Introduction to Neuronal Networks

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Questions and Answers

What is the primary function of dendrites in neuronal communication?

To integrate multiple signals and generate an action potential

To regulate the directionality of neuronal communication

To transmit the signal in the form of an action potential to the target neuron

To receive incoming signals that converge in the cell body (correct)

What is the direction of travel from one neuron to another?

From dendrites to cell body to axon (correct)

From axon to dendrites

From axon to cell body to dendrites

From cell body to dendrites to axon

What is the function of the cell body in neuronal communication?

To integrate multiple signals from dendrites (correct)

To transmit the signal to the target neuron

To regulate the strength of incoming signals

To generate an action potential

What is the term for the electrical signal transmitted along the axon to the target neuron?

Action potential Signup and view all the answers

Which of the following is NOT a learning outcome of this topic?

Describe the structure of the neuron Signup and view all the answers

What is the term for the neuronal networks that are built from recurrent wiring motifs?

Simple neural networks Signup and view all the answers

What triggers the exocytosis of synaptic vesicle content?

The entry of Ca2+ ions into the presynaptic neuron Signup and view all the answers

What determines the amplitude of an EPSP?

The amount of neurotransmitter released from the presynaptic neuron Signup and view all the answers

What can cause the decay of an EPSP?

All of the above Signup and view all the answers

What is the role of voltage-gated Ca2+ channels in synaptic communication?

To allow Ca2+ ions to enter the presynaptic neuron Signup and view all the answers

What is the main difference between EPSPs and IPSPs?

EPSPs are excitatory, while IPSPs are inhibitory Signup and view all the answers

What happens to the synaptic vesicle content after exocytosis?

It is released into the synaptic cleft and binds to postsynaptic receptors Signup and view all the answers

What can cause the amplitude of an EPSP to decrease over time?

The desensitization of postsynaptic receptors Signup and view all the answers

What is the role of enzymatic breakdown in synaptic communication?

To break down neurotransmitters in the synaptic cleft Signup and view all the answers

What is the outcome when an excitatory and an inhibitory neuron fire?

A below threshold graded potential is generated Signup and view all the answers

What is the primary difference between presynaptic and postsynaptic inhibition?

The specificity of the inhibited synapses Signup and view all the answers

What is the function of the Renshaw cell in recurrent inhibition?

To inhibit the α motor neuron Signup and view all the answers

What is an example of a neural network that involves convergence and divergence?

The knee jerk reflex Signup and view all the answers

What is the purpose of feedforward excitation in neural networks?

To enhance the strength of the signal Signup and view all the answers

What is the function of the dorsal root/trigeminal ganglion in the knee jerk reflex?

To transmit sensory information to the central nervous system Signup and view all the answers

What is the outcome of surround/lateral inhibition in neural networks?

Reduced signal strength Signup and view all the answers

What is the primary function of recurrent inhibition in neural networks?

To regulate motor neuron activity Signup and view all the answers

What is the primary function of EPSPs in a neuron?

To sum and generate depolarization, making it more likely to fire an action potential Signup and view all the answers

What is the outcome when IPSPs and EPSPs are in balance in a neuron?

The neuron's membrane potential remains at rest Signup and view all the answers

What is the primary function of Temporal Summation of EPSPs?

To integrate EPSPs from different synapses to generate a stronger response Signup and view all the answers

What is the effect of an Inhibitory neuron firing on the presynaptic terminal?

It blocks the release of neurotransmitters from the presynaptic terminal Signup and view all the answers

What is the result of Spatial Summation of EPSPs?

An increase in the likelihood of an action potential Signup and view all the answers

What is the primary function of Synaptic Modulation?

To decrease the strength of synaptic transmission Signup and view all the answers

What is the result of Presynaptic Inhibition?

A decrease in the release of neurotransmitters from the presynaptic terminal Signup and view all the answers

What determines the potential to fire an action potential in a neuron?

The balance of EPSPs and IPSPs Signup and view all the answers

Study Notes

Neuronal Networks

Direction of Travel from Neuron to Neuron

Dendrites receive incoming signals that converge in the cell body before being conveyed along the axon to transmit the signal in the form of an action potential to the target neuron.

Synaptic Communication

Ca2+ entry triggers exocytosis of synaptic vesicle content, which releases neurotransmitters (NT) that diffuse across the synaptic cleft and activate postsynaptic cell.
NT can activate receptors, causing excitatory postsynaptic potential (EPSP) or inhibitory postsynaptic potential (IPSP).

Integration of EPSP’s & IPSP’s

EPSPs and IPSPs are subthreshold events that determine whether a neuron or muscle will reach a threshold to fire an action potential.
EPSPs sum to generate depolarization (more likely to fire an action potential), while IPSPs sum to generate hyperpolarization (less likely to fire an action potential).
The balance of EPSPs and IPSPs, which act to cancel each other out, determines the potential to fire an action potential.

Spatial and Temporal Summation of EPSP’s

EPSPs can be graded, and their amplitude depends on the amount of NT released, the number of receptors, and the state of receptors.
Decay of EPSPs depends on dissociation of ligand, diffusion, and uptake (e.g., glutamate), and can also depend on desensitization (e.g., AMPA-type glutamate receptors).
Temporal summation of EPSPs occurs when multiple EPSPs arrive at the same synapse within a short time frame, increasing the likelihood of firing an action potential.

Synaptic Modulation

Presynaptic inhibition: a inhibitory neuron fires and blocks NT release at a specific synapse.
Postsynaptic inhibition: an inhibitory postsynaptic potential results in a below-threshold graded potential, reducing the likelihood of firing an action potential.
Presynaptic inhibition provides more specific control and precise inhibition of specific synapses, while postsynaptic inhibition provides general inhibition of all synapses equally.

Neural Networks

Neural networks consist of multiple interconnected neurons that process and transmit information.
Simple neural networks can be built using recurrent wiring motifs and can integrate information from multiple sources.

Building Networks

Networks can be built using different types of connections, including:
- Feedforward excitation
- Feedback excitation
- Feedforward inhibition
- Feedback inhibition
- Lateral inhibition
- Recurrent excitation
- Recurrent inhibition
These connections allow for the integration of information and the transmission of signals across the network.

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Description

This quiz covers the basics of neuronal networks, including how neurons communicate with each other and how multiple signals are integrated.