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Arne Dietrich - One of the best experts on this subject based on the ideXlab platform.
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Theory construction team
2015Co-Authors: Joshua N. Pritikin, Arne Dietrich, Joshua N, Brain I Anatomy, Karen I Schmidt, Steve Boker, Uva Grad StudentsAbstract:Recent neuroscience evidence indicates that a particular type of transient Hypofrontality, increased synchronization between limbic and cortical brain regions, is a common factor in both flow (optimal experience) and meditation (a contemplative experience). A novel research program is proposed to pinpoint how to cause this synchronization, and in turn, to examine its effects. Crucial is the development of measures of this type of transient Hypofrontality. Hypotheses are freely drawn from research on both meditation and flow, breaching traditional categorical boundaries. Preliminary correlational data is presented along with a plan for longitudinal evaluation
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Transient Hypofrontality as a mechanism for the psychological effects of exercise
Psychiatry research, 2006Co-Authors: Arne DietrichAbstract:Although exercise is known to promote mental health, a satisfactory understanding of the mechanism underlying this phenomenon has not yet been achieved. A new mechanism is proposed that is based on established concepts in cognitive psychology and the neurosciences as well as recent empirical work on the functional neuroanatomy of higher mental processes. Building on the fundamental principle that processing in the brain is competitive and the fact that the brain has finite metabolic resources, the transient Hypofrontality hypothesis suggests that during exercise the extensive neural activation required to run motor patterns, assimilate sensory inputs, and coordinate autonomic regulation results in a concomitant transient decrease of neural activity in brain structures, such as the prefrontal cortex, that are not pertinent to performing the exercise. An exercise-induced state of frontal hypofunction can provide a coherent account of the influences of exercise on emotion and cognition. The new hypothesis is proposed primarily on the strength of its heuristic value, as it suggests several new avenues of research.
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Consciousness
2004Co-Authors: Arne DietrichAbstract:the experience of flow is a state of transient Hypofrontality that enables the temporary suppression of th
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functional neuroanatomy of altered states of consciousness the transient Hypofrontality hypothesis
Consciousness and Cognition, 2003Co-Authors: Arne DietrichAbstract:It is the central hypothesis of this paper that the mental states commonly referred to as altered states of consciousness are principally due to transient prefrontal cortex deregulation. Supportive evidence from psychological and neuroscientific studies of dreaming, endurance running, meditation, daydreaming, hypnosis, and various drug-induced states is presented and integrated. It is proposed that transient Hypofrontality is the unifying feature of all altered states and that the phenomenological uniqueness of each state is the result of the differential viability of various frontal circuits. Using an evolutionary approach, consciousness is conceptualized as hierarchically ordered cognitive function. Higher-order structures perform increasingly integrative functions and thus contribute more sophisticated content. Although this implies a holistic approach to consciousness, such a functional hierarchy localizes the most sophisticated layers of consciousness in the zenithal higher-order structure: the prefrontal cortex. The hallmark of altered states of consciousness is the subtle modification of behavioral and cognitive functions that are typically ascribed to the prefrontal cortex. The theoretical framework presented yields a number of testable hypotheses.
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Functional neuroanatomy of altered states of consciousness: The transient Hypofrontality hypothesis
2003Co-Authors: Arne DietrichAbstract:Hypofrontality hypothesi
Daniel S Oleary - One of the best experts on this subject based on the ideXlab platform.
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Hypofrontality in neuroleptic naive patients and in patients with chronic schizophrenia assessment with xenon 133 single photon emission computed tomography and the tower of london
Archives of General Psychiatry, 1992Co-Authors: Nancy C Andreasen, Karim Rezai, Randall Alliger, Victor W Swayze, Michael Flaum, Peter T Kirchner, Gregg Cohen, Daniel S OlearyAbstract:The "Hypofrontality hypothesis" has been supported by many neuroimaging studies, but not all, perhaps because of heterogeneity of samples. The present study examined three different samples that permitted assessment of a variety of confounders, such as effects of long-term treatment, chronicity of illness, and presenting phenomenology: (1) 13 neuroleptic-naive schizophrenic patients, (2) 23 nonnaive schizophrenic patients who had been relatively chronically ill but were medication free for at least 3 weeks, and (3) 15 healthy normal volunteers. Regional cerebral blood flow was measured using single-photon emission computed tomography with xenon 133 as the tracer. The control condition consisted of looking at undulating colored shapes on a video monitor, while the experimental task was the Tower of London. We observed the Tower of London to be a relatively specific stimulant of the left mesial frontal cortex (probably including parts of the cingulate gyrus) in healthy normal volunteers. Both the neuroleptic-naive and the nonnaive patients lacked this area of activation, as well as a related one in the right parietal cortex (representing the circuitry specifically activated by the Tower of London). Decreased activation occurred only in the patients with high scores for negative symptoms. These results suggest that Hypofrontality is related to negative symptoms and is not a long-term effect of neuroleptic treatment or of chronicity of illness.
Judith A. Pratt - One of the best experts on this subject based on the ideXlab platform.
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Alternating Hemiplegia of Childhood-Related Neural and Behavioural Phenotypes in Na+,K+-ATPase a3 Missense Mutant Mice
2016Co-Authors: Greer S. Kirshenbaum, Neil Dawson, Judith A. Pratt, Jonathan G. L. Mullins, Tom H. Johnston, Mark J. Drinkhill, Ian J. Edwards, Susan H. Fox, Jonathan M. Brotchie, John C. RoderAbstract:Missense mutations in ATP1A3 encoding Na+,K+-ATPase a3 have been identified as the primary cause of alternating hemiplegia of childhood (AHC), a motor disorder with onset typically before the age of 6 months. Affected children tend to be of short stature and can also have epilepsy, ataxia and learning disability. The Na+,K+-ATPase has a well-known role in maintaining electrochemical gradients across cell membranes, but our understanding of how the mutations cause AHC is limited. Myshkin mutant mice carry an amino acid change (I810N) that affects the same position in Na+,K+-ATPase a3 as I810S found in AHC. Using molecular modelling, we show that the Myshkin and AHC mutations display similarly severe structural impacts on Na+,K+-ATPase a3, including upon the K+ pore and predicted K+ binding sites. Behavioural analysis of Myshkin mice revealed phenotypic abnormalities similar to symptoms of AHC, including motor dysfunction and cognitive impairment. 2-DG imaging of Myshkin mice identified compromised thalamocortical functioning that includes a deficit in frontal cortex functioning (Hypofrontality), directly mirroring that reported in AHC, along with reduced thalamocortical functional connectivity. Our results thus provide validation for missense mutations in Na+,K+-ATPase a3 as a cause of AHC
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Subanaesthetic ketamine treatment alters prefrontal cortex connectivity with thalamus and ascending subcortical systems
2011Co-Authors: Neil Dawson, Brian J. Morris, Judith A. PrattAbstract:Background: Acute treatment with subanaesthetic doses of NMDA receptor antagonists, such as ketamine, provides a translational model with relevance to many of the symp-toms of schizophrenia. Previous studies have focused specif-ically on the prefrontal cortex (PFC) because this region is implicated in many of the functional deficits associated with this disorder and shows reduced activity (Hypofrontality) in schizophrenia patients. Chronic NMDA antagonist treat-ment in rodents can also induce Hypofrontality, although paradoxically acute NMDA receptor antagonist adminis-tration induces metabolic hyperfrontality. Methods: In this study, we use 2-deoxyglucose imaging data in mice to characterize acute ketamine-induced alterations in regional functional connectivity, a deeper analysis of the consequen-ces of acute NMDA receptor hypofunction. Results: W
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subchronic and chronic pcp treatment produces temporally distinct deficits in attentional set shifting and prepulse inhibition in rats
Psychopharmacology, 2008Co-Authors: Brian J. Morris, Alice Egerton, Lee Reid, Sandie Mcgregor, Susan M Cochran, Judith A. PrattAbstract:Rationale We have previously demonstrated that subchronic (five daily administrations of 2.6 mg/kg PCP) and chronic intermittent administration of 2.6 mg/kg PCP to rats produces Hypofrontality and other neurochemical changes akin to schizophrenia pathology (Cochran et al., Neuropsychopharmacology, 28:265–275, 2003).
Heinrich Sauer - One of the best experts on this subject based on the ideXlab platform.
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decreased frontal activation in schizophrenics during stimulation with the continuous performance test a functional magnetic resonance imaging study
European Psychiatry, 1999Co-Authors: Hanspeter Volz, Christian Gaser, F Hager, R Rzanny, J Ponisch, H J Mentzel, W A Kaiser, Heinrich SauerAbstract:Summary ‐ The Continuous Performance Test (CPT) has become an essential constituent of the neuropsychological investigation of schizophrenia. Also, a vast number of brain imaging studies, mostly PET investigations, have employed the CPT as a cognitive challenge and established a relative Hypofrontality in schizophrenics compared to controls. The aim of the present investigation was to clarify whether this predescribed Hypofrontality could also be verified using functional magnetic resonance imaging (fMRI). 20 healthy volunteers and 14 schizophrenics on stable neuroleptic medication were included. Imaging was performed using the CPT-double-T-version and a clinical 1.5 T MRI-scanner with a single slice technique and a T2*-weighted gradient-echo-sequence. The schizophrenics exhibited a decreased activation in the right mesial prefrontal cortex, the right cingulate and the left thalamus compared to controls. These results obtained by fMRI are discussed in relation to published findings using PET. © Elsevier, Paris functional magnetic resonance imaging / schizophrenia / attention / Hypofrontality
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decreased frontal activation in schizophrenics during stimulation with the continuous performance test a functional magnetic resonance imaging study
European Psychiatry, 1999Co-Authors: Hanspeter Volz, Christian Gaser, F Hager, R Rzanny, J Ponisch, H J Mentzel, W A Kaiser, Heinrich SauerAbstract:The Continuous Performance Test (CPT) has become an essential constituent of the neuropsychological investigation of schizophrenia. Also, a vast number of brain imaging studies, mostly PET investigations, have employed the CPT as a cognitive challenge and established a relative Hypofrontality in schizophrenics compared to controls. The aim of the present investigation was to clarify whether this predescribed Hypofrontality could also be verified using functional magnetic resonance imaging (fMRI). 20 healthy volunteers and 14 schizophrenics on stable neuroleptic medication were included. Imaging was performed using the CPT-double-T-version and a clinical 1.5 T MRI-scanner with a single slice technique and a T2*-weighted gradient-echo-sequence. The schizophrenics exhibited a decreased activation in the right mesial prefrontal cortex, the right cingulate and the left thalamus compared to controls. These results obtained by fMRI are discussed in relation to published findings using PET.
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Decreased Frontal Activation in Schizophrenics during Stimulation with the Continuous Performance Test - a functional magnetic resonance imaging study
1999Co-Authors: -p. H. Volz, Christian Gaser, F Hager, R Rzanny, H J Mentzel, W A Kaiser, J. Pnisch, Heinrich SauerAbstract:INTRODUCTION One major finding of functional brain imaging studies in schizophrenia is Hypofrontality [4, 51]. This finding is inconsistent when patients are investigated at rest, some studies even demonstrated an increased activity in the frontal lobe especially when acute, neuroleptic free patients [15] were studied. Cognitive challenges more or less specific for frontal lobe functions increase the likelihood to detect Hypofrontality. The most widely used tests to demonstrate this behaviour-specific Hypofrontality are the Wisconsin Card Sorting Test (WCST), involving working memory and the ability to adapt behaviour based on performance feedback [30, 49], the Raven Progressive Matrices, which tap the ability to perceive sequential non-verbal abstract patterns [7, 27, 41], and the Continuous Performance Test (CPT). As animal studies suggest [31] attention requires the integrity of cingulate, thalamic, inferior parietal and prefrontal cortical function, with right hemisphere structu
Nancy C Andreasen - One of the best experts on this subject based on the ideXlab platform.
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Hypofrontality in neuroleptic naive patients and in patients with chronic schizophrenia assessment with xenon 133 single photon emission computed tomography and the tower of london
Archives of General Psychiatry, 1992Co-Authors: Nancy C Andreasen, Karim Rezai, Randall Alliger, Victor W Swayze, Michael Flaum, Peter T Kirchner, Gregg Cohen, Daniel S OlearyAbstract:The "Hypofrontality hypothesis" has been supported by many neuroimaging studies, but not all, perhaps because of heterogeneity of samples. The present study examined three different samples that permitted assessment of a variety of confounders, such as effects of long-term treatment, chronicity of illness, and presenting phenomenology: (1) 13 neuroleptic-naive schizophrenic patients, (2) 23 nonnaive schizophrenic patients who had been relatively chronically ill but were medication free for at least 3 weeks, and (3) 15 healthy normal volunteers. Regional cerebral blood flow was measured using single-photon emission computed tomography with xenon 133 as the tracer. The control condition consisted of looking at undulating colored shapes on a video monitor, while the experimental task was the Tower of London. We observed the Tower of London to be a relatively specific stimulant of the left mesial frontal cortex (probably including parts of the cingulate gyrus) in healthy normal volunteers. Both the neuroleptic-naive and the nonnaive patients lacked this area of activation, as well as a related one in the right parietal cortex (representing the circuitry specifically activated by the Tower of London). Decreased activation occurred only in the patients with high scores for negative symptoms. These results suggest that Hypofrontality is related to negative symptoms and is not a long-term effect of neuroleptic treatment or of chronicity of illness.