A stimulus that is sufficiently severe to be perceived this way is also provoking a pain response, which is conveyed by means of sensory neurons that are morphologically different from heat and cold afferent neurons, to different centers in the brain.
32.
Nociceptive signals received in the spinal cord from primary afferent neurons are projected " via " secondary afferent neurons, specifically, " via " the neospinothalamic tract, through the neothalamus, where the tract terminates, to the somatosensory cortex.
33.
Nociceptive signals received in the spinal cord from primary afferent neurons are projected " via " secondary afferent neurons, specifically, " via " the neospinothalamic tract, through the neothalamus, where the tract terminates, to the somatosensory cortex.
34.
Afferent neurons significant in dyspnea arise from a large number of sources including the carotid bodies, left heart failure leading to interstitial edema ( impairing gas exchange ), asthma causing bronchoconstriction ( limiting airflow ) and muscle fatigue leading to ineffective respiratory muscle action could all contribute to a feeling of dyspnea.
35.
During this time Perl became interested in how the activity of C-fiber afferent neurons was transferred to the cerebral cortex, a project that proved difficult, but which influenced his interest in these unmyelinated afferent fibers and their then-presumed participation in the detection and transmission of pain and temperature sensations to the brain.
