Top10 - The Most Fascinating Neuroscience Experiments Ever?
| 10. Libet's readiness potential; Free Will |  Benjamin Libet |
Libet, B. (1985). Unconscious cerebral initiative and the role of conscious will in voluntary action. Behavioral and Brain Sciences, 8:529-566.
Benjamin Libet received a Nobel Prize for his pioneering work into the subjective thresholds of consciousness and their implications for free will. If you're the type that thinks debating questions of free will are abitrary and ultimately pointless, fear not -- Libet squandered precious little time on the matter of whether or not the freedom of creating volition exists, but the degree to which it's manifested in the brain. Basically, what he did was study the brain's activity, on the order of milliseconds, when a subject reports being consciously aware of something, be it an object or a train of thought. What Libet found was that there is activation in various regions of the brain several milliseconds before a subject can report consciousness awareness.
Now, it's possible to dismiss this activation as the brain's vocalization of awareness, or the motor-response to initiatve that vocalization -- or the motor cue for presenting one's acknowledgement in some other form. Because Libet wasn't actually inside the minds of the subjects he tested, we can't know for sure what this activity was.
Libet theorized that when presented with a stimulus, the brain reacts instinctively -- just in case the stimulus is something dangerous. I mean, when you trip and fall, your arms shoot out to break your fall so that the pavement doesn't break your face. You don't consciously think about stretching your arms outright...it just happens. So Libet proposed that this is what happens after every stimulus, but that as the stimulus is broken down within the brain's processing regions, it enters conscious awareness after all the most dangerous evidence is taken into account first, and then, even while you're becoming aware of it, the brain is already initializing a response.
Implications: The argument of free will is a longstanding one within the realm of philosophy. Proponents of hard determinism will claim that every effect has its cause, and that life is simply a chain-reaction of effects caused by original causes. These people are often the armchair philosophers haunting your local Starbucks with a copy of The Republic hooked to macro on their laptop. Soft determinists don't go quite that far, but they still presume that most effects are the direct results of their causes.
What I think is that causes are very likely to produce an effect, but that numerous factors can ultimately contribute to stopping or altering the effect in question.
Libet liked to say that since the brain is already initializing your response to any given stimulus, what you really have is the power to deny instinct. Like if you put your finger to a flame, your instinct will be to recoil in pain and nurse your finger -- but with enough determination and pinache, you'll be able to keep your finger there and let it burn...going against every instinctive impulse your brain can produce.
So Libet liked to say that what we have really isn't "free will" -- it's "free won't".
9. Proof of Lucid Dreaming.
Laberge, S. (1980). Lucid dreaming: An exploratory study of consciousness during sleep. (PhD thesis, Stanford University, 1980), (University Microfilms No. 80-24, 691)
Stephen Laberge
In the 1980s, Stephen Laberge wrote a doctoral thesis that would lead to scientific, empirical proof in lucid dreaming. Before that, if you told all your buddies that you could wake yourself up while dreaming and do all sorts of crazy dream-state stuff -- if they've never had the experience, they could simply tell you that you're full of it.
Laberge provided real evidence that people absolutely can lucid dream and that it's possible to manipulate one's waking-life body during this state.
When you go to sleep, there's a mechanism in your brain that shuts off motor-output going down the spine. This means that when you're dreaming, your brain is legitimate responding to everything you're seeing -- the motor-regions of the brain light up in response to things you're seeing and doing in the dream -- but a mechanism exists that keeps this output from actually travelling to your muscles. Otherwise you'd be air-humping or actively mimicking the gestures required to shoot hordes upon hordes of fleshing-eating undead, depending on what you dream about.
Laberge noticed that some motor signals do make their connections. Rapid Eye Movement (REM) sleep is characterized as a stage of deep-sleep in which your eyes move very erratically behind closed eyelids. Your eyes move because they're actually reacting to what you're seeing while dreaming. Thus, Laberge knew that his eyes would move in his body if he was purposefully moving them during a lucid dream.
To prove it, his lab-hands attached an electromyograph (EMG) to his eyelids to gauge the electrical activity just below, sequenced by movement. So at a predisposed time (yes, he tells us that "dream time" can coincide with "real time" if you want it to), during a predisposed set of movements, Laberge moved his eyes back and forth -- enough times to set up the exact pattern of electrical activity he'd proposed.
Implications: Laberge's research shows that the mind is capable of manipulating the body while asleep, lending legitimacy to his theories about the lifestyle efficacy of lucid dreaming. This is significant because we spend a third of our lives asleep...so what if you could capitalize on that time and actually be learning things? Practising things? Inundating yourself with fake objects to overcome fears or simulate events to plan for them?
Laberge will be the first to tell you, the sky is the limit for lucid dreaming applications.
8. Contralateral Neglect
Paterson, A. Zangwill, O. L. (1944). Disorders of space perception association with lesions of the right cerebral hemisphere. Brain, 67, 331-358.
This one's a little older -- but still fascinating. Contralateral neglect was first named by Hughlings-Jackson to refer to a condition in which the subject has lost their right parietal cortex. Whether to lesion, abrasion, infection, whichever: the right parietal cortex had suffered damage and lost functionality in the subjects of this study.
Subjects with contralateral neglect ignore half of their body and half the world opposite the brain-damage. So an individual with right parietal loss tended to ignore the left side of reality.
What kind of behaviour would this lead to? Patients studied by Paterson and Zangwill would neglect shaving the left side of the face, putting an arm through the left opening of shirts, etcetera. When requested to draw pictures of objects closeby, patients would draw only the left side -- regardless of the object.
Implications: Studies like this reinforce the fact that things you might not have considered being "coded for" in the brain truly are represented. Research in this area -- that of spatial recognition -- have lead to breakthroughs in neuroscience for learning how the constant visual-recognition of the world is wired in the brain.
7. Plasticity
There are literally too many neuroplasticity studies to name and too many to consider when picking a number one. Neuroplasticity is the term given to describe the brain's ability to rapidly form new connections and reorganize itself in response to external events.
Let's say the brain forms a well-entrenched system of connections between neurons (the brain cells that communicate back and forth to produce sensations, perceptions, etc.) to give you a great chance at survival in the best possible way. So your brain has organized itself around walking around and performing daily tasks, but how does it respond if you're hit by a car and can no longer use your legs? What about all the motor-connections used by neurons within the brain? Do they simply take up space?
No.
The brain will actually reorganize itself to better suit your needs and strengthen connections between other motor-movements to give you better impulses in your new life.
Imagine there's a switchboard operator inside your brain,
changing connections to yield a stronger whole.
Implications: The ramifications of have a "plastic" brain, rather than a fixed-state into which your brain permanently moulds, means you can learn new things, new behaviours, discard old ones, and deal with even a catastrophic loss of function if you need to. The implications are that you have a brain not just hardwired to survive -- but able to rewire itself so you can survive in novel environments.
6. Manipulated Apathy in Lab Animals
Kluver, H. & Bucy, P. (1939). "Preliminary analysis of function of the temporal lobe in monkeys.". Archives of Neurology 42: 979–1000.
Heinrich Kluver & Paul Bucy
The Amygdala is an area of the brain important for emotional processing. Emotions are significant for evolutionary adaptation, because associating pleasurable experiences with happiness allow us to seek those experiences again -- like getting food and finding mates. Likewise, exhibiting emotion allows us to draw likeness to other humans and form cohesive groups, due to emotional attachments. As well, the emotion of fear is necessary for survival so that we don't go heedlessly barging into dangerous situations. Situations that may end in death or discomfort are associated with fear -- for the benefit of our longterm survival. Sure, these mechanisms can malfunction occasionally, as with unsubstantiated phobias or post-traumatic stress disorder.
Neuroscientists found that lesioning the amygdala in monkeys resulted in quite a few social and interpersonal malfunctions. Monkeys would show a lack of affect, hypersexuality (often toward inappropriate mates or objects), or even a complete lack of fear.
In some experiments, impairing the amygdala in laboratory mice has been shown to produce incurable rage. You ever see 28 Days Later? How they chemically produce a rage-virus and it slips out of the laboratory to eventually decimate much of the surrounding population? Well that's not entirely science fiction -- a virus like that is definitely possible, if it contained a pathogen that specifically latched onto, and subsequently eliminated, the amygdala or surrounding structures.
Kluver and Bucy, in a now famous experiment, demonstrated these effects experimentally by showing that lesions of the area in focus produced a whole host of deleterious effects. What makes their experiment famous is that the causes were so instrumentally manipulated and the effects so well documented.
Implications: The looming applications of this and research of its kind showed that emotions were not the seat of reason or the soul, but rather the functional integrity and chemical composition of the amygdala and other brain regions involved in processing emotion. Studies like this lead to our manipulation of chemical states in the brain to produce various emotional states. With the knowledge that emotional states could be produced, manipulated, or -- in the case of the Kluver-Bucy syndrome -- eradicated completely.