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Cook D.G.,Geriatric Research Education and Clinical Center | D'Ambrosio R.,Regional Epilepsy Center | D'Ambrosio R.,University of Washington | D'Ambrosio R.,Harborview Medical Center
Journal of Neurophysiology | Year: 2010

Astrocytic inwardly rectifying K+ currents (IIRK) have an important role in extracellular K+ homeostasis, which influences neuronal excitability, and serum extravasation has been linked to impaired KIR-mediated K+ buffering and chronic hyperexcitability. Head injury induces acute impairment in astroglial membrane IKIR and impaired K+ buffering in the rat hippocampus, but chronic spontaneous seizures appear in the perilesional neocortex- not the hippocampus-in the early weeks to months after injury. Thus we examined astrocytic KIR channel pathophysiology in both neocortex and hippocampus after rostral parasaggital fluid percussion injury (rpFPI). rpFPI induced greater acute serum extravasation and metabolic impairment in the perilesional neocortex than in the underlying hippocampus, and in situ whole cell recordings showed a greater acute loss of astrocytic IKIR in neocortex than hippocampus. IKIR loss persisted through 1 mo after injury only in the neocortical epileptic focus, but fully recovered in the hippocampus that did not generate chronic seizures. Neocortical cell-attached recordings showed no loss or an increase of IIRK in astrocytic somata. Confocal imaging showed depletion of KIR 4.1 immunoreactivity especially in processes-not somata-of neocortical astrocytes, whereas hippocampal astrocytes appeared normal. In naïve animals, intracortical infusion of serum, devoid of coagulation-mediating thrombin activity, reproduces the effects of rpFPI both in vivo and at the cellular level. In vivo serum infusion induces partial seizures similar to those induced by rpFPI, whereas bath-applied serum, but not dialyzed albumin, rapidly silenced astrocytic KIR membrane currents in whole cell and cellattached patch-clamp recordings in situ. Thus both acute impairment in astrocytic IKIR and chronic spontaneous seizures typical of rpFPI are reproduced by serum extravasation, whereas the chronic impairment in astroglial IKIR is specific to the neocortex that develops the epileptic focus. Copyright © 2010 The American Physiological Society.


Prete G.,University of Chieti Pescara | Laeng B.,University of Oslo | Fabri M.,Marche Polytechnic University | Foschi N.,Regional Epilepsy Center | Tommasi L.,University of Chieti Pescara
Neuropsychologia | Year: 2015

The valence hypothesis and the right hemisphere hypothesis in emotion processing have been alternatively supported. To better disentangle the two accounts, we carried out two studies, presenting healthy participants and an anterior callosotomized patient with 'hybrid faces', stimuli created by superimposing the low spatial frequencies of an emotional face to the high spatial frequencies of the same face in a neutral expression. In both studies we asked participants to judge the friendliness level of stimuli, which is an indirect measure of the processing of emotional information, despite this remaining "invisible". In Experiment 1 we presented hybrid faces in a divided visual field paradigm using different tachistoscopic presentation times; in Experiment 2 we presented hybrid chimeric faces in canonical view and upside-down. In Experiments 3 and 4 we tested a callosotomized patient, with spared splenium, in similar paradigms as those used in Experiments 1 and 2. Results from Experiments 1 and 3 were consistent with the valence hypothesis, whereas results of Experiments 2 and 4 were consistent with the right hemisphere hypothesis. This study confirms that the low spatial frequencies of emotional faces influence the social judgments of observers, even when seen for 28. ms (Experiment 1), possibly by means of configural analysis (Experiment 2). The possible roles of the cortical and subcortical emotional routes in these tasks are discussed in the light of the results obtained in the callosotomized patient. We propose that the right hemisphere and the valence accounts are not mutually exclusive, at least in the case of subliminal emotion processing. © 2015 Elsevier Ltd.


Prete G.,University of Chieti Pescara | D'Ascenzo S.,University of Modena and Reggio Emilia | Laeng B.,University of Oslo | Fabri M.,Marche Polytechnic University | And 2 more authors.
Journal of Neuropsychology | Year: 2015

We investigated how the brain's hemispheres process explicit and implicit facial expressions in two 'split-brain' patients (one with a complete and one with a partial anterior resection). Photographs of faces expressing positive, negative or neutral emotions were shown either centrally or bilaterally. The task consisted in judging the friendliness of each person in the photographs. Half of the photograph stimuli were 'hybrid faces', that is an amalgamation of filtered images which contained emotional information only in the low range of spatial frequency, blended to a neutral expression of the same individual in the rest of the spatial frequencies. The other half of the images contained unfiltered faces. With the hybrid faces the patients and a matched control group were more influenced in their social judgements by the emotional expression of the face shown in the left visual field (LVF). When the expressions were shown explicitly, that is without filtering, the control group and the partially callosotomized patient based their judgement on the face shown in the LVF, whereas the complete split-brain patient based his ratings mainly on the face presented in the right visual field. We conclude that the processing of implicit emotions does not require the integrity of callosal fibres and can take place within subcortical routes lateralized in the right hemisphere. © 2013 The British Psychological Society.


Prete G.,University of Chieti Pescara | Marzoli D.,University of Chieti Pescara | Brancucci A.,University of Chieti Pescara | Fabri M.,Marche Polytechnic University | And 2 more authors.
Behavioural Brain Research | Year: 2014

Hemispheric asymmetries have been widely explored in both the visual and the auditory domain, but little is known about hemispheric asymmetries in audio-visual integration. We compared the performance of a partially callosotomized patient, a total split-brain patient and a control group during the evaluation of the emotional valence of chimeric faces and dichotic syllables (an emotional syllable in one ear and white noise in the other ear) presented unimodally (only faces or only syllables) or bimodally (faces and syllables presented simultaneously). Stimuli could convey happy and sad expressions and participants were asked to evaluate the emotional content of each presentation, using a 5-point Likert scale (from very sad to very happy). In unimodal presentations, the partially callosotomized patient's judgments depended on the emotional valence of the stimuli processed by the right hemisphere, whereas those of the total split-brain patient showed the opposite lateralization; in these conditions, the control group did not show asymmetries. Moreover, in bimodal presentations, results provided support for the valence hypothesis (i.e., left asymmetry for positive emotions and vice versa) in both the control group and the partially callosotomized patient, whereas the total split-brain patient showed a tendency to evaluate the emotional content of the right hemiface even when asked to focus on the acoustic modality. We conclude that partial and total hemispheric disconnections reveal opposite patterns of hemispheric asymmetry in auditory, visual and audio-visual emotion processing. These results are discussed in the light of the right-hemisphere hypothesis and the valence hypothesis. © 2014 Elsevier B.V.


PubMed | Regional Epilepsy Center, Marche Polytechnic University and University of Chieti Pescara
Type: | Journal: Journal of neuropsychology | Year: 2016

A right-hemispheric superiority in spatial encoding based on geometric cues has been largely documented in a variety of species, together with a left-hemispheric specialization for encoding based on landmarks. In humans, hemispheric asymmetries for spatial encoding have been little explored. In this study, we compared a patient with a complete callosal resection (D.D.C.) and a patient with a wide callosal resection saving the splenium (A.P.), with healthy participants. In two 2D versions of the reorientation task, participants were asked to find the target corner of a rectangle-shaped environment, by exploiting either geometric information alone or the combination of geometric and landmark information. In Experiment 1, the landmark consisted of a coloured side of the rectangle; in Experiment 2, this cue was replaced by a coloured disc located inside the rectangle. In both experiments, the rectangular shape ensured the geometric cue. D.D.C. was always unable to recall the target, whereas A.P. correctly solved the task when only the geometric information was available, without difference with respect to the controls. Importantly, the performance of A.P. did not differ from controls when the right hemisphere was tested with the landmark cues (the task being carried out using the left hand), whereas when the left hemisphere was tested (right-hand session) his performance was worse than controls with the coloured side of the space, but it was better than controls with the coloured disc. The results are discussed comparing them with data collected on other species, and with theories of spatial processing.


PubMed | Regional Epilepsy Center, Marche Polytechnic University and University of Chieti Pescara
Type: | Journal: Neuroscience | Year: 2016

We investigated hemispheric asymmetries in categorization of face gender by means of a divided visual field paradigm, in which female and male faces were presented unilaterally for 150ms each. A group of 60 healthy participants (30 males) and a male split-brain patient (D.D.C.) were asked to categorize the gender of the stimuli. Healthy participants categorized male faces presented in the right visual field (RVF) better and faster than when presented in the left visual field (LVF), and female faces presented in the LVF than in the RVF, independently of the participants sex. Surprisingly, the recognition rates of D.D.C. were at chance levels - and significantly lower than those of the healthy participants - for both female and male faces presented in the RVF, as well as for female faces presented in the LVF. His performance was higher than expected by chance - and did not differ from controls - only for male faces presented in the LVF. The residual right-hemispheric ability of the split-brain patient in categorizing male faces reveals an own-gender bias lateralized in the right hemisphere, in line with the rightward own-identity and own-age bias previously shown in split-brain patients. The gender-contingent hemispheric dominance found in healthy participants confirms the previously shown right-hemispheric superiority in recognizing female faces, and also reveals a left-hemispheric superiority in recognizing male faces, adding an important evidence of hemispheric imbalance in the field of face and gender perception.


Conant L.L.,Medical College of Wisconsin | Wilfong A.,Baylor College of Medicine | Inglese C.,Regional Epilepsy Center | Schwarte A.,St Vincent Hospital Indiana Neuroscience Institute
Epilepsy and Behavior | Year: 2010

The nature and extent of the neuropsychological difficulties associated with childhood absence epilepsy (CAE) remain unclear. Because aberrant thalamocortical rhythms have been implicated in the pathogenesis of CAE, it was hypothesized that children with CAE would show greater difficulties in neuropsychological domains that are thought to be subserved by basal ganglia-thalamocortical circuits. Multivariate analysis of variance was used to compare the neuropsychological functioning of 16 children with CAE with that of 14 children with type 1 diabetes mellitus and 15 healthy children. The CAE group did not perform differently from the other groups on measures of intellectual functioning, memory, academic achievement, fine motor speed, or processing speed. In contrast, significant differences were found in problem solving, letter fluency, complex motor control, attention/behavioral inhibition, and psychosocial functioning. These results suggest that children with CAE show difficulties in neuropsychological functions thought to be subserved by the same regions implicated in the pathogenesis of the disorder. © 2010 Elsevier Inc.


Williamson D.J.,United Mobile | Williamson D.J.,University of South Alabama | Holsman M.,Puget Sound Veteran Affairs | Chaytor N.,University of Washington | And 5 more authors.
Clinical Neuropsychologist | Year: 2012

Participants with psychogenic non-epileptic seizures (PNES) who fail symptom validity testing (SVT) perform worse on neuropsychological testing than those who do not, consistent with results found in participants with different clinical presentations (e.g., mild traumatic brain injury). However, little is known about how variables typically associated with SVT failure in other populations (e.g., the presence of financial incentives, exaggerated report of psychopathology) correlate with SVT failure in participants with PNES. Likewise the relationship between SVT failure and reported abuse, one of the most frequently described demographic characteristics of the PNES population, has not been examined. We found that failure on the Word Memory Test (WMT) in 91 participants with PNES was strongly associated with reported abuse but, contrary to expectations, was not associated with the presence of financial incentives or severity of reported psychopathology. These results indicate that the factors driving WMT failure may differ significantly in participants with PNES in ways that are potentially clinically relevant. © 2012 Taylor & Francis Group, LLC.


Aguglia U.,University of Catanzaro | Aguglia U.,Regional Epilepsy Center | Beghi E.,Mario Negri Institute for Pharmacological Research | Labate A.,University of Catanzaro | And 10 more authors.
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2011

Purpose To study prognosis and prognostic predictors of sporadic non-lesional temporal lobe epilepsy (TLE). Method 474 patients with TLE were consecutively seen from April 1987 to April 2004. 190 had a sporadic non-lesional TLE and a follow-up longer than 2 years. 284 patients were excluded because of family history for TLE, incomplete history, poor compliance with treatment, psychogenic seizures, no brain MRI study, presence of intracranial lesions except for scattered T2 hyperintense spots on hemispheric white matter or mesial temporal sclerosis (MTS). The following prognostic predictors were considered: age at onset of epilepsy, gender, family history of non-TLE or febrile seizures, perinatal factors, history of febrile seizures, ictal phenomena, MTS and interictal EEG. The end point was time to 24 month seizure freedom after treatment onset. The X2 test, Student's t test, Kaplane-Meier survival curves with log rank test (univariate analysis) and Cox proportional hazards regression models (multivariate analysis) were used to assess seizure prognosis and prognostic predictors. Results At univariate analysis, patients achieving 24 month seizure freedom had a significantly older age at onset of epilepsy (33.5 ±19.9 vs 17.2 ±14.4 years), and lower occurrence of febrile seizures (11.0% vs 24.4%) and MTS (19.0% vs 35.6%). The chance of remission was directly correlated to age at onset of seizures and inversely correlated to a history of febrile seizures and to the presence of MTS. At multivariate analysis, age at onset of epilepsy was the only significant prognostic predictor. Conclusion Older age at onset predicts better prognosis in sporadic non-lesional TLE.


Thompson A.W.,University of Washington | Thompson A.W.,Regional Epilepsy Center | Hantke N.,Regional Epilepsy Center | Phatak V.,Regional Epilepsy Center | And 3 more authors.
Epilepsia | Year: 2010

Using 184 subjects with valid personality assessment interview (PAI) profiles and video-electroencephalography (VEEG)-confirmed diagnoses of epileptic seizures (ES; n = 109) or psychogenic nonepileptic seizures (PNES; n = 75), we present the diagnostic test performance of the PAI PNES Indicator and other PAI scales when used to differentiate PNES from ES. Subjects with PNES reported significantly higher somatic, conversion, depressed, anxious, and suicidal symptoms. As a diagnostic tool, the PNES Indicator does not add additional accuracy beyond the conversion subscale (SOM-C). The somatization (SOM-S) and physiological depression (DEP-P) subscales perform as well as the SOM-C subscale. The SOM-C scale (cut point ≥70) was 58.7% sensitive and 83.5% specific at diagnosing PNES. Assuming a 30% prevalence of PNES, the SOM-C scale has a positive predictive value (PPV) of 60.4% and negative predictive value (NPV) of 82.5%. Overall, the PAI SOM-C subscale does not appear more accurate than other psychometric tests used to differentiate PNES from ES. © 2009 International League Against Epilepsy.

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