Anto Bagic

Essential services, personnel, and facilities in specialized epilepsy centers-Revised 2010 guidelines

This document was developed by the members of the Committee to Revise the Guidelines for Services, Personnel, and Facilities at Specialized Epilepsy Centers. After discussions with the general membership they were adopted by the Board of the National Association of Epilepsy Centers. The Guidelines will be reviewed and updated when considered necessary by the Board.

Widespread abnormality of the γ-aminobutyric acid-ergic system in Tourette syndrome

Dysfunction of the γ-aminobutyric acid-ergic system in Tourette syndrome may conceivably underlie the symptoms of motor disinhibition presenting as tics and psychiatric manifestations, such as attention deficit hyperactivity disorder and obsessive-compulsive disorder. The purpose of this study was to identify a possible dysfunction of the γ-aminobutyric acid-ergic system in Tourette patients, especially involving the basal ganglia-thalamo-cortical circuits and the cerebellum. We studied 11 patients with Tourette syndrome and 11 healthy controls. Positron emission tomography procedure: after injection of 20 mCi of [(11)C]flumazenil, dynamic emission images of the brain were acquired. Structural magnetic resonance imaging scans were obtained to provide an anatomical framework for the positron emission tomography data analysis. Images of binding potential were created using the two-step version of the simplified reference tissue model. The binding potential images then were spatially normalized, smoothed and compared between groups using statistical parametric mapping. We found decreased binding of GABA(A) receptors in Tourette patients bilaterally in the ventral striatum, globus pallidus, thalamus, amygdala and right insula. In addition, the GABA(A) receptor binding was increased in the bilateral substantia nigra, left periaqueductal grey, right posterior cingulate cortex and bilateral cerebellum. These results are consistent with the longstanding hypothesis that circuits involving the basal ganglia and thalamus are disinhibited in Tourette syndrome patients. In addition, the abnormalities in GABA(A) receptor binding in the insula and cerebellum appear particularly noteworthy based upon recent evidence implicating these structures in the generation of tics.

Prefrontal Dynamics Underlying Rapid Instructed Task Learning Reverse with Practice

The ability to rapidly reconfigure our minds to perform novel tasks is important for adapting to an ever-changing world, yet little is understood about its basis in the brain. Furthermore, it is unclear how this kind of task preparation changes with practice. Previous research suggests that prefrontal cortex (PFC) is essential when preparing to perform either novel or practiced tasks. Building upon recent evidence that PFC is organized in an anterior-to-posterior hierarchy, we postulated that novel and practiced task preparation would differentiate hierarchically distinct regions within PFC across time. Specifically, we hypothesized and confirmed using functional magnetic resonance imaging and magnetoencephalography with humans that novel task preparation is a bottom-up process that involves lower-level rule representations in dorsolateral PFC (DLPFC) before a higher-level rule-integrating task representation in anterior PFC (aPFC). In contrast, we identified a complete reversal of this activity pattern during practiced task preparation. Specifically, we found that practiced task preparation is a top-down process that involves a higher-level rule-integrating task representation (recalled from long-term memory) in aPFC before lower-level rule representations in DLPFC. These findings reveal two distinct yet highly inter-related mechanisms for task preparation, one involving task set formation from instructions during rapid instructed task learning and the other involving task set retrieval from long-term memory to facilitate familiar task performance. These two mechanisms demonstrate the exceptional flexibility of human PFC as it rapidly reconfigures cognitive brain networks to implement a wide variety of possible tasks.

Olfactory pathogenesis of idiopathic Parkinson disease revisited

Idiopathic Parkinson disease (PD) is traditionally considered a movement disorder with hallmark lesions located in the substantia nigra pars compacta (SNpc). However, recent histopathological studies of some PD cases suggest the possibility of a multisystem disorder which progresses in a predictable sequence as described in Braaks staging criteria. The disease process starts in the dorsal motor nucleus of the vagus (dmX) and anterior olfactory nucleus and bulb, and from there, spreads through the brainstem nuclei to ultimately reach the SNpc, which then presents as symptomatic PD. In this article, we would like to revisit the olfactory pathogenesis of PD based on Braaks staging system and review anatomical pathways supporting such a possibility. We also suggest some biomarkers for early stages of PD. Additionally, we present and discuss the possibility that a prion‐like process underlies the neurodegenerative changes in PD.

Involvement of Insula and Cingulate Cortices in Control and Suppression of Natural Urges

The physiology of control and suppression of natural urges is not well understood. We used [(15)O]H(2)O positron-emission tomography imaging to identify neural circuits involved in suppression of spontaneous blinking as a model of normal urges. Suppression of blinking was associated with prominent activation of bilateral insular-claustrum regions, right more than left; activation was also found in bilateral anterior cingulate cortex (ACC), supplementary motor areas, and the face area of the primary motor cortex bilaterally. These results suggest a central role for the insula possibly together with ACC in suppression of blinking.

Decoding and Cortical Source Localization for Intended Movement Direction With MEG

Magnetoencephalography (MEG) enables a noninvasive interface with the brain that is potentially capable of providing movement-related information similar to that obtained using more invasive neural recording techniques. Previous studies have shown that movement direction can be decoded from multichannel MEG signals recorded in humans performing wrist movements. We studied whether this information can be extracted without overt movement of the subject, because the targeted users of brain-controlled interface (BCI) technology are those with severe motor disabilities. The objectives of this study were twofold: 1) to decode intended movement direction from MEG signals recorded during the planning period before movement onset and during imagined movement and 2) to localize cortical sources modulated by intended movement direction. Ten able-bodied subjects performed both overt and imagined wrist movement while their cortical activities were recorded using a whole head MEG system. The intended movement direction was decoded using linear discriminant analysis and a Bayesian classifier. Minimum current estimation (MCE) in combination with a bootstrapping procedure enabled source-space statistical analysis, which showed that the contralateral motor cortical area was significantly modulated by intended movement direction, and this modulation was the strongest ∼100 ms before the onset of overt movement. These results suggest that it is possible to study cortical representation of specific movement information using MEG, and such studies may aid in presurgical localization of optimal sites for implanting electrodes for BCI systems.

American Clinical Magnetoencephalography Society Clinical Practice Guideline 1: recording and analysis of spontaneous cerebral activity.

The following are considered “minimum standards” for the routine clinical recording and analysis of spontaneous magnetoencephalography (MEG) and EEG in all age-groups. Practicing at minimum standards should not be the goal of an MEG center but rather a starting level for continued improvement. Minimum standards meet only the most basic responsibilities of the patient and the referring physician. These minimum standards have been put forth to improve standardization of procedures and to facilitate interchange of recordings and reports among laboratories (centers) in the United States. Epilepsy is currently the only approved clinical indication for recordings of spontaneous cerebral activity.

Panic attack symptoms differentiate patients with epilepsy from those with psychogenic nonepileptic spells (PNES)

Psychogenic nonepileptic spells (PNES) are frequently challenging to differentiate from epileptic seizures. The experience of panic attack symptoms during an event may assist in distinguishing PNES from seizures secondary to epilepsy. A retrospective analysis of 354 patients diagnosed with PNES (N=224) or with epilepsy (N=130) investigated the thirteen Diagnostic and Statistical Manual-IV-Text Revision panic attack criteria endorsed by the two groups. We found a statistically higher mean number of symptoms reported by patients with PNES compared with those with epilepsy. In addition, the majority of the panic attack symptoms including heart palpitations, sweating, shortness of breath, choking feeling, chest discomfort, dizziness/unsteadiness, derealization or depersonalization, fear of dying, paresthesias, and chills or hot flashes were significantly more frequent in those with PNES. As patients with PNES frequently have poor clinical outcomes, treatment addressing the anxiety symptomatology may be beneficial.

American Clinical Magnetoencephalography Society Clinical Practice Guideline 2: Presurgical Functional Brain Mapping Using Magnetic Evoked Fields

The following are “minimum standards” for the routine clinical recording of magnetic evoked fields (MEFs) in all age-groups. Practicing at minimum standards should not be the goal of a magnetoencephalography (MEG) center but rather a starting level for continued improvement. Minimum standards meet only the most basic responsibilities to the patient and the referring physician. These minimum standards have been put forth to improve standardization of procedures, to facilitate interchange of recordings and reports among laboratories in the United States, and to confirm the expectations of referring physicians. Recommendations regarding Laboratory (Center) Environment and Preparation for MEG Recordings are detailed in the American Clinical Magnetoencephalography Society Clinical Practice Guideline (CPG) 1 : Recording and Analysis of Spontaneous Cerebral Activity, except for its EEG aspect that is not considered necessary (although may be helpful in trained hands) for MEFs (presurgical functional brain mapping).

Medical comorbidities in patients with psychogenic nonepileptic spells (PNES) referred for video-EEG monitoring

Differentiating between psychogenic nonepileptic spells (PNES) and epileptic seizures without video-EEG monitoring is difficult. The presence of specific medical comorbidities may discriminate the two, helping physicians suspect PNES over epilepsy earlier. A retrospective analysis comparing the medical comorbidities of patients with PNES with those of patients with epilepsy was performed in 280 patients diagnosed with either PNES (N = 158, 74.7% females) or epilepsy (N = 122, 46.7% females) in the Epilepsy Monitoring Unit (EMU) of the University of Pittsburgh Medical Center over a two-year period. Patients with PNES, compared to those with epilepsy, were mostly female, significantly more likely to have a history of abuse, had more functional somatic syndromes (fibromyalgia, chronic fatigue syndrome, chronic pain syndrome, tension headaches, and irritable bowel syndrome), and had more medical illnesses that are chronic with intermittent attacks (migraines, asthma, and GERD). The presence of at least of one these disorders may lead physicians to suspect PNES over epilepsy and expedite appropriate referral for video-EEG monitoring for diagnosis.