In biology, the nervous system is a highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor nerves or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory nerves or afferent. Spinal nerves are mixed nerves that serve both functions. The PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems. Somatic nerves mediate voluntary movement. The autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems. The sympathetic nervous system is activated in cases of emergencies to mobilize energy, while the parasympathetic nervous system is activated when organisms are in a relaxed state. The enteric nervous system functions to control the gastrointestinal system. Both autonomic and enteric nervous systems function involuntarily. Nerves that exit from the cranium are called cranial nerves while those exiting from the spinal cord are called spinal nerves.
At the cellular level, the nervous system is defined by the presence of a special type of cell, called the neuron, also known as a "nerve cell". Neurons have special structures that allow them to send signals rapidly and precisely to other cells. They send these signals in the form of electrochemical impulses traveling along thin fibers called axons, which can be directly transmitted to neighboring cells through electrical synapses or cause chemicals called neurotransmitters to be released at chemical synapses. A cell that receives a synaptic signal from a neuron may be excited, inhibited, or otherwise modulated. The connections between neurons can form neural pathways, neural circuits, and larger networks that generate an organism's perception of the world and determine its behavior. Along with neurons, the nervous system contains other specialized cells called glial cells (or simply glia), which provide structural and metabolic support.
Nervous systems are found in most multicellular animals, but vary greatly in complexity. The only multicellular animals that have no nervous system at all are sponges, placozoans, and mesozoans, which have very simple body plans. The nervous systems of the radially symmetric organisms ctenophores (comb jellies) and cnidarians (which include anemones, hydras, corals and jellyfish) consist of a diffuse nerve net. All other animal species, with the exception of a few types of worm, have a nervous system containing a brain, a central cord (or two cords running in parallel), and nerves radiating from the brain and central cord. The size of the nervous system ranges from a few hundred cells in the simplest worms, to around 300 billion cells in African elephants.The central nervous system functions to send signals from one cell to others, or from one part of the body to others and to receive feedback. Malfunction of the nervous system can occur as a result of genetic defects, physical damage due to trauma or toxicity, infection, or simply senesence. The medical specialty of neurology studies disorders of the nervous system and looks for interventions that can prevent or treat them. In the peripheral nervous system, the most common problem is the failure of nerve conduction, which can be due to different causes including diabetic neuropathy and demyelinating disorders such as multiple sclerosis and amyotrophic lateral sclerosis. Neuroscience is the field of science that focuses on the study of the nervous system.
Hello I'm new here as you can tell by my username and I had a question on some research I'm doing. Now it is common knowledge that brain cells and even whole neural network can be transplanted. But my question is on the neural networks. Like for example I was reading that sxuality is determined...
I'm learning about a very basic model neuron, in which only potassium and chloride is permeable.
Why is it that when the extracellular concentration of potassium is increased, the neuron become depolarized, whereas when extracellular concentration of chloride is reduced, the neural membrane...
I have seen articles dealing with the growth of brain cells using stem cells. I have also seen, in the past, research attempting to mimic neural connections (using traditional silicon chips) for use in computing.
I have searched for any mention of research into using actual living brain cells...
Homework Statement
Hi, I have created a web-site which is supposed to walk someone with a minor or major in undegraduate mathematic through implementing a simple neural network. I would like some feed-back or comments on my work in order to determine whther the content thus far is...
I'm trying to make a neural network in python, but I'm having a lot of trouble. Specifically after I have the network set up, what weights to initially assign to each neuron's inputs, the threshold, and evolving the networks to do what you want.
Here is my neuron class.
class Neuron...
Hello people,
I would like some references, be it book or papers about the process of neural impulses at a single neuron level.
My only reference so far is a book from 1974 (Stochastic models in biology) and so is probably outdated despite having around 30 pages on the subject.
The more...
I'm working on a project which deals with temperature control of a room. the idea is to control temperature within a limit.
I have prior data which i used to train a neural network which is 99.5% accurate. there are 5 inputs (x , y , z , A , B) and there is one output (T).
Now I want to...
I'm working on a project which deals with temperature control of a room. the idea is to control temperature within a limit.
I have prior data which i used to train a neural network which is 99.5% accurate. there are 5 inputs (x , y , z , A , B) and there is one output (T).
Now I want to...
Hello,
I'm going to be studying Computer Science and Physics at the University of Nebraska (Incoming Freshman). I wish to switch to computer engineering for sure, but I have had a great deal of interest in brain interfacing. When I'm reviewing research documents and such it's starting to seem...
I developed a multi-layer perceptron so I could better understand the underlying structure as well as modify it easily versus MATLAB's nntoolbox generate code. I have successfully trained the network for a given set of inputs and targets. The question now is how do I use this trained network...
I've written a program for character recognition but now upon testing I am unsure about a couple things. I'm having problems with training and simulating the network. Here is my interpretation of how network training goes.
Suppose I want to recognize the letters in the ABCD image attached. In...
I'm working on a fingerprint recognition project and have run into a road block. As of now, I am using a 3 layer feed-forward neural network to find the minutiae in a fingerprint. If a minutiae is detected, it's location in the image (row, col) and the type (n types) of bifurcation is noted...
Homework Statement
I am trying to train a neural network using the following training set:
(4,6)
(9,10)
(1,2)
(6,2)
So, if I enter input 4, it should give me 6. If I enter 9, output should be 10.
If I enter 3.5, it should approximate an output based on the training examples...
Hello everyone!
Searching for applications of artificial neural networks (ANNs) to real world problems, all I found were applications to computer science problems (e.g. face recognition, OCR, automated control of systems and machines etc.) and some very experimental works (e.g., crime forecast...
Homework Statement
Hi there,
I was wondering if anyone out there was familiar with image classification algorithms. I have been creating histograms of pixel intensity distributions.
For example, suppose I have 100 images of a tiger and 100 images of a lion.
I create 100 histograms using...
Hello all
I'm trying to design a Neural network based control system which will do the following
i have 120 computer servers with
a. power
b. temperature of server inlet
c. temperature of server outlet
Now i have readings for all 3 operating from 5kw to 35 kw in steps of 5 kw
My server...
Hi,
I have just started programming for Neural networks. I am currently working on understanding how a Backpropogation (BP) neural net works. While the algorithm for training in BP nets is quite straightforward, I was unable to find any text on why the algorithm works. More specifically, I am...
Hi!
I attended a class in neural networks and I learned something about ART and SOM.
I learned how to implement the learning algorithm, but then? I wasn't told how to use the trained net! I looked in Google and I didn't find much, everybody talks on how to train a neural net, but nobody says...
I'm trying to implement this example http://www.cs.bham.ac.uk/~jxb/INC/l3.pdf (page 15)
I'm trying to do Iteration training, but it seems as if the results always converging to a steady error rate that is too large to be acceptable, the values centering around 0 while they should be close to -1...
Hello,
I'm interested in neural network programming but I am a beginner.
Recently I wrote an example in C++ that I found in a book. It was a feedforward 3 layers network that learns the examples with the backpropagation algorithm. The aim of the network was to learn to "throw a stone": I taught...
I know and have known for a while now that I want to be involved with neural prosthetics, and artificial limbs and muscles. I eventually plan on getting a graduate degree in biomedical engineering, but for the sake of knowledge, experience, and security, I plan to get my undergrad degree in one...
Hello!
I have been contemplating this question for a few days now and I am interested to know if anyone here has any input on the matter, and to critique my reasoning.
There are other threads on this, none of which, from what I could find, made a distinction between homosexual behaviour and...
Homework Statement
P = [data(1:65,11:100) data(1:65,411:500)]; % Input, all together 180 data set, 65 dimension
T = [ones(1,90) zeros(1,90);
zeros(1,90) ones(1,90)]; % Actual output, first 90 data set belong to class I and the next 90 belong to class II
net =...
I'm looking for advice. I have an assignment to train a neural network. I am confident in my abilities to write the code and train the neural network. The problems are:
1. I lack an idea. I'd like to do something interesting and potentially useful, obviously.
2. I need a rather large data...
A recent thread on free will did not meet the criteria of the forum, but perhaps a similar discussion could be generated by borrowing directly from the example in the rules:
"The research of Benjamin Libet suggests that our decisions to act occur before our conscious awareness of them. Isn't...
I came across this link: http://spie.org/x648.html?product_id=540785
Paper abstract:
It was published in a journal called "Quantum Information and Computation II". I checked the accepted journal list of physicsforums (this one http://www.thomsonscientific.com/cgi...cgi?PC=MASTER ) and in...
As the title indicates, this post is directed towards the subject of Drugs and Toxins that affect the nervous system. I'll be writing a report on this and it is up to me to pick a specific drug or toxin to write about. I was just wondering what you all have to say about the subject. Maybe there...
In neural network the learning algorithm ends when the mean squared error value is less than or equal to a value we have precised.
But i don't understand why we are comparing with the mean squared error and not the mean error?
What does the mean squared error represent?
Well, with some degree of uncertainty that this thread is going to start any kind of conversation that could go anywhere – I am not really posing any questions, I’m not sure if it is proscribed or even intended that all threads should start with a question – I wanted to mention something I saw...
Hello again,
Im trying to build a neural network using C++. Has anyone had a go? I think the potential implications are really interesting and would like to hear about how people might have implemented them. Another general one for anyone.
I'm currently doing a project on neural network controller for an internal combustion engine to reduce emissions level. Can anyone assist me in training such models (neural networks)
Greetings,
I am new in this forum, but I have a question about Plasma televisions. I was told that they have an adverse effect on eyesight. Can anyone elaborate? I tried looking on www.altavista.com for Journals and Information on the medical aspect, but there is nothing but...
Mainly, I'm only curious about the nifty device's function for reading "brain waves" shown at 5:00 in this video:
It only cost like 120 bucks. What do you folks think? Are there any neuroscientists on here that know if the readings are accurate enough for amateur analysis on one's self...
Hi
I've done by bachelors in Electrical Engineering. I was planning to apply for the Masters in Neural Systems and Computing at ETH Zurich. Any idea about how is the course?
Hi Members
I need to do PhD research on application of artificial neural networks in image classification (radar images), could someone please advive on where I can find the relevant and useful information: eg books, contacts, advisable University for one to enroll for PhD studies, papers etc...
I was watching a film in my behavioral neuroscience class yesterday and it showed a connection between neurons forming. (not an animation, this was filmed using a microscope) You could actually see an axon and dendrite moving closer and closer together. Then when they got close enough they...
I'm a novice here..but in virtual neural networks, does adding more virtual neurons improve the performance of the network in terms of recognizing patterns? Has this been experimentally verified anywhere? Can you then make an analogy that the same would happen in a biological neural network? Or...
Homework Statement
Implement (AND, NAND) gates using MATLAB.
Homework Equations
The Attempt at a Solution
I've succeeded to implement a single perceptron that has a single output and multi inputs.
Here is the code I've written...
Hi guys,
If there's anyone out there who has knowledge in this area, I'm seeking to find out how to model memory consolidation using neural networks.
I was thinking of using a Hopfield network to train another Hopfield network. The first network would represent the hippocampus, and the...
Is there any place to put up posts on neural networks?
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Don't be fooled by the apparent humanity of this poster. He is really a computer pretending to be goat. A very smart goat...
I was wondering if the theory of Neural Darwinism
So, I read this popularising book, talking about Neural Darwinism, (Israel Rosenfield, The invention of memory) that was contesting the idea of brain modularity (the idea that the brain is divided into functional regions, interacting which...
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CALL FOR PAPERS
13th International Conference on Neural Information Processing (ICONIP2006)
Hong Kong Convention and Exhibition Centre, Hong Kong...
At different places across the USA and other countries, a new field is popping up called neural engineering. I am assuming that it is similar to cybernetics and I've seen some of the research they are doing and it looks very very cool...
Are any of you involved in that? If so, what kind of...
For next week's journal club I will be presenting
"Neural Activity in Speech-Sensitive Auditory Cortex During Silence", Hunter et al. PNAS Jan 3, 2006 http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=16371474
Along with this paper, I would also like to present
"Where the...