13 How neurons communicate

Summary

The lecture explains how neurons communicate through an electrical process, focusing on the concept of action potentials. It discusses the threshold needed for neurons to fire and transmit information to other neurons via synapses. The analogy of firing a gun is used to explain the 'all-or-none' law, where neurons either fire completely or not at all. It also introduces the 'refractory period,' a rest phase after firing, during which the neuron cannot fire again. A more detailed video on Canvas is recommended for further learning.

Takeaways

• ⚡ Neurons communicate information via an electrical process, but the actual messengers are chemicals called neurotransmitters.
• 🧠 The transmission of information between neurons occurs when an electrical impulse triggers the release of neurotransmitters.
• 📉 A neuron at rest is in its 'resting potential,' which means it isn't being stimulated.
• 🚦 The 'threshold' is a critical membrane potential that must be reached for an action potential (electrical impulse) to occur.
• 🔫 The 'all or none law' states that a neuron either fires completely or doesn't fire at all, similar to firing a gun.
• 🚀 Once the threshold is reached, an action potential travels down the axon and triggers the release of neurotransmitters into the synapse.
• ⏳ After firing, neurons enter the 'absolute refractory period,' during which they cannot fire again for a brief period.
• 📉 The refractory period prevents neurons from continuously firing and forces them to have a break before they can fire again.
• 🔄 After the refractory period, the neuron returns to its resting potential and can fire again if the right conditions are met.
• 📽️ A more detailed video on this process, including action potentials, is available on Canvas for additional learning.

Q & A

What is the main process by which neurons communicate information?

Neurons communicate information through an electrical process, though the actual messengers involved are chemicals.

What is the resting potential in a neuron?

The resting potential is the baseline electrical state of a neuron when it is not being stimulated or transmitting information.

What is the threshold in neuronal communication?

The threshold is the membrane potential required to trigger an action potential. It is a critical level that must be reached for the neuron to transmit information.

What happens if the neuron doesn't reach the threshold?

If the neuron doesn't reach the threshold, no action potential occurs, and the neuron returns to its resting potential.

What is an action potential?

An action potential is an electrical impulse that travels down the axon of a neuron, triggering the release of neurotransmitters into the synapse.

What is the 'all or none' law in neuronal firing?

The 'all or none' law states that a neuron either fires completely or does not fire at all; there is no partial firing.

What is the absolute refractory period?

The absolute refractory period is the time after an action potential during which the neuron cannot fire another action potential, allowing the neuron to rest.

Why is the refractory period important in neuronal communication?

The refractory period prevents continuous firing of neurons, allowing them to rest and preventing overstimulation. It limits the maximum firing rate of a neuron.

What role do dendrites play in neuronal communication?

Dendrites receive neurotransmitters from neighboring neurons if they have the proper receptors, facilitating the continuation of communication between neurons.

What does the video on Canvas cover in more detail?

The video on Canvas covers the process of action potentials in more detail, offering additional insights beyond the lecture's content.

Outlines

00:00

🧠 Understanding Neuron Communication

This paragraph introduces how neurons communicate information through an electrical process, even though the messengers are chemical. It describes the process as a mix of electrical and chemical transmissions, where neurons must reach a threshold to fire and transmit information across the synapse. The concept of resting potential, threshold, and action potential is explained, including failed attempts to reach the threshold and how the successful triggering of an action potential results in neurotransmitter release. The 'all-or-none' law is highlighted, stating that a neuron either fully fires or it doesn't at all. Finally, the concept of refractory periods is introduced, which limits how often neurons can fire.

05:00

💡 The Importance of Refractory Periods

This paragraph dives deeper into the refractory period, a resting phase where neurons cannot fire again immediately after an action potential. The refractory period limits the firing rate of neurons, preventing continuous, unchecked firing. This provides neurons with necessary breaks before another action potential can occur. The paragraph concludes by encouraging viewers to watch a more detailed video on action potentials and reminds them that the next lecture will continue to explore this topic further.

Keywords

💡Neuron

A neuron is a nerve cell that is the fundamental unit of the brain and nervous system. In the video, neurons are described as the cells responsible for transmitting information through electrical impulses. This process is key to understanding how the brain communicates signals, such as sensory information or muscle commands.

💡Axon

An axon is a long, threadlike part of a neuron that conducts electrical impulses away from the neuron's cell body. The video explains that the electrical signal or action potential travels down the axon to trigger the release of neurotransmitters, which are chemical messengers, into the synapse.

💡Dendrite

Dendrites are the branching structures of a neuron that receive messages from other neurons. In the video, dendrites are mentioned as the parts of the neuron that pick up neurotransmitters after they are released into the synapse, if they are in the correct situation to do so.

💡Action Potential

An action potential is an electrical impulse that travels down the axon of a neuron. It is the signal that triggers the release of neurotransmitters. The video emphasizes that this impulse follows the 'all or none' law, meaning a neuron either fully fires an action potential or does not fire at all.

💡Resting Potential

Resting potential is the state of a neuron when it is not transmitting an electrical signal. The video explains that the resting potential represents the neuron's baseline state when it is not being stimulated. It is contrasted with the active state of the neuron when an action potential is triggered.

💡Threshold

The threshold is the critical level of membrane potential that must be reached for an action potential to be triggered. In the video, it is shown as a key point in the graph that must be crossed for the neuron to fire an action potential. If the threshold is not reached, the neuron does not fire.

💡Synapse

A synapse is the small gap between neurons where neurotransmitters are released to communicate between cells. In the video, it is explained that once the action potential reaches the end of the axon, neurotransmitters are released into the synapse, allowing nearby neurons to receive the signal through their dendrites.

💡Neurotransmitter

Neurotransmitters are chemicals that carry signals from one neuron to another across the synapse. The video touches on how the electrical impulse (action potential) triggers the release of neurotransmitters, which are then picked up by other neurons if the conditions are right.

💡All or None Law

The 'all or none law' refers to the principle that a neuron either fires completely or not at all. The video uses this analogy to compare firing a neuron to firing a gun — either the neuron reaches the threshold and sends an action potential, or nothing happens.

💡Absolute Refractory Period

The absolute refractory period is the time after a neuron fires during which it cannot fire again. In the video, this period is described as a resting time for the neuron after an action potential, preventing continuous firing and limiting the maximum firing rate of the neuron.

Highlights

Neurons communicate through a combination of electrical and chemical processes.

The transmission of information between neurons is primarily an electrical process.

Neurons have a resting potential when they are not being stimulated.

For a neuron to transmit information, it must reach a critical threshold called the 'membrane potential.'

When the threshold is met, an action potential occurs, triggering the neuron to fire.

The action potential is an electrical impulse that travels down the axon.

Action potentials lead to the release of neurotransmitters into the synapse.

The 'all or none law' states that a neuron either fires completely or not at all.

A neuron cannot partially fire; it's either fully activated or it remains inactive.

After an action potential, the neuron enters the absolute refractory period, where it cannot fire again.

The absolute refractory period acts as a rest phase, limiting the neuron's firing rate.

The neuron eventually returns to its resting potential, ready to fire again if stimulated.

Refractory periods are essential for preventing continuous firing of neurons.

The video on Canvas provides a detailed explanation of the action potential process.

This lecture emphasizes the importance of understanding electrical impulses and thresholds in neuron communication.

Transcripts

so now that we know what axons and

dendroides are we need to talk about how

neurons actually communicate this

information so I already said that

basically it's a electrical process in

terms of how this actually happens the

actual Messengers themselves are

chemicals but the way everything is

transmitted from one neur to another is

through an electrical process so there

are things we need to go over with all

this and I do have a video on canvas

that will go over this whole process in

a little bit more detail then how I'm

going to go over it I figure it doesn't

hurt to have an extra rendition of this

material because it is a little

confusing so essentially what happens is

like I said we have this whole

electrical process but this isn't a

continuous process certain things have

to happen in order for one on to to

transmit that information into the

synapse so if we were to actually graph

everything

out this is this whole communication

process and what happens when basically

one neuron fires and you know takes that

information and releases it into the

synapse so another neur can pick it up

so here we have what's known as our

resting potential this is basically what

the neuron is set at when it's not being

stimulated and then there's this very

light gray line right here this is the

threshold the threshold is this membrane

potential that's necessary in order to

trigger an action

potential so basically it's this

critical level that's needed for an

action potential to happen an action

potential is that actual electrical

trigger of this uh neuron so it's you

know this electrical trigger of this

information in this neuron it's

basically going to force this neuron to

transmit this

information so here we have a few

attempts where the San you know tried to

hit that actual threshold but did not

and as you can see here nothing happened

it basically went back to that resting

potential but in this case we're

following this red

line we actually do hit that threshold

we hit that point where it's possible

for an action potential to happen it's

this critical level that's needed so an

action potential is this electrical

impulse that travels down the

axon and what it does is it triggers the

release of those neurotransmitters we'll

talk about neurotransmitters soon into

the synapse and then other neurons near

by can pick up those

neurotransmitters if they have the

proper uh let's just say situation

because it's very specific how this

happens through their

dendrites now an action potential is

similar to like firing a gun either you

fire the gun or you

don't so there's something known as the

all or none law it's basically this

whole idea that either a neuron fires or

it

doesn't so in this case looking at this

curve the neuron fired but in these

situations it did not so you can't have

a situation where the neuron you know

half fires the information or anything

like that either it fires the

information or it

doesn't

now this whole process I'm trying to

find my cursor this whole process is

showing the neuron actually firing that

information it's that whole electrical

impulse but then as you can see here it

doesn't return to normal it doesn't

return to that resting potential it

actually goes under a little

bit this whole area

Here is known as the absolute refractory

period s referred to as a refractory

period just depends on you know which

person is teaching the information this

is a period after an action potential in

which another action potential cannot be

triggered

it's essentially a rest period for this

neuron and then as you can see the

neuron then goes back to that resting

potential here and another action

potential could take place if the

certain sit or certain circumstances

have been met so there's certain things

that have to be met in order to get to

that threshold part like said the video

that I'm going to post on canvas goes

over this in a little bit more detail in

some ways it goes over more detail than

you need to know but it'll go over a

little bit more

detail so basically what happens in the

absolute refractory period is the neuron

cannot fire again and this rest period

really limits the maximum firing rate of

the neuron which really could be a good

thing it gives this situation where you

know you can't have a neuron just

continuously firing this

information it has to have a little of a

break

so it actually it's a good thing and

then I'll go back to that resting

potential and then you know if the

neuron's able to hit that threshold

another action potential can

occur so that's all I'm going to say in

this lecture video like I said there is

another video on canvas that goes into

an action potential specifically so

definitely take a look at that

especially if you are kind of new to

this information or it's been a while um

and I will see you in the next lecture

video where we'll continue talking about

this whole

process