Bcia Neuroanatomy/neurophysiology Test 2

Thalamic-cortical circuits generate cortical EEG rhythms in the upper cortical layers. Thousands of synapses are synchronized together, due to their shared input signals, so they simultaneously depolarize (become more positive) or hyperpolarize (become more negative).

Sodium channels open permitting sodium ion entry when a neuron reaches the threshold of excitation. This allows a neuron's membrane potential to briefly become positive and produces the action potential.

Axoaxonic synapses specifically involve communication between terminal buttons and can impact the neurotransmitter release by the postsynaptic neuron. They do not directly control the firing rate of the presynaptic neuron, contribute to neural integration, or exchange ions.

When a neuron is at rest, the inside of an axon is negatively charged compared to the outside due to the distribution of ions across the neuronal membrane.

Nodes of Ranvier play a crucial role in the propagation of action potentials along myelinated axons in the nervous system. They are essential for the saltatory conduction of electrical impulses.

Neuron terminal buttons are specialized structures at the ends of neuron branches that are responsible for releasing neurotransmitters to communicate with other neurons. They do not supply nutrients, provide insulation, or transmit electrical impulses.

Dendrites are the branched extensions of a neuron that receive signals from other neurons and carry those signals to the cell body (soma) for processing.

The correct term for the voltage level that triggers an action potential is the threshold of excitation, which is approximately 20 mV more positive than a neuron's resting potential.

Presynaptic facilitation and presynaptic inhibition occur at the terminal button and are mediated by axoaxonic synapses. Presynaptic facilitation increases neurotransmitter release while presynaptic inhibition decreases it.

Neurotransmitter binding to a metabotropic receptor initiates signaling cascades that lead to long-lasting neuronal changes like an increase in vigilance.

An IPSP is a negative change in a neuron's membrane potential that makes it less likely to initiate an action potential. Both positive potassium ions leaving a neuron and negative chloride ions entering a neuron can produce IPSPs.

The amygdala plays a key role in emotional responses, particularly in processing emotions such as aggression, defense, fear, and regulation of reproductive behaviors. The caudate nucleus, hippocampus, and thalamus have different functions within the brain and are not primarily responsible for these specific behaviors.

Autoreceptors are presynaptic neuron receptors that are linked to a G-protein and help neurons adjust the synthesis and release of neurochemicals through the second-messenger system.

Electrostatic pressure is one of two processes (the other is diffusion) that determine the distribution of ions inside and outside of a neuron's membrane.

Ion channels are specialized proteins in neuronal membranes that allow the passage of ions, whereas G proteins, autoreceptors, and voltage gates serve different functions in cellular signaling.

Ionotropic receptors are ligand-gated ion channels that produce rapid and short-lived postsynaptic potentials.

The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes the nerves that branch out from the CNS. The endocrine system is responsible for hormone production and regulation, and the muscular system is responsible for movement.

The membrane potential is the difference in electrical potential between the inside and outside of a cell. Resting potential refers to the membrane potential of a cell at rest, threshold of excitement is the level of depolarization required to trigger an action potential, and action potential is the brief change in electrical membrane potential during the passage of an impulse along a neuron.

In the mechanism of action potential, a brief drop in membrane resistance to sodium ions allows sodium ions to enter the neuron, leading to depolarization and initiation of the action potential.

Projection fibers are axons that project from one brain region to another, while nuclei are clusters of cell bodies, local circuit fibers refer to connections within the same brain region, and ganglia are clusters of nerve cell bodies outside the central nervous system.