Ask a Neuroscience Professor

[Birdjaguar]

When you say that you don't believe that humans have free will, to what extent do you feel that everyday choices about the food we eat and the words we speak are linked to "forces" our conscious minds do not control?

 

[emzie]

If there's a finite amount of neurons in the brain, and thus, a finite amount of pathways for memories to be stored, is knowledge / memory limited?

Though, as I understand it (albeit, rather poorly, probably!) to use your brain so much as to retain all information going into it, you'd probably be melting down (seizures ect).

 

[angeleyes]

Thanks for your answers.

Do you think that the philosophers of the mind has really anything important to say about their subject, or should they just wait for the neuroscientists till they have revealed all the secrets of the brain? (this may take a while....)

 

[El_Machinae]

Philosophers of the Mind should gobble up the data and then come up with testable theories. I suspect that solving the "Theory of Mind" will require multiple viewpoints.

With that said, is there a way to repair/prevent neuron loss and damage since over time since they kind of wear out like old tires?

Bluntly, yes. The loss and gaining of neurons is too subtle of an event for our consciousness to notice (which is amazing in itself, if you think about it: consciousness is too 'large' to notice the underpinnings). This means that you can, theoretically, lose and gain neurons without disrupting the 'sense of self'.

It was awhile ago, but I recall reading studies of implanted neurons being used to uptake knowledge that the animal learned after the surgery (I don't remember if it was mice or monkeys ). I *think*, but am not sure, that you can get older neurons to 'train' implanted neurons with their older memories and then let the older neurons die. This means that the complete 'you' could be retained even if there was turnover in neurons. This is not really a surprise, considering our atoms are completely turned over a few times in our lives and we don't mind.

Of course, the process needs to be discovered still.

Don’t know that work. There is a growing literature on stimulation for various conditions eg. Vagus nerve stimulation for epilepsy.

I saw a TED talk about a guy who invented a TMS 'gun' that people could use to stop an epileptic attack or a migrane (if they're of the type where the condition starts from a consistent focal point)

I won’t touch that one as it depends on the definition of sentient. Monkeys have more intellectual skills than newborns for whatever that’s worth.

I was just teasing. In my experience, people who study the brain are entirely unwilling to make a stand on the issue. It's only laypeople who get into heated debates.

Don’t know depression much or the glia theory. My wife works on it and thinks it is a neuroinflammatory condition involving microglia activation.

Is your wife better at keeping a good mood than most people? In other words, does all this knowledge translate into being able to keep herself happier?

Very hard to making convincing mouse models of psychiatric diseases.

I'd imagine.
In fact, I cannot imagine the moral dilemma of making a mouse that you're sure is hearing voices.

How is memory actually stored in the brain? For example: how do I remember words and images that I've seen?

In general, your brain is constantly receiving input from the senses. These input are then processed and then discarded (or, 'lost') because the firings aren't seen as significant. However, you have analysis centers* in the brain which help assign importace to incoming data (these centers receive a processed signal from the sensory areas). When the ACs register data that are deemed 'important', they fire neurons which allow the memory to be stored. I suspect that they send transmitters to the location where the sense data is being processed and then fire transmitters to increase the likelihood that the firing sense neurons retain the signal (whether short-term or even long-term).

*There are multiple ACs: the frontal cortex can 'pay attention' and thus cause sensory data to be retained. The amygdala notices 'emotional' events and then will encourage emotional-causes sensations to be retained.

 

[El_Machinae]

When you say that you don't believe that humans have free will, to what extent do you feel that everyday choices about the food we eat and the words we speak are linked to "forces" our conscious minds do not control?

Well, liking sugar and disliking the taste of rot is something beyond our immediate control. We're wired to like sugar, biologically. We could be wired to like the taste of rot, if someone were to put rot-sensors on our sugar-tasting taste buds.

 

[C~G]

Philosophers of the Mind should gobble up the data and then come up with testable theories.

There are even people that consider philosophers should wait quantum physics in order to make valid theory about consciousness example.
But of course they themselves speculate with this all the time.

Then there are some neuroscientists (Edelman example) that have jumped the bandwagon with their own theory of mind and it seems they lack the ability to make theory based into their concepts.

So, as Michael Shermer said in his TED talk about in general about science, people need both data and theory to come to reasonable conclusions.

I suspect that solving the "Theory of Mind" will require multiple viewpoints.

I agree with this view.
Multiple povs are required and I think many of the views are in essence in very similar but for some reason people aren't ready to try to combine them but rather to stick with their own explanations about everything to be true.

It almost looks like these people are wired differently in a way that when they try to explain the same thing they do it just using different terms with little bit different basic premise or stand point which makes them look all too different...

I might jump later for some questions.

 

[Rambuchan]

Are the traditional five senses all there are? Are they really independent of each other (functionally and geographically within the brain) or do these 'centres' overlap each other?

Why do we dream? How do we dream?

What does the neuroscience community in general make of Freud's "Id, ego, and super-ego"?

---

Good on you for starting this thread up. And thanks

 

[Fifty]

What does the neuroscience community in general make of Freud's "Id, ego, and super-ego"?

I dunno about neuroscienctists but philosophers are starting to take Freud serious again. PM if you want a cool paper about it.

@everyone: Just to clear up any misconceptions, modern philosophy of mind/neutoscience/psychology is keenly aware of advances in neuroscience and is almost always consistent with them. No philosophers think that consciousness doesn't arise from the brain.

 

[Mark1031]

How is memory actually stored in the brain? For example: how do I remember words and images that I've seen?

The truth is we don't know for sure. I try to figure that out when I'm not wasting time at CFC. The basic theory is that changes in connections between neurons based on how active they are is the underlying basis of memory. Take Pavlovian conditioning for example. A dog hears a bell and sees food at the same time. The food activates a whole series of neurons that ultimately lead to salvation. The bell activates a whole series of neurons that respond to sound. At certain points in the brain the food neurons will receive inputs from the sound neurons. Those neurons will be more active when the bell and food are present together. The connections of the sound neurons to the food neurons will be be made stronger. Now when the animal hears just the bell it will tend to activate neurons that were previously activated only by the food thus making the animals salivate to the sound. That's the idea in a nutshell.

How does recall work? Again we do not know. We actually don't know a lot of basic things. For example, I just found out today that we got a paper accepted in which we show that the same neurons that are activated during learning get reactivated during recall and that the strength of the recall is correlated with the level of reactivation. If you understand what I just said it seems like a pretty basic things that is assumed about how the brain works, yet it had never been shown.

Do you ever bump into Dr. Ramachandran? I guess your lines of research don't have much to do with each other, but it must be thrilling to work in such a rich environment.
I've met him a couple of times but we've never really talked. San Diego has a great neuroscience community.

Do you or the other neuroscience people ever interact with some of the famous philosophers of neuroscience down there (most especially the Churchlands)? Do you have any views towards their work?

Again I've met Pat Churchland and heard one of her talks quite a few years ago. I'm not sure what she's working on now. I'm not going to critique specific colleagues publicly and I find value in most intellectual activity. With that said, I am coming from a very molecular viewpoint. I want to understand how molecules and synapses change and where they change and what regulates that change when we learn things. To me this is the basic building block of all of the emergent properties of the brain. In that context I tend to feel that theory of mind and consciousness are premature.

Is a Doctorate's Degree prerequisite for a faculty position at a college? Simple answer is yes.

Why can't I find my car keys?

Because of salience. Think of all the sensory inputs and motor actions you make in any given five minutes period. The real interesting question is how do we decide what to remember. Now if you happen to put your keys down on the toaster and electrocute yourself in the process I can assure you you will remember the keys location.

What does the Neuroscientific community in General feel about psychology? What about you personally? Do you see them as competing or complementary schools of thought? Does this include less biologically minded psychologists?

There is a huge transition in which psychology and psychiatry are being incorporated into the biological sciences. This is a good thing IMO. There are older people in the fields that have resisted this transition but they have essentially lost the battle. I'm not sure how undergraduate psychology departments are managing this but IMO they should have cellular and molecular biology requirements in that field.

When you say that you don't believe that humans have free will, to what extent do you feel that everyday choices about the food we eat and the words we speak are linked to "forces" our conscious minds do not control?

Ah free will. I had a long thread on free will a while back. To summarize my opinion. There are many things that impinge upon our brains that make us feel as if we control the decision to get up and go eat a doughnut. Those are neuronal and hormonal communications from the rest of our body which determine our hunger status as well as our need for various nutrients, sensory inputs, do we see a doughnut, our past memories- did we find previous experiences eating donuts to be highly rewarding, and finally random chance-did a few doughnut neurons just happened to fire spontaneously.

If there's a finite amount of neurons in the brain, and thus, a finite amount of pathways for memories to be stored, is knowledge / memory limited?

Of course they're not an infinite number of neurons in the brain however the theoretical storage capacity of the human brain is ridiculously large.

Though, as I understand it (albeit, rather poorly, probably!) to use your brain so much as to retain all information going into it, you'd probably be melting down (seizures ect).

Sort of, if current theories of memory are correct

Are the traditional five senses all there are? Are they really independent of each other (functionally and geographically within the brain) or do these 'centres' overlap each other?

In humans as far as I know, yes. I believe some birds can sense magnetic fields through iron containing organelles.

Why do we dream? How do we dream?

Don't know. However, one theory is that we've reactivate neuronal circuits during sleep to help stabilize memories. We dream through neuronal activity in relevant neocortical regions while at the same time blocking motor outputs.

What does the neuroscience community in general make of Freud's "Id, ego, and super-ego"?

I have never heard Freud mentioned it in a single neuroscience lecture that I can remember. He may get some credit for the notion of sub conscious in the field of emotional learning and anxiety.

 

[Cheezy the Wiz]

In humans as far as I know, yes. I believe some birds can sense magnetic fields through iron containing organelles.

I've read that humans, at least at one time, used a small collection of iron in the head to navigate. I don't know if we still have that or not.

 

[Samuelson]

Do you think that, in the distant future, we will be able to map out all of the nuerons and sypnasis in a human brain? And if so, do you think it will be possible to simulate a brain using computer electron circuits instead of nuerons?

 

[Perfection]

How do nuerons process data and perform operations?

Do they work like logic gates or some sort of anolog analogue?

 

[El_Machinae]

Don't know. However, one theory is that we've reactivate neuronal circuits during sleep to help stabilize memories. We dream through neuronal activity in relevant neocortical regions while at the same time blocking motor outputs.

I've also read that we run through scenarios that we find scary, and then our brain makes reactions to scary situations. This is why kids have more nightmares, and why adults are able to control their fear better. We're more prepared for a scary situation.

 

[Mark1031]

Do you think that, in the distant future, we will be able to map out all of the nuerons and sypnasis in a human brain? And if so, do you think it will be possible to simulate a brain using computer electron circuits instead of nuerons?

Yes, there is a whole field of computational neurobiology that tries to make computer programs that model the brain or to design computers based on the way the brain functions. You can actually get neuron-silicon connections to form so you could have hybrid machines that use both biological and non-biological material.

How do nuerons process data and perform operations?

Do they work like logic gates or some sort of anolog analogue?

Input is probably analogue, output is digital. A neuron receives 1000s of small synaptic inputs that can vary linearly in strength. These currents then sum to produce an all or nothing electrical output, action potential.

I've also read that we run through scenarios that we find scary, and then our brain makes reactions to scary situations. This is why kids have more nightmares, and why adults are able to control their fear better. We're more prepared for a scary situation.

I hadn't heard that. You seem to know a lot of neuroscience. What do you do?

 

[Perfection]

Input is probably analogue, output is digital. A neuron receives 1000s of small synaptic inputs that can vary linearly in strength. These currents then sum to produce an all or nothing electrical output, action potential.

Well it strikes me that there would need to be some sort system analagous to a logical inverter are there ways in which an action potential could prevent another action potential from going off?

 

[frob2900]

How is memory actually stored in the brain? For example: how do I remember words and images that I've seen?

I don't know about the peer-review status of these ideas, but interesting nevertheless: http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm

According to them brain memory is on the order of terabytes.

Question: Are the ideas from many-body physics (condensed matter/collective phenomena/phase transitions etc.) having any influence on neuroscience? Some physicists like to pretend that the ideas from many-body theory can be applied to model neurological phenomena.

No idea if its true, but I've only read physicists on the matter, so I'd be interested to hear another perspective.

 

[C~G]

I've also read that we run through scenarios that we find scary, and then our brain makes reactions to scary situations. This is why kids have more nightmares, and why adults are able to control their fear better.

That is one of the theories presented by some.

We're more prepared for a scary situation.

Or our brain is more used to the processing of dreams and perceiving dreams aren't true?
Then again it rises the question whether the dreams of adults are more believable in order to make them good scenarios to run but it doesn't answer why some dreams emerge to consciousness during sleep and why we member some? Certain things get picked from memories to the dreams but which and why?
Or is sleep some kind of unfragmenting program so those memories/information we need in the future are more accessible to us as we revisit them during sleep? Or is it about deciding whether to throw them into trashbin?
There are numerous questions and scenarios to the question "why we dream?"

I have only read Dennet and I did think he had something to contribute. My reply in the thread was prompted by the trashing of Dawkins and reading what was purported to be a professional debate on the existence of God. Much to my surprise it was essentially a debate on dualism, which definitely does not take into account modern neuroscience. That combined with what I consider overly pompous verbosity just sort of irked me.

It turned me off too.

It's back to metaphysical foolishness. Then again we have to understand what they are debating about. It might be useless try to make people of religion to understand physicalism as the base idea immediately.

Qualia is again an attempt to make a mystery where there is none IMO. Basically it comes down to the inability to explain what smell is. It is a dissatisfaction with the explanation that a smell is the activity of particular sets of neurons because this may be experienced differently by different people and we can’t explain what that mystical “experienced” means. Well Penfield showed that perceptions, smells, memories are just neural activity, you can produce experience with electrical stimulation. It may not be satisfying to some people but that is the way it is.

I have to say that this is the part that makes me bewildered about neuroscientists.
Of course we can consider it only as "neural activity" just like that the birds fly since they flap their wings and flow on air but don't you think it isn't necessary to explain how it all started and why such thing happen in the first place?
The whole idea is to tie the neural activity to the percepted mental phenomena (first person perspective) and possibly seek how they correlate with each other and regarding the huge amount of information about the brain already gathered but still lacking details the effort is done in quite simple theoretical level.

In general we could maybe explain that Qualia has to do with recognising pattern of certain sort of stimulus that correlates itself with certain earlier similar experienced patterns or is just tune with genetically decided patters. But Qualia in general has to do with one's conscious experience and what we think experience and reality is so in essence to order to how and why we experience reality we must understand these issues. Or Do androids dream of electic sheep?

The position "it happens to us through neutral activity" doesn't explain to who it happens. What seems to be the case that ultimately that kind of physicalism leads into back homuncus in Cartesian Theater as it doesn't explain how the "first person/user illusion" is created neither why? And I don't mean "why?" in sense how "why people die?" but in sense how it has evolved and what's the reason for it. "It just appears" doesn't explain anything.
It should be also noted how this kind of information affects pretty much everything ranging from behavioral biology even to economics.

Trying to explain in theory how and why is the field of philosophy and that's why I believe example Dennett is almost dead close to in terms of general framework deeply rooted to also neuroscientist findings. And simple reason is because he does crossfield research.

David Chalmers has different point of view and IMO some interesting insight about some things but I rather see it as addition to Dennett's (and similar) models rather than totally considering it to be valid contradicting theory.

There are tons of interesting questions about the brain and mind and I have not seen any that are not in the domain of neuroscience. There is no need to invent mystical ones.

IMO the field of neuroscience is about the "hardware of the brain" while philosophy of mind (and partly also some psychology) is about the "software of the brain". Therefore they are both needed. It's mighty hard make MS Paint to work without proper hardware solution and it's mighty hard made it happen without knowing proper logical rules of programming, programming languages or understanding how the data changes into the picture and interface having options on screen.

In kind of analogue, in this field people still work with old "supercomputers" and just recently there's has been some understanding that personal computers could some day arrive into each home.

But that is just my layman talk.

This might have been posted but, Mark1031, what do you make out of this news?
Tiny brain no obstacle to French civil servant

 

[angeleyes]

[....] and finally random chance-did a few doughnut neurons just happened to fire spontaneously.

spontaneously: have you any idea why neurons fire sometimes spontaneously? Is this inbuild, i mean if neurons would never do this, it would be bad for us? Does it have an evolutionary purpose?

 

[El_Machinae]

Well it strikes me that there would need to be some sort system analagous to a logical inverter are there ways in which an action potential could prevent another action potential from going off?

Some neurons project onto other neurons, and then can send a signal discouraging an action potential, if that's what you mean.

Action potentials also take time to recover from, so one action potential will prevent another action potential from starting for X-microseconds.

IMO the field of neuroscience is about the "hardware of the brain" while philosophy of mind (and partly also some psychology) is about the "software of the brain". Therefore they are both needed.

By analogy, I think it's similar to how people working on Relativity and QM are trying to build a "Theory of Everything". They're coming from different directions, but the end-goal is the same.

I wonder how much a researcher will eventually have to worry about subjective research. Getting feedback from a patient while hunting down the "Homunculus" is tough to 100% be confident of, because we run into strange situations where the "self" is separated from the neural machinery needed to communicate with the researcher. For example, the "self" seems to be on the other side of someone with Wernicke's Aphasia (so, it's not the 'self' that's doing the speaking). Or, with alien-hand syndrome, you've got the person saying that they don't intend for the hand to move, but we really can't easily say where the 'self' is. In the end, you'd only know for sure if you felt it yourself. I'm guessing that TMS will be needed for these type of data.

But, more data and tools = good. I sometimes worry that we're not smart enough to understand consciousness. Heck, our brains are probably ad-hocing consciousness together from a great deal of the unconscious brain parts and thus shouldn't be expected to retain a full understanding of consciousness in the conscious segments of the brain.

So, in the end, I hope we're smart enough to figure out how to make ourselves smarter. That way we can get to whatever minimum brain power is required to understand consciousness.

spontaneously: have you any idea why neurons fire sometimes spontaneously? Is this inbuild, i mean if neurons would never do this, it would be bad for us? Does it have an evolutionary purpose?

"Spontaneous" probably just means that they're not firing due to an action potential or stimulus from a known-source of firing. There could be a host of thermodynamc/QM reasons why a neuron would fire. A good jostling might get a neuron to fire, for example. And that would start a cascade.

 

[angeleyes]

[....]"Spontaneous" probably just means that they're not firing due to an action potential or stimulus from a known-source of firing. There could be a host of thermodynamc/QM reasons why a neuron would fire. A good jostling might get a neuron to fire, for example. And that would start a cascade.

True, but has it been proven that this random firing has a function? Does it bring us somewhere we would not have been without it?