Deep learning is a branch of AI that automatically extracts features from raw data through multiple layers of abstraction using neural networks inspired by the human brain's structure.
Key types of neural networks include Feedforward Neural Networks, Convolutional Neural Networks (CNNs), Recurrent Neural Networks (RNNs), and Transformers, each designed for specific data types like images or sequential data.
Common challenges in deep learning are underfitting and overfitting, with solutions like transfer learning, Generative Adversarial Networks (GANs), self-supervised learning, attention mechanisms, and Explainable AI (XAI) to improve model performance and interpretability.