Search

Detecting emotional facial expressions is an initial and indispensable component of face-to-face communication. Neuropsychological studies on the neural substrates of this process have shown that bilateral amygdala lesions impaired the detection of emotional facial expressions. However, the findings were inconsistent, possibly due to the limited number of patients examined. Furthermore, whether this processing is based on emotional or visual factors of facial expressions remains unknown. To investigate this issue, we tested a group of patients (n = 23) with unilateral resection of medial temporal lobe structures, including the amygdala, and compared their performance under resected- and intact-hemisphere stimulation conditions. The participants were asked to detect normal facial expressions of anger and happiness, and artificially created anti-expressions, among a crowd with neutral expressions. Reaction times for the detection of normal expressions versus anti-expressions were shorter when the target faces were presented to the visual field contralateral to the intact hemisphere (i.e., stimulation of the intact hemisphere; e.g., right visual field for patients with right hemispheric resection) compared with the visual field contralateral to the resected hemisphere (i.e., stimulation of the resected hemisphere). Our findings imply that the medial temporal lobe structures, including the amygdala, play an essential role in the detection of emotional facial expressions, according to the emotional significance of the expressions., (© 2021. The Author(s).)

The amygdala and uncus are located close to important neurovascular structures. We describe a safe technique for resection of amygdala and uncus. Under general anesthesia, the patient is positioned supine, with the head rotated approximately 20 degrees to the unoperated side and slightly extended. By using a trans-anterior T 1 subpial approach, the inferior horn of the lateral ventricle is opened, and hippocampectomy is performed. We treat an imaginary plane formed by the inferior circular sulcus of the insula, the endorhinal sulcus, and the inferior choroidal point as the upper border of amygdalar resection. After confirming the position of the inferior choroidal point, the border between the temporal stem and uncus is exposed from anterior to posterior. This border is continuous with the endorhinal sulcus. By exposing the endorhinal sulcus, the anterior choroidal artery and optic tract can be visualized. The amygdala is disconnected through complete exposure of the endorhinal sulcus to the inferior choroidal point. After the lateral side of the uncus is disconnected, the amygdala and uncus are removed en bloc. Since April 2014, we have used the described procedure to remove amygdalar-uncal lesions in 15 patients. The lesion was completely removed in all cases without complications. Histological specimens were obtained in all cases. Our procedure enables safe and complete removal of amygdalar-uncal lesions. Imagining the plane formed by the inferior circular sulcus, inferior choroidal point, and endorhinal sulcus is essential for complete removal of the lesion and for preserving important structures.

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., (© 2017 Wiley Periodicals, Inc.)

Objective: To identify semiological and scalp/sphenoidal electroencephalographic (EEG) features of epilepsy with amygdalar lesion (AL)., Methods: This study included 17 patients with epilepsy and distinct AL on MRI, who underwent resective surgery. There were nine female and eight male patients with ages at surgery ranging from 8 to 48 (mean 26.3) years. Postoperative seizure outcome was Engel class I or seizure-free in 12 patients, class II in four, and class III in one. Pathological examination revealed dysembryoplastic neuroepithelial tumor in eight cases, astrocytoma in two, mixed oligoastrocytoma in three, ganglioglioma in two, localized encephalitis in one, and cortical dysplasia in one. Semiology and scalp/sphenoidal EEG findings of these patients (AL group) were compared with those of 20 mesial temporal lobe epilepsy patients with hippocampal sclerosis (HS) who underwent resective surgery with favorable seizure outcome (Engel class I) (control group)., Results: Increased tonic components during seizure were more frequently seen in AL group (58.8%) than in control group (20%). Interictal unitemporal slow waves were more frequently found in AL group (58.8%) than in control group (20%). Ictal EEG revealed generalized (not only bitemporal) onset in six patients in AL group (35.3%), but none in control group. The generalized EEG onset patterns in AL group included spike and wave complexes, rhythmic spikes, and delta waves., Conclusion: Patients with AL had increased tonic components during seizure and generalized ictal EEG onset more frequently than patients with HS. These findings suggest widespread epileptic network involving subcortical structures such as the thalamus and the brainstem in patients with AL., (Copyright © 2015 Elsevier B.V. All rights reserved.)

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., (Copyright © 2014 Elsevier Inc. All rights reserved.)

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., (© 2013.)

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.

Neuroimaging studies have reported greater activation of the human amygdala in response to emotional facial expressions, especially for fear. However, little is known about how fast this activation occurs. We investigated this issue by recording the intracranial field potentials of the amygdala in subjects undergoing pre-neurosurgical assessment (n=6). The subjects observed fearful, happy, and neutral facial expressions. Time-frequency statistical parametric mapping analyses revealed that the amygdala showed greater gamma-band activity in response to fearful compared with neutral facial expressions at 50-150 ms, with a peak at 135 ms. These results indicate that the human amygdala is able to rapidly process fearful facial expressions., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: The eye gaze of other individuals conveys important social information and can trigger multiple psychological activities; some of which, such as emotional reactions and attention orienting, occur very rapidly. Although some neuroscientific evidence has suggested that the amygdala may be involved in such rapid gaze processing, no evidence has been reported concerning the speed at which the amygdala responds to eye gaze., Methodology/principal Findings: To investigate this issue, we recorded electrical activity within the amygdala of six subjects using intracranial electrodes. Subjects observed images of eyes and mosaics pointing in averted and straight directions. The amygdala showed higher gamma-band oscillations for eye gaze than for mosaics, which peaked at 200 ms regardless of the direction of the gaze., Conclusion: These results indicate that the human amygdala rapidly processes eye gaze.

The eyes of an individual act as an indispensable communication medium during human social interactions. Functional neuroimaging studies have revealed that several brain regions are activated in response to eyes and eye gaze direction changes. However, it remains unclear whether the temporal pole is one of these regions. Furthermore, if the temporal pole is activated by these stimuli, the timing and manner in which it is activated also remain unclear. To investigate these issues, we analyzed intracranial electroencephalographic data from the temporal pole that were obtained during the presentation of eyes and mosaics in averted or straight directions and their directional changes. Time–frequency statistical parametric mapping analyses revealed that the bilateral temporal poles exhibited greater gamma-band activation beginning at 215 ms in response to eyes compared with mosaics, irrespective of the direction. Additionally, the right temporal pole showed greater gamma-band activation beginning at 197 ms in response to directional changes of the eyes compared with mosaics. These results suggest that gamma-band oscillations in the temporal pole were involved in the processing of the presence of eyes and changes in eye gaze direction at a relatively late temporal stage compared with the posterior cortices. [ABSTRACT FROM AUTHOR]

Human faces transmit multiple valuable signals, and neuroimaging studies have shown that the amygdala is active in response to facial stimuli. However, little has been known about the temporal profile of amygdala activation during facial signal processing until recently. Here we review three recent studies conducted by our group in which we recorded amygdala intracranial electroencephalography in humans. The subjects were engaged in tasks that required automatic processing of faces, eye gazes and emotional expressions. Time-frequency statistical parametric mapping analyses revealed that the amygdala showed gamma-band activation in response to emotional expressions, gazes and faces, with peak latencies at about 100 ms, 200 ms and 250 ms, respectively. These results suggest that: (1) the amygdala performs multiple-stage processing in response to these facial signals using different visual input routes, and (2) amygdala activation for processing all of these facial signals is rapid, which could be prior to or simultaneous with conscious awareness of faces. [ABSTRACT FROM AUTHOR]

Summary: Purpose: This report examined the underlying mechanism of psychosis associated with epilepsy. Methods: An adult patient with epilepsy manifesting acute psychosis during long-term EEG monitoring is presented, together with a literature review on this subject. Results: A 25-year-old woman with intractable temporal lobe epilepsy developed acute psychosis while she underwent long-term intracranial EEG monitoring. After a clustering of seizures, she manifested psychotic symptoms including hallucination, stupor, and repeated fear. The transition of psychotic symptoms corresponded to the changes in frequency and morphology of seizure discharges restricted to the left amygdala. Improvement of psychosis coincided with disappearance of seizure discharges. Conclusions: This case confirmed a close relationship between psychotic symptoms and seizure discharges in the left amygdala. It is suggested that paroxysmal bombardment of the medial temporal lobe structure may be a pathogenetic factor of acute psychosis associated with epilepsy. [ABSTRACT FROM AUTHOR]