The amygdala is the neurological 'hub' of human emotion

For centuries, scientists believed that we were born with all the nerve cells we would need during our lifetimes, and that the gradual death of these nerve cells over time was responsible for the classic mental symptoms of aging—loss of memory, dementia, and difficulty learning new things. But beginning in the 1960s, researchers started to find evidence that new nerve cells were born in the brains of adult rats, and later in adult monkeys. Finally, in 1998, Fred Gage, a neuroscientist at The Salk Institute for Biological Studies, demonstrated that the human brain was also capable of generating new nerve cells after birth. Hippocampus Located deep inside the brain, this area serves as the hub for making and storing memories. It’s the only region of the human brain that can grow new nerve cells, even in adults. Entorhinal Cortex The entorhinal cortex acts as a gateway between the hippocampus and the rest of the cortex Amygdala Located in front of the hippocampus, the amygdala is your emotional nexus. Intimately connected to your senses, nerve cells in this region are primed to generate fear, anxiety and anger. This type of information can often be the most powerful part of a memory. Because of its role in regulating emotions, the amygdala is emerging as an important player in addiction biology. Just as it layers potent emotional information onto memories, making them potentially more salient, the amygdala may also reinforce the pleasurable feelings of addictive drugs, leading users to seek out those blissful states again and again. Cerebellum We can’t actively think about everything that we do in a day, such as coordinating movement—that’s the job of the cerebellum. Nestled toward the back of the brain, this region is responsible for our balance and fine motor control, as well as overseeing some our more routine movements, such as walking. We don’t have to think about putting one foot in front of the other—we just do. Frontal Lobe Activity in this area is responsible for many of the higher level activities that distinguish us as human—such as thought, planning and decision-making, as well as more complex experiences such as regret and morality. Parietal Lobe This region processes incoming information from our five senses, and helps us to orient ourselves in space and coordinate movement. Sensory information is a critical part of memories. Temporal Lobe Nerve cells in this are busy processing auditory information from the environment and helping to develop language skills. They coordinate the translation of sounds into words that have meaning for us. Occipital Lobe This area is the visual processing center of our brain.

A woman is shown with an angry, intense facial expression. Part of her brain anatomy is visible, highlighting the amygdala, which is the brain's processor for emotions. Sleep-deprived people have more activity in the amygdala, corresponding to feelings of stress and depression.

The limbic system is composed of structures within and below the cortex, such as the hypothalamus, amygdala, hippocampus, and cingulate gyrus. It deals with the interpretation of emotions, motivation, the process of learning, and the storage and retrieval of memory.

Creating memories is one of the brain's most remarkable functions. By relying on an intricate network of connected nerves in different parts of the brain, we can record an experience, store it like a biological file stuffed with emotions and sensory legacies and then recall it at will. The amygdala is your emotional nexus. Intimately connected to your senses, nerves in this region are primed to generate fear, anxiety and anger.

The limbic system regulates emotion and other behaviors. It includes parts of the cerebral cortex located near the center of the brain, including the cingulate gyrus and the hippocampus as well as the thalamus, hypothalamus and amygdala.

The anatomy of the basolateral complex and central nucleus of the amygdala are illustrated in this diagram.

Imagine the world as a swirling mass of information—to grab hold of something elusive, you need to focus your attention on it, concentrate and make an effort to capture it. Your brain then takes several steps in order to form lasting memories.Attention, Sensory Perception, and Emotional Stimulation Various nerve cells in different parts of the brain are activated in a specific circuit that combines all sorts of incoming information, from sensory perceptions of smell, sound and sight to emotional ones generated by the amygdala. Short Term Memory These impressions last only up to 30 seconds, and won’t be retained unless you make a conscious effort to hold on to them. Without such targeted attention, they can easily be replaced by other impressions. In most cases, the amount of information available in short term memory is also limited; the average person can retain about four pieces of information at a time, or the equivalent of the seven digits in a phone number. Consolidation While you sleep, your hippocampus and amygdala are still active, busily transferring what you’ve experienced while you were awake to other parts of the brain that regulate higher level thought. Long Term Memory Once these cognitive areas of the brain are involved, the information becomes like a dossier, annotated with all the relevant information that came with the experience, from sensory details to location and emotional ones. Access and Re-storage Every time you pull up a memory, this dossier is altered slightly, by the time and place in which it was recalled. So a memory gets altered slightly every time it’s accessed and replaced. A Memory at Work A memory is more of a process than a biological thing; and depending on the sensory or emotional information available at the time a memory is generated, a single memory can range across different parts of the brain. Making a Memory Last All of us can recall events or experiences that are months, even years old. Yet those memories aren’t dependent on the proper nerve cell circuits firing constantly to keep that recall alive. So researchers have proposed a process called long term potentiation (LTP) that may be responsible for reinforcing certain patterns of nerve cell activity that might be critical for forming long term memories. How Long Term Potentiation Works First Stimulus This is the triggering event for a memory; it could be incoming information generated by sensory nerve cells in the eyes, ears, nose, tongue or skin. Triggering a Response Chemical changes in nerve cells register the event. But in LTP, the initial stimulus is enhanced by the constant firing or activation of several nerve cells at the same time. This boost in the signal amplitude can last for weeks, and results in changes in the way the chemicals that communicate between nerve cells work. Strengthening the Pattern The changes in chemical activity result in alterations in the structure of the nerve cell endings, and these modifications can lead to the formation of new ways for nerve cells to talk to one another. These alternative pathways could now form the basis for circuits that can remain active for longer periods of time, reinforcing memories.

The anatomy of the basolateral complex and central nucleus of the amygdala are illustrated in this diagram.

The amygdala is the neurological 'hub' of human emotion