Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. In the central nervous system , a synapse is a small gap at the end of a neuron that allows a signal to pass from one neuron to the next.
Synapses are found where nerve cells connect with other nerve cells. Synapses are key to the brain's function , especially when it comes to memory. The term synapse was first introduced in by physiologist Michael Foster in his "Textbook of Physiology" and is derived from the Greek synapsis , meaning "conjunction. When a nerve signal reaches the end of the neuron, it cannot simply continue to the next cell.
Instead, it must trigger the release of neurotransmitters which can then carry the impulse across the synapse to the next neuron. Once a nerve impulse has triggered the release of neurotransmitters, these chemical messengers cross the tiny synaptic gap and are taken up by receptors on the surface of the next cell. These receptors act much like a lock, while the neurotransmitters function much like keys. Neurotransmitters may excite or inhibit the neuron they bind to.
Think of the nerve signal like the electrical current, and the neurons like wires. Synapses would be the outlets or junction boxes that connect the current to a lamp or other electrical appliance of your choosing , allowing the lamp to light.
Synapses are composed of three main parts:. An electrical impulse travels down the axon of a neuron and then triggers the release of tiny vesicles containing neurotransmitters.
These vesicles will then bind to the membrane of the presynaptic cell, releasing the neurotransmitters into the synapse. These chemical messengers cross the synaptic cleft and connect with receptor sites in the next nerve cell, triggering an electrical impulse known as an action potential. There are two main types of synapses:. In a chemical synapse, the electrical activity in the presynaptic neuron triggers the release of chemical messengers, the neurotransmitters. Memory may also involve the creation of new synapses.
In fact, recent research indicates that it is the synapses, rather than the neurons themselves, that may be the first to show the effects of these conditions. This story by Christina Sumners originally appeared in Vital Record. After a traumatic brain injury caused her to lose her memory, an Aggie Ring helped first-generation student Jennifer Rodriguez remember her goals.
When his daughter heard the news, she decided to surprise him. Subscribe Press Room Search. January 5, Share 4K. Related Stories. IPSPs however, bring the potential down, meaning it will be less likely to cause action potential and can cancel out the excitatory effect of the EPSPs.
EPSPs and IPSPs interact with each other when a postsynaptic neuron combines or summates all the excitatory and inhibitory signals it receives and then makes a decision as to whether to fire an action potential. There are two types of summation that can occur at this stage:. For example, if there are two single excitatory signals EPSPs that arrive at the postsynaptic neuron from two different dendrites, they cannot reach the threshold for action potential on their own.
However, they can sum up together to reach the threshold and cause an action potential of the postsynaptic neuron. If an inhibitory signal IPSP also enters through another dendrite, this can counteract the two EPSPs and could prevent the neuron from firing action potential. This is an instance of spatial summation. If the same two EPSPs arrive from the presynaptic neuron to the postsynaptic neuron, but at slightly different times, they can still cause an action potential to fire.
This is because postsynaptic potentials are not instantaneous, and they can survive in a neuron for a while before dissipating. This is an instance of temporal summation. For a synapse to function effectively, they must be shut off once the signal is sent. This signal termination allows the postsynaptic neuron to return to its resting potential state, ready for new signals. When neurotransmitters get released into the synaptic cleft, not all of them are able to attach to the receptors of the next neuron.
The synaptic cleft must be cleared of all neurotransmitters at signal termination, which can be done by either being broken down by enzymes, diffused away, or re-uptake occurs.
Re-uptake is when neurotransmitters get reabsorbed back into the presynaptic neuron from which they came from. Transporter proteins from the presynaptic membrane remove the neurotransmitters from the synaptic cleft, carrying the neurotransmitter back into the presynaptic neuron. The neurotransmitter then either gets re-packaged into the synaptic vesicles and stored until it is next needed again, or they are broken down by enzymes. Serotonin is a type of neurotransmitter which is associated with a variety of psychological and bodily functions such as mood, sexual desire, appetite, sleep and memory.
If there are imbalances in the way serotonin is transmitted between neurons, through too much reuptake of this neurotransmitter, then this has implications for contributing to mood disorders, specifically depression.
Selective serotonin reuptake inhibitors SSRIs are a type of medication, also known as antidepressants , which work in a way to increase the amount of serotonin being transmitted between cells.
SSRIs essentially aid in blocking the reuptake of serotonin into the presynaptic cell, meaning there is more serotonin in the synaptic cleft. If there is more serotonin in the synaptic cleft, it is more likely that serotonin will reach the receptors of the postsynaptic cell. As SSRIs allow more serotonin to pass along between neurons, they have been shown to alleviate mood disorders, making them a common therapy for depression.
Plasticity refers to how much something can be changed or adapted through growth and reorganization. It was once believed that once synapses were formed, they remain the same forever, never changing.
However, it is now understood that activity, or lack of activity, can affect the strength of synapses, or even change the number and structure of synapses in the brain. Therefore, the more the synapses are used, the stronger they can become and the more influence they can have over postsynaptic neurons. Likewise, not fully using synapses can weaken them and can have a detrimental impact over the long-term.
Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years. Guy-Evans, O. Synapse definition and function. Simply Psychology. Toggle navigation.
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