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Conscious Perception (conscious + perception)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Peripheral sensitization in migraine,role for P2X purinergic receptors in the dura,vascular sensory pathway

DRUG DEVELOPMENT RESEARCH, Issue 6 2007
Ernest A. Jennings
Abstract Peripheral sensitization is still considered a prime contributor underlying the mechanisms of migraine. Trigeminal primary afferent neurons are the first neurons in the dural nociceptive pathway, and activation results in conscious perception of pain. Peripheral sensitization can lower the activation threshold of primary afferent neurons, rendering them more excitable, allowing for increases in release of neurotransmitter from both central and peripheral terminals. Increase in neurotransmitter release from central terminals contributes to excitation of second-order neurons, while the release of peptides from peripheral terminals has been implicated in neurogenic inflammation. Adenosine 5,-triphosphate (ATP) causes pain in human studies, and depolarize sensory neurons. There is evidence of the action of ATP at many levels in the dura,vascular sensory pathway. Animal studies have shown that some P2X receptors are located in neurons innervating the dura, including the P2X3 receptor, which is most often shown to be involved in nociceptive pathways. In this article, we briefly review peripheral sensitization in relation to migraine and provide emphasis for P2X receptor involvement where it is available. Drug Dev Res 68:321,328, 2007. © 2007 Wiley-Liss, Inc. [source]

A correlation analysis between four energy-field scanning devices and conscious perception of bodily issues

FOCUS ON ALTERNATIVE AND COMPLEMENTARY THERAPIES AN EVIDENCE-BASED APPROACH, Issue 2004
MD Abadi
[source]

Mapping the time course of nonconscious and conscious perception of fear: An integration of central and peripheral measures

HUMAN BRAIN MAPPING, Issue 2 2004
Leanne M. Williams
Abstract Neuroimaging studies using backward masking suggest that conscious and nonconscious responses to complex signals of fear (facial expressions) occur via parallel cortical and subcortical circuits. Little is known, however, about the temporal differentiation of these responses. Psychophysics procedures were first used to determine objective thresholds for both nonconscious detection (face vs. blank screen) and discrimination (fear vs. neutral face) in a backward masking paradigm. Event-related potentials (ERPs) were then recorded (n = 20) using these thresholds. Ten blocks of masked fear and neutral faces were presented under each threshold condition. Simultaneously recorded skin conductance responses (SCRs) provided an independent index of stimulus perception. It was found that Fear stimuli evoked faster SCR rise times than did neutral stimuli across all conditions, indicating that emotional content influenced responses, regardless of awareness. In the first 400 msec of processing, ERPs dissociated the time course of conscious (enhanced N4 component) from nonconscious (enhanced N2 component) perception of fear, relative to neutral. Nonconscious detection of fear also elicited relatively faster P1 responses within 100 msec post-stimulus. The N2 may provide a temporal correlate of the initial sensory processing of salient facial configurations, which is enhanced when top-down cortical feedback is precluded. By contrast, the N4 may index the conscious integration of emotion stimuli in working memory, subserved by greater cortical engagement. Hum. Brain Mapping 21:64,74, 2004. © 2003 Wiley-Liss, Inc. [source]

Cortical processing of near-threshold tactile stimuli: An MEG study

PSYCHOPHYSIOLOGY, Issue 3 2010
Anja Wühle
Abstract In the present study we tested the applicability of a paired-stimulus paradigm for the investigation of near-threshold (NT) stimulus processing in the somatosensory system using magnetoencephalography. Cortical processing of the NT stimuli was studied indirectly by investigating the impact of NT stimuli on the source activity of succeeding suprathreshold test stimuli. We hypothesized that cortical responses evoked by test stimuli are reduced due to the preactivation of the same finger representation by the preceding NT stimulus. We observed attenuation of the magnetic responses in the secondary somatosensory (SII) cortex, with stronger decreases for perceived than for missed NT stimuli. Our data suggest that processing in the primary somatosensory cortex including recovery lasts for <200 ms. Conversely, the occupancy of SII lasts ,500 ms, which points to its role in temporal integration and conscious perception of sensory input. [source]