Skip Navigation

The Brain, Neurons and Brain Chemistry

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Tadzia GrandPré, PhD

Chemical Communication

Each of the billions of neurons in the nervous system communicate with one another and with other cells, such as muscle cells, through special junctions known as synapses. Some neurons share synapses with thousands of other cells. Others connect with only a few cells. 

In some cases, instead of binding to the receiving neuron, neurotransmitters simply float (diffuse) away from the synapse. Other neurotransmitters are broken down or degraded by enzymes found within the synaptic cleft. Many neurotransmitters are transported, whole, back into the neuron that released them. Some drugs, such as cocaine and fluoxetine (Prozac®), exert their effects by interfering with the removal of neurotransmitters from the synapse.

Sometimes, neurons do not communicate through neurotransmitters. Instead, an electrical charge passes directly from neuron to neuron through what is known as an electrical synapse. This type of signaling, in which the communicating neurons are very close together, is very fast and allows many interconnected neurons to fire at the same time. Electrical synapses are less common than chemical synapses, but they are very important for the normal development and function of the nervous system.

Related Content

  • Brain Chemistry

    Brain Chemistry Teacher Guide

    Students learn about the brain, neurons, chemical communication in the body, and how our choices can affect brain function and performance. (9 activities)

Funded by the following grant(s)

NIH Blueprint for Neuroscience Research Science Education Award, National Institute on Drug Abuse, and NIH Office of the Director

The Learning Brain: Interactive Inquiry for Teachers and Students
Grant Number: 5R25DA033006

Science Education Partnership Award, NIH

Filling the Gaps: K-6 Science/Health Education
Grant Number: 5R25RR013454