Does stress affect your memory? - Elizabeth Cox — Transcript

Full transcript

1. 0:08You spend weeks studying for an important test.
2. 0:10On the big day, you wait nervously as your teacher hands it out.
3. 0:14You’re working your way through, when you’re asked to define ‘ataraxia.’
4. 0:18You know you’ve seen it before, but your mind goes blank.
5. 0:21What just happened?
6. 0:23The answer lies in the complex relationship
7. 0:25between stress and memory.
8. 0:27There are many types and degrees of stress
9. 0:29and different kinds of memory,
10. 0:30but we’re going to focus on how short-term stress
11. 0:32impacts your memory for facts.
12. 0:35To start, it helps to understand how this kind of memory works.
13. 0:39Facts you read, hear, or study
14. 0:41become memories through a process with three main steps.
15. 0:45First comes acquisition:
16. 0:46the moment you encounter a new piece of information.
17. 0:49Each sensory experience activates a unique set of brain areas.
18. 0:53In order to become lasting memories,
19. 0:55these sensory experiences
20. 0:57have to be consolidated by the hippocampus,
21. 0:59influenced by the amygdala,
22. 1:00which emphasizes experiences associated with strong emotions.
23. 1:05The hippocampus then encodes memories,
24. 1:07probably by strengthening the synaptic connections
25. 1:10stimulated during the original sensory experience.
26. 1:13Once a memory has been encoded,
27. 1:15it can be remembered, or retrieved, later.
28. 1:17Memories are stored all over the brain,
29. 1:19and it’s likely the prefrontal cortex that signals for their retrieval.
30. 1:24So how does stress affect each of these stages?
31. 1:27In the first two stages,
32. 1:28moderate stress can actually help experiences enter your memory.
33. 1:32Your brain responds to stressful stimuli
34. 1:34by releasing hormones known as corticosteroids,
35. 1:38which activate a process of threat-detection
36. 1:40and threat-response in the amygdala.
37. 1:43The amygdala prompts your hippocampus
38. 1:45to consolidate the stress-inducing experience into a memory.
39. 1:48Meanwhile, the flood of corticosteroids from stress
40. 1:52stimulates your hippocampus,
41. 1:54also prompting memory consolidation.
42. 1:56But even though some stress can be helpful,
43. 1:58extreme and chronic stress can have the opposite effect.
44. 2:02Researchers have tested this by injecting rats directly with stress hormones.
45. 2:06As they gradually increased the dose of corticosteroids,
46. 2:10the rats’ performance on memory tests increased at first,
47. 2:13but dropped off at higher doses.
48. 2:15In humans, we see a similar positive effect with moderate stress.
49. 2:20But that only appears when the stress is related to the memory task—
50. 2:24so while time pressure might help you memorize a list,
51. 2:27having a friend scare you will not.
52. 2:29And the weeks, months, or even years
53. 2:31of sustained corticosteroids that result from chronic stress
54. 2:35can damage the hippocampus
55. 2:37and decrease your ability to form new memories.
56. 2:41It would be nice if some stress also helped us remember facts,
57. 2:44but unfortunately, the opposite is true.
58. 2:47The act of remembering relies on the prefrontal cortex,
59. 2:50which governs thought, attention, and reasoning.
60. 2:53When corticosteroids stimulate the amygdala,
61. 2:56the amygdala inhibits, or lessens the activity of,
62. 2:59the prefrontal cortex.
63. 3:01The reason for this inhibition is so the fight/flight/freeze response
64. 3:05can overrule slower, more reasoned thought in a dangerous situation.
65. 3:10But that can also have the unfortunate effect
66. 3:12of making your mind go blank during a test.
67. 3:15And then the act of trying to remember can itself be a stressor,
68. 3:19leading to a vicious cycle of more corticosteroid release
69. 3:22and an even smaller chance of remembering.
70. 3:25So what can you do to turn stress to your advantage
71. 3:28and stay calm and collected when it matters the most?
72. 3:31First, if you know a stressful situation like a test is coming,
73. 3:35try preparing in conditions similar to the stressful environment.
74. 3:38Novelty can be a stressor.
75. 3:40Completing practice questions under time pressure,
76. 3:43or seated at a desk rather than on a couch,
77. 3:45can make your stress response to these circumstances
78. 3:48less sensitive during the test itself.
79. 3:50Exercise is another useful tool.
80. 3:52Increasing your heart and breathing rate
81. 3:55is linked to chemical changes in your brain
82. 3:57that help reduce anxiety and increase your sense of well-being.
83. 4:00Regular exercise is also widely thought to improve sleeping patterns,
84. 4:04which comes in handy the night before a test.
85. 4:06And on the actual test day,
86. 4:08try taking deep breaths to counteract your body’s flight/fight/freeze response.
87. 4:12Deep breathing exercises have shown measurable reduction in test anxiety
88. 4:17in groups ranging from third graders to nursing students.
89. 4:21So the next time you find your mind going blank at a critical moment,
90. 4:24take a few deep breaths until you remember ataraxia:
91. 4:27a state of calmness, free from anxiety.