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5

Generally speaking, yes. For reference see this paper in Nature This is Fig. 7 from it with comment: Reason is that most axons are not passive tubes of electrolyte with leakage (in which case AP would be attenuated along it) but rather active media with membrane potential across that have ion channels that reproduce initial action potential along the ...


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As you pointed out sodium as sodium enters the cell depolarizes (becomes more positive). Recall the sodium gates open the more positive the voltage is, which in turn opens more sodium gates. If a patch of neural membrane is depolarized, the charge diffuses into the nearby patches of neural membrane. This will open the sodium channels of the nearby membrane ...


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Short answer Temperature differences of 0.02 degrees Celcius can be distinguished, dependent on various factors including experimental conditions and bodily location. Background The ability to discriminate temperature differences depends on whether it is a cooling or heating pulse, the skin temperature, the duration of the temperature stimulus, age, bodily ...


5

I did a quick search and found some research in this area. Sleep inertia is the technical term for feeling groggy for a while after waking up. In a review article by Patricia Tassi, Alain Muzet (Sleep inertia. Sleep Medicine Reviews. Volume 4, Issue 4, August 2000, Pages 341–353), they define sleep inertia as Sleep inertia is a transitional state of ...


4

Short answer(s) Someone with a damaged larynx may still speak with the use of a speech aid (electronic larynx). The ability to understand speech does not necessarily mean one can speak normally. There are neurological disorders where folks can understand speech, but have difficulty producing it. Background A full removal of the larynx (laryngectomy) ...


3

Short answer Action potentials differ in shape between neuronal cell types, and action potentials may even change shapes during action potential propagation within one and the same axon. Background Once an action potential is sent from a given neuron down the axon, does the shape and amplitude remain constant as it is propagated? Although the ...


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Short answer(s) Widening of the action potential increases neurotransmitter release; Generally, an action potential results in the release of about one vesicle of neurotranmitters; An action potential does not have to lead to neurotransmitter release - the chance being anywhere between 9 - 100%, depending on the synapse under investigation. ...


3

Neurons encode the "largness" of the stimulus in firing frequency. Neurotransmitters are stored in vesicules near the end of the axon. It has been shown that neurotransmitter release follows Poisson-distribution and that usually a single "packet" (quantum) is released - this is known as quantal release. Although the actual number of molecules in a single ...


3

Short answer Given your comments you are referring to the cause of fainting after being triggered by certain stressors. The reason is a sudden drop in blood pressure due to parasympathetic nervous system activation (vagus nerve activity). This leads to reduced blood flow to your brain, which results in a brief loss of consciousness (Mayo Clinic). Background ...


3

You can whisper without a larynx. "Patients who have undergone partial or full laryngectomy are typically unable to speak anything more than hoarse whispers, without the aid of prostheses or specialized speaking techniques." (source) So the remainder of the vocal tract is capable of enough modulation to present typical human speech in many languages. I ...


3

Short answer Slowly adapting mechanoreceptors in the skin mediate the perception of static pressure stimuli, while rapidly adapting skin receptors mediate swiftly changing (e.g., vibratory) stimuli. Background There are various skin receptors. Hairy skin, such as that encountered on the arm, contains at least four specialized mechanoreceptors, namely ...


2

At the molecular level this is called receptor desensitization. This is the reason why for example spices (like red hot chili paper) taste more pungent the first time you put them in your mouth and less and less subsequent times (in this case the receptor is called TRPV1). Mechanosensory perception is mediated, at least in part, by similar transient ...


2

Nice question(s). I will go through them in sequence. Safe current limits. With regard to electrical stimuli it is current density that determines safety limits. Therefore, in medical devices, it is not a matter of what is a safe maximum current level, but what is the maximum safe current level given the surface of the electrode? And in terms of skin ...


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Sleeping is a biological stage which we presume as a relaxation period but its really a highly functional stage for brain. Most of the memory related processing such as management of working memory and cognitive functions such as decision making, reasoning, and episodic memory are closely related with sleep. Dolphins never sleep in the sense that we do, ...


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I was doing some more research and stumbled upon this paper here by Dr. Izhikevich that describe neurons as a system that can exhibit resonance. The author built a model that he calls the resonate and fire, which is a linear piece-wise model of a neuron. The interesting thing, and why I bring it up, is it can respond to a "two inhibitory pulses, that if ...


2

A microelectrode is quite literally a small electrode and they come in a variety of shapes. The glass pipette electrode you are specifically referring to is mostly used for patch clamp experiments. Patch clamp experiments are performed using various configurations: Source: Leica So basically there is the cell-attached configuration, where a patch of ...


2

Speech is generated by generating a frequency spectrum with the vocal folds, and then filtering it with the upper vocal tract. Whistling is done by blowing air over shaped tongue and lips. So, give someone a laryngectomy. They still retain the upper vocal tract (and so can still whistle), but they cannot generate the source vibrations to speak. Do it as ...


1

The primary somatosensory and primary motor cortices are distinct cortical areas. According to the structural classification of Brodmann, the primary somatosensory cortex is referred to as Brodmann's areas 1,2 and 3 (BA1, BA2 and BA3). The primary motor cortex is referred to as Brodmann's area 4 (BA4). The primary sensory cortex is sometimes denoted by S1, ...


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Short answer Action potentials are always generated after a depolarization step. Background Action potentials are generated by prior depolarization of a neuron, typically by the action of an excitatory neurotransmitter. An action potential is per definition a sharp depolarization, followed by a somewhat slower re-polarization step. The most important step ...


1

Answer version1 (read the comments, I leave v1 for the those who can make the same assumptions in the future) To answer the question we should clarify some general concepts and processes mentioned it the clause: EMG is performed by means of direct placement of the electrode (the are two types here - surface-EMG and needle-EMG) on/into the skeletal ...


1

Short answer In case of Pacinian corpusles, the adaptation is generally ascribed to the mechanical characteristics of the outer capsule of the receptor. The capsule's onion-like structure quickly molds itself to pressure stimuli, thereby rapidly desensitizing the receptor. Background There are two classes of mechanoreceptors in the skin based on their ...



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