Final Review Flashcards
Sound wave
Undulating displacement of molecules caused by changing pressure
Frequency
Number of cycles that a wave completes in a given amount of time
Measured in hertz (Hz), or cycles per second
Corresponds to our perception of pitch
Low pitch, low frequency (fewer cycles/second)
High pitch, high frequency (many cycles/second)
Differences in frequency are heard as differences in pitch
Amplitude
The intensity, or loudness, of a sound, usually measured in decibels (dB)
The magnitude of change in air molecule density
Corresponds to our perception of loudness
Soft sound, low amplitude
Loud sound, high amplitude
Complexity
Pure tones - Sounds with a single frequency
Complex tones - Sounds with a mixture of frequencies
Fundamental frequency - The rate at which the complex waveform pattern repeats
Overtones - Set of higher frequency sound waves that vibrate at whole number (integer) multiples of the fundamental frequency
Hearing for Humans
- 20 to 20,000 Hz (young adults)
- Prolonged exposure to sounds louder than 100 decibels is likely to damage human hearing
Auditory System
Ear collects sound waves from surrounding air
Converts mechanical energy to electrochemical neural energy
Routed through the brainstem to the auditory cortex
Outer Ear
Pinna
External ear canal
Tympanic membrane
Pinna
Funnel-like external structure designed to catch sound waves in the surrounding environment and deflect them into the ear canal
External ear canal
Amplifies sound waves somewhat and directs them to the eardrum
Tympanic membrane
Aka ear drum
Vibrates based on frequency of sound waves
Connects to middle ear
Middle Ear
Air-filled chamber that comprises the ossicles
Ossicles - Bones in the middle ear - Hammer (Malleus), Anvil (Incus), Stirrup (Stapes)
Connects the eardrum to the oval window of the cochlea, located in the inner ear
Inner Ear
Cochlea Organ of Corti Basilar membrane Hair cells Tectorial membrane
Cochlea
Fluid-filled inner ear structure that contains the auditory receptor cells
Organ of Corti
Receptor cells and the cells that support them
Basilar membrane
Receptor surface in the cochlea that transduces sound waves to neural activity
Hair cells
Sensory neurons in the cochlea tipped by cilia
When stimulated by waves in the cochlear fluid, outer hair cells generate graded potentials in inner hair cells, which act as the auditory receptor cells
Tectorial membrane
Membrane overlying hair cells
Auditory Receptors
Transduction of sound waves to neural activity takes place in the hair cells
(3500 inner hair cells (auditory receptors)
12,000 outer hair cells (alter stiffness of tectorial membrane))
Broca’s area
Anterior speech area in the left hemisphere that functions with the motor cortex to produce the movements needed for speaking
Wernicke’s area
Posterior speech area at the rear of the left temporal lobe that regulates language comprehension
Also called the posterior speech zone
Aphasia
Inability to speak or comprehend language despite having normal comprehension or intact vocal mechanisms
Mapping by brain stimulation
- Auditory cortex: patients often reported hearing various sounds (e.g., ringing that sounded like a doorbell, a buzzing noise, birds chirping)
- A1: produced simple tones (e.g., ringing sounds)
- Wernicke’s area: apt to cause some interpretation of a sound (e.g., buzzing sound to a familiar source such as a cricket)
Disrupting speech
Supplementary speech area on the dorsal surface of the frontal lobes stopped ongoing speech completely (speech arrest)
Eliciting speech
Stimulation of the facial areas in the motor cortex and the somatosensory cortex produces some vocalization related to movements of the mouth and tongue
Using fMRI
Simple auditory stimulation, such as bursts of noise, analyzed by area A1
More complex auditory stimulation, such as speech syllables, analyzed in adjacent secondary auditory areas
Lateralization
Process whereby functions become localized primarily on one side of the brain
Analysis of speech takes place largely in the left hemisphere
Analysis of musical sounds takes place largely in the right hemisphere
How is music different than language/speaking
Infants show learning preferences for musical scales versus random notes
Children and adults are very sensitive to musical errors: biased toward perceiving regularity in rhythms?
Sensitive Period for Language
There is likely a sensitive period for language acquisition that runs from about 1 to 6 years of age
Properties of Music
- Loudness, or amplitude, of a sound wave: subjective
- Pitch: position of each tone on a musical scale
- Fundamental frequency
- Quality: The timbre of a sound, regardless of pitch
Music Processing
Music processing is largely a right-hemisphere specialization
The left hemisphere plays some role in certain aspects of music processing, such as those involved in making music
Recognizing written music, playing instruments, and composing
Music as Therapy
Parkinson’s: Listening to rhythm activates the motor and premotor cortex and can improve gait and arm training after stroke
Parkinson patients who step to the beat of music can improve their gait length and walking speed
-Also effective for mood disorders (depression)
Tonotopic representation
Hair cell cilia at the base of the cochlea are maximally displaced by high-frequency waves that we hear as high pitched sounds
Hair cell cilia at the apex are displaced the most by low frequency waves that we hear as low-pitched sounds
Each hair cell is maximally responsive to a particular frequency and also responds to nearby frequencies
How do we hear different amplitudes?
The greater the amplitude of the incoming sound waves, the higher the firing rate of bipolar cells in the cochlea
More intense sound waves trigger more intense movements of the basilar membrane, causing more shearing action of the hair cells, which leads to more neurotransmitter release onto bipolar cells
Interaural Time differences (ITD)
Estimate the location of a sound both by taking cues derived from one ear and by comparing cues received at both ears
Each cochlear nerve synapses on both sides of the brain to locate a sound source
Neurons in the brainstem compute the difference in a sound wave’s arrival time at each ear
Interaural Intensity Differences (IID)
Another mechanism for source detection is relative loudness on the left and the right
Head acts as an obstacle (sound shadow) to higher frequency sound waves, which do not easily bend around it
As a result, higher-frequency waves on one side of the head are louder than on the other
Echolocation
Ability to identify and locate an object by bouncing sound waves off it
Locate targets and analyze features of the target and the environment
Analysis of the differences in return times of echoes is key
Echoes differ with respect to an object’s distance and texture
Echolocation in humans
Compared brain activity (using fMRI) between controls and blind ‘echolocation experts’
Specifically in response to the sound of echoes
Motivation
Behavior that seems purposeful and goal directed
Types of motivated behaviours
Regulatory
-Things that keep us alive
-Eating, drinking, temperature, waste elimination, salt balance
Nonregulatory
-Sexual behaviour, parenting, aggression, curiosity, reading/studying
Chemosignals
(chemical signals) play a central role in motivated and emotional behavior
-Identify group members
-Mark territories
-Identify favorite and forbidden foods
-Form associations among odors, tastes, and emotional events
Olfaction and Gustation
Olfaction
Scent interacts with chemical receptors in the olfactory epithelium: receptor surface for olfaction
Each olfactory receptor cell sends a process ending in 10 to 20 cilia into a mucous layer, the olfactory mucosa
Metabotropic activation of a specific G protein leads to an opening of sodium channels and a change in membrane potential
Olfactory Pathway(s)
Receptor cells project to olfactory bulb
Many olfactory targets (amygdala and pyriform cortex) bypass the thalamus
Thalamic connection does project to the orbitofrontal cortex - Emotional, social, and eating behaviors
-Body odours activate brain regions involved in emotional processing
-A stranger’s odour activates the amygdala and insular cortex
Gustation
Sweet, sour, salty, bitter, umami
Especially sensitive to glutamate
Taste receptors are grouped into taste buds
Gustatory stimuli interact with the receptor tips, or microvilli - Ion channels open, leading to changes in membrane potential
Gustatory Pathway(s)
Cranial nerves 7, 9, and 10 form the main gustatory nerve, the solitary tract
-Gustatory region in the insula is dedicated to taste
-Primary somatosensory region is responsive to tactile information (localizing tastes and textures on tongue)
Gustatory nerve to orbital cortex: mixture of olfactory and gustatory input gives rise to perception of flavor
Hypothalamus
Receives inputs from the frontal lobes and limbic system
Influences behaviors selected by the limbic system
Sends its axons to control brainstem circuits that produce motivated behaviors
Maintains homeostasis by acting on both the endocrine system and the autonomic nervous system
Controls an amazing variety of motivated behaviors ranging from heart rate to feeding and sexual activity
Steroid hormone
Fat-soluble chemical messenger synthesized from cholesterol
Examples: gonadal (sex) hormones
Peptide/protein hormone
Chemical messenger synthesized by cellular DNA that acts to affect the target cell’s physiology
Examples: insulin, growth hormone
Amine hormones
Small, simple, modified amino acid
Examples: thyroid hormones, NE, Epi, melatonin
Homeostatic hormones
Maintain internal metabolic balance and regulation of physiological systems
Gonadal (sex) hormones
Control reproductive functions, sexual development, and behavior
Glucocorticoids
Secreted in times of stress; important in protein and carbohydrate metabolism
Hypothalamus
Produces neurohormones to stimulate the pituitary gland
Posterior pituitary
Hypothalamus makes peptides (e.g., oxytocin) that are transported down axons to terminals in the posterior pituitary
Capillaries in the posterior pituitary’s vascular bed pick up these peptides
Peptides then enter the bloodstream, which carries them to distant targets
EX. Oxytocin - social/emotional behavior
Neural tissue
Anterior pituitary
Hypothalamus controls the release of anterior pituitary hormones by producing releasing hormones
Releasing hormones
Peptides released by the hypothalamus to increase or decrease the release of hormones from the anterior pituitary
Glandular tissue
Pituitary gland
Secretes releasing hormones to influence target endocrine glands
Target endocrine glands
Release appropriate hormones into the blood to act on target organs and tissues
Feedback loops
Control the amount of hormone released
Hormones influence the hypothalamus to decrease secretion of releasing hormones
Neural regulation
Other brain regions (e.g., limbic system and frontal lobes) influence hormone release
Excitatory and inhibitory influences exerted by cognitive activity can influence hypothalamic neurons
Experiential responses
Experience can alter the structure and function of hypothalamic neurons
Electrical Stimulation of Hypothalamus
Eating and drinking Digging Displaying fear Predatory or attack behavior Reproductive behavior
Eating Behaviour - Hypothalamus
receives input from the enteric nervous system (such as information about blood glucose levels)
Hormone systems (such as information about the level of appetite-diminishing CCK)
Parts of the brain that process cognitive factors
Eating Behaviour - Amygdala
Damage alters food preferences and abolishes taste aversion learning
Eating Behaviour - Orbital prefrontal cortex
Receives input from the olfactory bulb
Damage may result in decreased eating because of diminished sensory responses to food odor and perhaps taste
Hedonic
refers to many types of pleasure
Anhedonia
refers to the lack of pleasure
May be due to dysfunction in the reward system
Reward
Learning (associations between cues and rewarding stimuli)
Motivation for the reward and the cues that predict them (Wanting, incentive)
Affective (hedonic) responses (Liking or evaluation of pleasure)
Robinson and Berridge
Wanting and liking have separable neural systems
A rat with damage to the dopamine pathway to the forebrain doesn’t eat, But spraying a food solution into its mouth produces facial expressions indicative of liking, It has no desire to eat (no wanting) but still finds food pleasurable (liking)
A rat with a self-stimulation electrode in the lateral hypothalamus will often eat heartily while the stimulation is on, During stimulation, rats react more aversively to tastes such as sugar and salt than when stimulation is off, The stimulation increases wanting but not liking
Wanting
Dopamine projections to the prefrontal cortex and striatum predominantly
Widespread
Liking
Hedonic “hotspots”
Seem to use opioids and endocannabinoids
Mesolimbic dopamine system
Ventral tegmental area (midbrain) to nucleus accumbens
Dopamine release rises markedly when animals are engaged in intracranial self-stimulation
Amount of dopamine released somehow determines how rewarding an event is
(Neuro)psychopharmacology
the study of how drugs affect the nervous system and behaviour
Drugs
Chemical compounds administered to produce a desired change
Psychoactive drugs
substances that act to alter mood, thought, or behaviour
- Management of neuropsychological illness
- Recreational use
- Potential for abuse
Zoopharmacognosy
Behavior in which nonhuman animals self-medicate
Barriers to Drugs
Cell membranes
Capillary walls
The placenta
The blood–brain barrier
The blood–brain barrier
Prevents most substances, including drugs, from entering the brain via the bloodstream
Endothelial cells in capillaries throughout the body are not tightly joined; it’s easy for substances to move into and out of the bloodstream
Endothelial cell walls in the brain are fused to form tight junctions, so most substances cannot squeeze between them
Areas not protected by blood-brain barrier
Pineal gland
Pituitary gland
Area postrema
Approximately 98% of substances that may alter brain function cannot cross the BBB
Dose
Drugs bind to receptors with different strengths
- Binding affinity (low = weak; high = strong)
Some drugs bind to multiple receptor types but with different affinities
Higher doses of drug leads to more receptors being activated
Drug molecules can activate receptors to different degrees
- Efficacy (low/no = doesn’t activate; high = fully activate)
Dose-response curves
Tell us the relationship between the dose and the effects of the drug
Can tell us how ‘safe’ the drug is
- ED50 = effective dose for 50%
- LD50 = lethal dose for 50%
- Therapeutic index = distance between ED50 and LD50
Where do drugs act in the brain
Synthesis of neurotransmitter Storage of neurotransmitter in vesicles Release from the presynaptic cell Interaction with the receptor Inactivation of excess neurotransmitter Reuptake into presynaptic cell Degradation of excess neurotransmitter
Agonists
Drugs that enhance the function of a synapse
Can also have partial agonists
Antagonists
Drugs that block the function of a synapse
Removal of Drugs
Drugs are catabolized (broken down) through a myriad of mechanisms: - Liver – cytochrome P450 enzymes - Kidneys - Intestines, etc. Excretion may occur via: - Urine - Feces - Sweat - Exhalation - Breast milk
Tolerance
A decrease in response to a drug with the passage of time
Typically a result of repeated, regular use of a drug
Robinson and Becker study (1986)
Rats were given periodic injections of the same dose of amphetamine
Number of times the animal reared (stood up on its back legs) was counted
Increased rearing developed with the periodic injections
How tolerance and sensitization occur
Increase in the amount of neurotransmitter released
Increase in the number of receptors present on the postsynaptic membrane
Decrease in the rate of transmitter metabolism/reuptake
Changes in the number of synapses
Metabolic tolerance
The number of enzymes that breaks down alcohol increases
Cellular (functional) tolerance
Neurons adjust to minimize the effects of alcohol
Adding or removing receptors in the postsynaptic membrane
Learned tolerance
You learn how to cope with daily living while under the influence
- Cross-tolerance
Cross-tolerance
The tolerance for one drug is carried over to another
Common for drugs that act on the same receptor type
Sensitization
Increased responsiveness to successive equal doses of a drug
More likely to occur as a result of occasional use of a drug
Before a person becomes dependent on or addicted to a drug, he or she must be sensitized by numerous experiences with the drug away from the home environment
Psychedelics
- Act on serotonin
- Alters sensory perception and produces peculiar experiences
- Clinical trials in humans have shown high doses reduces depression ratings in patients with treatment-resistant depression
Cannabis
- Interacts with the cannabinoid 1 (CB1) receptor found on neurons
- Reduces anxiety, enhances forgetting, reduces nausea and vomiting in cancer patients, stimulates appetite, treats chronic pain
- Regular use of cannabis has been associated with changes in brain structure (reward system) and function (cognitive impairments)
- Heavy use of cannabis has been associated with increased risk for schizophrenia
Anti-psychotics
Acts on dopamine
Used to treat symptoms
- Positive: hallucinations, delusions, bizarre behaviour
- Negative: emotional dysregulation, impaired motivation
- Cognitive: memory and attentional problems, difficulty making decisions and plans
Dopamine hypothesis of schizophrenia
Holds that some forms of the disease may be related to excessive dopamine activity—especially in the frontal lobes
First-generation antipsychotics
- Preferentially bind to D2 receptors
- Work well for relieving the positive symptoms
Second-generation antipsychotics
- Have dopamine and non-dopamine targets
- Trying to target the negative symptoms
Stimulants
Stimulant: any drug that increases the activity of the nervous system
Produce alertness
Include: caffeine, nicotine, cocaine, amphetamine, others
Caffeine
Binds to adenosine receptors without activating them
Also inhibits an enzyme that ordinarily breaks down the second messenger, cyclic adenosine monophosphate (cAMP); the resulting increase in cAMP leads to increased glucose production, making more energy available and allowing higher rates of cellular activity
Nicotine
At low doses, it’s a stimulant, but at very high doses, it dampens neuronal activity
Stimulates acetylcholine nicotinic receptors
Indirectly causes the release of acetylcholine and several other neurotransmitters, including dopamine
Potentially lethal poison, but tolerance develops rapidly
Amphetamine
Increases dopamine in the synaptic cleft by reversing the dopamine transporter
Amphetamine (Adderall) and methylphenidate (Ritalin) are medically prescribed to treat ADHD
A widely used illegal amphetamine derivative is methamphetamine
Substance abuse
A pattern of drug use in which people rely on a drug chronically and excessively, allowing it to occupy a central place in their life
Addiction
A complex brain disorder characterized by escalation, compulsive drug taking, and relapse; called substance use disorder per the DSM-5
Frequent use
Leading to physical dependence and abuse
Often associated with tolerance
Withdrawal symptoms
Physical dependence
Physically dependent on the drug to function
When drug use stops, withdrawal symptoms start
Withdrawal symptoms
Physical and psychological behavior displayed by an addict when drug use ends
Withdrawal effects are usually opposite to the drug effects
Examples: muscle aches and cramps, anxiety attacks, sweating, nausea, convulsions, death
Psychomotor activation
Increased behavioral and cognitive activity so that at certain levels of consumption, the drug user feels energetic and in control
- Stimulants
- Opioids
- Sedative hypnotics
Adverse childhood experiences
Environmental factors, called adverse childhood experiences (ACEs), are associated with an increased risk of drug initiation and drug addiction
Can include emotional, physical, and sexual abuse or neglect, among other experiences
Gender
Females are twice as sensitive to drugs as males, on average
Women are more likely than men to abuse nicotine, alcohol, cocaine, amphetamine, opioids, cannabinoids, caffeine, and PCP
Genetics
Despite some evidence of a genetic contribution, no gene or set of genes has been found
Any satisfactory explanation of drug abuse will require genetic and learning
Personality traits
Unusual risk taking may be a trait common to drug abusers
Epigenetics
Can account both for the enduring behaviors that support addiction and for the tendency of drug addiction to be inherited
Pleasure
Take the drug for its pleasurable effects These typically wear off, but drug use continues
Dependence/Withdrawal
Want to avoid withdrawal symptoms
An addict may abstain from a drug for months, long after any withdrawal symptoms have abated, yet still be drawn back to using
Incentive sensitization
There are two separate systems for wanting and liking
Wanting - Mesolimbic dopamine system
Liking - Opioid neurons
Wanting
Sensitizes with repeated drug use; craving increases
Involves learning associations
Over time the brain learns that certain cues predict the drug
Those “incentives” become sensitized such that seeing a drug-linked cue produces wanting/craving for the drug
Liking
Tolerance develops with repeated drug use
Pleasure decreases
Frontal cortex
Makes the decision to take a drug
Opioid systems
Related to pleasurable experiences
Dopaminergic system
Producing wanting of the drug
Striatum (Caudate + Putamen)
Voluntary control of drug taking gives way to unconscious processes—a habit
How do we treat drug addiction
The approaches to treating drug abuse vary depending on the drug
The two most used drugs, alcohol and tobacco, are legal
The drugs that carry the harshest penalties, cocaine and heroin, are used by far fewer people
Treating drug abuse is difficult in part because legal proscriptions are irrational
Emotions
Cognitive interpretations of subjective feelings
Three components of emotion
- Autonomic response (e.g., increased heart rate). Hypothalamus and associated structures as well as ENS.
- Subjective feelings (e.g., fear). Amygdala and parts of frontal lobes.
- Cognitions (e.g., thoughts about the experience). Cerebral cortex.
Which brain areas are involved in emotion
Cingulate gyrus Mammillothalamic tract Fornix Anterior thalamus Hippocampal formation Amygdala Prefrontal cortex All areas involved in emotions involved in other functions as well
Hippocampal formation
Hippocampus
- Distinctive three layered subcortical structure of the limbic system lying in the medial temporal region of the temporal lobe
- Takes part in species specific behaviors, memory, and spatial navigation
- Parahippocampal cortex/gyrus
Amygdala
Almond-shaped collection of nuclei in the limbic system
Receives input from all sensory systems
Many neurons respond to more than one sensory modality (multimodal)
Sends projections primarily to the hypothalamus and brainstem
Intimately connected to the functioning of the frontal lobes
Involved in emotion
Influences autonomic and hormonal responses via connections with the hypothalamus
Influences conscious awareness of the consequences of events and objects via connections with the prefrontal cortex
Klüver–Bucy syndrome - Removal of amygdala
Symptoms in monkeys:
Tameness and loss of fear
Indiscriminate dietary behavior
Greatly increased autoerotic, homosexual, and heterosexual activity with inappropriate object choice
Tendency to attend to and react to every visual stimulus
Tendency to examine all objects by mouth
Visual agnosia (inability to recognize objects)
Why Amygdala is Essential
Electrical stimulation produces an autonomic response (such as increased blood pressure and arousal) as well as a feeling of fear
Olfactory information connects directly to the amygdala in the human brain
Fear
The emotional reaction to threat
Innate and learned components
Avoid other organisms, objects, places that could kill you
Stick to things that are safe
Damage to the amygdala affects both innate and learned fear
Fear reactions
Defensive behaviours
Protect from threat/harm
Aggressive behaviours
Threaten or harm
(Relatively) Easy to study
Mice/rats – colony-intruder task
Cats vs mice
Fear Conditioning
Auditory fear conditioning
Specific sounds linked with foot shock
Low road: Thalamus → amygdala = Unconscious response
High road: Thalamus → cortex or hippocampus → amygdala
Conscious response: Contextual fear conditioning, Specific environments linked with foot shock Involves hippocampus as well, Discriminate between environment
Emotional memory
Memory for the affective properties of stimuli or events
Can be implicit or explicit
Amygdala is critical for emotional memory
Emotionally arousing experiences
Emotionally driven neurochemical and hormonal activating systems (probably cholinergic and noradrenergic) stimulate the amygdala
The amygdala in turn modulates the laying down of emotional memory circuits in the rest of the brain, especially in the medial temporal and prefrontal regions and in the basal ganglia
Prefrontal Cortex
Contributes to specifying the goals of movement
Controls selection of movements appropriate to the particular time and context
Selection may be cued by internal information, such as memory and emotion, or it may be a response to context (environmental information)
Damage to the prefrontal cortex
Severe effects on social and emotional behavior
Inability to feel and express one’s own emotions and to recognize the emotional expression of others
Apathy and loss of initiative or drive
Inability to plan and organize leads to poor decision making
Affective Disorders
Major depression
- Characterized by prolonged feelings of worthlessness and guilt, disruption of normal eating habits, sleep disturbances, a general slowing of behavior, and frequent thoughts of suicide
- Has a genetic component (many genes can contribute → no specific gene implicated)
- Early-life stress may produce epigenetic changes in the prefrontal cortex, higher susceptibility to depression later on
Traditional Depression Treatment
Traditional
-Monoamine oxidase inhibitors (MAOIs): Inhibit enzyme that breaks down monoamine NTs (DA, 5-HT, NE)
- Tricyclics: Block reuptake of monoamine NTs
- Selective serotonin reuptake inhibitors (SSRIs): Block reuptake of serotonin specifically
-Serotonin-norepinephrine reuptake inhibitors (SNRIs): Block reuptake of serotonin and norepinephrine
Cognitive behavioural therapy (CBT)
As effective as SSRIs
Combined with SSRIs = more effective than either alone
Depression Treatment
Most often used in treatment(drug)-resistant cases
Electroconvulsive shock therapy (ECT)
Psychedelics
Deep brain stimulation
Repetitive transcranial magnetic stimulation (rTMS)
Anxiety
Generalized anxiety disorder
Persistently high levels of anxiety, often accompanied by maladaptive behaviors to reduce anxiety; thought to be caused by chronic stress
Phobia
Clearly defined dreaded object or greatly feared situation
Panic disorder
Recurrent attacks of intense terror that come on without warning and without apparent relation to external circumstances
Treating anxiety
Anxiolytics
-Barbiturates used occasionally
-Highly addictive
Benzodiazepines
-Most common treatment
-Augment/enhance GABA’s inhibitory effect by binding to the GABA-A receptor
-Newer drugs target the serotonin system (agonists)
Stress
A process in which an agent exerts force on an object
Any circumstance that upsets homeostatic balance
Stressor
A stimulus that challenges the body’s homeostasis and triggers arousal
Stress response
Physiological and behavioral arousal; any attempt to reduce the stress
Activating a stress response
Fast-acting: primes the body immediately for fight or flight (epinephrine) (sympathetic)
Slow-acting: both mobilizes the body’s resources to confront a stressor and repairs stress-related damage (cortisol – a glucocorticoid hormone) (parasympathetic)
How do we end a stress response?
Hippocampus is well suited to detecting cortisol in the blood and instructing the hypothalamus to reduce blood cortisol levels
Too much cortisol will damage neurons in the hippocampus
There is a vicious cycle involving prolonged stress, cortisol levels, and hippocampal functioning
Structure of Stress Response
Hypothalamus –> pituitary gland –> endocrine gland
Risks for increased stress
Sleep dysregulation, worry and rumination, avoidant behaviour, relationship tension, lack of social support
Being Proactive for Stress
Regulate and create routines Watch your self-talk Turn down media noise Schedule activities Keep social contact
Reducing Stress
-Spend time in nature: 20 min can reduce cortisol levels
-Mindfulness / meditation
-MBSR or MBCT programs → used to reduce stress, depression, anxiety, Reduces activity in the amygdala
Exercise
-Can improve how the body handles stress
-Can provide a time-out from stressors
-May increase neurogenesis in the hippocampus
