The human brain contains a structure named the hippocampus, a term derived from the Greek for “seahorse” due to its curved shape. There are two of these structures, one located in each of the brain’s hemispheres, deep within the medial temporal lobes. The hippocampus is a component of the limbic system, a collection of brain structures involved in emotion, motivation, and memory.
Core Responsibilities of the Hippocampus
The hippocampus is responsible for the formation of new explicit memories, which are the recollections of facts and events. It acts as a processing center for new information, beginning the process of memory consolidation. This involves converting short-term memories into more stable, long-term memories that are then stored in other regions of the cerebral cortex.
This brain region is also important for learning, as the ability to acquire and store new information is linked to memory formation. As we learn, the hippocampus processes incoming sensory details and helps associate them with existing knowledge. For instance, it helps link the smell of gingerbread with the broader context of a holiday memory.
A defining function of the hippocampus is its role in spatial navigation and memory. It creates and maintains “cognitive maps,” which are mental representations of our physical environment that allow us to remember locations and navigate. Its connections to areas involved with emotion, like the amygdala, also mean it plays a part in attaching emotional significance to memories.
Consequences of Hippocampal Impairment
Damage to the hippocampus can lead to specific memory deficits. Severe injury to both the left and right hippocampus often results in anterograde amnesia, the inability to form new long-term memories after the event that caused the damage. Individuals with this condition can recall memories from before their injury but struggle to retain new information, such as what they ate for breakfast.
The hippocampus is particularly susceptible to damage in the early stages of neurodegenerative diseases, most notably Alzheimer’s disease. This is a primary reason why one of the first symptoms of Alzheimer’s is memory loss and disorientation. As the disease progresses, the atrophy, or shrinking, of the hippocampus becomes more pronounced, correlating with worsening memory function.
Beyond disease, the hippocampus can be negatively affected by chronic stress and certain mental health conditions. Prolonged exposure to stress hormones, such as cortisol, can impair the structure and function of the hippocampus. Conditions like post-traumatic stress disorder (PTSD) and major depression are often associated with a reduction in hippocampal volume.
Nurturing Your Hippocampus
The hippocampus is one of the few areas in the adult brain where neurogenesis, the birth of new neurons, can occur. This process suggests the brain has a capacity for plasticity and repair, and certain lifestyle choices can influence this phenomenon.
Regular physical activity, particularly aerobic exercise, is strongly linked to improved hippocampal health. Exercise boosts blood flow to the brain, which delivers oxygen and nutrients that support neuron function and growth. High-quality sleep is also necessary, as it plays a direct part in the memory consolidation processes that the hippocampus oversees. A balanced diet rich in antioxidants and omega-3 fatty acids may also contribute to a healthy brain environment.
Continuously engaging the mind through learning and mentally challenging activities helps support cognitive function. Pursuing new hobbies, reading, or solving puzzles can stimulate the neural circuits within the hippocampus and other brain regions. Maintaining strong social connections and effectively managing stress are also important for protecting the hippocampus from the negative effects of stress hormones. These practices collectively contribute to cognitive reserve, enhancing the brain’s ability to withstand age-related changes.