How do negative ions affect neurons?

Negative ions can influence neuronal activity by affecting the electrical balance within and outside of the neurons. When the concentration of negative ions increases around neurons, it can create a hyperpolarized state, which increases the negativity inside the neuron relative to the outside. This hyperpolarization makes it more difficult for the neuron to reach the threshold necessary for firing an action potential.

In this context, if negative ions are present in higher concentrations, they inhibit the firing of neurons. This means that neurons are less likely to transmit signals, as the depolarization required to trigger an action potential is harder to achieve.

Consequently, the effect of negative ions can lead to a situation where neurons are less responsive or actively firing, aligning with the choice indicating that they don't allow neurons to fire effectively. This understanding is critical in pharmacology and neuroscience, as it helps clarify how various ions and chemical environments influence neural communication.