Neural networks are a subset of artificial intelligence that mimic the way the human brain processes information. They consist of interconnected nodes, or neurons, organized into layers, including an input layer, hidden layers, and an output layer. These networks are designed to recognize patterns and relationships in data, enabling them to learn and make predictions. By adjusting the weights and biases of connections between neurons during training, neural networks can improve their accuracy over time. They are widely used in various applications, such as image and speech recognition, making them a powerful tool in machine learning and deep learning.