Showing posts with label neuroscience. Show all posts
Showing posts with label neuroscience. Show all posts

Sunday, September 2, 2007

Unsolved problems in Neuroscience

I thought readers of this blog would find this Wikipedia entry of great interest. Reductionistic materialists assume that science has already proven that mind = brain, and that anyone who disagrees with that assessment is simply uninformed, a religious zealot, or deluded. But perhaps that is just a case of an assumption of knowledge providing an obstacle to understanding? This list of the unsolved problems in neuroscience (most of which have been investigated, over and over again, for the past hundred years!) shows just what materialists have not even begun to explain about mind and consciousness.

Here is the Wikipedia article, in full:


Some of the yet unsolved problems of neuroscience include:


  • Self awareness: What is the neuronal basis of subjective experience, wakefulness, alertness, arousal and attention? What is its function?

  • Perception: How does the brain transfer sensory information into coherent, private percepts? What are the rules by which perception is organized? What are the features/objects that constitute our perceptual experience of internal and external events? How are the senses integrated? Is face perception special (e.g. innate)? What is the relationship between subjective experience and the physical world?

  • Learning and Memory: Where do our memories get stored and how are they retrieved again? How can learning be improved? What is the difference between explicit and implicit memories? How plastic is the mature brain?

  • Development: How and why did the brain evolve (the way it did)? What are the molecular determinants of individual brain development?

  • Sleep: Why do we dream? What are the underlying brain mechanisms? What is its relation to anesthesia?

  • Cognition and Decisions: How and where does the brain evaluate reward value and effort (cost) to modulate behavior? How does previous experience alter perception and behavior? What are the genetic and environmental contributions to brain function?

  • Language: How is it implemented neurally? What is the basis of semantic meaning?

  • Diseases: What are the neural bases (causes) of mental diseases like psychotic disorders (e.g. mania, schizophrenia), Parkinson's disease, Alzheimer's disease or addiction? Is it possible to recover loss of sensory or motor function?




Materialists assume that each and every one of these unanswered questions will be resolved through reductionist explanations, in terms of neurons and neural firing patterns. However, the lack of progress on many of these items should bring that unstinting faith into some question. . .

Saturday, July 14, 2007

Hubris part II (Repost from AMNAP 1.0)

Last week, I linked to an article in the Guardian showing amazing recovery for some PVS (persistent vegetative state) patients given a particular kind of sleeping pill.

Here is additional evidence from another article in the Guardian that at least some PVS patients are not hopeless vegetables but instead awake and aware of their environment:


A 23-year-old woman who has been in a vegetative state since suffering devastating brain damage in a traffic accident has stunned doctors by performing mental tasks for them. Brain scans revealed that the woman, who has shown no outward signs of awareness since the accident in July last year, could understand people talking to her and was able to imagine playing tennis or walking around her home when asked to by doctors.
The discovery has astounded neuroscientists who believe it could have dramatic implications for life and death decisions over other patients diagnosed as being in a persistent vegetative state (PVS). Last year, an intense legal battle over the life of Terri Schiavo, a woman diagnosed as PVS, was brought to an end when US courts upheld the decision to remove her feeding tube in March. She died 13 days later in a Florida care home.

Neuroscientists at the Medical Research Council's cognition and brain sciences unit at Cambridge and the University of Liege in Belgium used a brain scanning technique called functional magnetic resonance imaging (fMRI) to detect signs of awareness in the woman, the first time scientists have been able to do so in a PVS patient. The technique is now likely to become a standard way of determining how conscious vegetative patients are.

"This is extremely important. It's the difference between life and death. From cases in the UK and the US, we know that end-of-life decisions are of course extremely important and this will definitely change the way we deal with these patients. When you have signs of consciousness, you cannot decide to stop hydration and nutrition," said Steven Laureys, a neurologist at the University of Liege and co-author of the study which appears in the journal Science today.

Researchers led by Adrian Owen at Cambridge University began tests on the woman five months after her accident. Although she had emerged from a coma, she was diagnosed as being in a vegetative state, in which patients enter a cycle of sleeping and waking and even open their eyes, but are completely unresponsive.

Scientists ascertained that the woman could understand speech by playing a variety of sentences. Using the fMRI scanner, which takes snapshots of brain activity every second or two, they spotted different parts of her brain lighting up depending on which sentence she heard.

Previous attempts to spot signs of awareness in PVS patients have been inconclusive because brains can respond to some actions automatically. The uncertainty forced the scientists to come up with a test that would show categorically whether the patient was conscious or not.

Dr Owen said: "We said to her, when you hear the word 'tennis', we want you to imagine being on the centre court of Wimbledon playing a big rally and every time the ball comes to you, you struggle to get it back. Then, we had a second scenario in which we wanted her to imagine going from room to room in her home."

The two scenarios were chosen to trigger activity in different parts of her brain so they would be picked up by the scanner. While thinking about tennis, the scientists hoped to see a part of the brain called the premotor cortex, which governs limb movement, flicker into life. If she thought about walking around her flat, they expected to see a brain region called the parahippocampal gyrus, which handles mental maps of places, light up.

During the scans, the scientists said the words "tennis", "home" or "rest" every 30 seconds and looked for changes in her brain activity. Remarkably, after each word, her brain lit up as expected, suggesting she was responding to the instructions. Further tests showed her brain activity was indistinguishable from that of healthy volunteers doing the same task.

Scientists now have to discover how common it is for others in a vegetative state to be similarly aware of their surroundings. The woman in the study has since been able to follow her own reflection in a mirror, leaving open the possibility the brain scans may simply have picked up very early signs of her recovery.

Hubris (Repost from AMNAP 1.0)

I'm sure we all remember the spectacle last year of Terri Schaivo's last days. Court decisions came down, then were appealed appealed to higher courts. In the end, Schaivo - who we were told emphatically was "already gone" years ago - was pulled off her feeding tube and dehydrated to death and was laid to rest.

Practically the entire "scientific" medical community assured all of us that Schaivo's condition was permanent, that the real Terri Schaivo was hopelessly gone. But what if the medical consensus was based on a flawed understanding of how human consciousness works? What if our memories and personalities are not really "stored" in our brains after all, but simply accessed through them. In that case recovery from extremely severe brain damage seems much more reasonable.

This week, the Guardian published a fascinating article about a new treatment for "hopeless" PVS cases that is bringing many of them back to life:


We have always been told there is no recovery from persistent vegetative state - doctors can only make a sufferer's last days as painless as possible. But is that really the truth? Across three continents, severely brain-damaged patients are awake and talking after taking ... a sleeping pill. And no one is more baffled than the GP who made the breakthrough. Steve Boggan witnesses these 'strange and wonderful' rebirths.

For three years, Riaan Bolton has lain motionless, his eyes open but unseeing. After a devastating car crash doctors said he would never again see or speak or hear. Now his mother, Johanna, dissolves a pill in a little water on a teaspoon and forces it gently into his mouth. Within half an hour, as if a switch has been flicked in his brain, Riaan looks around his home in the South African town of Kimberley and says, "Hello." Shortly after his accident, Johanna had turned down the option of letting him die.

Three hundred miles away, Louis Viljoen, a young man who had once been cruelly described by a doctor as "a cabbage", greets me with a mischievous smile and a streetwise four-move handshake. Until he took the pill, he too was supposed to be in what doctors call a persistent vegetative state.
Across the Atlantic in the United States, George Melendez, who is also brain-damaged, has lain twitching and moaning as if in agony for years, causing his parents unbearable grief. He, too, is given this little tablet and again, it's as if a light comes on. His father asks him if he is, indeed, in pain. "No," George smiles, and his family burst into tears.

It all sounds miraculous, you might think. And in a way, it is. But this is not a miracle medication, the result of groundbreaking neurological research. Instead, these awakenings have come as the result of an accidental discovery by a dedicated - and bewildered - GP. They have all woken up, paradoxically, after being given a commonly used sleeping pill.

Across three continents, brain-damaged patients are reporting remarkable improvements after taking a pill that should make them fall asleep but that, instead, appears to be waking up cells in their brains that were thought to have been dead. In the next two months, trials on patients are expected to begin in South Africa aimed at finding out exactly what is going on inside their heads. Because, at the moment, the results are baffling doctors.

The remarkable story of this pill and its active ingredient, zolpidem, begins in 1994 when Louis Viljoen, a sporty 24-year-old switchboard operator, was hit by a truck while riding his bike in Springs, a small town 30 minutes' drive east of Johannesburg. He suffered severe brain injuries that left him in a deep coma. He was treated in various hospitals before being settled in the Ikaya Tinivorster rehabilitation centre nearby. Doctors expected him to die and told his mother, Sienie Engelbrecht, that he would never regain consciousness. "His eyes were open but there was nothing there," says Sienie, a sales rep. "I visited him every day for five years and we would speak to him but there was no recognition, no communication, nothing."

The hospital ward sister, Lucy Hughes, was periodically concerned that involuntary spasms in Louis's left arm, that resulted in him tearing at his mattress, might be a sign that deep inside he might be uncomfortable. In 1999, five years after Louis's accident, she suggested to Sienie that the family's GP, Dr Wally Nel, be asked to prescribe a sedative. Nel prescribed Stilnox, the brand name in South Africa for zolpidem. "I crushed it up and gave it to him in a bottle with a soft drink," Sienie recalls. "He couldn't swallow properly then, but I helped him and sat at his bedside. After about 25 minutes, I heard him making a sound like 'mmm'. He hadn't made a sound for five years.

"Then he turned his head in my direction. I said, 'Louis, can you hear me?' And he said, 'Yes.' I said, 'Say hello, Louis', and he said, 'Hello, mummy.' I couldn't believe it. I just cried and cried."

Hughes was called over and other staff members gathered in disbelief. "Sienie told me he was talking and I said he couldn't be - it wasn't possible," she recalls. "Then I heard him. His mother was speechless and so were we. It was a very emotional moment."

Louis has now been given Stilnox every day for seven years. Although the effects of the drug are supposed to wear off after about two and a quarter hours, and zolpidem's power as a sedative means it cannot simply be taken every time a patient slips out of consciousness, his improvement continues as if long-dormant pathways in his brain are coming back to life.