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1.
Brain Cogn ; 174: 106121, 2024 02.
Article in English | MEDLINE | ID: mdl-38142536

ABSTRACT

A depersonalization episode occurred unexpectedly during an electroencephalogram (EEG) recording for a study. Experience reports tracked the time course of this event and, in conjunction, with EEG data, were analyzed. The source activity across canonical frequency bands was analyzed across four periods ended by retrospective experience reports (depersonalization was reported in the 2nd period). Delta and theta decreases occurred across all time periods with no relation to reported events. Theta and alpha increases occurred in right secondary visual areas following depersonalization, which also coincided with surges in beta and gamma. The largest increases occurred in bilateral fronto-polar and medial prefrontal cortex, followed by inferior left lateral fronto-insula-temporal cortices and right secondary visual cortex. A high frequency functional network with a principal hub in left insula closely overlapped inferior left cortical gamma band-power increases. Bilateral frontal increases in gamma are consistent with studies of dissociation. We interpret gamma and later beta, alpha, and theta band increases as arising from the generation of visual priors, in the absence of precise visual signals, which constrain interoceptive and proprioceptive predictions to reestablish a stable sense of physiological-self. Beta showed local increases following the pattern of gamma but showed no changes in functional connectivity.


Subject(s)
Cerebral Cortex , Electroencephalography , Humans , Retrospective Studies , Temporal Lobe , Head
2.
Front Hum Neurosci ; 17: 955171, 2023.
Article in English | MEDLINE | ID: mdl-37457498

ABSTRACT

Social communication is fraught with ambiguity. Negotiating the social world requires interpreting the affective signals we receive and often selecting between channels of conflicting affective information. The affective face-word Stroop (AFWS) provides an experimental paradigm which may identify cognitive-affective control mechanisms underpinning essential social-affective skills. Initial functional magnetic resonance imaging (fMRI) study of the AFWS identified right amygdala as driving this affective conflict and left rostral anterior cingulate cortex (rACC) as the locus of conflict control. We employed electroencephalogram (EEG) and eLORETA source localization to investigate the timing, location, and sequence of control processes when responding to affective conflict generated during the AFWS. However we designated affective word as the response target and affective face as the distractor to maximize conflict and control effects. Reaction times showed slowed responses in high vs. low control conditions, corresponding to a Rabbitt type control effect rather than the previously observed Grattan effect. Control related activation occurred in right rACC 96-118 ms post-stimulus, corresponding to the resolution of the P1 peak in the Visual Evoked Potential (VEP). Face distractors elicit right hemisphere control, while word distractors elicit left hemisphere control. Low control trials require rapid "booting up" control resources observable through VEPs. Incongruent trial activity in right fusiform face area is suppressed 118-156 ms post stimulus corresponding to onset and development of the N170 VEP component. Results are consistent with a predicted sequence of rapid early amygdala activation by affective conflict, then rACC inhibition of amygdala decreasing facilitation of affective face processing (however, amygdala activity is not observable with EEG).

3.
JMIR Res Protoc ; 11(12): e36328, 2022 Dec 08.
Article in English | MEDLINE | ID: mdl-36480249

ABSTRACT

BACKGROUND: The colonization of Australia is responsible for complex layers of trauma for the First Nations peoples of the continent. First Nations Australians' well-being is irrevocably tied to the well-being of the land. The application of a landscape-based approach to collaborative research shows promise in enabling genuine relationships that yield rich and informative data. However, there is a lack of practical evidence in the field of landscape research-research tied to First Nations Australians' worldviews of landscape. OBJECTIVE: This study aims to deepen shared knowledges of well-being and healing on Australian soils. We aim to examine ritual co-design as a novel method for deepening these shared knowledges. METHODS: This research comprises a qualitative and participatory action research design operationalized through an Indigenist approach. It is a 2-phase project that is co-designed with First Nations Australians. Phase 1 of this project is a relational study that endeavors to deepen the theory underpinning the project, alongside the development of meaningful and reciprocal community connections. Phase 2 is a series of 3 participatory action research cycles to co-design a new communal ritual. This process seeks to privilege First Nations Australians' voices and ways of knowing, which are themselves communal, ritual, and symbolic. The framework developed by psychiatrist Carl Jung informs the psychological nature of the enquiry. An Indigenist approach to landscape research recasts the Jungian frame to enable a culturally safe, context-specific, and landscape-based method of qualitative research. RESULTS: The research is in the preliminary stages of participant recruitment. It is expected that data collection will commence in late 2022. CONCLUSIONS: It is expected that this qualitative and co-designed project will strengthen the cross-cultural co-designer relationships and that the data gathered from these relationships, and the accompanying practical outcomes, will provide new insight into the interaction between human and landscape well-being. The field of landscape research is in an embryonic phase. This new field is embedded in the understanding that First Nations Australians' well-being is irrevocably tied to the well-being of the land, and this study seeks to build on this evidence base. A strength of this research is the relational methodology, in which First Nations Peoples' needs and desires will inform future research directions. It is limited by its context specific nature; however, it is expected that findings will be usable in guiding future research directions in the multidisciplinary field of landscape research. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/36328.

4.
Front Hum Neurosci ; 16: 744487, 2022.
Article in English | MEDLINE | ID: mdl-35321264

ABSTRACT

Depersonalization (DP) and derealization (DR) refer to states of dissociation in which one feels a sense of alienation in relation to one's self and environment, respectively. Whilst transient episodes often diminish without treatment, chronic experiences of DP and DR may last for years, with common treatments lacking a strong evidence base for their efficacy. We propose a theoretical explanation of DP and DR based on interoceptive predictive coding, and discuss how transient experiences of DP and DR may be induced in the non-clinical population using virtual reality. Further, we review the use of heartbeat evoked potentials in detecting the neural correlates of DP and DR allowing for an objective measure of these experiences in the non-clinical population. Finally, we discuss how the induction and detection of transient experiences of DP and DR in the non-clinical population could shed light on how the brain constructs one's sense of self and reality.

5.
J Child Sex Abus ; 30(8): 953-976, 2021.
Article in English | MEDLINE | ID: mdl-34353238

ABSTRACT

This Australian study explores a person's self-reported exposure to childhood abuse to identify the characteristics that are predictive of clinical levels of dissociation in adulthood. The final sample comprised 303 participants, including 26 inpatients and outpatients (24 females and two males) receiving treatment for a dissociative disorder (DD), and 277 university participants, including 220 controls (186 females, 34 males), 31 with elevated levels of dissociation consistent with a DD or posttraumatic stress disorder (27 females and four males), and 26 with clinical levels of dissociation (20 females and six males). The findings demonstrate clinical levels of dissociation and DDs occur in individuals reporting a history of childhood abuse, particularly sexual abuse and experiences that are potentially life-threatening to a child, such as choking, smothering, and physical injury that breaks bones or teeth, or that compromise the child's survival needs, including threats of abandonment and deprivation of basic needs. Females who disclosed being sexual abused in addition to being choked or smothered had a 106-fold risk of clinical levels of dissociation. As expected, self-reported amnesia was prevalent in the dissociative groups. Yet, even in the control group, one-third of those disclosing sexual abuse reported an unclear memory of it. Strong similarities in abuse experiences were found between the clinical sample and those in the university sample with clinical levels of dissociation (which is unlikely to have previously been diagnosed). The dissociative groups reported higher rates of corroboration of their abusive experiences. The findings support the traumatic etiology of dissociation.


Subject(s)
Child Abuse, Sexual , Child Abuse , Adult , Australia , Child , Dissociative Disorders/epidemiology , Female , Humans , Male , Physical Abuse
7.
J Trauma Dissociation ; 22(3): 265-287, 2021.
Article in English | MEDLINE | ID: mdl-32791032

ABSTRACT

This paper investigated a 60-item version of the Multidimensional Inventory of Dissociation (MID) with the potential to capture the full range of dissociative symptoms that characterize each of the dissociative disorders (DD). The 28-item Dissociative Experiences Scale (DES) was designed to capture a wide range of dissociative phenomena, but college population studies indicate it may not be adept at identifying the full range of dissociative symptoms and disorders. The 218-item MID has the advantage of capturing the full range of dissociative symptoms and has diagnostic capabilities for all DSM-5 DD, but the disadvantage of taking considerably longer than the DES to complete. Using university students and staff (N = 313), this paper investigated a 60-item version of the MID with the potential to capture the full range of dissociative symptoms that characterize each of the DD. Results indicate the MID-60 has a nearly identical factor structure to the full MID, excellent internal reliability, and content and convergent validity. Using the MID-60, at least 8% of participants at an Australian university were positive for a DD and, on average, participants self-reported having dissociative experiences 13% of the time. The present study's findings suggest the MID-60 is a promising alternative to the DES, with results about the prevalence of DDs and dissociative experiences consistent with those found using clinical interviews and the DES.


Subject(s)
Dissociative Disorders , Universities , Australia , Diagnostic and Statistical Manual of Mental Disorders , Dissociative Disorders/diagnosis , Humans , Psychometrics , Reproducibility of Results
8.
J Trauma Dissociation ; 21(1): 16-61, 2020.
Article in English | MEDLINE | ID: mdl-31461395

ABSTRACT

This meta-analysis of 31,905 college students includes 12 studies diagnosing Dissociative Disorders (DD) and 92 studies measuring dissociation with the Dissociative Experiences Scale (DES). Prevalence rates were used to separately test the plausibility of the Trauma Model (TM) and the Fantasy Model (FM) of dissociation. Results show 11.4% of students sampled meet criteria for DD, which is consistent with the prevalence of experiencing multiple (types of) trauma during childhood (12%), but is not consistent with the very low prevalence expected from the role of fantasy-proneness proposed in the FM. DES scores varied significantly across the 16 countries and were not higher in North America, but in countries that were comparatively unsafe. The least well-known DD was the most common, which is inconsistent with the FM which holds that the diagnosed person is enacting a familiar social role. There was no evidence that DES scores had decreased over recent decades, which does not support FM assertions that DD were a fad of the 1990s. Three of the five hypotheses tested provided clear support for the TM and a fourth hypothesis provided partial support for the TM. None of the five hypotheses tested supported the FM. The finding that DD were slightly more common in college populations than the general population did not support predictions of either model. The theoretical perspective of the authors moderated DES scores, although this is unlikely due to experimenter bias as studies led by FM theorists had significantly higher DES scores than those led by TM theorists.


Subject(s)
Dissociative Disorders/epidemiology , Students/psychology , Universities , Adolescent , Humans , Prevalence , Young Adult
9.
Article in English | MEDLINE | ID: mdl-29034102

ABSTRACT

This article summarizes key advances in hypnosis research during the past two decades, including (i) clinical research supporting the efficacy of hypnosis for managing a number of clinical symptoms and conditions, (ii) research supporting the role of various divisions in the anterior cingulate and prefrontal cortices in hypnotic responding, and (iii) an emerging finding that high hypnotic suggestibility is associated with atypical brain connectivity profiles. Key recommendations for a research agenda for the next decade include the recommendations that (i) laboratory hypnosis researchers should strongly consider how they assess hypnotic suggestibility in their studies, (ii) inclusion of study participants who score in the middle range of hypnotic suggestibility, and (iii) use of expanding research designs that more clearly delineate the roles of inductions and specific suggestions. Finally, we make two specific suggestions for helping to move the field forward including (i) the use of data sharing and (ii) redirecting resources away from contrasting state and nonstate positions toward studying (a) the efficacy of hypnotic treatments for clinical conditions influenced by central nervous system processes and (b) the neurophysiological underpinnings of hypnotic phenomena. As we learn more about the neurophysiological mechanisms underlying hypnosis and suggestion, we will strengthen our knowledge of both basic brain functions and a host of different psychological functions.

10.
Neurosci Conscious ; 2017(1): nix005, 2017.
Article in English | MEDLINE | ID: mdl-30042839

ABSTRACT

Hypnotic amnesia is a functional dissociation from awareness during which information from specific neural processes is unavailable to consciousness. We test the proposal that changes in topographic patterns of cortical oscillations in upper-alpha (10-12 Hz) band selectively inhibit the recall of memories during hypnotic amnesia by blocking availability of locally processed information at specific points in retrieval. Participants were prescreened for high or low hypnotic susceptibility. Following hypnotic induction, participants were presented with a series of 60 face stimuli and were required to identify affective expressions. Participants received a suggestion for amnesia for these faces. They were then presented with a set of 30 old and 30 new faces and identified each as old or new. Amnesia suggestion was lifted and recall tested using the remaining 30 old faces and another 30 new faces. Exact Low Resolution Brain Electromagnetic Tomography source analyses are reported for 64 channel event-related electroencephalogram recorded from highs showing reversible amnesia to old faces. For high-susceptible participants, the amnesia suggestion significantly increased old faces wrongly identified while for low-susceptible participants amnesia suggestion increased the new faces wrongly identified. There were no differences between high- and low-susceptible participants following reversal of the suggestion. For previously seen faces which were wrongly identified, compared to new faces correctly identified, (late) evoked upper-alpha is significantly higher in right BA7 in a region implicated in top-down executive control to assist recall of visual information. Lagged nonlinear connectivity between cortical sources in upper-alpha in the same condition showed significantly increased connectivity between right BA34 (parahippocampal gyrus) and right BAs 7, 20 and 22. Integration between these regions is essential for recall of recent faces. During amnesia, spatial and temporal coordination of upper-alpha appears to suppress integrated functioning of these regions (hence recall). These patterns were absent after reversal of amnesia suggestion.

11.
Front Hum Neurosci ; 8: 528, 2014.
Article in English | MEDLINE | ID: mdl-25104928

ABSTRACT

Altered state theories of hypnosis posit that a qualitatively distinct state of mental processing, which emerges in those with high hypnotic susceptibility following a hypnotic induction, enables the generation of anomalous experiences in response to specific hypnotic suggestions. If so then such a state should be observable as a discrete pattern of changes to functional connectivity (shared information) between brain regions following a hypnotic induction in high but not low hypnotically susceptible participants. Twenty-eight channel EEG was recorded from 12 high susceptible (highs) and 11 low susceptible (lows) participants with their eyes closed prior to and following a standard hypnotic induction. The EEG was used to provide a measure of functional connectivity using both coherence (COH) and the imaginary component of coherence (iCOH), which is insensitive to the effects of volume conduction. COH and iCOH were calculated between all electrode pairs for the frequency bands: delta (0.1-3.9 Hz), theta (4-7.9 Hz) alpha (8-12.9 Hz), beta1 (13-19.9 Hz), beta2 (20-29.9 Hz) and gamma (30-45 Hz). The results showed that there was an increase in theta iCOH from the pre-hypnosis to hypnosis condition in highs but not lows with a large proportion of significant links being focused on a central-parietal hub. There was also a decrease in beta1 iCOH from the pre-hypnosis to hypnosis condition with a focus on a fronto-central and an occipital hub that was greater in high compared to low susceptibles. There were no significant differences for COH or for spectral band amplitude in any frequency band. The results are interpreted as indicating that the hypnotic induction elicited a qualitative change in the organization of specific control systems within the brain for high as compared to low susceptible participants. This change in the functional organization of neural networks is a plausible indicator of the much theorized "hypnotic-state."

12.
Front Hum Neurosci ; 8: 197, 2014.
Article in English | MEDLINE | ID: mdl-24959124

ABSTRACT

Meditation proficiency is related to trait-like (learned) effects on brain function, developed over time. Previous studies show increases in EEG power in lower frequency bands (theta, alpha) in experienced meditators in both meditation states and baseline conditions. Higher gamma band power has been found in advanced Buddhist meditators, yet it is not known if this occurs in Yoga meditation practices. This study used eLORETA to compare differences in cortical source activity underlying scalp EEG from intermediate (mean experience 4 years) and advanced (mean experience 30 years) Australian meditators from the Satyananda Yoga tradition during a body-steadiness meditation, mantra meditation, and non-meditation mental calculation condition. Intermediate Yoga meditators showed greater source activity in low frequencies (particularly theta and alpha1) during mental calculation, body-steadiness and mantra meditation. A similar spatial pattern of significant differences was found in all conditions but the number of significant voxels was double during body-steadiness and mantra meditation than in the non-meditation (calculation) condition. These differences were greatest in right (R) superior frontal and R precentral gyri and extended back to include the R parietal and occipital lobes. Advanced Yoga meditators showed greater activity in high frequencies (beta and especially gamma) in all conditions but greatly expanded during meditation practice. Across all conditions (meditation and non-meditation) differences were greatest in the same regions: R insula, R inferior frontal gyrus and R anterior temporal lobe. Distinct R core networks were identified in alpha1 (8-10 Hz) and gamma (25-42 Hz) bands, respectively. The voxels recruited to these networks greatly expanded during meditation practice to include homologous regions of the left hemisphere. Functional interpretation parallels traditionally described stages of development in Yoga proficiency.

13.
J Neurosurg ; 117(3): 455-62, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22794320

ABSTRACT

Neurosurgery has played an important role in the development of neuroscience and the science of consciousness. In this paper, the authors reflect on some of the historical contributions of neurosurgeons to the science of consciousness and discuss the ways in which clinical neurosurgery can contribute to the science of consciousness in the 21st century. An approach to the "hard problem" is proposed based on the principles of psychophysics, and the opportunities offered by intracranial recording and stimulation in patients capable of reporting changes in subjective experience are discussed. Such an approach will allow the systematic study and description of the bridging relationships between neurobiology and conscious experience.


Subject(s)
Consciousness , Neurobiology/history , Neurobiology/trends , Neurosurgery/history , Neurosurgery/trends , Brain/physiology , History, 19th Century , History, 20th Century , History, 21st Century , Humans , Monitoring, Physiologic , Neurosurgical Procedures , Philosophy , Psychophysics
14.
Int J Clin Exp Hypn ; 59(2): 198-210, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21390979

ABSTRACT

Conventional accounts of the McCollough Effect (ME) have focused on strictly bottom-up processing accounts of the phenomenon, most commonly involving the fatiguing of orientation-selective neurons; although association-learning mechanisms have also gained acceptance. These lower order accounts do not take into account higher order variables related to key personality traits and/or associated cognitive control processes. This article reports the use of confirmatory factor analysis and follow-up structural equation style regressions that model MEs and also the part played by the personality trait of dissociation. After considering the relative impact of age and dissociative processes, the article concludes that trait dissociation is positively associated with reports of MEs.


Subject(s)
Dissociative Disorders/psychology , Figural Aftereffect , Orientation , Adult , Age Factors , Factor Analysis, Statistical , Female , Humans , Male , Middle Aged , Models, Statistical , Personality , Regression Analysis , Surveys and Questionnaires , Young Adult
15.
Int J Clin Exp Hypn ; 55(1): 84-113, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17135065

ABSTRACT

The literature suggests that aspects of hypnotizability may be involved in the etiology and maintenance of self-defeating eating. However, interpretation of the published research findings has been complicated by the use of instruments that appear to have measured different or, at best, only related facets of the underlying constructs. This article reports relationships between weight, shape, dietary concerns, hypnotizability, dissociative capacity, and fantasy proneness. Implications for a key role for hypnosis in the treatment of eating behaviors, attitudes, and concerns are discussed.


Subject(s)
Attitude , Feeding Behavior , Feeding and Eating Disorders/psychology , Hypnosis , Anorexia Nervosa/psychology , Anorexia Nervosa/therapy , Bulimia/psychology , Bulimia/therapy , Dissociative Disorders/psychology , Dissociative Disorders/therapy , Fantasy , Feeding and Eating Disorders/therapy , Humans , Personality Assessment , Suggestion , Treatment Outcome
16.
Platelets ; 16(8): 453-61, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16287612

ABSTRACT

The role of platelet glycoprotein Ib as a thrombin receptor has been often a subject of controversy. We have investigated the role of the thrombin receptors, GPIb and protease-activated receptor (PAR)-1. Tyrosine phosphorylation in whole platelet lysates and in cytoskeletal extracts was evaluated after activation with thrombin and with the thrombin receptor-activating peptide (TRAP). Different experimental approaches were applied including: (i) congenital deficiency of platelet GPIb (Bernard Soulier syndrome, BSS), (ii) antibody to GPIb (AP1), (iii) selective protease cleavage (metalloprotease), and (iv) antibody to (PAR)-1. After activation of control platelets with thrombin or TRAP, multiple proteins became tyrosine phosphorylated in platelet lysates and some of them associated with the cytoskeletal fraction. These effects were absent in BSS platelets. Presence of AP1 or metalloprotease treatment showed an inhibitory effect when platelets were activated with a low concentration of thrombin or TRAP. Blockade of PAR-1 with a specific antibody, SPAN 12, inhibited platelet response to both agonists. This study reinforces the hypothesis that GPIb is the high-affinity receptor for thrombin. The signaling mechanisms occurring through tyrosine phosphorylation of proteins triggered by thrombin seem to be dependent on intact GPIb. Moreover, our results indicate that both receptors, GPIb and PAR-1, are necessary to achieve a full platelet response to thrombin.


Subject(s)
Blood Platelets/physiology , Hemostatics/pharmacology , Platelet Activation/drug effects , Platelet Glycoprotein GPIb-IX Complex/metabolism , Protein Processing, Post-Translational/drug effects , Thrombin/pharmacology , Bernard-Soulier Syndrome/metabolism , Cell-Free System/metabolism , Hemostatics/metabolism , Humans , Phosphorylation/drug effects , Receptor, PAR-1/metabolism , Thrombin/metabolism , Tyrosine/metabolism
17.
Brain Res Bull ; 67(4): 298-303, 2005 Oct 30.
Article in English | MEDLINE | ID: mdl-16182937

ABSTRACT

The role of alterations in mismatch negativity (MMN) in hypnosis was examined by recording MMN of the auditory ERP at frontal (F3, Fz, and F4) and mastoid (M1 and M2) placements. Frontal MMN is believed to reflect activity in right anterior cortical generators, whereas MMN at mastoid leads reflects generators located bilaterally in the temporal auditory cortex. MMN recordings were obtained in 11 low and 12 high hypnotically susceptible participants in three successive blocks; pre-hypnosis, hypnosis and post-hypnosis. Frontal (but not temporal) MMN showed a significant quadratic trend across testing conditions. It increased during hypnosis and then dropped post-hypnosis for both susceptibility groups. Linear trends for frontal and temporal MMN showed directly opposite patterns of change in the interaction between hypnotic susceptibility and testing blocks. Frontal MMN built up linearly over the test blocks in high relative to low susceptibility participants. Temporal MMN showed the reverse pattern and increased linearly across test conditions in those with low relative to high hypnotic susceptibility.


Subject(s)
Auditory Perception/physiology , Contingent Negative Variation/physiology , Frontal Lobe/physiology , Hypnosis , Acoustic Stimulation , Brain Mapping , Dose-Response Relationship, Radiation , Electroencephalography/methods , Humans , Time Factors
18.
Neuroimage ; 27(4): 969-78, 2005 Oct 01.
Article in English | MEDLINE | ID: mdl-15964211

ABSTRACT

Hypnosis can profoundly alter sensory awareness and cognitive processing. While the cognitive and behavioral phenomena associated with hypnosis have long been thought to relate to attentional processes, the neural mechanisms underlying susceptibility to hypnotic induction and the hypnotic condition are poorly understood. Here, we tested the proposal that highly hypnotizable individuals are particularly adept at focusing attention at baseline, but that their attentional control is compromised following hypnosis due to a decoupling between conflict monitoring and cognitive control processes of the frontal lobe. Employing event-related fMRI and EEG coherence measures, we compared conflict-related neural activity in the anterior cingulate cortex (ACC) and control-related activity in the lateral frontal cortex (LFC) during Stroop task performance between participants of low and high hypnotic susceptibility, at baseline and after hypnotic induction. The fMRI data revealed that conflict-related ACC activity interacted with hypnosis and hypnotic susceptibility, in that highly susceptible participants displayed increased conflict-related neural activity in the hypnosis condition compared to baseline, as well as with respect to subjects with low susceptibility. Cognitive-control-related LFC activity, on the other hand, did not differ between groups and conditions. These data were complemented by a decrease in functional connectivity (EEG gamma band coherence) between frontal midline and left lateral scalp sites in highly susceptible subjects after hypnosis. These results suggest that individual differences in hypnotic susceptibility are linked with the efficiency of the frontal attention system, and that the hypnotized condition is characterized by a functional dissociation of conflict monitoring and cognitive control processes.


Subject(s)
Cognition/physiology , Conflict, Psychological , Frontal Lobe/physiology , Hypnosis , Adult , Attention/physiology , Electroencephalography , Female , Functional Laterality/physiology , Gyrus Cinguli , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Nerve Net/physiology , Neuropsychological Tests
19.
Psychol Bull ; 131(1): 98-127, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15631555

ABSTRACT

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.


Subject(s)
Brain/diagnostic imaging , Brain/physiology , Consciousness Disorders , Arousal/physiology , Diet , Dreams/physiology , Electroencephalography , Humans , Positron-Emission Tomography , Sleep/physiology , Starvation
20.
Int J Clin Exp Hypn ; 52(3): 232-49, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15370356

ABSTRACT

Woody and Bowers's dissociated-control theory predicts impaired performance on tasks indexing frontally mediated supervisory attentional functions during hypnosis, especially for high susceptibles. This prediction is tested using Stroop task behavioral performance to measure aspects of anterior-mediated supervisory attentional function. All measures of anterior-mediated attentional functions significantly declined during hypnosis. Interactions be-tween susceptibility and hypnosis condition showed specific changes among hypnotized high susceptibles. Total Stroop errors (failures of attentional suppression) were significantly higher in hypnosis for high, but not low, susceptibles. Tellegen's experiential mental set was highest for hypnotized highs. Use of rehearsal strategy (instrumental set) decreased significantly in hypnosis but more so for highs than lows. Results suggest that "absorption" in hypnosis may be a consequence of dissociated anterior attentional control. It is proposed that dissociated control emerges from the functional disconnection of left dorsolateral prefrontal cortex and anterior cingulate cortex.


Subject(s)
Attention , Dissociative Disorders/psychology , Hypnosis , Adolescent , Adult , Attention/physiology , Color Perception/physiology , Discrimination Learning/physiology , Dissociative Disorders/physiopathology , Female , Gyrus Cinguli/physiopathology , Humans , Male , Neuropsychological Tests , Prefrontal Cortex/physiopathology , Reaction Time/physiology , Reading , Reproducibility of Results , Semantics
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