Question about Enzymes and The Brain, please answer

[Soulja]

Ok, i have a question that my science teacher did not have the least clue. If enzymes speed up the chemical reaction of a "thought". Then do people that learn faster have more enzymes in the brain? Also, if you somehow added enzymes to the brain, would the brain be able to create thoughts faster?

[Giles]

I'm not sure how you would measure the speed of a 'thought'.

 

In nerve signalling, all the important stuff is taking place by transfer of ions or signalling molecules across membranes. This transfer is carried out by proteins in the cell surface membrane (remember an enzyme is just one kind of protein).

 

Action potentials do travel more rapidly along axons with a larger diameter, i.e. a larger membrane area/unit length. A larger membrane area means (I assume) more protein 'pumps' or 'channels' , so I think you are correct in this limited sense.

 

(more on nerve signalling here:

http://faculty.washington.edu/chudler/ap.html

http://faculty.washington.edu/chudler/synapse.html)

[Matzi]

Isn't learning also depending on the number of synapsis? I learned something like that at school.

[Radical Edward]

Originally posted by Giles

Action potentials do travel more rapidly along axons with a larger diameter,

 

don't forget myelin

[Giles]

I didn't. I just thought it would confuse the issue.

[fafalone]

The electrochemical signals that make up thoughts and learning travel at a maximum rate not controlled by the amount of enzyme present. If there is enough of the enzyme present, the reaction does not proceed. If there is enough, the reaction proceeds at a fixed rate. Thinking or learning slower or faster is related to efficiency; how many synapses are used, and how well connected these are. Once a neurotransmitter is excreted through the terminal bud, it diffuses across the membrane without the aid of enzymes. Enzymes are involved in reuptake, but inhibiting these enzymes doesn't slow things down; it stops them. This is the basis of chemical gases such as sarin and VX. As to the relation between diameter and rate, the ion pumps and channels are not enzymes; they are integral membrane proteins. Not all proteins are enzymes. Also, I suspect the difference in speed is negligible, since the diameters don't vary by any extremely large degree.

 

I'm a neuroscience major

[RAB]

Wouldnt it be frustrating if you could think the way you do now but do it 10X faster? Remember, you wouldnt be able to move 10X faster, only think faster.

 

It seems like all organizims, including us, process information at a speed fairly well matched to the physics of its environment. An important part of that environmnt is the animal's own body.

 

Big animals have big brains that think. Small animals have small brains that, as far as we know, dont think but are very effecient at reacting at lightning speed. Small creatures need to react fast to escape danger or capture quick moving food. We large anmals dont need to react that fast so we can enjoy the luxury of rational thought that requires a large brain.

[fafalone]

While the nerve impulse propagates at a nearly identical speed from human to human and in all chordates, efficiency allows the speed of thought to vary. Some people have pathways that allow them to instantly do complex math problems it would take other people quite a while to do in their head.

Reaction times, vary; this is a direct illustration of synaptic rather than cognitive speed; since reflex tests use the reflex arc rather than the central nervous system.

But it's quite clear that people can think faster than others.

[Glider]

Originally posted by fafalone

Reaction times, vary; this is a direct illustration of synaptic rather than cognitive speed; since reflex tests use the reflex arc rather than the central nervous system.But it's quite clear that people can think faster than others.

 

Not necessarily. The reflex arc is a self contained functional unit connecting the afferent (dorsal horn) and efferent (ventral horn) via interneurons within the spinal cord. This responds to extreme stimuli (e.g. touching a hot-plate) and causes a withdrawal reflex.

 

Reaction time tests are different; often testing people's reaction to a visual or auditory stimulus. This involves a system much more complicated than the reflex arc. For example, it involves signal transduction and perceptual systems (to detect the stimulus), cognitive systems, to recognise the stimulus and differenciate it from other environmental stimuli, and also to select the appropriate response (this involves areas of the anterior cingulate gyrus), and then motor areas of the cortex and cerebellum to effect the response. Given all this, it's quite amazing that it all takes place in around 500ms.

 

I don't personally know how one could measure the speed of thought. Whilst it may be apparent that 'some people think faster than others' this is usually a function of memory and recall. The stronger the association between a cue and the information required, the faster the recall. However, this is a function of learning, not the velocity of neural volleys.

[fafalone]

What's involved depends on the stimulus. An extremely hot sources will activate temperature sensitive neurons; the reaction is controlled exclusively by the reflex arc; the neurons in the spinal cord "think" if you will.

[RAB]

A simple test for measuring "thinking speed" could be to read a short story and then answer questions about the story that would involve logic to answer correctly. The testee would not be allowed to review the story after initially reading it. Measure the time it will take to do the test.

[fafalone]

That is dependent on memory storage efficiency.

[Glider]

True. That would be a test of memory.

[RAB]

Yes it is a test of memory, but the speed in which it can be done with a perfect score (getting all the answers correct) , wouldnt that be an indication of thinking speed?

[Giles]

We could choose to define thinking speed like that, but it's tantamount to IQ testing - it doesn't measure (or have any demonstrated connection with) any physical velocity, and varies depending on methodology.

[Glider]

Exactly. You could classify it broadly as 'thinking speed' but it would actually be a measure of the time taken to consciously retrieve information. This time varies dependent upon factors such as familiarity with the information, associations between different information (i.e. 'traces') and whether or not you have that information in the first place. Given the nature of nerve conduction, if there were any differences in conduction rate between individuals, it would be so infinitesimally small that a test of memory or free recall would stand absolutely no chance of detecting them.

 

As far as I know, the only thing that can result in a significant reduction in conduction velocity are certain types of neuropathy and particularly de-myelinating diseases of the central nervous system (e.g. multiple sclerosis).

[RAB]

So, what you are meaning is actual velocity of the neural impulses in the brain that constitute rational thought, or I guess any kind of thought? That would be difficult to measure.

 

Certain people, idiot savants for example, can calculate extensive math problems at incredible speed. Are they consciously "thinking" when they do that? Or is their brain performing on its own, so to speak?

 

Maybe a standard math problem, simple in nature, could be a relative measure of "thinking speed". For comparitive purposes only.

[fafalone]

The speed of the nerve impulse is not related to the speed of thinking, period.

[Glider]

Concisely put sir, and quite right.

 

Certain people, idiot savants for example, can calculate extensive math problems at incredible speed. Are they consciously "thinking" when they do that? Or is their brain performing on its own, so to speak?

 

The precise process by which 'idiot savants' perform these feats is not understood. However, it is known that pre-conscious processes occur at amazing speeds. For example, people presented with emotionally valenced information show a measurable response indicating that pre-conscious recognition and classification of the stimulus occurs within 250 milliseconds. However, the individual is not aware of this, and in fact it has been shown that they need not even be aware of the stimulus. The stimulus only has to be within the receptive field of a sensory modality, it does not have to be registered consciously. This form of 'automatic evaluation' has been described as "Universal and unconditional".

 

It has been suggested that the processes involved in the feats performed by 'idiot savants' are similar; that it is an automaticity which occurs beneath conscious awareness and without intent (once the action has been initiated). This would account for the individual not being able to explain the methodoly he/she used to reach an answer, and also the speed with which the answer is achieved.

[willhoward]

Hi this is my first post here.

 

Does the learning process and the synapsis process have any connection with dopamine levels in the brain?

 

I believe dopamine speeds up the processes in the mind and would thereby be related to this discussion. If the processes of memory forming and retention are affected by speed, then dopamin, being a 'velocity' control chemical, would affect learning.

 

I also question the relationship between the chemical dopamine and the label applied to the marijuana drug as 'dope'. Further note could be made of the attribute of marijuana of creating short term memory problems and thereby reducing short term learning abilities.

 

I wonder if anybody can clarify the position on these things?

[willhoward]

'scuse me, posted same thing twice. >>

[willhoward]

As for 'idiot savants' and mathematical recall. Maths is a unique subject, the procedures becme, if well learnt almost a part of the autonomic system itself. Like walking, talking and the processes of logical thought. These things are not available to a person who has never trained in them or been exposed to them previously. Do you note how in society some think logically while others, of no lesser capacities do not? (i would say this is a sociological fact, it is a fact of faculty development and culture as opposed to a lck of it.)

Given, stimulus and motivation drive higher faculties, e.g. running, heavier processes in math etc.

 

As for 'lightening speed' mathematics, beyond the thought behind the act of leaving the chair to go to answer the door or retrieve the bottle of beer from the fridge, or reading the pages of a book; beyond the initiative of the wont and/or desire to do so, how many are aware of the deeper processes which actually drive the muscles? It is very rarely I walk while thinking 'left, right, left, right', and I never ask the neuro receptors and motor neurons in my brian to control the miriads of muscles involved in the process of walking.

 

Biological mechanics are a marvel of the subconcious! And the sub conscious is so complex I have no hope of understanding it! I'll stick to building bridges )

[scicop]

Hi this is my first post here.

 

Does the learning process and the synapsis process have any connection with dopamine levels in the brain?

 

I believe dopamine speeds up the processes in the mind and would thereby be related to this discussion. If the processes of memory forming and retention are affected by speed' date=' then dopamin, being a 'velocity' control chemical, would affect learning.

 

I also question the relationship between the chemical dopamine and the label applied to the marijuana drug as 'dope'. Further note could be made of the attribute of marijuana of creating short term memory problems and thereby reducing short term learning abilities.

 

I wonder if anybody can clarify the position on these things?[/quote']

 

Ok I'll address these questions in the order received.

 

1. Whereas the learning process has been attributed predominantly to glutamate, its receptors (NMDA, AMPA), and downstream effectors such as mediators of gene expression and protein synthesis, Dopamine DOES have a role in modulating neuronal activity and connectivity associated with "learning". Dopamine production and the expression of its receptors are in regions associated with formation of pleasurable memories (and as well as fine motor control..but not important for this posting).

Food, sex, as well as alcohol and drugs of abuse lead to increased activity of certain dopamine producing neurons (VTA, a brain region), which leads to its release in the Nucleus Accumbens (the so called seat of drug addiction) at high concentrations. The excess dopamine is sufficient mediate the development of behaviors the lead to the seeking of things that are pleasurable, though downsteam modulation of glutermateric (glutamate..involved in memory formation) and GABAergic (also involved in memory formation..though inhibitory) activity. So yes, it does modulate the formation of certain memories, limited by it the neuronal location of its production and site of action.

 

2. Dopamine does not speed up the processes in the mind. There is no "velocity" in memory formation, rather there is "quantity". Depending on the receptor subtype (and neuron) dopamine can increase or decrease neuronal activity (i.e. neurotransmitter release).

 

3.Marijuana increases dopamine release as well as opioids, such as endorphines (ie.met enkeph) which make you feel good. Marijuana sensitizes the reward circuit to pleasurable things, this is why marijuana users can easily get addicted to other substances..and visa versa. I can go in more detail, but I dont think you want that.

 

Marijuana contains cannabinoids which, in the CNS selectively activates CB1 cannabinoid receptors, which play a huge role in mediating synaptic activity in almost all areas of the brain, not just dopamine. CB1 receptor activation tends to be inhibiting to glutamatergic and GABAergic neuronal activity (memory regulating neurotransmitters) ubiquitously thoughout the brain, especially in the hippocampus where alot of these studies have been done. CB1 is works though a weirdo mechanism which I won't bother explaining, but now I think you can understand how memory can be affected by Mary Jane.

 

Hope this helps.