How Does the Brain Think Under Stress? 

Edited and published by Wellness Monster Mark

Stress affects memory and emotion. It’s more than us being overloaded and not paying attention. Stress affects how the brain uses information and retains memories. Research over the last few decades has found areas in the mind change during periods of stress.

Research in the Journal of Neuroscience said that changes that happen in the brain when stressed are connected to our emotions and scattered memory. Because of more stress, the mind ignores facts and depends more on emotions.

cortisone 3d
Cortisone molecule

Cortisone, the stress hormone, can undermine our physical, mental, and emotional health. There’s a connection between severe stress and possible mental health disorders such as post-traumatic stress disorder, anxiety, and depression. There may be temporary and permanent changes in the brain because of stress. Stress may cause a chemical change that causes irritability. A French study said when an enzyme is activated by stress, it strikes at a molecule in the hippocampus which controls synapses. When the synapses are changed, there aren’t as many neural connections made. This can make people lose sociability, not engage with friends, and have poor memory or understanding.

Severe stress can make the brain smaller. Traumatic life events can hurt the memory and ability to learn by lessening the gray matter in parts of the brain tied to emotions, self-control, and physiological processes. Severe stress or depression can cause loss of volume in the prefrontal cortex which is linked to emotional and cognitive impairment. The prefrontal cortex develops after the teenage years. People can have a genetic marker that can interrupt the creation of synaptic connections between brain cells. A study in 2008 on mice showed that temporary stress could cause errors in communication in brain cells linked to memory and learning.

A traumatic event can cause brain cells to die. When we learn new things, we create neurons in the hippocampus, the part of the brain linked to learning, memory, and emotion. According to Scientific American, constant stress can stop the creation of new neurons in the hippocampus and may change the speed of connections between hippocampal cells. An animal study proved one traumatic event can harm newly generated neurons in the hippocampus. University of California at Berkley scientists discovered that the severely stressed brain makes more myelin-producing cells and fewer neurons than the average brain would which leads to overabundant myelin (protective coating around neurons) in the hippocampus. The hippocampus is affected by emotional distress because of the negative effects of cortisol, a stress hormone. Cortisol can affect the heart, lungs, circulation, metabolism, immune system, and skin.

stressStress can affect memory by activating the mind’s threat reaction. When cortisol limits the hippocampus’ activity, it enlarges the size and activity of the amygdala, the mind’s center for emotional reactions and motivations. Fight-or-flight reaction, threat detection, and fear processing happen in the amygdala. More action means we’re ready to respond to a perceived threat. This can limit ability to receive new information. Also, it can exaggerate emotional responses. Adrenaline activates the amygdala which causes fear. Neuropeptide S is released and heightens alertness and anxiety.

Stress can affect learning. Severe stress keeps the brain from storing memories. Dendritic spines in the hippocampus deteriorate because of cortisol, and the deterioration impairs the mind’s ability to identify and store information. A large stress response can limit neural pathways in the prefrontal cortex. Self-control, impulse control, memory, and reasoning are limited which is bad for learning. A study at Mount Sinai School of Medicine said dendrites can regrow if stress goes away, but they cannot bounce back after extreme stress. People can have weaker enzymes that are needed to return the brain back to normal after stress.

A study involving baby monkeys tested effects of stress on development and mental health. Half the monkeys were under their peers’ care for six months, and the other half stayed with their mothers. Afterwards, the monkeys went back to their usual environments for several months before scientists scanned their brains. For the monkeys who were taken away from their mothers and stayed with peers, the areas of the brains connected to stress were bigger. This proves stress can affect our brains.

In another study, rats that were exposed to severe stress had hippocampuses that decreased in size. There’s a theory post-traumatic stress disorder can decrease the hippocampus.

stressed-studentThere are stress hormones such as adrenaline, noradrenaline, and cortisol. They are glucocorticoids that help us act during danger. Too many of these hormones can be dangerous. When we are stressed out, we go into cortisol dominance which hurts learning, attention span, and memory.

Cortisol can be dangerous. It can hurt brain cells if there is too much of it. Early age-related memory loss can result. So can depression. Too much cortisol may overtake the good-feeling hormones like serotonin. Too much stress can permanently lower the serotonin levels.

The heartbeat gets stronger as stress increases. The fast heartbeat alerts the brain’s prefrontal cortex which involves thought processing and decision making. This alerts the brain to stop temporarily and have the midbrain take over. This is the “kill or be killed” part of the brain. During this, instinct and training begin, and rational thought and reasoning end.

Stress can eliminate brain chemicals which can lead to a variety of conditions such sleep disturbances, racing thoughts and concentration problems, absent-mindedness, obsessive or compulsive actions, and more worry, guilt, and hostility. Stress can also interfere with logical thinking.

Men and women can have different responses to stress. According to a study, women’s stress hormone receptors are not as flexible as men’s so women may be more at risk of having stress-related conditions such as post-traumatic stress disorder or depression than men.

The body decides if a situation is stressful. This is based on sensory input and processing(what we see and hear), and retained memories(what occurred in past, similar situations). The hypothalamus in the brain regulates stress response. A stress response alerts the pituitary gland and the adrenal medulla. The Hypothalamic Pituitary-Adrenal(HPA) is important. It regulates long-term stress.

Various functions in the brain are activated when stress occurs. This can cause our mental processes to be different and may possibly lead to mental health disorders.


How Stress Can Change the Size of Our Brains and What We Can Do to Lower It

Image Credits:

3d vise and brain, stress concept [ID 66341878 © Dny3dcom |]

Stress [ID 13934686 © Martinmark |]

Young stressed student girl studying and preparing MBA test exam in stress tired and overwhelmed. Overworked, attractive. [ID 50617300 © Ocusfocus |]

Ball-and-stick model of the cortisone molecule. [By Benjah-bmm27 – Own work, Public Domain,]