Brain and Behavior: Computing with Neurons

These flashcards cover essential concepts regarding the structure and function of neurons, mechanisms of action potentials, neurotransmitter functions, and the integration of signals within neurons.

What are neurons?

Neurons are discrete cells that have long axons, synapse on dendrites, are electrically excitable, and use glutamate or GABA as their neurotransmitter.

What mechanism generates resting potentials in neurons?

Resting potentials are generated by the balance between potassium ions flowing down their concentration gradient and the prevailing voltage gradient.

How do action potentials travel along axons?

Action potentials propagate via internal current flow that triggers adjacent membrane patches to fire all-or-nothing action potentials.

What role do myelin sheaths play in action potentials?

Myelin sheaths increase conduction speed and metabolic efficiency of action potential propagation along axons.

What occurs during the depolarization phase of an action potential?

During depolarization, sodium ions rush into the axon, making the membrane more positively charged.

What is spatial summation in terms of neuronal integration?

Spatial summation is the process by which multiple distal synaptic inputs combine at the cell body to produce a single significant electrical signal.

What distinguishes ionotropic receptors from metabotropic receptors?

Ionotropic receptors allow ions to flow through their pore when activated, while metabotropic receptors activate enzymes generating second messenger proteins.

What is the function of the sodium-potassium pump?

The sodium-potassium pump moves 3 sodium ions out and 2 potassium ions in, consuming ATP to maintain the resting potential.

What happens to the action potential during the refractory period?

During the refractory period, action potentials cannot propagate because the axon segments behind them are in a refractory state.

What neurotransmitter is primarily involved in excitatory synaptic transmission?

L-glutamate is the main excitatory neurotransmitter in the central nervous system.

What triggers the release of glutamate from the presynaptic terminal?

The influx of calcium ions into the presynaptic terminal triggers the movement of synaptic vesicles towards the synaptic cleft to release glutamate.

How do neurons differ from one another?

Neurons vary in size, shape of their dendritic trees, length of axons, and types of neurotransmitters used.

What defines the action potential threshold in a postsynaptic neuron?

An action potential is fired only when the membrane depolarization at the axon hillock exceeds the action potential threshold.

What is the integrate-and-fire model of neuron function?

In the integrate-and-fire model, neurons sum inputs and fire action potentials only if the sum exceeds a threshold.

How do neurons encode information?

Neurons encode information primarily through their action potential firing rate.