neuroscience – Page 2 – Brainy Behavior

September 5, 2008

Learning and Recall – Hippocampal Firing

Today in Science a team of scientists (Hagar Gelbard-Sagiv, Roy Mukamel, Michal Harel, Rafael Malach, and Itzhak Fried) at the Weizmann Institute of Science in Israel, UCLA, and Tel Aviv University published their research where they directly recorded via implanted electrodes the firing of hippocampus neurons during learning and free recall. This represents the first time in humans this has been done. Here’s the abstract from Science:

The emergence of memory, a trace of things past, into human consciousness is one of the greatest mysteries of the human mind. Whereas the neuronal basis of recognition memory can be probed experimentally in human and nonhuman primates, the study of free recall requires that the mind declare the occurrence of a recalled memory (an event intrinsic to the organism and invisible to an observer). Here, we report the activity of single neurons in the human hippocampus and surrounding areas when subjects first view television episodes consisting of audiovisual sequences and again later when they freely recall these episodes. A subset of these neurons exhibited selective firing, which often persisted throughout and following specific episodes for as long as 12 seconds. Verbal reports of memories of these specific episodes at the time of free recall were preceded by selective reactivation of the same hippocampal and entorhinal cortex neurons. We suggest that this reactivation is an internally generated neuronal correlate of the subjective experience of spontaneous emergence of human recollection. (Published Online September 4, 2008; Science DOI: 10.1126/science.1164685)

The New York Times also has an article about the research.

February 4, 2008

Building a Better Brain

Let’s look forward a number of years. Bioengineering is at the point where replacing people’s organs with lab-grown ones is standard procedure. Gone are the days of transplant patients taking anti-rejection medications for the rest of their lives. Transplanted organs are all manufactured using stem cells from their own body, from bone marrow or from skin or any number of different sources. New organs are rapidly grown using modified growth hormones to speed up their development. A complete new organ is grown within a few weeks, a surgery performed, and the transplant patient home within days. Because of the relative low cost of such procedures, all have access to transplants. Replacing hearts, livers, lungs, kidneys, and other organs increased the life expectancy dramatically with most people living well over 100 years. Scientists are on the verge of transplanting the first manufactured brain. Knowledge of neural networks and cognition is at the point where a person’s entire knowledge system and all memories can be downloaded and stored as a backup. Scientists are working on manufacturing an entire replica human body as a “clone” in case a person is seriously injured. While individual organs come fairly cheap, a whole body is prohibitively expensive. A large portion of the cost is the brain. Even though scientists have created working brains, their success rate is still only about 5% (but always getting better). They go through a lot of brains.

Some people use this new biotechnology for creating backups of their bodies. Other people have started using it to enhance the performance of their existing body. In laboratory situations scientists are able to create organs that are effectually perfect. They are created in well-controlled situations and don’t have to go through the gauntlet of normal development, with exposure to teratogens, fluctuations in nutrition, and all the other things that can affect development. Popular organs to replace are hearts and lungs. People are able to run faster than ever before due to more efficient hearts and lungs. Other people get new legs or arms with well-sculpted muscles. Still other receive nanotech implants to enhance normal biological performance. None of this is being done in the United States or in the United Kingdom but there are plenty of countries that don’t outlaw the procedures

With the common body enhancing going on many people want to enhance their brains. They want a new brain created with certain gyri a little bit bigger and cortex a little bit thicker. Some researchers are working on improving the speed and efficiency of neurotransmitting. Most of the improvements in brain design come from turning on and off certain genes at different time points in development and providing the lab-grown brains optimal nutrients and stimulation. These enhancements can create brains that can learn 1000 times more in 1000 times less time.

I’ve taken a bit of liberty in my hypothetical treatment of bioengineering and biotechnology in the unspecified future. There is little, scientifically-speaking, that stands in the way of us as humans eventually reaching this point. The question is, should we? Should we seek to create immortal and essentially all-knowing humans through science. Supposing humans can build better brains and bodies, should they control and manipulate natural biological processes to the extent that they can create “superbeings”? I’m not going to answer any of the questions; I just want to raise them. With our great advances in bioengineering, technology, and neuroscience, where do we draw the line, assuming we do draw a line? Do we eradicate all developmental, genetic, and environmental diseases and disorders. Do we cure epilepsy, cancer, Autism, Alzheimer’s Disease, and ever other disorder? Do we enhance some functioning, such as hearts or muscles but not the brain?

With all advances in science, we have to always be mindful of the underlying morality and ethics of the advances. we need to make sure that our advances do not out-pace our morals.

January 25, 2008February 26, 2008

The Guillotine and Neuroscience

The air was chilly in 19th Century Paris as a criminal was led to his fate. A Guillotine The man had committed a crime and was sentenced to pay. A crowd gathered to watch his punishment. There standing before him was the fateful Madame, the progeny of a French engineer. This Woman with the acerbic jaw was to seal the criminal’s fate. He faced the crowd wide-eyed and fearful, pleading for his life. His pleas seemed to fall on deaf ears as the frenzied crowd prepared for the spectacle. A German man stood waiting to play his part. Theodor Bischoff was not there to enjoy the public execution, he was there in the name of science. As the executioner led the criminal to the apparatus named after Joseph Guillotin (who by the way did not invent the guillotine), Bischoff approached. The blade fell and the criminal’s head dropped to the ground. Bischoff quickly rushed over to the head to perform his experiment.

Bischoff wanted to know whether or not consciousness was centered in the head – in the brain – and if any awareness resided after the beheading. He quickly thrust his fingers at the poor criminal’s eyes to see if there was any eye-blink. There was none. He placed smelling salts under the nose, with no reaction. Finally he spoke the word, “Pardon!” into an ear. Again, no response. He was satisfied with the results and concluded that consciousness did in fact reside in the brain and that it ended when the head was severed. His early neuroscience experiment was complete.

While this approach seems unorthodox at best today, early researchers had to resort sometimes to interesting techniques in order to investigate the influence of the brain on behavior, emotions, and consciousness. Their research methods were often seriously flawed but the work they did was important. Each new discovery led to our current understanding of the brain. So while we have much better methods to research the brain than antagonizing disembodied heads, our current research as neuropsychologists and neuroscientists is founded on the research of such creative men as Bischoff.

Note: I dramatized the story and as such, it is a bit of historical fiction. I don’t know if Bischoff was in Paris, he might have been in Germany when he did the experiment. However, Bischoff did perform this experiment.

January 8, 2008February 26, 2008

Biological Determinism

Free Will As someone with a strong neurobiological foundation, I believe that the brain is the center of all behavior. What is the evidence for that belief? Remove someone’s brain and see if they have any behavior (note: I’m not endorsing this behavior, I’m merely postulating a hypothetical situation). Without the brain, there is no behavior. So, the brain is necessary for behavior but is it sufficient?

In psychology we often talk about necessary and sufficient conditions for behavior. That is, you may need a certain factor in order for a behavior to happen but without other factors, the behavior will not occur. For example, you need water to live – it is necessary – but you also need food, so thus not sufficient. So, the brain is necessary for behavior but can all behavior be explained solely by the brain? Another way of phrasing this question is, “Does biology determine all behavior?” The term for this belief is biological determinism.

To answer the question we first have to investigate and uncover other potential influences on (causes of) behavior. If behavior is biologically determined, do people have free will? That is, do people really have the ability to consciously make and choose different behavior? Or are all behaviors simply determined at the neuronal (or genetic) level and free will is only an illusion? This post is an expansion on one of my previous posts concerning alternative assumptions to naturalism in neuroscience.

If you really believe that the brain (and by reductionism, genes) are solely responsible for behavior, then you cannot believe that people have free will. You also cannot believe that the environment is directly responsible for behavior – it can influence it – but at the core, your genes and your neurons create behaviors. Alternatively, you can believe that humans have free will, that we can make choices because of or in spite of our biology. Agency can influence biology and biology can influence agency – they are not mutually exclusive categories. While the brain is a necessary condition for behavior, it is not sufficient; agency is a factor in human behavior.