Could someone explain the inhibition or stimulation of a postsynaptic neruon by a presynaptic neuron?
97213
Both inhibition and stimulation begin with the same action, release of some signal from a presynaptic neuron onto a postsynaptic neuron.  In most cases, this is a chemical signal where the presynaptic neuron releases small amounts of neurotransmitter into the synaptic cleft between the pre and postysnaptic neurons.  The neurotransmitter then binds to a receptor on the postsynaptic membrane which then leads to some change in the postsynaptic neuron.  This change could be immediate (opening and/or closing of channels in the membrane) or delayed (activation of some chemical cascade within the neuron).\n\nGenerally, inhibition of a postsynaptic neuron occurs when these changes result in a decrease in the likelihood that the postsynaptic cell will fire an action potential.  This could be by increasing the polarization of the cell membrane or by interfering with processes/channels that would otherwise cause the cell to depolarize.\n\nExcitatation of a postsynaptic neuron is when the effect of the cell causes the cell to increase it's likelihood of firing either by opening channels that cause the balance of ions on either side of the membrane to become less polarized, or by decreasing the threshold required for the cell to fire an action potential.\n\nIt is important to recognize that the neurotransmitter does not determine if the presynaptic effect on the postsynaptic neuron is either excitatory or inhibitory, but rather the events that follow neurotransmitter binding to the postsynaptic receptor.  In other words, the chemical doesn't determine what happens to the cell, the action of the receptor does.
762876
All the receptors of the brain have not been cloned and characterized yet.\n\nLet's start with the signals, or ligands, which bind to receptors first.  An incomplete list:\nCalcium, Potassium, Sodium, Glutamate, Gamma amino butyric acid, Dopamine, Serotonin, Norepeinephrine.  All these molecules have excitatory or inhibitory effects on neurons of the brain.\n\nGiven the fact that the brain is composed of nerves, or neurons, then the excitatory and inhibitory chemical ions, and the excitatory and inhibitory hormones will all have receptors.  These cehmicals and hormones are generally called "signals".  To further complicate matters... :)  ... these different signals also bind to different subtypes of receptors.  For example serotonin (also known as 5-HT) has at least 3 receptors that I know of (5-HT1R, 5-HT2R, and 5-HT3R).  It is reasonable to assume that there are more than just one type of receptor for each signal.\n\nSorry for such a vague answer, but the neuroanatomy and neurobiology of the brain is still too "young" a science in order to answer this question exactly.  I hope this answer has helped you.
454698
http://neuro.psyc.memphis.edu/NeuroPsyc/np-l2-pref.htm\nhas some stuff on it
887631
1. Nerve impulse signal integrity and discrimination for neural synaptic interface.\n\n2. Artificial muscle (polymer hydogel)\n\n3. Artificial bone using nanotechnology to grow as the subject grows this would also apply also to the artificial muscles.
548091
try this link and it should answer your question it is with diagram!\n\nhttp://en.wikipedia.org/wiki/Central_nervous_system
276196
Nervous system is devided in to two parts: central(CNS) and peripheral nervous systems(PNS).CNS is the brain and the spinal cord,PNS is composed of many nerves that contains neurones (nerve fibers),these neurones are of two types,Efferent(sensory) neurones carry the messages from the different body organs to the CNS,while the afferent(motor) neurones carry the messages from the CNS back to the different organs. When any part of the system is stimulated by any stimulant;whether it is external or internal,this stimulation will be carried as a message to the CNS where it is translated and then appropriate action is planned, this action then is carried by the motor neurones back to target cells or organs to carry on the plan of action tward that stimulant...It's  a complicated process that really shows the power of the creator who designed it---our lord
846839
My hunch is that with a bit more time separation between the stimuli, that the nerve cells would have time to recover between firing signals, and that they could build a greater action potential.  \n\nI'm a bit perplexed as to why you'd be tackling this problem at 7:30 AM on Thanksgiving Day......or are you in Europe?
637350
INFORMATION IS CONDUCTED ELETROCHEMICALLY BY THE NEURONS THROUGH VARYING CONCENTRATIONAS OF Na and K ions across the myelin seath of the neurons.in a neuron at rest there is more conc. of k ions on the inner side(this is the polarised region) and more conc. of Na ions on the outer side(depolarised region) .thus the inner side is at a greater potential than the outer side .when a stimulas is received the conc. in a particular regin of the neuron begins to change. K IONS move to the outer side and Na ions move to the inner side.now in that part of the neuron the outer membrane is at a higher potential than the the inner membrane. in the outer region the Kions are surrounded by large number of Na ions due to this a current sink develops and the K ion move back to the inner side while Na ions move back to the outer region and this region gets repolarised.but the region next to this gets deolarised in the process.thus the nerve impulse travels across the neuron as a wave of polarisation, depolarisation and repolarisation.\n           as the nerve impulse reaches the terminals of the neuron called dendrites the vesicles present there release ascetylcholine and this neurotransmitter transfers messages from one neuron to another and the above process continues till the message reaches the concerned organ.
335959
Synapses are specialized junctions through which cells of the nervous system signal to one another and to non-neuronal cells such as muscles or glands. A synapse between a motor neuron and a muscle cell is called a neuromuscular junction.\n\nSynapses allow the neurons of the central nervous system to form interconnected neural circuits. They are thus crucial to the biological computations that underlie perception and thought. They also provide the means through which the nervous system connects to and controls the other systems of the body.\n\nThe human brain contains a huge number of synapses, with young children having about 1,000 trillion. This number declines with age, stabilizing by adulthood. Estimates for an adult vary from 100 to 500 trillion synapses.\n\nThe word "synapse" comes from "synaptein" which Sir Charles Scott Sherrington and his colleagues coined from the Greek "syn-" meaning "together" and "haptein" meaning "to clasp".
1185534
I think you would do well to look a while at this excellent - but - simpliefied source on neuroscience:\n\nhttp://faculty.washington.edu/chudler/introb.html
353806
T-tubules transmit nerve impulses throughout the muscle.  Think of it this way.  Your biceps muscle is composed of many different muscle cells working together.  When your brain tells your biceps to contract, does it send individual nerves to every single muscle cell?  No it doesn't (I guess that really isn't an obvious answer).  This is where the T-tubules come in.  They transmit electrical impulses from one muscle cell to another.  This way, only some muscle cells need to be activated by a nerve--the rest will be signaled through the T-tubule network, so that all of the muscle cells will contract together.\n\nSo what happens when you block the T-tubules?  Your muscle doesn't work so well anymore.  You might still get cell-to-cell communication (I'm not sure), but even if you did, it would be slow so that the muscle fibers would not contract synchronously.\n\nAddendum: It's been 6 or 7 years since I last studied physiology, so I think you should listen to the professor, not me!
77122
http://en.wikipedia.org/wiki/Image:Neuron.jpg
728454
Well i haven't seem the whole question, but I think u mean how the axon limits the rate of firing of action potentials. Remember that the neurones need to repolraise after n action potential has been generated. This is as the ions diffuse in and out f the axon, restoring the resting potential.
410329
Ok, Franko got it started-The action potential is propagated along the sensory axons, through the ulnar or other nerve (depending on exactly what part of your hand touched the stove), through the dorsal root ganglia (which is where the cell bodies for the sensory axon live) to the spinal cord.  There, they will release neurotransmitters at synapses with secondary sensory dendrites and cell bodies (which will send a signal on up the spinal cord to the brain) In addition, they will release neurotransmitters at synapses with interneurons, which synapse with motor neurons.  There motorneurons send axons to a number of muscles, such as the bicep.  A signal is generated at the motorneuron, sent down the axon, which then terminates on motor end-plates, which stimulate the muscle to contract, and thus pull the hand away.
309197
Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a neuron and another cell. According to the dogma of the 1960s.\n\nA neurotransmitter's effect is determined by its receptor. For example, GABA can act on both rapid or slow inhibitory receptors (the GABA-A and GABA-B receptor respectively). Many other neurotransmitters, however, may have excitatory or inhibitory actions depending on which receptor they bind to.\n\nNeurotransmitters may cause either excitatory or inhibitory post-synaptic potentials. That is, they may help the initiation of a nerve impulse in the receiving neuron, or they may discourage such an impulse by modifying the local membrane voltage potential. In the central nervous system, combined input from several synapses is usually required to trigger an action potential. Glutamate is the most prominent of excitatory transmitters; GABA and glycine are well-known inhibitory neurotransmitters.\n\nMany neurotransmitters are removed from the synaptic cleft by a process called reuptake (or often simply uptake). Without reuptake, the molecules might continue to stimulate or inhibit the firing of the postsynaptic neuron. Another mechanism for removal of a neurotransmitter is digestion by an enzyme. For example, at cholinergic synapses (where acetylcholine is the neurotransmitter), the enzyme acetylcholinesterase breaks down the acetylcholine. Neuroactive peptides are usually removed from the cleft by diffusion, and eventual broken down by proteases
644584
they are known as neurotransmitters \nan example in acetylcholine
379668
Synapse barriers?  I know what a synapse is (simply, space between neurons), but I've never heard of synapse barriers.  There's a neuropsychologist wandering around somewhere on Yahoo Answers who would be the one to ask.