The long-term development of public attitudes towards people with epilepsy in the Czech Republic: 1981, 1984, 1998 and 2009 studies.

OBJECTIVE: The long-term development of public attitudes towards people with epilepsy (PWE) was studied. METHODS: Four questions (Q) used in Czech questionnaires for studies in 1981, 1984, 1998 and 2009 concerned: Q1, familiarity with the concept of epilepsy; Q2, tolerance towards children with epilepsy; Q3, whether epilepsy is considered to be a mental disease; and Q4, attitudes towards employment of PWE. RESULTS: The quality of information about epilepsy increased significantly between 1981 and 1998, 1981 and 2009, and 1998 and 2009. The 1981 and 1984 studies reflected a level of information inferior to the levels seen in Germany and the USA, and the difference had almost disappeared in 1998 and 2009. CONCLUSIONS: The long-term follow-up studies in Czech Republic displayed a permanent increase in knowledge about epilepsy. This may reflect the progress in the spread of information, the efforts of patient associations and specialists and perhaps also a change in general attitudes towards people with disabilities. The dramatic change of information levels in Czech surveys could also reflect the change of the political system in 1989. A question that remains to be answered is the extent to which the positive trend reflects positive attitudes in real life. The answers to questions concerning whether people would be willing to help a person having a seizure remain unsatisfactory. Greater efforts should be made to improve the situation of PWE and to minimize their stigmatization.

The posterior medial cortex is involved in visual but not in verbal memory encoding processing: an intracerebral recording study.

The objective is to study the involvement of the posterior medial cortex (PMC) in encoding and retrieval by visual and auditory memory processing. Intracerebral recordings were studied in two epilepsy-surgery candidates with depth electrodes implanted in the retrosplenial cingulate, precuneus, cuneus, lingual gyrus and hippocampus. We recorded the event-related potentials (ERP) evoked by visual and auditory memory encoding-retrieval tasks. In the hippocampus, ERP were elicited in the encoding and retrieval phases in the two modalities. In the PMC, ERP were recorded in both the encoding and the retrieval visual tasks; in the auditory modality, they were recorded in the retrieval task, but not in the encoding task. In conclusion, the PMC is modality dependent in memory processing. ERP is elicited by memory retrieval, but it is not elicited by auditory encoding memory processing in the PMC. The PMC appears to be involved not only in higher-order top-down cognitive activities but also in more basic, rather than bottom-up activities.

Long-term vagus nerve stimulation in children with focal epilepsy.

OBJECTIVES: The aim of the study was to evaluate the long-term efficacy and hospitalization rates in children with refractory focal epilepsy treated by vagus nerve stimulation. MATERIALS AND METHODS: We retrospectively analyzed 15 children with intractable focal epilepsy treated by vagus nerve stimulation (mean age of 14.6 ± 2.5 years at the time of implantation). We analyzed the treatment effectiveness at 1, 2, and 5 year follow-up visits. We counted the average number of urgent hospitalizations and number of days of urgent hospitalization per year for each patient before and after the VNS implantation. RESULTS: The mean seizure reduction was 42.5% at 1 year, 54.9% at 2 years, and 58.3% at 5 years. The number of responders was 7 (46.7%) at 1 year and 9 (60%) at both 2 and 5 years. The mean number of urgent hospitalizations per patient was 1.0 ± 0.6 per year preoperatively and 0.3 ± 0.5 per year post-operatively (P < 0.0001). The mean number of days of urgent hospitalization per patient was 9.3 ± 6.1 per year preoperatively and 1.3 ± 1.8 per year post-operatively ( < 0.0001). CONCLUSIONS: Vagus nerve stimulation is an effective method of treating children with refractory focal epilepsy. It leads to a substantial decrease in the number and duration of urgent hospitalizations.

Tolerability and safety of perampanel: two randomized dose-escalation studies.

OBJECTIVES: To evaluate, for the first time in patients with epilepsy, the tolerability and safety of escalating doses of oral perampanel, a novel, selective, non-competitive AMPA antagonist, as adjunctive therapy for refractory partial-onset seizures. MATERIALS AND METHODS: Two consecutive, randomized, double-blind, dose-escalation studies recruited adults (18-70 years) with uncontrolled partial-onset seizures receiving one to three concomitant antiepileptic drugs. In study 206, patients were treated for 12 weeks (8-week dose-titration, 4-week dose-maintenance) with placebo or perampanel (up to 4 mg/day, dosed once- or twice-daily). In study 208, patients received placebo or perampanel once-daily (up to 12 mg) for 16 weeks (12-week titration, 4-week maintenance). RESULTS: Overall, 153 patients were randomized into study 206 (perampanel twice-daily, n = 51; perampanel once-daily, n = 51; placebo, n = 51). Study 208 included 48 patients (perampanel once-daily, n = 38; placebo, n = 10). The highest dose in study 206 - 4 mg/day - was well tolerated, with similar proportions of patients tolerating once-daily (82.4%) and twice-daily (82.4%) perampanel and placebo (82.4%) treatments. In study 208 most patients tolerated doses of ≥ 6 mg perampanel once-daily in a Kaplan-Meier analysis. In both studies, the most common adverse events were CNS-related; most were of mild/moderate severity. CONCLUSIONS: Perampanel was well tolerated across doses of 4-12 mg/day. The studies showed preliminary evidence of efficacy and identified doses to be evaluated in larger clinical studies.

Perampanel Study 207: long-term open-label evaluation in patients with epilepsy.

OBJECTIVES: Evaluate interim long-term tolerability, safety and efficacy of adjunctive perampanel, a novel α-amino-3-hydroxy-5-methyl-5-isoxazolepropionic acid (AMPA)-receptor antagonist, in patients with refractory partial-onset seizures. MATERIALS AND METHODS: Study 207, an open-label extension (OLE) study (ClinicalTrials.gov identifier: NCT00368472), enrolled patients (18-70 years) who completed one of two randomized, placebo-controlled, dose-escalation Phase II studies. The OLE Treatment Phase comprised a 12-week Titration Period (2 mg increments of perampanel every 2 weeks to 12 mg/day, maximum) and a Maintenance Period, during which patients continued treatment up to a planned maximum of 424 weeks (~8 years). Interim analysis data cut-off date was 1 December, 2010. RESULTS: Of 180 patients completing the Phase II studies, 138 enrolled in study 207. At the time of interim analyses (approximately 4 years after study start), over a third (n = 53, 38.4%) remained on perampanel; 41.3% (n = 57) of patients had >3 years of exposure; and 13.0% (n = 18) had at least 4 years' exposure. Mean ± standard deviation (SD) duration of exposure was 116 ± 75 weeks and mean ± SD dose during the OLE Maintenance Period was 7.3 ± 3.3 mg. No new safety signals emerged with long-term treatment. Consistent with previous studies, the most common treatment-emergent adverse events were as follows: dizziness, headache and somnolence. Overall median (range) per cent change from baseline in seizure frequency per 28 days during open-label treatment was -31.5% (-99.2 to 512.2). CONCLUSIONS: Long-term - up to 4 years - adjunctive perampanel had a favourable tolerability profile in patients with refractory partial-onset seizures. Improvements in seizure control were maintained with long-term treatment.

Involvement of the subthalamic nucleus and globus pallidus internus in attention.

We studied the appearance of cognitive event-related potentials (ERPs) and event-related de/synchronizations (ERD/S) in the subthalamic nucleus (STN) and globus pallidus internus (GPi). We particularly focused on the rare non-target (distractor) stimuli processing. ERPs and ERD/S in the alpha and beta frequency range were analyzed in seven Parkinson's disease patients and one primary dystonia patient with implanted deep brain stimulation (DBS) electrodes. A visual three-stimulus protocol was used (frequent stimulus, target stimulus, and distractor). The non-target and distractor-related waveforms manifested similar shapes. A specific positive ERP peak around 200 ms and a low alpha frequency ERS were detected from the STN as a response to the distractor stimuli in six of the patients with Parkinson's disease and also in the primary dystonia patient's GPi. This positivity probably reflects an attentional orienting response to the distractor stimuli. The STN and GPi are probably involved in attentional cerebral networks.

Peri-ictal bed leaving in temporal lobe epilepsy: incidence and lateralizing value.

We analyzed peri-ictal bed leaving (PBL) symptoms in 105 patients with temporal lobe epilepsy (TLE). All patients were classified as Engel I at the 2-year follow-up visit. Histopathological examination revealed hippocampal sclerosis (TLE-HS) in 64 patients and other lesions in 38 patients (TLE-other); 3 patients had no lesions. We reviewed 412 seizures. PBL was defined as lateralized leaving of the bed occurring during the seizure or up to 3 minutes after the end of the seizure. PBL was observed in 28 of 105 patients (26.7%), and in 45 of 412 seizures (10.9%). PBL occurred more frequently in patients with TLE-HS than in patients with TLE-other (32.8% vs 17.1%, P=0.058). PBL was ipsilateral to the seizure onset in 71.4% of patients and 71.2% of seizures (P=0.012 and P<0.001). In patients with TLE-HS, PBL was ipsilateral to seizure onset in 76.2% of patients and 81.2% of seizures (P=0.008 and P<0.001). In patients with TLE-other, PBL was ipsilateral to seizure onset in 42.8% of patients and 46.1% of seizures. There were no differences in the incidence and lateralizing value between patients with right-sided and those with left-sided TLE. PBL is a relatively frequent peri-ictal sign in patients with TLE. The side of PBL in patients with TLE-HS lateralizes the seizure onset to the ipsilateral temporal lobe.

The effect of cortical repetitive transcranial magnetic stimulation on cognitive event-related potentials recorded in the subthalamic nucleus.

We studied whether the cognitive event-related potentials (ERP) in the subthalamic nucleus (STN) are modified by the modulation of the inferior frontal cortex (IFC) and the dorsolateral prefrontal cortex (DLPFC) with repetitive transcranial magnetic stimulation (rTMS). Eighteen patients with Parkinson's disease who had been implanted with a deep brain stimulation (DBS) electrode were included in the study. The ERPs were recorded from the DBS electrode before and after the rTMS (1 Hz, 600 pulses) over either the right IFC (10 patients) or the right DLPFC (8 patients). The ERPs were generated by auditory stimuli. rTMS over the right IFC led to a shortening of ERP latencies from 277 +/- 14 ms (SD) to 252 +/- 19 ms in the standard protocol and from 296 +/- 17 ms to 270 +/- 20 ms in the protocol modified by a higher load of executive functions (both P < 0.01). The application of rTMS over the DLPFC and the sham stimulation over the IFC showed no significant changes. The shortening of ERP latency after rTMS over the right IFC reflected the increase in the speed of the cognitive process. The rTMS modulation of activity of the DLPFC did not influence the ERP. Connections (the IFC-STN hyperdirect pathway) with the cortex that bypass the BG-thalamocortical circuitries could explain the position of the STN in the processing of executive functions.

Long-term levetiracetam treatment in patients with epilepsy: 3-year follow up.

OBJECTIVES: To assess the long-term efficacy and tolerability of levetiracetam in routine clinical practice. MATERIALS AND METHODS: We retrospectively analysed 218 patients, mostly adults, presenting mostly with localisation-related epilepsy, treated with levetiracetam as adjunctive therapy or monotherapy for up to 36 months. The primary points evaluated were: long-term retention rate, reasons for discontinuing levetiracetam and the percentage of seizure-free patients. RESULTS: The retention rate at 6, 12, 24 and 36 months following the commencement of levetiracetam treatment was 91.7, 75.2, 60.1 and 53.7% respectively. Sixty-seven (30.7%) patients discontinued levetiracetam treatment. During the clinical audit evaluation period, surgical resection or implantation of VNS was performed in 31 (14.3%) patients. In 53 of the 67 patients (79.1%), the treatment was discontinued due to lack of efficacy; in 14 patients (20.9%) treatment was discontinued due to adverse events. In total, 24 of 218 patients (11.0%) were seizure-free for 36 months. CONCLUSIONS: Levetiracetam is an effective and well-tolerated option for long-term treatment of epilepsy in adults.

Occurrence and lateralizing value of "rare" peri-ictal vegetative symptoms in temporal lobe epilepsy.

We retrospectively investigated rare peri-ictal vegetative symptoms (PIVS) in 380 seizures of 97 patients with temporal lobe epilepsy (TLE): 234 seizures of 60 patients with TLE with mesiotemporal sclerosis (TLE/MTS) and 146 seizures of 37 patients with TLE with other lesions (TLE/non-MTS) who were at least 2 years after epilepsy surgery and classified as Engel I. We assessed the following PIVS: peri-ictal cough (pC), peri-ictal water drinking (pWD), peri-ictal vomiting (pV), and peri-ictal spitting (pS). We observed pC in 24.7% of patients and 10% of seizures; pWD in 14.4% of patients and 5.9% of seizures; pV and pS occurred more rarely. Both pWD and pC occurred significantly more often in those with TLE of the non- language-dominant hemisphere. The limited occurrence of pV and pS made it impossible to perform statistical analysis for these symptoms. In patients with TLE, pC and pWD were quite frequent; we observed pV and pS less frequently. Both pC and pWD have a significant lateralizing value in TLE.

The level of frontal-temporal beta-2 band EEG synchronization distinguishes anterior cingulate cortex from other frontal regions.

Recent findings indicate that complex cognitive functions are organized at a global level in the brain and rely on large-scale information processing requiring functional integration of multiple disparate neural assemblies. The critical question of the integration of distributed brain activities is whether the essential integrative role can be attributed to a specific structure in the brain or whether this ability is inherent to the cognitive network as a whole. The results of the present study show that mean values of the running correlation function in frontal-temporal EEG pairs with one electrode in the anterior cingulate cortex (ACC) are significantly higher than the same values in other frontal-temporal pairs. These findings indicate a particular role of the ACC in large-scale communication, which could reflect its unique integrative functions in cognitive processing.

Cognitive network interactions and beta 2 coherence in processing non-target stimuli in visual oddball task.

Spatiotemporal dynamics of event-related potentials (ERP) evoked by non-target stimuli in a visual oddball experiment and the presence of coherent oscillations in beta 2 frequency band of decomposed EEG records from peristimulus period were investigated by means of intracranial electrodes in humans. Twenty-one patients with medically intractable epilepsy participated in the study. The EEG signal was recorded using platinum electrodes implanted in several cortical and subcortical sites. Averaged 2 s EEG records were analyzed. Task-specific EEG changes were found in each patient, ERPs were derived from 92 electrodes used (96 % of possible cases). In the majority of analysed cases, ERPs were composed of several distinct components, and their duration was mostly longer than 1 s. The mean onset of the first ERP component was 158+/-132 ms after the stimulus (median 112 ms, minimum value 42 ms, maximum value 755 ms), and large variability of these onset times was found in all the investigated structures. Possible coherence between neural activities of remote brain sites was investigated by calculating running correlations between pairs of decomposed EEG records (alpha, beta 1, beta 2 frequency bands were used, total number of correlated pairs was 662 in each frequency band). The record pairs exhibiting highly correlated time segments represented 23 % of all the investigated pairs in alpha band, 7 % in beta 1 band, and 59 % in beta 2 band. In investigated 2 s record windows, such segments were distributed evenly, i.e. they were also found before the stimulus onset. In conclusion, the results have implicated the idea that a lot of recorded ERPs was more or less by-products of chance in spreading a signal within the neuronal network, and that their functional relevance was somewhat linked with the phenomenon of activity synchronization.

Beta 2-band synchronization during a visual oddball task.

The study investigated whether specific changes in phase synchrony in the beta 2 frequency band of EEG (25-35 Hz) occurred during a recognition task. The level of synchrony was examined between one hundred and eighty loci in the frontal and temporal lobes of eight epileptic patients with intracerebral electrodes; the EEG records were obtained during a visual oddball task. In each pair of records, the correlation curves were created from the sequence of correlation coefficients calculated. These curves consisted of irregular oscillations between the maximal and minimal r-values. Transient highly synchronized activity was observed during the whole time course of the experiment in all record pairs investigated and a significant relationship was found between the number of such episodes and the mean correlation coefficient (Spearman R 0.84; N 3240; p<0.001). On averaged curves, which were calculated using stimulus onsets as the trigger of averaging, a significant increase of the mean correlation coefficient in the post-stimulus epoch was found (p<0.01 after both target and non-target stimuli; t-test for dependent samples). As the cognitive demand significantly increases after stimulus presentation, the results are considered to be the first evidence from intracranial recording of increased synchronization in the beta 2 frequency band related to the cognitive activity.

Executive functions processed in the frontal and lateral temporal cortices: intracerebral study.

OBJECTIVE: The study was designed to investigate the neurocognitive network in the frontal and lateral temporal cortices that is activated by the complex cognitive visuomotor tasks of letter writing. METHODS: Eight epilepsy surgery candidates with implanted intracerebral depth electrodes performed two tasks involving the writing of single letters. The first task consisted of copying letters. In the second task, the patients were requested to write any other letter. The cognitive load of the second task was increased mainly by larger involvement of the executive functions. The task-related ERD/ERS of the alpha, beta and gamma rhythms was studied. RESULTS: The alpha and beta ERD as the activational correlate of writing of single letters was found in the sensorimotor cortex, anterior cingulate, premotor, parietal cortices, SMA and the temporal pole. The alpha and beta ERD linked to the increased cognitive load was present moreover in the dorsolateral and ventrolateral prefrontal cortex, orbitofrontal cortex and surprisingly also the temporal neocortex. Gamma ERS was detected mostly in the left motor cortex. CONCLUSIONS: Particularly the temporal neocortex was activated by the increased cognitive load. SIGNIFICANCE: The lateral temporal cortex together with frontal areas forms a cognitive network processing executive functions.

Intracerebral ERD/ERS in voluntary movement and in cognitive visuomotor task.

In order to study cerebral activity related to preparation and execution of movement, evoked and induced brain electrical activities were compared to each other and to fMRI results in voluntary self-paced movements. Also, the event-related desynchronization and synchronization (ERD/ERS) were studied in complex movements with various degrees of cognitive load. The Bereitschaftspotential (BP) and alpha (8-12 Hz) and beta (16-24 Hz) ERD/ERS rhythms in self-paced simple movements were analyzed in 14 epilepsy surgery candidates. In previous studies, the cortical sources of BP were consistently displayed contralateral to the movement in the primary motor cortex and somatosensory cortex, and bilateral in the supplementary motor area (SMA) and in the cingulate cortex. There were also small and inconstant BP generators in the ipsilateral sensorimotor, premotor, and dorsolateral prefrontal cortex. Alpha and beta ERD/ERS were also observed in these cortical regions. The distribution of contacts showing ERD or ERS was larger than of those showing BP. In contrast to BP, ERD, and ERS frequently occurred in the orbitofrontal, lateral and mesial temporal cortices, and inferior parietal lobule. The spatial location of brain activation for self-paced repetitive movements, i.e., writing simple dots, was studied using event-related functional MRI (fMRI) in 10 healthy right-handed subjects. We observed significant activation in regions known to participate in motor control: contralateral to the movement in the primary sensorimotor and supramarginal cortices, the SMA and the underlying cingulate, and, to a lesser extent, the ipsilateral sensorimotor region. When the fMRI was compared with the map of the brain areas electrically active with self-paced movements (intracerebral recordings; Rektor et al., 1994, 1998, 2001b, c; Rektor, 2003), there was an evident overlap of most results. Nevertheless, the electrophysiological studies were more sensitive in uncovering small active areas, i.e., in the premotor and prefrontal cortices. The BP and the event-related hemodynamic changes were displayed in regions known to participate in motor control. The cortical occurrence of oscillatory activities in the alpha-beta range was clearly more widespread. Four epilepsy surgery candidates with implanted depth brain electrodes performed two visuomotor-cognitive tasks with cued complex movements: a simple task--copying randomly presented letters from the monitor; and a more complex task--writing a letter other than that which appears on the monitor. The second task demanded an increased cognitive load, i.e., of executive functions. Alpha and beta ERD/ERS rhythms were evaluated. Similar results for both tasks were found in the majority of the frontal contacts, i.e., in the SMA, anterior cingulate, premotor, and dorsolateral prefrontal cortices. The most frequent observed activity was ERD in the beta rhythm; alpha ERS and ERD were also present. Significant differences between the two tasks appeared in several frontal areas--in the dorsolateral and ventrolateral prefrontal and orbitofrontal cortices (BA 9, 45, 11), and in the temporal neocortex (BA 21). In several contacts localized in these areas, namely in the lateral temporal cortex, there were significant changes only with the complex task--mostly beta ERD. Although the fMRI results fit well with the map of the evoked activity (BP), several discrepant localizations were displayed when the BP was compared with the distribution of the oscillatory activity (ERD-ERS). The BP and hemodynamic changes are closely related to the motor control areas; ERD/ERS represent the broader physiological aspects of motor execution and control. The BP probably reflects regional activation, while the more widespread ERD/ERS may reflect the spread of task-relevant information across relevant areas. In the writing tasks, the spatial distribution of the alpha-beta ERD/ERS in the frontal and lateral temporal cortices was partially task dependent. The ERD/ERS occurred there predominantly in the more complex of the writing tasks. Some sites were only active in the task with the increased demand on executive functions. In the temporal neocortex only, the oscillatory, but not the evoked, activity was recorded in the self-paced movement. The temporal appearance of changes of oscillatory activities in the self-paced movement task as well as in the cued movement task with an increased load of executive functions raises the interesting question of the role of this region in cognitive-movement information processing.

Long-term levetiracetam treatment of epilepsy patients: clinical audit.

PURPOSE: The long-term efficacy and tolerability of levetiracetam (LEV) was analysed in 218 epilepsy patients. One hundred and ninety-nine patients were treated for at least 6 months. We evaluated LEV efficacy for all types of seizures together, and for simple partial, complex partial and secondary generalized seizures individually. RESULTS: A significant decrease in the number of seizures occurred after 6 months of treatment (p<0.001). Mean seizure frequency (irrespective of type) before LEV was 19.2 a month. The mean monthly frequency at 6, 12, 24 and 36 months dropped to 12.7, 10.5, 9.7 and 7.1 seizures a month, respectively. The mean percentage reduction in seizures at these times was 45.7, 52.1, 59.1 and 64.2% and the number of responding patients was 51.3, 54.2, 59.8 and 62.2%. The number of patients completely seizure free was 18.6, 16.7, 15.2 and 16.2%. We found similar results in the last three categories for partial simple, complex and secondary generalized seizures individually. Side effects in 18.3% of patients caused treatment discontinuation in 6.4%. The most frequent were somnolence, moodiness and dizziness. The retention rate at 6, 12, 24 and 36 months was 0.848, 0.72, 0.62 and 0.5, respectively. CONCLUSIONS: LEV is effective and well tolerated for long-term treatment of epilepsy.

Cognitive functioning after repetitive transcranial magnetic stimulation in patients with cerebrovascular disease without dementia: a pilot study of seven patients.

AIMS: Examine whether one session of high frequency repetitive transcranial magnetic stimulation (rTMS) applied over the left dorsolateral prefrontal cortex (DLPFC) would induce any measurable cognitive changes in patients with cerebrovascular disease and mild cognitive deficits. PATIENTS AND METHOD: Seven patients with cerebrovascular disease and mild executive dysfunction entered the randomised, controlled, blinded study with a crossover design. rTMS was applied either over the left DLPFC (an active stimulation site) or over the left motor cortex (MC; a control stimulation site) in one session. Each patient participated in both stimulation sessions (days 1 and 4) and the order of stimulation sites (DLPFC or MC) was randomised. A short battery of neuropsychological tests was performed by a blinded psychologist prior to and after each rTMS session. Psychomotor speed, executive function, and memory were evaluated. RESULTS: The only mild but significant stimulation site-specific effect of rTMS was observed in the Stroop interference results (i.e. improvement) after the stimulation of DLPFC but not MC in comparison with the baseline scores (Wilcoxon, Z=-2.03, p=0.04). Patients improved in the digit symbols subtest of the Wechsler adult intelligence scale-revised after both rTMS sessions regardless of the stimulation site (DLPFC or MC; Z=-2.06, p=0.04 and Z=-2.06, p=0.04, respectively). There was no measurable effect of rTMS in any other neuropsychological test. CONCLUSION: Our pilot study results showed that one session of the high frequency rTMS applied over the left DLPFC was safe in patients with cerebrovascular disease and mild executive deficits, and may induce measurable positive effects on executive functioning.

Sensitivity of PPI analysis to differences in noise reduction strategies.

BACKGROUND: In some fields of fMRI data analysis, using correct methods for dealing with noise is crucial for achieving meaningful results. This paper provides a quantitative assessment of the effects of different preprocessing and noise filtering strategies on psychophysiological interactions (PPI) methods for analyzing fMRI data where noise management has not yet been established. METHODS: Both real and simulated fMRI data were used to assess these effects. Four regions of interest (ROIs) were chosen for the PPI analysis on the basis of their engagement during two tasks. PPI analysis was performed for 32 different preprocessing and analysis settings, which included data filtering with RETROICOR or no such filtering; different filtering of the ROI "seed" signal with a nuisance data-driven time series; and the involvement of these data-driven time series in the subsequent PPI GLM analysis. The extent of the statistically significant results was quantified at the group level using simple descriptive statistics. Simulated data were generated to assess statistical improvement of different filtering strategies. RESULTS: We observed that different approaches for dealing with noise in PPI analysis yield differing results in real data. In simulated data, we found RETROICOR, seed signal filtering and the addition of data-driven covariates to the PPI design matrix significantly improves results. CONCLUSIONS: We recommend the use of RETROICOR, and data-driven filtering of the whole data, or alternatively, seed signal filtering with data-driven signals and the addition of data-driven covariates to the PPI design matrix.

Basal ganglia involvement in sensory and cognitive processing. A depth electrode CNV study in human subjects.

OBJECTIVE: Intracranial recordings were taken from the basal ganglia (BG) in order to explore the possible role of the BG in the cognitive processing of sensory information. METHODS: Ten patients with intractable temporal lobe epilepsy, who were candidates for epilepsy surgery, underwent intracranial recordings with depth electrodes. A frontal approach was used for the insertion of diagonal depth electrodes into the amygdalo-hippocampal complex (AH complex). These electrodes passed through the BG. The putamen was explored in 8 patients; the nucleus caudatus and pallidum were explored in two patients. The contingent negative variation (CNV) paradigm was tested using auditory warning stimuli and visual imperative stimuli followed by a hand flexion. The auditory and visual middle and late latency potentials evoked by the warning and imperative stimuli were analyzed. RESULTS: (1) Auditory evoked potentials (EPs): the amplitude potential gradient was observed with latencies of (a) 150-195ms (9 patients); (b) 215-290ms (9 patients); and (c) 350-600ms (10 patients). Negative potentials, with latencies of 100 and 110ms were observed in two patients. (2) Visual EPs: (a) 160-195ms (9 patients); (b) 210-295ms (9 patients); and (c) 330-550ms (7 patients). Negative potentials with latencies between 100 and 120ms were observed in 4 patients. CNV was obtained from the BG in 8 patients; a phase reversal was observed twice. CONCLUSIONS: (1) The BG generate middle and late latency EPs in a cognitive paradigm linked to the motor task. (2) The BG generate CNV. (3) The BG could play an integrative role in the processing of sensory, cognitive, and motor information.

Movement-related potentials in the basal ganglia: a SEEG readiness potential study.

OBJECTIVES: The brain potentials preceding and accompanying self-paced acral limb movements (Bereitschaftspotential/readiness potential (RP) paradigm) were studied in 12 patients. METHODS: Intracranial electrodes were implanted in order to explore intractable epilepsy. The electrodes were introduced into sites corresponding to the electroclinical characteristics of each patient's epileptic seizures. In 7 patients, several depth electrodes were implanted orthogonally, in the temporal, fronto-orbital and prefrontal cortex. In 4 patients, subdural strip electrodes were used for the exploration of the fronto-temporal convexity. There were no RPs recorded in these areas. No contacts were placed in the central region known to generate cortical RP. In all the patients, one or two diagonal electrodes passed through or touched the basal ganglia to reach the amygdala and the hippocampus. The putamen was explored in 11 patients (in 3 of them bilaterally); the caudate head was explored in two patients, and the pallidum was explored in two patients. RESULTS: RP with a clear amplitude gradient was present in all explored structures, however a phase reversal was never observed. RP was observed in the caudate in all recordings, and in the pallidum in one patient. It was recorded in the putamen in 8 out of the 11 explored patients. RPs were displayed contralaterally to the movement 9 times in 13 explorations, and ipsilaterally 4 times in 9 explorations. The shape of RP resembled the RP shape in the cortex and on the scalp. Movement accompanying potentials (MAPs) were also present in all 3 explored structures. The electrophysiological characteristics of MAP differed from RP, indicating separate generators. In the basal ganglia, RPs preceded the onset of movement by 500-1500 ms, at an average of 1080 (+/-330) ms. It seems that the RP in the basal ganglia starts slightly later than the RP in the motor cortices. That should be definitely demonstrated in patients with simultaneous recordings from cortical and subcortical structures. RP and MAP were displayed synchronously in the cortex and in the basal ganglia during most of the premovement period, as well as during the execution of movement. RP generators were reported by several authors in other deeply located structures, i.e. in the thalamus and in the brain-stem. CONCLUSIONS: Based on all these recordings, we presume that the RPs recorded on the scalp are generated simultaneously in several cortical as well as subcortical structures.