CNS Class 4 - Central Modulation, Sensitization, Disease & Terminology Flashcards
There are modifiers of ________ transmission as it travels from the tissues to the brain.
Afferent
Local inhibition or gating in the dorsal horn and filtering in the thalamus are examples of _________ modulation.
Ascending Modulation
T/F - Ascending modulation is often called central modulation.
False - DESCENDING modulation is often called central modulation.
While __________ modulation is most often discussed in the context of pain, it can also be used to weaken or suppress sensory experience of other types of stimuli.
Descending Modulation
T/F - The understanding of descending mechanisms is still incomplete.
True
One of the first major commenters on the phenomena of descending modulation was ____ _______.
H.K. Beecher
H.K. Beecher was a WW2 _________ who noted how frequently wounded ________ felt little or no pain, especially initially.
Physician
Soldiers
__________ modulation has been observed of injured athletes in the heat of competition.
Descending Modulation
The purpose of _______ experience is to bring attention to important matters, often because of a need for ________ or reflection.
Sensory
Response
T/F - The sensory experience may be eliminated or weakened in the presence of other purpose or distraction.
True
At the brain level, the following are all involved in __________ modulation:
- Parts of the cortex
- Thalamus
- Insula
- Amygdala
- Hypothalamus
Descending Modulation
T/F - Exogenous opioids are chemicals released with descending modulation.
False - ENDOGENOUS opioids are chemicals released with descending modulation.
__________ and ___________ are the body’s version of morphine or heroin. They are communicated to a group of nuclei in the ________ and brainstem.
Endorphins
Enkephalins
Midbrain
T/F - Dopamine is also involved with endogenous opioids and descending modulation.
True
Activation of the midbrain’s ______________ ____ area initiates a complex intercommunication process that results in the release of modulators from brainstem zones like the _____ ______.
Periaqueductal Gray Area (PAG)
Raphe Nuclei
Modulators released from the PAG include neurotransmitters such as _________ (5-HT), norepinephrine (NE) and endocannabinoid substances such as __________, which is similar to THC.
Serotonin (5-HT)
Anandamide
Modulators in turn act on neurons in the dorsal horn by directly inhibiting at the ________ where ___ fibres and ___ delta fibres are attempting to activate second order spinothalamic tract neurons.
Synapses
C Fibres
A Delta Fibres
T/F - Modulators activate local inhibitory neurons to “open the gate.”
False - Modulators activate local inhibitory neurons to “CLOSE the gate.”
Modulators also inhibit firing of the second order neurons themselves and these local neurons use ______ and _______.
GABA
Glycine
T/F - Endorphins and enkephalins cannot produce effects in the spinal cord.
False - Endorphins and enkephalins CAN ALSO produce effects in the spinal cord.
Because of the scale of the centres and pathways involved in the descending modulation mechanisms, they can be impaired by any number of traumatic and ____________ causes.
Pathological
Types of pathological pain or sensation can result from aberrant ___________ or CNS analysis, or from failure of _______ modulation mechanisms, or both.
Nociception
Central Modulation
T/F - Mood states, mental health, traumatic history and chronicity can all alter central modulation in ways that affect sensory experience.
True
T/F - The more anxious a person is, the less intense their experience of pain.
False - The more anxious a person is, the MORE intense their experience of pain.
Based on the neurochemistry of anxiety and stress, the predominance of ___________ nervous system activation enhances pain perception and pain distress (suffering).
Sympathetic Nervous System
T/F - Central modulation is rendered less effective when people are stressed out.
True
Central modulation is complex because of the number of individual physical and _______________ factors that come into play, especially if dysfunctional stress becomes entrenched and when _______ illness is present.
Psychoemotional
Anxiety
With central _____________, signals coming from sensory receptors along first order neurons are normal and should cause no pain. But at the ______ horn of the spinal cord, they are amplified, and by the time they reach the _____, what should have been a normal message has been turned right up to be a message of pain.
Central Sensitization
Dorsal Horn
Brain
A term used to describe situations where a person’s history of physical and/or emotional trauma creates hyperfacilitation of pain and other distressing symptoms along with reduced effectiveness of descending modulation.
Central Sensitization
Over time, central _____________ becomes entrenched via causing altered neuron health and function, dysfunctional synapses and various changes in neurochemical production and function.
Central Sensitization
_______ pain syndromes, such as fibromyalgia, are interwoven with central sensitization.
Chronic Pain Syndromes
Central sensitization can be complicated by ____________, meaning that the person is expressing mental or emotional distress as physical symptoms.
Somatization
Anxiety, central sensitization and depression are ______________ and often present in varying degrees in the same person over time.
Interconnected
Anxiety, pain and distress cause __________ by depleting serotonin, dopamine, endogenous opioid and ______________ volumes in the CNS.
Depression
Norepinephrine
Mood
T/F - Depression itself does not deplete neurochemicals that are used to restore and balance mood.
False - Depression itself DOES deplete neurochemicals that are used to restore and balance mood.
Since neurochemicals like serotonin and norepinephrine are involved in __________ modulation, it means that their effectiveness in that role is reduced as an intrinsic aspect of depression. This results in the pain and other ________ discomfort symptoms that are part of the clinical presentation of depression.
Descending Modulation
Physical
The following are manifestations of depression that is ____________ in nature:
- Agitation
- Loss of appetite
- Decreased libido
- Suicidal ideation
- Aggressive behaviour (verbal or physical)
- Irritability
Serotonergic
The following are manifestations of depression that is _____________ in nature:
- Decreased concentration
- Slowness
- Loss of energy
- Weakness
- Tiredness
- Reduced self-care (hygiene)
Noradrenergic
_______ effects that reduce or suppress uncomfortable symptoms seem to work in large part by enhancing central modulation.
Placebo
T/F - The effects of massage therapy have placebo components, especially via the therapeutic relationship and effects of touch on the brain.
True
Neuron loss or ________ can lower firing rate, adding to the brain’s interpretation difficulties.
Scarring
____________, edema and chemicals released by damaged tissue can cause intense, irritable firing patterns.
Inflammation
Abnormal firing patterns can occur anywhere along the pathways that carry transmission to the sensory cortex and often promote proximal ______________ confusion.
Proximal Depolarization
________, compression and demyelination are additional factors that can cause interpretation challenges and also create transmission pattern __________.
Ischemia
Asynchrony
T/F - A cluster of demyelinated axons, such as in multiple sclerosis, will transmit faster than same-function neurons that are intact.
False - A cluster of demyelinated axons, such as in multiple sclerosis, will transmit MORE SLOWLY than same-function neurons that are intact.
When it comes to multiple sclerosis, the information arrives in __________ batches, producing a more baffling interpretation challenge that often results in the assignment of dysfunctional _________ experiences.
Disordered
Sensation
T/F - Sensation can be activated without a stimulus when there is damage to a first order neuron’s receptor or axon.
True
A specific symptom caused by peripheral nerve damage occurring mostly with median, sciatic (tibial) and C8/T1 spinal nerve injuries. It reflects damage/irritation to the sympathetic vasomotor neurons within the affected nerve.
Complex Regional Pain Syndrome II (CRPS II/Causalgia)
The primary symptom of CRPS II is an intense “_______” pain that usually has a “shooting” quality, often accompanied by ________ of the skin.
“Burning”
Erythema
___________ pain is a common phenomenon when there is irritation or damage in the sensory nervous system.
Neuropathic
Neuropathic pain due to __________ nerve damage can be caused by:
- Trauma
- Neuralgias
- Shingles (ex. Herpes Zoster)
- Facet joint issues
- Amputation (ex. Phantom Limb)
Peripheral
Neuropathic pain due to _______ nerve damage can be caused by:
- Transverse myelitis
- Spinal stenosis
- Multiple sclerosis
- CNS infections
- Stroke
Central
__________, diabetes and chemotherapy can cause systemic damage in both the peripheral and central nervous system.
Alcoholism
Possible mechanisms of ___________ pain include:
- Sprouting of sympathetic post-ganglionic nerve fibres on first order afferent endings and first order sensory cell bodies
- Lowered threshold for firing of c fibres and a delta fibres
- Proliferation of alpha adranergic receptors on first order sensory afferent endings and first order cell bodies
- Possible ephaptic afferent activation
- Permanent hyperactivation of wide dynamic range neurons
Neuropathic Pain
Possible mechanisms of ___________ pain include:
- Glutamate excitotoxic cell death of inhibitory neurons
- Inadequacy of central descending serotonin, norepinephrine, opioid peptide pathways to control nociception
- Immobilization by pain decreases gating of nociceptive input, limiting physical therapy to initiate gate
- Sprouting of c fibres in spinal cord
- Extension of interneuron dendrites into additional spinal cord laminae
Neuropathic Pain
The presentation of neuropathic pain can vary substantially as well, from numb, ________ sensations to “burning” or “electric shock” or “________” to more everyday types of pain.
Tingling
“Stabbing”
T/F - Neuropathic pain can often be triggered by non-nociceptive stimuli. It may be continuous or more episodic.
True
T/F - Neuropathic pain is often mild and easy to live with.
False - Neuropathic pain is often SEVERE and VERY CHALLENGING to live with.
Things like _______, illness, intense emotional states, anxiety and depression can make neuropathic pain _____.
Fatigue
Worse
There are a range of treatment approaches recommended for addressing ___________ pain, such as:
- Anticonvulsant
- Analgesic/antidepressant medications
- Physiotherapy
- Massage therapy
- Psychotherapy
- Acupuncture
- Relaxation practices
Neuropathic Pain
Absence of any sensation; the stimulus does not produce any of the expected sensation.
Anaesthesia
___________ can be induced, for example by using nerve-blocking agent in dental work.
Anaesthesia
Diminished sensation; the experience matches the nature of the stimulus, but is less strong than expected. Often referred to as numbness.
Hypoesthesia
Heightened or exaggerated sensation; the experience accurately matches the stimulus, but produces an exaggerated or unexpectedly strong response.
Hyperaesthesia
Hyperaesthesia can occur because of neuronal irritation or damage, but also for a range of _______________ reasons.
Psychoemotional
Abnormal sensations, such as “pins and needles” or “bugs crawling on the skin”; the sensation experienced does not correlate with the stimulus.
Paraesthesia
T/F - There is in fact reliable paraesthesia stimulus because it is a naturally produced sensation.
False - There is in fact NO reliable paraesthesia stimulus because it is NOT a naturally produced sensation.
____________ can also occur when there is reduced blood flow to a nerve.
Paraesthesia
When a paraesthesic sensation is painful, such as “hot pokers” or “electric burning”; dramatically strange and painful types of sensory experience.
Dysaesthesia
Instead of the expected sensation, an innocuous or non-nociceptive stimulus results in pain, typically a “regular” sort of pain experience.
Allodynia
T/F - Allodynia results in an increased pain threshold.
False - Allodynia results in A REDUCED pain threshold.
_________ can be caused by local nerve damage/irritation, by problems in the CNS circulatory or appreciation centres and also by poor central modulation.
Allodynia
The response to a nociceptive stimulus is weak; the sensation is not as strong as predictable because of the stimulus.
Hypalgesia
Heightened sensitivity to painful stimuli; the person experiences an unexpectedly strong pain intensity as compared to the predicted response to the stimulus; may be accompanied by strong subjective/emotional response.
Hyperalgesia (aka. Hyperalgia)
T/F - With hyperalgesia, often there is a continuation of the pain after the stimulation has ceased, sometimes for quite an extended period.
True
