Retrograde amnesia, or retrograde amnesia, is the loss of access to memories of events that occurred, or information that was learned, prior to the event that caused the disease. It is caused by a negative impact on episodic memory, autobiographical memory, and explicit memory, while retaining procedural memory intact without any difficulty in learning new knowledge or forming new long-term memories. Retrograde amnesia can be classified as temporary or permanent based on the severity of the injury and is usually governed by Ribot's law; the ability to retrieve distant memories may be easier than retrieving memories close to the time of the event. The type of information that is forgotten can be very specific, such as a single event, or more general, resembling a general amnesia. It should not be confused with anterograde amnesia, which deals with the inability to form new memories after the event that caused the disease. The hippocampus is the most important brain region involved in memory consolidation. During the consolidation process, the hippocampus acts as an intermediary that quickly stores new information until it is transferred to the neocortex for long-term storage. The temporal lobe, which contains the hippocampus and the surrounding cortex, has a reciprocal relationship with the neocortex. The temporal lobe is temporarily required when consolidating new information; however, as the learning process becomes stronger, the neocortex becomes more independent of the temporal lobe. Causes of retrograde amnesia include traumatic brain injuries or a traumatic event, which is called psychogenic amnesia, or an infection that crosses the blood-brain barrier, which may lead to brain damage and encephalitis, or it may occur due to surgery that causes damage to some parts of the brain that are important in memory formation. Electroconvulsive therapy may cause retrograde amnesia. Retrograde amnesia has also been found in patients with alcoholism and Korsakoff syndrome. There is no cure for the disease, but exposing the patient to experiences and information from his previous life, called reminiscence therapy, may be helpful; although its positive results in restoring memory are not proven. Fortunately, memory may also be restored using spontaneous recovery and neuroplasticity.