Bidirectional electric communication between the inferior occipital gyrus and the amygdala during face processing.

Faces contain multifaceted information that is important for human communication. Neuroimaging studies have revealed face-specific activation in multiple brain regions, including the inferior occipital gyrus (IOG) and amygdala; it is often assumed that these regions constitute the neural network responsible for the processing of faces. However, it remains unknown whether and how these brain regions transmit information during face processing. This study investigated these questions by applying dynamic causal modeling of induced responses to human intracranial electroencephalography data recorded from the IOG and amygdala during the observation of faces, mosaics, and houses in upright and inverted orientations. Model comparisons assessing the experimental effects of upright faces versus upright houses and upright faces versus upright mosaics consistently indicated that the model having face-specific bidirectional modulatory effects between the IOG and amygdala was the most probable. The experimental effect between upright versus inverted faces also favored the model with bidirectional modulatory effects between the IOG and amygdala. The spectral profiles of modulatory effects revealed both same-frequency (e.g., gamma-gamma) and cross-frequency (e.g., theta-gamma) couplings. These results suggest that the IOG and amygdala communicate rapidly with each other using various types of oscillations for the efficient processing of faces. Hum Brain Mapp 38:4511-4524, 2017. © 2017 Wiley Periodicals, Inc.

Significance of Very-High-Frequency Oscillations (Over 1,000Hz) in Epilepsy.

OBJECTIVE: We previously reported ictal very-high-frequency oscillations (VHFO) of 1,000 to 2,500Hz recorded by subdural macroelectrodes using a 10-kHz sampling rate. The purpose of this study was to clarify the clinical significance of ictal VHFO in neocortical epilepsy. METHODS: This study included 13 patients with neocortical epilepsy who underwent subdural electrode implantation and had at least 1 seizure recorded at a 10-kHz sampling rate and were followed for more than 2 years postoperatively. Extent of resection was determined considering the seizure onset zone (SOZ) and irritative zone, structural lesion, and functional areas. Areas showing VHFO and those with HFO were not taken into consideration. The presence or absence of VHFO (>1,000 Hz), HFO (200-1,000Hz) and SOZ, and completeness of resection of these areas were compared with postoperative seizure outcome. RESULTS: Seven patients had favorable (Engel class Ia) and 6 had unfavorable outcomes (other classes). VHFO was recorded in 6 of 7 patients with a favorable outcome. On the contrary, VHFO was recorded in only 1 of 6 patients with unfavorable outcome. The presence of VHFO was significantly associated with favorable outcome. VHFO was recorded on a limited number of electrodes, and VHFO-generating areas were resected completely, whereas HFO-generating areas and/or SOZ were not always resected completely in both favorable and unfavorable outcome groups. INTERPRETATION: The presence of ictal VHFO may be predictive of favorable outcome. Ictal VHFO may be a more specific marker than ictal HFO or SOZ for identifying the core of epileptogenic zone.

Involvement of flocculin in negative potential-applied ITO electrode adhesion of yeast cells.

The purpose of this study was to develop novel methods for attachment and cultivation of specifically positioned single yeast cells on a microelectrode surface with the application of a weak electrical potential. Saccharomyces cerevisiae diploid strains attached to an indium tin oxide/glass (ITO) electrode to which a negative potential between -0.2 and -0.4 V vs. Ag/AgCl was applied, while they did not adhere to a gallium-doped zinc oxide/glass electrode surface. The yeast cells attached to the negative potential-applied ITO electrodes showed normal cell proliferation. We found that the flocculin FLO10 gene-disrupted diploid BY4743 mutant strain (flo10Δ /flo10Δ) almost completely lost the ability to adhere to the negative potential-applied ITO electrode. Our results indicate that the mechanisms of diploid BY4743 S. cerevisiae adhesion involve interaction between the negative potential-applied ITO electrode and the Flo10 protein on the cell wall surface. A combination of micropatterning techniques of living single yeast cell on the ITO electrode and omics technologies holds potential of novel, highly parallelized, microchip-based single-cell analysis that will contribute to new screening concepts and applications.

Halarchaeum grantii sp. nov., a moderately acidophilic haloarchaeon isolated from a commercial salt sample.

Three moderately acidophilic, halophilic archaeal strains, MH1-243-3T, MH1-243-5 and MH1-243-6, were isolated from a commercial salt sample made from seawater in Okinawa, Japan. Cells of the three strains were pleomorphic and stained Gram-negative. Colonies of the strains were orange-red-pigmented. Strain MH1-243-3T was able to grow at 15-27 % (w/v) NaCl (optimum 24 °C), at pH 4.5-6.5 (pH 5.5) and at 35-50 °C (45 °C). Strains MH1-243-5 and MH1-243-6 grew within slightly different ranges (shown in text). The 16S rRNA gene sequences of the three strains were identical, and the closest phylogenetic relative was Halarchaeum salinum MH1-34-1T with 97.0 % similarity. The rpoB' gene sequences of the three strains were also identical, and the closest phylogenetic relative was Halarchaeum acidiphilum JCM 16109T with 92.0 % similarity. The DNA G+C content of MH1-243-3T, MH1-243-5 and MH1-243-6 was 65.2 mol%. The levels of DNA-DNA relatedness amongst the three strains were 84.1-99.8 %, while that between MH1-243-3T and H. salinum MH1-34-1T was 30.6 % and 31.6 % (reciprocally), and those between MH1-243-3T and type strains of other species in the genus Halarchaeum were 42.3-29.4 %. Based on the phenotypic, genotypic and phylogenetic analyses, it is proposed that the isolates should represent a novel species of the genus Halarchaeum, for which the name Halarchaeum grantii sp. nov. is proposed. The type strain is MH1-243-3T ( = JCM 19585T = KCTC 4142T), isolated from commercial sea salt produced in Okinawa, Japan. MH1-243-5 ( = JCM 19586) and MH1-243-6 ( = JCM 18422) are additional strains of the species.

Aneurinibacillus tyrosinisolvens sp. nov., a tyrosine-dissolving bacterium isolated from organics- and methane-rich seafloor sediment.

A novel Gram-positive-staining, strictly aerobic and heterotrophic bacterium, designated strain LL-002T, was isolated from organics- and methane-rich seafloor sediment at a depth of 100 m in Kagoshima Bay, Kagoshima, Japan. Colonies were lustreless and translucent white in colour. The temperature, pH and salt concentration ranges for growth were 10-30 °C, pH 6.0-6.5 and 0-1 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain LL-002T belongs to the genus Aneurinibacillus of the family Paenibacillaceae. 16S rRNA gene sequence similarities between strain LL-002T and the type strains of species of the genus Aneurinibacillus were 92.8-95.7 %; the highest sequence identity was with the type strain of Aneurinibacillus migulanus. The DNA G+C content of strain LL-002T was 46.2 mol%. MK-7 was the predominant menaquinone. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0, and the cell-wall peptidoglycan contained meso-diaminopimelic acid and glutamic acid, glycine and alanine in addition to muramic acid and glucosamine. The peptidoglycan type was A1γ. In DNA-DNA hybridization assays between strain LL-002T and the type strains of the other species of the genus Aneurinibacillus, the level of hybridization was 6.3-30.1 %. On the basis of its biological features and the 16S rRNA gene sequence comparison presented here, strain LL-002T is considered to represent a novel species of the genus Aneurinibacillus, for which the name Aneurinibacillus tyrosinisolvens sp. nov. is proposed; the type strain is LL-002T ( = NBRC 110097T = CECT 8536T).

Preservation of absolute pitch after right amygdalohippocampectomy for a pianist with TLE.

Absolute pitch (AP) ability is a rare musical phenomenon. In the literature, it has been suggested that the relative specialization for pitch processing is in the right temporal lobe in the non-AP population. Since the anatomic basis for absolute pitch is not fully understood and cases of temporal lobe epilepsy of AP possessors are extremely rare, applicability of resection as a treatment of epilepsy in this particular area should be evaluated with caution. In the present study, we examined an AP possessor who suffered from medically refractory temporal lobe epilepsy and underwent right selective amygdalohippocampectomy (SAH). The SAH procedure clearly avoided disturbing important structures for AP, inasmuch as postsurgically she preserved her AP ability and was seizure-free. She did well post-operatively in the test of pure sine wave tones with short reaction time, which could be identified as "true" absolute pitch.

Brevundimonas denitrificans sp. nov., a denitrifying bacterium isolated from deep subseafloor sediment.

A novel Gram-stain-negative, aerobic, heterotrophic, stalked and capsulated bacterium with potential denitrification ability, designated strain TAR-002(T), was isolated from deep seafloor sediment in Japan. Colonies lacked lustre, and were viscous and translucent white. The ranges of temperature, pH and salt concentration for growth were 8-30 °C, pH 6.0-10.0 and 1-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain TAR-002(T) belongs to the genus Brevundimonas of the class Alphaproteobacteria. Levels of similarity between the 16S rRNA gene sequence of strain TAR-002(T) and those of the type strains of species of the genus Brevundimonas were 93.5-98.9%; the most closely related species was Brevundimonas basaltis. In DNA-DNA hybridization assays between strain TAR-002(T) and its phylogenetic neighbours, Brevundimonas lenta DS-18(T), B. basaltis J22(T), Brevundimonas subvibrioides ATCC 15264(T) and Brevundimonas alba DSM 4736(T), mean hybridization levels were 6.4-27.7%. The G+C content of strain TAR-002(T) was 70.3 mol%. Q-10 was the major respiratory isoprenoid quinone. The major fatty acids were C(18:1)ω7c and C(16:0), and the presence of 1,2-di-O-acyl-3-O-[D-glucopyranosyl-(1 → 4)-α-D-glucopyranuronosyl]glycerol (DGL) indicates the affiliation of strain TAR-002(T) with the genus Brevundimonas. On the basis of biological characteristics and 16S rRNA gene sequence comparisons, strain TAR-002(T) is considered to represent a novel species of the genus Brevundimonas, for which the name Brevundimonas denitrificans sp. nov. is proposed; the type strain is TAR-002(T) ( =NBRC 110107(T) =CECT 8537(T)).

Thalassospira alkalitolerans sp. nov. and Thalassospira mesophila sp. nov., isolated from a decaying bamboo sunken in the marine environment, and emended description of the genus Thalassospira.

Two marine bacteria, designated strains MBE#61(T) and MBE#74(T), were isolated from a piece of sunken bamboo in the marine environment in Japan. Both of these strains were Gram-stain-negative, but had different cell shapes: MBE#61(T) was spiral, whereas MBE#74(T) was rod-shaped. The temperature, pH and salt concentration ranges for growth of strain MBE#61(T) were 4-38 °C (optimal at 32 °C), pH 4.5-11.0 (optimal at pH 7.0-8.0) and 1-11 % (optimal at 2 %) NaCl, whereas those of strain MBE#74(T) were 4-36 °C (optimal at 30 °C), pH 4.0-10.5 (optimal at pH 7.0-8.0) and 1-12 % (optimal at 4 %) NaCl. Phylogenetic analysis based on partial 16S rRNA gene sequences revealed that both strains belong to the genus Thalassospira within the class Alphaproteobacteria. Similarity between the 16S rRNA gene sequence of strain MBE#61(T) and those of the type strains of species of the genus Thalassospira was 97.5-99.0 %, and that of strain MBE#74(T) was 96.9-98.6 %; these two isolates were most closely related to Thalassospira lucentensis QMT2(T). However, the DNA-DNA hybridization values between T. lucentensis QMT2(T) and strain MBE#61(T) or MBE#74(T) were only 16.0 % and 7.1 %, respectively. The DNA G+C content of strain MBE#61(T) was 54.4 mol%, and that of strain MBE#74(T) was 55.9 mol%. The predominant isoprenoid quinone of the two strains was Q-10 (MBE#61(T), 97.3 %; MBE#74(T), 93.5 %). The major cellular fatty acids of strain MBE#61(T) were C18 : 1ω7c (31.1 %), summed feature 3 comprising C16 : 0ω7c/iso-C15 : 0 2-OH (26.1 %) and C16 : 0 (20.9 %); those of strain MBE#74(T) were C16 : 0 (26.2 %), C17 : 0 cyclo (19.9 %) and C18 : 1ω7c (12.1 %). On the basis of these results, strain MBE#61(T) and strain MBE#74(T) are considered to represent novel species of the genus Thalassospira, for which names Thalassospira alkalitolerans sp. nov. and Thalassospira mesophila sp. nov. are proposed. The type strains are MBE#61(T) ( = JCM 18968(T) = CECT 8273(T)) and MBE#74(T) ( = JCM 18969(T) = CECT 8274(T)), respectively. An emended description of the genus Thalassospira is also proposed.

Enhancing thermostability and the structural characterization of Microbacterium saccharophilum K-1 ß-fructofuranosidase.

A ß-fructofuranosidase from Microbacterium saccharophilum K-1 (formerly known as Arthrobacter sp. K-1) is useful for producing the sweetener lactosucrose (4(G)-ß-D-galactosylsucrose). Thermostability of the ß-fructofuranosidase was enhanced by random mutagenesis and saturation mutagenesis. Clones with enhanced thermostability included mutations at residues Thr47, Ser200, Phe447, Phe470, and Pro500. In the highest stability mutant, T47S/S200T/F447P/F470Y/P500S, the half-life at 60 °C was 182 min, 16.5-fold longer than the wild-type enzyme. A comparison of the crystal structures of the full-length wild-type enzyme and three mutants showed that various mechanisms appear to be involved in thermostability enhancement. In particular, the replacement of Phe447 with Val or Pro induced a conformational change in an adjacent residue His477, which results in the formation of a new hydrogen bond in the enzyme. Although the thermostabilization mechanisms of the five residue mutations were explicable on the basis of the crystal structures, it appears to be difficult to predict which amino acid residues should be modified to obtain thermostabilized enzymes.

Genetic and functional diversity of ß-N-acetylgalactosamine-targeting glycosidases expanded by deep-sea metagenome analysis.

ß-N-Acetylgalactosamine-containing glycans play essential roles in several biological processes, including cell adhesion, signal transduction, and immune responses. ß-N-Acetylgalactosaminidases hydrolyze ß-N-acetylgalactosamine linkages of various glycoconjugates. However, their biological significance remains ambiguous, primarily because only one type of enzyme, exo-ß-N-acetylgalactosaminidases that specifically act on ß-N-acetylgalactosamine residues, has been documented to date. In this study, we identify four groups distributed among all three domains of life and characterize eight ß-N-acetylgalactosaminidases and ß-N-acetylhexosaminidase through sequence-based screening of deep-sea metagenomes and subsequent searching of public protein databases. Despite low sequence similarity, the crystal structures of these enzymes demonstrate that all enzymes share a prototype structure and have diversified their substrate specificities (oligosaccharide-releasing, oligosaccharide/monosaccharide-releasing, and monosaccharide-releasing) through the accumulation of mutations and insertional amino acid sequences. The diverse ß-N-acetylgalactosaminidases reported in this study could facilitate the comprehension of their structures and functions and present evolutionary pathways for expanding their substrate specificity.

Eicosapentaenoic acid plays a role in stabilizing dynamic membrane structure in the deep-sea piezophile Shewanella violacea: a study employing high-pressure time-resolved fluorescence anisotropy measurement.

Shewanella violacea DSS12 is a psychrophilic piezophile that optimally grows at 30MPa. It contains a substantial amount of eicosapentaenoic acid (EPA) in the membrane. Despite evidence linking increased fatty acid unsaturation and bacterial growth under high pressure, little is known of how the physicochemical properties of the membrane are modulated by unsaturated fatty acids in vivo. By means of the newly developed system performing time-resolved fluorescence anisotropy measurement under high pressure (HP-TRFAM), we demonstrate that the membrane of S. violacea is highly ordered at 0.1MPa and 10°C with the order parameter S of 0.9, and the rotational diffusion coefficient D(w) of 5.4µs(-1) for 1-[4-(trimethylamino)pheny]-6-phenyl-1,3,5-hexatriene in the membrane. Deletion of pfaA encoding the omega-3 polyunsaturated fatty acid synthase caused disorder of the membrane and enhanced the rotational motion of acyl chains, in concert with a 2-fold increase in the palmitoleic acid level. While the wild-type membrane was unperturbed over a wide range of pressures with respect to relatively small effects of pressure on S and D(w), the ΔpfaA membrane was disturbed judging from the degree of increased S and decreased D(w). These results suggest that EPA prevents the membrane from becoming hyperfluid and maintains membrane stability against significant changes in pressure. Our results counter the generally accepted concept that greater fluidity is a membrane characteristic of microorganisms that inhabit cold, high-pressure environments. We suggest that retaining a certain level of membrane physical properties under high pressure is more important than conferring membrane fluidity alone.

Brevundimonas abyssalis sp. nov., a dimorphic prosthecate bacterium isolated from deep-subsea floor sediment.

A novel Gram-negative, aerobic, psychrotolerant, alkali-tolerant, heterotrophic and dimorphic prosthecate bacterium, designated strain TAR-001(T), was isolated from deep-sea floor sediment in Japan. Cells of this strain had a dimorphic life cycle and developed an adhesive stalk at a site not coincident with the centre of the cell pole, and the other type of cell, a swarm cell, had a polar flagellum. Colonies were glossy, viscous and yellowish-white in colour. The temperature, pH and salt concentration range for growth were 2-41 °C, pH 6.5-10.0 and 1-4% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain TAR-001(T) belongs to the family Caulobacteraceae of the class Alphaproteobacteria, and lies between the genus Brevundimonas and the genus Caulobacter. Levels of similarity between the 16S rRNA gene sequence of strain TAR-001(T) and those of the type strains of Brevundimonas species were 93.3-95.7%; highest sequence similarity was with the type strain of Brevundimonas diminuta. Levels of sequence similarity between those of the type strains of Caulobacter species were 94.9-96.0%; highest sequence similarity was with the type strain of Caulobacter mirabilis. The G+C content of strain TAR-001(T) was 67.6 mol%. Q-10 was the major respiratory isoprenoid quinone. The major fatty acids were C18:1ω7c and C16:0, and the presence of 1,2-di-O-acyl-3-O-[D-glucopyranosyl-(1→4)-α-D-glucopyranuronosyl]glycerol suggests strain TAR-001(T) is more closely to the genus Brevundimonas than to the genus Caulobacter. The mean DNA-DNA hybridization levels between strain TAR-001(T) and the type strains of two species of the genus Brevundimonas were higher than that of the genus Caulobacter. On the basis of polyphasic biological features and the 16S rRNA gene sequence comparison presented here, strain TAR-001(T) is considered to represent a novel species of the genus Brevundimonas, for which the name Brevundimonas abyssalis sp. nov. is proposed; the type strain is TAR-001(T) (=JCM 18150(T)=CECT 8073(T)).

Polycladomyces abyssicola gen. nov., sp. nov., a thermophilic filamentous bacterium isolated from hemipelagic sediment.

A novel filamentous bacterium, designated strain JIR-001(T), was isolated from hemipelagic sediment in deep seawater. This strain was non-motile, Gram-positive, aerobic, heterotrophic and thermophilic; colonies were of infinite form and ivory coloured with wrinkles between the centre and the edge of the colony on ISP2 medium. The isolate grew aerobically at 55-73 °C with the formation of aerial mycelia; spores were produced singly along the aerial mycelium. These morphological features show some similarities to those of the type strains of some species belonging to the family Thermoactinomycetaceae. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain JIR-001(T) belongs to the family Thermoactinomycetaceae within the class Bacilli. Similarity levels between the 16S rRNA gene sequence of strain JIR-001(T) and those of the type strains of Thermoactinomycetaceae species were 85.5-93.5%; highest sequence similarity was with Melghirimyces algeriensis NariEX(T). In the DNA-DNA hybridization assays between strain JIR-001(T) and its phylogenetic neighbours the mean hybridization levels with Melghirimyces algeriensis NariEX(T), Planifilum fimeticola H0165(T), Planifilum fulgidum 500275(T) and Planifilum yunnanense LA5(T) were 5.3-7.5, 2.3-4.7, 2.1-4.8 and 2.5-4.9%, respectively. The DNA G+C content of strain JIR-001(T) was 55.1 mol%. The major fatty acids were iso-C15:0, iso-C17:0, iso-C16:0 and C16:0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, glucolipid, phosphatidylserine, an amino-group containing phospholipid, an unknown phospholipid and two unknown lipids. The predominant menaquinone was MK-7 and the cell-wall peptidoglycan contained meso-diaminopimelic acid, glutamic acid and alanine. On the basis of phenotypic characteristics and 16S rRNA gene sequence comparisons, strain JIR-001(T) is considered to represent a novel species in a new genus of the family Thermoactinomycetaceae, for which the name Polycladomyces abyssicola gen. nov., sp. nov. is proposed. The type strain of Polycladomyces abyssicola is JIR-001(T) (=JCM 18147(T)=CECT 8074(T)).

Mesial temporal lobe epilepsy with no specific histological abnormality: a distinct surgically remediable syndrome.

PURPOSE: The purposes of the study were twofold: to clarify the clinical features and surgical outcome of mesial temporal lobe epilepsy (MTLE) with no specific histological abnormality and to determine the optimal surgical strategy. METHODS: Twelve patients who met the following criteria were included: (1) normal preoperative MRI; (2) intracranial EEG findings consistent with mesial temporal onset of seizures; (3) selective amygdalohippocampectomy (AHE) was performed, and the patient was followed for more than 2years postoperatively; and (4) hippocampal histopathology was nonspecific. Clinical characteristics, intracranial EEG findings, and postoperative seizure outcome were examined. These twelve patients were compared with twenty-one patients with MTLE with unilateral hippocampal sclerosis (HS) on MRI who underwent intracranial EEG before resection (control group). RESULTS: In patients with MTLE with no specific histological abnormality, the age at onset was significantly higher, the history of febrile seizures was significantly less frequent, and preoperative IQ score was significantly higher than that in the control group. The proportion of patients with bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG was 50% in patients with MTLE with nonspecific histopathology and was significantly higher than that in the control group. Seizure outcome was classified as Engel class I in seven patients, class II in three, class III in one, and class IV in one. Seizure outcome was favorable even in three patients with seizures originating more frequently from the side contralateral to the resected side. CONCLUSIONS: Mesial temporal lobe epilepsy with no specific histological abnormality is a clinical entity distinctly different from MTLE with HS. Bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG is very common. Although the presence of lateral temporal and/or extratemporal epileptogenicity should always be kept in mind, postoperative seizure outcome after AHE is favorable even in cases with bitemporal independent and/or nonlateralizing seizure onset.

Transthyretin Variant Amyloidosis with a TTR A97D (p.A117D) Mutation Manifesting Remarkable Asymmetric Neuropathy.

We herein report a 68-year-old Japanese man with sporadic variant transthyretin (ATTRv) amyloidosis harboring the novel variant A97D (p.A117D) in TTR. He had slow development of asymmetric neuropathy, unintentional weight loss, mild autonomic failure and mild cardiomyopathy. TTR amyloid deposition on the gastric duodenal mucosa was detected. In silico analyses predicted that TTR A97D (p.A117D) altered the structure and function of the TTR protein. ATTRv amyloidosis is often difficult to diagnose in non-endemic regions due to its diverse phenotypes, such as atypical peripheral nerve involvement and a rare family history.

Temporal profile of amygdala γ oscillations in response to faces.

Neuroimaging studies have reported greater activation of the human amygdala in response to faces than to nonfacial stimuli, yet little is known about the temporal profile of this activation. We investigated this issue by recording the intracranial field potentials of the amygdala in participants undergoing preneurosurgical assessment (n = 6). Participants observed faces, mosaics, and houses in upright and inverted orientations using a dummy target detection task. Time-frequency statistical parametric mapping analyses revealed that the amygdala showed greater gamma-band activity in response to faces than to mosaics at 200-300 msec, with a peak at 255 msec. Gamma-band activation with a similar temporal profile was also found in response to faces versus houses. Activation patterns did not differ between upright and inverted presentations of stimuli. These results suggest that the human amygdala is involved in the early stages of face processing, including the modulation of subjective perception of faces.

Uneven interhemispheric connections between left and right primary sensori-motor areas.

To clarify the characteristics of interhemispheric connections, we investigated cortico-cortical evoked potentials (CCEP) in human. Fourteen patients with temporal lobe epilepsy who underwent invasive EEG monitoring with bilaterally implanted subdural electrodes were studied. Electric pulse stimuli were given in a bipolar fashion at two adjacent electrodes on and around the motor area (MA) or sensory area (SA), and CCEP responses were recorded by averaging electrocorticograms from the contralateral hemisphere. Seventy-two pairs of electrodes were stimulated, and 468 recordings were analyzed. Fifty-one of 468 recordings demonstrated CCEP responses. Of 51 responses, 16 consisted of an initial positive triphasic wave (Type 1), 27 had an initial negative biphasic wave (Type 2), and 8 showed an initial positive biphasic wave (type 3). The mean latencies of the earliest peaks were 13.1, 28.9, and 29.4 ms in Types 1, 2, and 3 responses, respectively. The responses were more frequently evoked by stimulating facial MA (f-MA) and nonfacial MA (nf-MA) than by stimulating SA or noneloquent area. In both f-MA and nf-MA stimulation, the responses were more frequently recorded at the contralateral f-MA than at the contralateral nf-MA or other areas. SA stimulation never evoked CCEP responses at the contralateral MA or SA. The amplitudes were maximal when f-MA was stimulated and responses recorded at the contralateral f-MA. These findings suggest that the interhemispheric connections are uneven. Both f-MA and nf-MA send dense interhemispheric connections to the contralateral f-MA. SA may have no or only rare direct connection with the contralateral MA or SA.

Ictal very low frequency oscillation in human epilepsy patients.

Using intracranial electroencephalographic recordings, we identified a distinct brain activity in 3 patients with refractory epilepsy characterized by very early occurrence from 8 minutes 10 seconds to 22 minutes 40 seconds prior to clinical seizure onset, periodical appearance of slow negative baseline shift, long interpeak interval of 40 to 120 seconds, and disappearance after clinical seizure. We named this activity "very low frequency oscillation" (VLFO), which reflected a dynamic process during the preictal state. This observation may render new insight into epileptogenesis and provide additional information concerning the epileptogenic zone as well as prediction of epileptic seizures.

Mutations in LGI1 gene in Japanese families with autosomal dominant lateral temporal lobe epilepsy: the first report from Asian families.

Autosomal dominant lateral temporal lobe epilepsy (ADLTE) caused by LGI1 (leucine-rich gene, glioma-inactivated-1) mutations is a rare familial epileptic syndrome characterized by the auditory ictal manifestation and rare nocturnal generalized seizures. We have examined the sequence of the LGI1 gene in four Japanese families with lateral temporal lobe epilepsy having characteristic auditory features, and identified one novel (1421G>A), and one reported (1418C>T) point mutation each in two families. These two mutations were 3 bp apart in the LGI1 gene and caused adjoining amino acid substitutions. The two families presented different clinical phenotypes and seizure control to drug treatment. These findings suggest that LGI1 mutations in Japanese ADLTE families may not be uncommon, and that diverse clinical phenotypes make adequate diagnosis of ADLTE difficult when only based on clinical information.

Ear movement induced by electrical cortical stimulation.

Cortical areas that control ear movement have not been reported in humans. We describe a rare case in which ear auricle movement was induced by extraoperative electrical cortical stimulation. A 21-year-old man with intractable localization-related epilepsy was admitted for presurgical evaluation. Subdural electrodes were implanted over the right temporal and frontal regions. Tonic upward contraction of the left ear auricle was elicited by stimulating the subdural electrode on the posterior portion of the right superior temporal gyrus close to the end of the Sylvian fissure. No other body movements or auditory symptoms were elicited. A possible mechanism underlying this rare phenomenon is discussed.