Stress and Cognition The Neuroscience Behind Stress, Memory & Thinking

Debra S. Austin, PhD, JD

Sixty minutes of thinking of any kind is bound to lead to confusion and unhappiness. ~ James Thurber ~

Areas of the brain involved in learning Neuroscience of memory formationDifference between emotions and feelings Impact of negative emotions on learningSuggestions to maximize cognitive function

Learning about the BrainFirst Illustrated Brain Manual

Cerebri Anatome 1664Modern brain research

Animal Studies Brain Scans

Brain Structure Scanning: X-Ray, CT, MRIBrain Activity Scanning: EEG, fMRI, MEG, PET, DTI

Brain Facts3 lbsSize of a coconutWalnut shapedConsistency of Jell-O or chilled butterEvolved from the top of the spine upRequires

25% of calories consumed20% of oxygen breathed25% of body’s total blood flow

Primitive BrainBrain Stem, Hindbrain, or Reptilian BrainGoverns basic motor functions

Breathing, digestion, heartbeat, sleeping, balance

Key Parts: brain stem, midbrain, cerebellum

Engaged when struggling for survival

Emotional Brain Inner Brain or Limbic SystemManages circadian rhythm, hunger, sex

hormones, addiction, and emotionsKey Parts (in pairs, one in each

hemisphere): amygdala, hippocampus, hypothalamus, thalamus, nucleus accumbens, and ventral tegmental

Engaged when experiencing an emotional response or creating new memories

Thinking Brain

Cerebral Cortex Key Parts

Two hemispheres linked by the corpus callosum Four major lobes

Frontal lobe (language, reasoning, movement) Occipital lobe (vision) Temporal lobe (hearing) Parietal Lobe(taste, temperature, touch)

Outer layer is grey matter - densely-packed neurons Inner layer is white matter

Engaged when using reasoning and logic to conduct higher-order thinking

Brain Cells Neurons Communication nerve cells Shaped like trees Information travels from the

branches (dendrites) down the trunk (axon) and across a tiny gap (synapse)to the next group of dendrites

Chemicals (neurotransmitters) carry the information over the synaptic gap

Electrical-Chemical-Electrical

Over 100 Neurotransmitters Serotonin (mood, anxiety, sleep) Endorphins (reduce pain, increase pleasure) Oxytocin (bonding) Acetylcholine (attentiveness, memory) Glutamate (learning, memory) Dopamine (motivation, pleasure, meaning)

Brainy VocabularyTriune Brain Structure

primitive, emotional & thinking brainsNeuron

tree-shaped brain cell & unit of communicationNeurogenesis

the birth of new brain cells In the Hippocampus & Olefactory Bulbs

Neuroplasticity changes in your brain

Connectome unique system map of neuron data pathways

Your ConnectomeYou are your synapsesYour brain is a work in progressNeurons that fire together wire together

Nondeclarative Memories Cannot be experienced in conscious awareness

Procedural Memories Stored in cerebellum (primitive brain) Skiing, dancing, driving

Fear Memories Stored in amygdala (emotional brain) Flashbacks and phobias

Declarative MemoriesRequire conscious thought to be recalledStored in both emotional and thinking

brainEpisodic Memories - Autobiographical

personal experiences

Semantic Memories - Learned Knowledge: facts, concepts & words

Parts of Brain Involved in Learning Thinking Brain

Frontal Lobe language, reasoning, movement

Occipital Lobevision

Temporal Lobehearing

Parietal Lobetaste, temperature, touch

Emotional Brain Thalamus Amygdala Hippocampus

Laying Down a MemoryConsolidation: a Memory Trace is

converted to Long-Term Memory and becomes stable in the brain

Encoding: processing sensory informationThinking Brain

Information enters via the sensesEmotional Brain

Thalamus focuses attention, screens information, and sends it to the Hippocampus

Amygdala checks information for emotional content

Thinking & Emotional Brain Consolidation Loop

Consolidation During Sleep Information travels a neural loop from

Thinking Brain (sensory lobe of origin) to Emotional Brain (Hippocampus) & repeats

Takes 2-10 years Once memory is fully consolidated, the

Hippocampus lets go of its relationship with the Cortex

Consolidated memories are distributed throughout the Cortex

EmotionAn unconscious and automatic response

to an emotional stimulus that results in physical changes increased heart rate & blood pressure Sweaty palms Blushing

Six Primary Emotions

Fear Anger Sadness

Disgust

Surprise

Joy

FeelingsEmotions are experienced as feelingsFeelings are the conscious perceptions

of emotional responses

Stress Engineering

Amount of resistance a material offers to being reshaped

In Humans Physiological response to stressor that is

measurable by another party Stressor must be perceived as negative Stressed person must feel she has no control

over the stressor Stress involves some combination of 4 of the 6

primary emotions: fear, anger, sadness and/or disgust

Types of Stress Acute Stress

Short-lived Triggers fight or flight response Can be helpful by assisting focus on novel

intellectual challenge or marshaling resources for a significant physical challenge

Chronic Stress Long-lasting Occurs during situations like a troubled intimate

relationship, financial struggles after a job loss, or treatment for a life-threatening illness

Emotional StimulusEndocrine System

Secretion & regulation of hormones in bloodstream

Autonomic SystemMediates physiological changes in body

Skeletal Motor SystemControls behaviors such as freeze, fight,

flight, and facial expressions

Endocrine System Main Stress Hormones: Adrenalin

& Glucocorticoids Major Glucocorticoid is Cortisol

Glucocorticoids tell the Autonomic System to Elevate heart rate & blood

pressure Mobilize energy Slow digestion Suppress immune system

Evolutionary Purpose – quick response to ensure survival

Elevated GlucocorticoidsPhysical

Impaired Immune Response Increased Appetite & Food Cravings Increased Body Fat Increased PMS & Menopause SymptomsDecreased Muscle Mass, Bone Density &

LibidoEmotional

Increased Mood Swings, Irritability & Anger

Increased Anxiety & Depression

Memory Consolidation

Your Brain on Glucocorticoids Suppression of Neurogenesis (birth of new brain

cells) in Hippocampus Damage to Hippocampus can create cycle where

greater amounts of Glucocorticoids are released, producing additional Hippocampal atrophy

Hippocampal Neurodegeneration & Cell Death

Impact of Stress on CognitionDeterioration in memory, concentration,

problem-solving, math performance, language processing, curiosity, creativity, and motivation

Hippocampi shrink in sizeDepressionPost-Traumatic Stress DisorderRepeated exposure to jet lag

Reverse Hippocampal DamageIncrease Neurogenesis

ExerciseHealthful SleepAntidepressants

ExerciseEnhances blood and oxygen flowStimulates production of Brain Derived

Neurotropic Factor (BDNF)30 minutes of aerobic exercise 2 to 3

times per week + strength training for maximum cognitive benefit

Increased Blood Flow Improves blood flow deeper into body

tissuesEnhances distribution of food and

elimination of waste Increases blood volume in HippocampusMaintains health and functioning of

Hippocampus

BDNF Protein that helps

Create new neurons Protect existing neurons Encourage synapses formation

BDNF production enhanced by Exercise Calorie Reduction Intellectual Stimulation Curcumin (active ingredient in spice Turmeric) Omega-3 Fat DHA

Sleep 90 Minutes to 2 Hours to Stage 5 REM Sleep Hippocampus & Amygdala very active during REM Communication between neurons at rate equal to or higher

than when awake Memory consolidation genes activated during REM, which

helps formation of new neural connections

Sleep Research Subjects awakened during REM lost ability to learn

new information Loss of 1 night of sleep = 30% cognitive decline Loss of 2 nights of sleep = 60% cognitive decline Less than 6 hours of sleep for 5 nights in a row =

60% cognitive decline Sleep Deprivation

Diminishes attention, working memory, executive function, quantitative skills, logical reasoning ability, mood, and fine & gross motor control

Accelerates Aging Process Impairs ability to use fuel/food creating risk of

diabetes and obesity

Circadian Rhythm Arousal System

Neurons, hormones & chemicals keep body awake Sleep Drive

Neurons, hormones & chemicals put body to sleep Larks (Early Chronotypes)

10% of population Productive early in day & want to sleep about 9pm

Owls (Late Chronotypes) 20% of population Productive late in day & may want to retire at 3am

Hummingbirds 70% in middle of the spectrum

Siesta Time Arousal System & Sleep Drive flat-line in the

afternoon Causes a desire to nap Naps improve cognition

26-minute nap improved NASA pilot performance by 34%

45-minute nap improved cognition for at least 6 hours

Antidepressants Increase the rate of neurogenesis Includes SSRIs (selective serotonin uptake

inhibitors)

Maximize Cognitive Function Commit to and perform regular exercise Make regular and adequate sleep a priority If treated with antidepressants, continue

treatment

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