Amygdala function

hippocampus, region of the hippocampus is hippokampus ( hippos, meaning “horse,” and kampos, meaning “sea monster”), since the structure’s shape resembles that of a Anatomy of the hippocampus The anatomy of the hippocampus is of chief importance to its function. The hippocampus receives input from and sends output to the rest of the brain via a structure known as the entorhinal cortex, which is located beneath the Principal neural circuits The subregions of the hippocampus are connected by two principal neural circuits: the trisynaptic circuit and the monosynaptic circuit. The trisynaptic circuit forwards information from the entorhinal cortex to the dentate gyrus via the perforant path, which perforates through the subiculum. Information then flows from the dentate gyrus to CA3 via the mossy fibre pathway (so named for the extensive branching of its Morphological distinctions The CA fields contain three layers (in contrast to the rest of the brain’s six-layered cortex) and use pyramidal cells (neurons with dendrites that spread to give the cell body a triangular appearance) as the principal excitatory cells. The CA3 region of the hippocampus contains a large excitatory recurrent The Human Brain The dentate gyrus is morphologically distinct from CA fields and contains densely packed granule cells (neurons with relatively small cell bodies). The dentate gyrus is also one of only two regions in the brain known to house Sources of input The hippocampus receives input from mod...

The amygdalae, a pair of small almond-shaped regions deep in the brain, help regulate emotion and encode memories—especially when it comes to more emotional remembrances. Now, new research from Emory University suggests that direct stimulation of the amygdala via The amygdala and memory The amygdala may be best known as the part of the brain that drives the so-called “fight or flight” response. While it is often associated with the body’s fear and stress responses, it also plays a pivotal role in memory. “One role we are very familiar with, when it comes to the amygdala and memory, is that of emotional salience,” says Jon T. Willie, M.D., Ph.D., neurosurgeon and director of the laboratory for behavioral neuromodulation at Emory University in Atlanta. “If you have an emotional experience, the amygdala seems to tag that memory in such a way so that it is better remembered.” The pioneering work of James McGaugh, a neuroscientist at University of California Irvine and member of the Dana Alliance for Brain Initiatives, has shown, time and time again, that strong emotions help humans and other animals acquire and retain lasting memories—and that the amygdala helps modulate that effect. This makes sense from an evolutionary perspective: The amygdala is often thought of as being a sort of survival-oriented brain area. Things that have strong emotions associated with them, good and bad, are likely to be the things that allow a species to not only stay alive, but also thrive in its ...

Share on Pinterest SCIENCE PHOTO LIBRARY/Getty Images We’ve all had that moment where we look back and think “Why in the world did I do that?” Amygdala hijack may happen when strong emotions, such as anger, fear, or even extreme excitement, make it difficult or impossible to think straight. This mechanism can cause you to act in ways you later regret. Have you ever experienced road rage? Or quit your job in the heat of the moment? That’s the amygdala hijack. The amygdala is a collection of nuclei located deep in a part of the brain known as the temporal lobe. The term is Latin for “almond,” referring to the almond-like shape of the amygdala’s most prominent section. While we often refer to it in the singular (amygdala), we actually have two amygdalae — one in each cerebral hemisphere. The amygdala is part of the limbic system, a set of brain structures that help regulate our behavioral and emotional responses. And though it’s probably best known for its role in the The amygdala is involved in the following functions: • detecting threats • triggering a body response (e.g., pulling your hand off a hot stove) • fear conditioning (e.g., being afraid to drive after getting in a car accident) • processing positive emotions • encoding emotional memories The “amygdala hijack” is a term coined by psychologist Daniel Goleman in his 1995 book “ Essentially, the rational brain is bypassed and signals are sent straight to the “emotional brain.” Later, the thinking part of your brain pr...

What Can Damage the Amygdala? While our skull protects our brain from damage, the amygdala is not immune from both internal and external damage. Dr. Lakhan shares, “The amygdala can be damaged by stroke, infections like the Herpes Simplex Virus, neurodegenerative diseases like Alzheimer’s, and brain tumors.” You can also sustain a concussion or For example, if you experience a stroke, the brain can reorganize itself and rearrange neural pathways to compensate and allow functioning despite the damage. What Happens When the Amygdala Is Activated? The amygdala becomes triggered (or activated) in response to perceived threats in order to keep you safe by activating After the threat is gone, or after you realize that there was no threat to begin with, the amygdala is meant to power back down with the help of your frontal lobe. Dr. Lakhan says, “There are mechanisms to dampen this response so that you are not in a constant state of anxiety. The frontal part of your brain actually puts the brakes on the amygdala and says basically, there are no more pressing things.” However, for some, the frontal lobe does not effectively shut down the amygdala’s triggered state. As noted previously, this can occur following trauma. If you live in a chronically stressful or traumatic state, the amygdala may remain activated long-term out of necessity. When you must always be on alert for danger, the amygdala can switch on and not switch off in an effort to ensure your survival. While this can ke...

The limbic system is a group of interconnected structures located deep within the brain. It’s the part of the brain that’s responsible for behavioral and emotional responses. Scientists haven’t reached an agreement about the full list of structures that make up the limbic system, but the following structures are generally accepted as part of the group: • Hypothalamus. In addition to controlling emotional responses, the • Hippocampus. The • Amygdala. The • Limbic cortex. This part contains two structures, the cingulate gyrus and the parahippocampal gyrus. Together, they impact mood, motivation, and judgement. From a biological standpoint, fear is a very important emotion. It helps you respond appropriately to threatening situations that could harm you. This response is generated by stimulation of the amygdala, followed by the hypothalamus. This is why some people with brain damage affecting their amygdala don’t always respond appropriately to dangerous scenarios. When the amygdala stimulates the hypothalamus, it initiates the fight-or-flight response. The hypothalamus sends signals to the adrenal glands to produce hormones, such as As these hormones enter the bloodstream, you might notice some physical changes, such as an increase in: • heart rate • breathing rate • blood sugar • perspiration In addition to initiating the fight-or-flight response, the amygdala also plays a role in fear learning. This refers to the process by which you develop an association between certain ...

What Is PTSD? PTSD is a mental health condition that can develop in response to a trauma that may have occurred recently or in the distant past. Generally, the trauma would involve some sense of threat to life or threat of bodily harm affecting either you or a loved one. Core symptoms of PTSD include some type of re-experiencing (e.g., nightmares, flashbacks, or emotional flooding), attempts to avoid reminders of the event or associated emotions, hyper-arousal (e.g., feeling constantly on edge), and distressing thoughts or emotional reactions. These symptoms need to last for at least two weeks and interfere with functioning or cause significant distress. What Brain Areas are Implicated in PTSD? PTSD symptoms develop due to dysfunction in two key regions: The Amygdala This is a small almond-shaped structure located deep in the middle of the temporal lobe. The amygdala is designed to: • Detect threats in • Activate the sympathetic • Help you store new emotional or threat-related memories The Prefrontal Cortex (PFC) The Prefrontal Cortex is located in the frontal lobe just behind your forehead. The PFC is designed to: • Regulate attention and awareness • Make decisions about the best response to a situation • Initiate conscious, voluntary behavior • Determine the meaning and emotional significance of events • Regulate emotions • Inhibit or correct dysfunctional reactions When your brain detects a threat, the amygdala initiates a quick, automatic defensive (“fight or flight”) ...