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EPSPs, like IPSPs, are graded (i.e. they have an additive effect). When multiple EPSPs occur on a single patch of postsynaptic membrane, their combined effect is the sum of the individual EPSPs. Larger EPSPs result in greater membrane depolarization and thus increase the likelihood that the postsynaptic cell reaches the threshold for firing an ...
It is now known that periodic breathing also tends to occur during sleep, it can occur in healthy persons, and the apnea in periodic breathing is usually central sleep apnea rather than obstructive sleep apnea. Periodic breathing during sleep occurs typically in adult patients with congestive heart failure. Periodic breathing is also a normal ...
Symptoms of infantile apnea occur most frequently during the rapid eye movement (REM) stage of sleep. [4] The nature and severity of breathing problems in patients can be detected in a sleep study called a polysomnography which measures the brain waves, heartbeat, body movements and breathing of a patient overnight. [4]
If the postsynaptic cell is sufficiently depolarized, an action potential will occur. For example, in low-threshold spikes depolarizations by the T-type calcium channel occur at low, negative, membrane depolarizations resulting in the neuron reaching the threshold. Action potentials are not graded; they are an all-or-none response.
Sleep apnea is a common sleep disorder that affects more than 20 percent of people in the United States. It happens when your breathing temporarily stops while you sleep. Depending on the severity ...
Therefore, in order to achieve threshold and generate an action potential, the postsynaptic neuron has the capacity to add up all of the incoming EPSPs based on the mechanism of summation, which can occur in time and space. Temporal summation occurs when a particular synapse is stimulated at a high frequency, which causes the postsynaptic ...
Causes may include heart failure, kidney failure, narcotic poisoning, intracranial pressure, and hypoperfusion of the brain (particularly of the respiratory center). The pathophysiology of Cheyne–Stokes breathing can be summarized as apnea leading to increased CO 2 which causes excessive compensatory hyperventilation, in turn causing decreased CO 2 which causes apnea, restarting the cycle.
Breath-holding spells occur in approximately 5% of the population with equal distribution between males and females. They are most common in children between 6 and 18 months and usually not present after 5 years of age. They are unusual before 6 months of age. A positive family history can be elicited in 25% of cases.