Neuro/Psych Disorders for Final Exam
Neuro/ Psych Disorders
Chapter 14
• First-Order Neurons
• Transmit sensory information from the periphery to the CNS
• Second-Order Neurons
• Communicate with various reflex networks and sensory pathways in the
spinal cord and travel directly to the thalamus
• Third-Order Neurons
Relay information from the thalamus to the cerebral cortex
I. Pathway from the Spinal Cord to the thalamic level of sensation
Discriminative Pathway relays precise information regarding spatial orientation. There is input
from multiple receptors.
**Anterolateral pathway- sends signals for pain, thermal sensation, crude
touch, and pressure.
**Stereognosis- is the ability to sense the shape and size of an object in the
absence of visualization.
This is based on precise information from muscle, tendon and joint receptors.
This is a complex process that requires both the discriminative system and
higher order parietal association cortex to be functioning properly.
For example, you can find your cell phone in your bag without seeing it, or
you can feel a screwdriver in your hand and know what it is without actually
seeing it.
The discriminative pathways- relay information to the brain for perception,
arousal, and motor control.
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, A) Mechanisms of Pain
First order Neurons- Detect stimuli that threaten the integrity of innervated
tissues
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,Second order- Neurons Process Nociceptive information
Third order- neurons project pain information to the brain.
Nociceptors are pain receptors:
2 types: A Delta Fibers – fast pain, C Fibers smaller and slower
B) Transmissions of Pain
Pain is experienced as bright, sharp, or stabbing in nature.
Diffuse, dull, aching, and unpleasant sensations that commonly are associated
with chronic and visceral pain
*Neospinothalamic Tract: Sharp stabbing pain
*Paleospinothalamic Tract: Dull aching pain commonly associated with
chronic and visceral pain
Pain Threshold - The point at which a stimulus is perceived as painful
Pain Tolerance - The maximum intensity or duration of pain that a person is
willing to endure before the person wants something done about the pain
• Allodynia – extremely sensitive to touch
Nociceptive pain- Nociceptors are sensory receptors that are activated by
noxious insults to periphery tissue. The endings of the peripheral pain fibers
are free nerve endings - These receptive endings are widely distributed in the
skin, dental pulp, periosteum (tissue that covers bones), meninges, and some
internal organs.
The nociceptors translate noxious stimuli into action potentials that are transmitted
by a dorsal root ganglion to the dorsal horn of the spinal cord.
NOCICEPTIVE PAIN - nociceptors (pain receptors) are activated in response to
actual or impending tissue injury.
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, Internal organs- visceral pain
Neuropathic Pain arises from direct injury
C. Types of pain
*Cutaneous pain: sharp pain with burning, can be abrupt or slow in onset. Origin
in skin and subcutaneous tissues.
*Deep Somatic pain: originates in deep body structures (periosteum, muscles,
tendons, joints, blood vessels). – More diffuse than cutaneous pain. Can be
produced by strong pressure on bone, ischemia to a muscle, and tissue damage can
produce deep somatic pain. Sprained ankle is an example of deep somatic pain.
Visceral Pain: has origins in the visceral organs and is the most common pain
produced by disease
Referred - Originates at a visceral site but perceived as originating in part of the
body wall that is innervated by neurons entering the same segment of the nervous
system
*Nociceptive afferents are conducting the sensation of pain along the cranial and
spinal nerve pathways of the ANS.*
• Cognitive–behavioral
• Relaxation
• Distraction
• Imagery
• Biofeedback
• Physical agents
• Heat and cold
• Stimulus-induced analgesia
Acupuncture and acupressure
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