the quixotic custodian of the 20th century’s most famous brain.

In 1955, he had conducted a routine autopsy of Albert Einstein after the 76-year-old physicist died at Princeton Hospital. The remains were to be cremated. Harvey, however, decided to preserve the organ responsible for the theory of relativity and the principle of the atomic bomb.

Harvey believed that Einstein’s brain tissue, pickled in warm formalin, embodied some clue to the mystery of intelligence. He held on to that hope through 40 years of indecision.

Eventually, it led the soft-spoken Harvey to Sandra Witelson. She had brains, dozens of them — the largest collection of normal brains in the world — at McMaster University in Ontario.

An enduring riddle

Every one posed a riddle that had shaped her research for 30 years: How does the structure of the brain influence intelligence?

A professor of psychiatry and neuroscience, Witelson grappled with such a fundamental mystery by studying a somewhat smaller one: why certain abilities develop on one side of the brain rather than the other.

The two hemispheres of the brain are almost symmetrical physically but can seem to be separate minds when it comes to awareness and mental processing. They even have different problem-solving styles, researchers report. Yet they work together seamlessly to produce a single mind.

By 1977, Witelson was trying to learn why language skills developed on the left side of the brain for all right-handers but on the right side for many left-handers.

To compare the two sides, she needed normal brains — more than anyone had gathered before.

For 10 years, she worked through a network of doctors and nurses, hoping to persuade terminal cancer patients to make a last contribution to medicine. Her research was funded by the U.S. National Institutes of Health.

By 1987, 120 men and women had agreed to donate their brains after death. They all submitted to thorough psychological and intelligence tests so that each brain would be accompanied by a detailed profile of the mind that had animated it.

Billions and trillions

In the prime of life, the cerebral cortex contains 25 billion neurons linked through 164 trillion synapses.

Thoughts thread through 7.4 million miles of dendrite fibers and 62,000 miles of axons so compacted that the entire neural network is no larger than a coconut.

No two brains are identical, nor are two minds ever the same.

Wherever Witelson looked, she discerned subtle patterns that only gender seemed to explain.

The brains in Witelson’s freezer are contested terrain in a controversy over gender equality and mental performance.

Her findings — published in Science, the New England Journal of Medicine, the Lancet and other peer-reviewed journals — buttress the proposition that basic mental differences between men and women stem in part from physical differences in the brain.

Witelson is convinced that gender shapes the anatomy of male and female brains in separate but equal ways beginning at birth.

Men’s brains, for instance, are typically bigger — but on the whole, no smarter.

“What is astonishing to me,” Witelson said, “is that it is so obvious that there are sex differences in the brain and these are likely to be translated into some cognitive differences, because the brain helps us think and feel and move and act.

“Yet there is a large segment of the population that wants to pretend this is not true.”

Battle lines

No one knows how these neural differences between the sexes translate into thought and behavior — whether they might influence the way men and women perceive reality, process information, form judgments and behave socially.

But even at this relatively early stage in exploration of the brain’s microanatomy, battle lines between scientists, equal-rights activists and educators have formed.

Some activists fear that research like Witelson’s could be used to justify discrimination based on gender differences, just as ill-conceived notions of human genetics once influenced laws codifying racial stereotypes about blacks, Asians and Jews.

Other experts argue that the physical differences Witelson observed may result not from the brain’s basic design but from conditioning that begins in infancy, when the brain produces neurons at a rate of half a million a minute and reaches out to make connections 2 million times a second.

Spurred by learning, neurons and synapses are ruthlessly pruned, a process that continues in fits and starts throughout adolescence, then picks up again in middle age.

The role of experience

“The brain is being sculpted gradually through sets of interactions,” said Anne Fausto-Sterling, a gender studies expert at Brown University. “Even when something in the brain appears biological, it may have come to be that way because of how the body has experienced the world.”

As Witelson’s research helped establish, however, the mental divide between the sexes is more complex and more rooted in the fundamental biology of the brain than many scientists once suspected.

Men and women appear to use different parts of the brain to encode memories, sense emotions, recognize faces, solve certain problems and make decisions. Indeed, when men and women of similar intelligence and aptitude perform equally well, their brains appear to go about it differently, as if nature had separate blueprints, researchers at the University of California, Irvine reported this year.

“If you find that men and women have fundamentally different brain architectures while still accomplishing the same things,” said neuroscientist Richard Haier, who conducted the study, “this challenges the assumption that all human brains are fundamentally the same.”

Yet, for the most part, scientists have been unable to document such patterns conclusively.

No one, however, had scrutinized as many brains as Witelson.

She began by studying the corpus callosum, the cable of nerves that channels all communication and cooperation between the brain’s two hemispheres.

Examining tissue samples through a microscope, she discovered that the more left-handed a person was, the bigger the corpus callosum.

To her surprise, however, she found that this held true only for men. Among women there was no difference between right-handers and left-handers.

“Once you find this one difference,” she remembered thinking, “it implies that there will be a cascade of differences.”

As she systematically analyzed the brains in her refrigerator, she discovered that other neural structures seemed larger or smaller among men, depending on whether the man had been right-handed or left-handed.

They were relatively the same size in women. “The relationships that we were finding were always — and I do mean always — different for men and women,” she said.

She narrowed her study to right-handed men and women, still looking for differences in microscopic anatomy between the left side of the brain and the right side. She meticulously counted the neurons in sets of tissue in which each sample measured 280 microns wide — about twice the thickness of a human hair — and 3 millimeters deep.

Staring through the microscope, she was baffled.

“I had the first two patients, and they were so very different,” Witelson said. “I kept looking and looking at them, trying to see what the difference could be.”

Then she consulted the donor documentation for each tissue sample. “Finally, I saw that one was a man, and one was a woman.”

The hidden clue

Among women, the neurons in the cortex were closer together. There were as many as 12 percent more neurons in the female brain.

That might explain how women could demonstrate the same levels of intelligence as men despite the difference in brain size.

“So among female brains, the cortex is constructed differently, with neurons packed more closely together,” she said.

Witelson probed deeper. She knew that the human cortex was a sandwich of six layers, each packed with neurons.

She peeled away the sheets of the temporal lobe — a region associated with perception and memory — in several of her brain specimens. She discovered that the increased neural density occurred only on layers 2 and 4, which form the hard wiring for signals coming into the brain.

Then she analyzed the microscopic structure of the prefrontal cortex. There the crowding of neurons was evident only in layers 3, 5 and 6, which carry the wiring for outbound signals.

Just to be sure, she checked left-handed brains as well as right-handed brains. She found the same sex differences when she surveyed her left-handed brains.

Perhaps, she speculated, these neuron-rich layers in an area associated with perception and speech were the reason women scored more highly than men on tasks involving language and communication.

Slowly, she formed a theory: The brains of men and women are indeed different from birth. Yet the differences are subtle. They might be found only among the synapses in brain structures responsible for specific cognitive abilities.

For so long, scientists had championed the idea of larger brains as an indicator of intellect. Witelson, however, gradually became convinced that overall brain size didn’t matter.

“One of the things that firmed it up for me,” she recalled, “was the case of Einstein.”

At Princeton Hospital, Harvey weighed Einstein’s brain on a grocer’s scale. It was 2.7 pounds — less than the average adult male brain.

He had the fragile organ infused with fixative and dissected it into 240 pieces, each containing about two teaspoons of cerebral tissue. He shaved off 1,000 hair-thin slivers to be mounted on microscope slides for study.

For years, Harvey agonized over how next to proceed. His odd pursuit inspired two books: “Possessing Genius” by Carolyn Abraham and “Driving Mr. Albert” by Michael Paterniti. Through the decades, however, he drifted in obscurity.

Finally in 1985, pioneering neuroanatomist Marion Diamond at the University of California, Berkeley persuaded him to part with four small plugs of brain tissue. Diamond discovered that the physicist’s brain had more cells servicing, supporting and nurturing each neuron than did 11 other brains she studied. These unusual cells were in a region associated with mathematical and language skills.

When they published their findings, the researchers speculated that these neurons might help explain Einstein’s “unusual conceptual powers.”

Critics contended the study was riddled with flaws, its findings meaningless.

Eventually, Harvey mailed bits of Einstein’s motor cortex to a researcher at the University of Alabama, who reported that the cortex appeared to be thinner than normal but with more tightly packed neurons.

Had it simply been compacted by time and storage conditions?

DNA testing revealed nothing. The preservative fluids apparently had scrambled Einstein’s genetic code.

A meeting of minds

Then in 1995, Harvey read Witelson’s research paper on gender differences and neuron density in the Journal of Neuroscience.

He was 84, still hoping that his tissue samples had something to teach about the neural geography of genius. To make ends meet, he was working in a plastics factory.

Harvey carefully packed Einstein’s brain in the back of his battered Dodge and drove north to Witelson’s laboratory. “I had the brain in a big jar,” Harvey, now 94, recalled.

At midnight, he crossed over the Rainbow Bridge by Niagara Falls into Canada.

Customs officials asked if he had anything to declare. Just a brain in the trunk, he told them. They waved him through.

Witelson could barely contain her curiosity.

Einstein’s brain — so far from ordinary in its intellectual achievement — might reveal a telltale anatomical signature. Size alone certainly could not account for his brain power.

“Here was somebody who was clearly very clever; yet his overall brain size was average,” Witelson said. “It certainly tells you that, in a man, sheer overall brain size can’t be a crucial factor in brilliance.”

She judiciously selected 14 pieces of Einstein’s brain. She took parts of his right and left temporal lobes, and the right and left parietal lobes.

Going to work

Witelson and her colleagues carefully compared the 40-year-old tissue samples with dozens of normal male and female brains in her collection. She also compared them with brains from eight elderly men to account for any changes due to Einstein’s age at the time of his death.

She found that one portion of Einstein’s brain perhaps related to mathematical reasoning — the inferior parietal region — was 15 percent wider than normal.

Witelson also found that it lacked a fissure that normally runs along the length of the brain. The average human brain has two distinct parietal lobe compartments; Einstein’s had one.

Perhaps the synapses in this area were more densely interconnected.

“Maybe this was one of the underlying factors in his brilliance,” she said. “Maybe that is how it works.”

She took it as confirmation of her suspicions about the anatomy of intelligence. If there were differences affecting normal mental ability, they would show up in the arrangements of synapses at particular points in the brain.

A born genius

Einstein, she was convinced, had been born with a one-in-a-billion brain.

“We suggest that the differences we see are present at birth,” Witelson said. “It is not a consequence of environmental differences.”

She turned again to the brains in her refrigerator. Wherever she looked, she began to see evidence of how microanatomy might underlie variations in mental abilities.

As she matched the brain specimens to the intellectual qualities of their owners, she discovered that differences in the size of the corpus callosum were linked to IQ scores for verbal ability, but only in women. She found that memory was linked to how tightly neurons were packed, but only in men.

Witelson determined that brain volume decreased with age among men, but hardly at all among women. Moreover, those anatomical changes appeared to be closely tied to a gradual decline in mental performance in men. “There is something going on in the male brain,” she said, “that is not going on in the female brain.”

Copyright © 2005 The Seattle Times Company