Integrating multisensory inputs to generate accurate perception and guide behavior is among the most critical functions of the brain. Subcortical regions such as the amygdala are involved in sensory processing including vision and audition, yet their roles in multisensory integration remain unclear. In this study, we systematically investigated the function of neurons in the amygdala and adjacent regions in integrating audiovisual sensory inputs using a semi-chronic multi-electrode array and multiple combinations of audiovisual stimuli. From a sample of 332 neurons, we showed the diverse response patterns to audiovisual stimuli and the neural characteristics of bimodal over unimodal modulation, which could be classified into four types with differentiated regional origins. Using the hierarchical clustering method, neurons were further clustered into five groups and associated with different integrating functions and sub-regions. Finally, regions distinguishing congruent and incongruent bimodal sensory inputs were identified. Overall, visual processing dominates audiovisual integration in the amygdala and adjacent regions. Our findings shed new light on the neural mechanisms of multisensory integration in the primate brain.
Animals ; Macaca ; Acoustic Stimulation ; Auditory Perception/physiology* ; Visual Perception/physiology* ; Amygdala/physiology* ; Photic Stimulation

Post-traumatic stress disorder (PTSD) has been reported to be associated with a higher risk of cardiovascular disease. The amygdala may have an important role in regulating cardiovascular function. This study aims to explore the effect of amygdala glutamate receptors (GluRs) on cardiovascular activity in a rat model of PTSD. A compound stress method combining electrical stimulation and single prolonged stress was used to prepare the PTSD model, and the difference of weight gain before and after modeling and the elevated plus maze were used to assess the PTSD model. In addition, the distribution of retrogradely labeled neurons was observed using the FluoroGold (FG) retrograde tracking technique. Western blot was used to analyze the changes of amygdala GluRs content. To further investigate the effects, artificial cerebrospinal fluid (ACSF), non-selective GluR blocker kynurenic acid (KYN) and AMPA receptor blocker CNQX were microinjected into the central nucleus of the amygdala (CeA) in the PTSD rats, respectively. The changes in various indices following the injection were observed using in vivo multi-channel synchronous recording technology. The results indicated that, compared with the control group, the PTSD group exhibited significantly lower weight gain (P < 0.01) and significantly decreased ratio of open arm time (OT%) (P < 0.05). Retrograde labeling of neurons was observed in the CeA after microinjection of 0.5 µL FG in the rostral ventrolateral medulla (RVLM). The content of AMPA receptor in the PTSD group was lower than that in the control group (P < 0.05), while there was no significant differences in RVLM neuron firing frequency and heart rate (P > 0.05) following ACSF injection. However, increases in RVLM neuron firing frequency and heart rate were observed after the injection of KYN or CNQX into the CeA (P < 0.05) in the PTSD group. These findings suggest that AMPA receptors in the amygdala are engaged in the regulation of cardiovascular activity in PTSD rats, possibly by acting on inhibitory pathways.
Rats ; Animals ; Rats, Sprague-Dawley ; Stress Disorders, Post-Traumatic ; Receptors, AMPA ; 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology* ; Receptors, Glutamate/metabolism* ; Amygdala ; Weight Gain ; Medulla Oblongata/physiology* ; Blood Pressure

Although a great number of studies have investigated the changes of resting-state functional connectivity (rsFC) in patients with mental disorders, such as depression and schizophrenia etc, little is known how stable the changes are, and whether temporal sad or happy mood can modulate the intrinsic rsFC. In our experiments, happy and sad video clips were used to induce temporally happy and sad mood states in 20 healthy young adults. We collected functional magnetic resonance imaging (fMRI) data while participants were watching happy or sad video clips, which were administrated in two consecutive days. Seed-based functional connectivity analyses were conducted using the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and amygdala as seeds to investigate neural network related to executive function, attention, and emotion. We also investigated the association of the rsFC changes with emotional arousability level to understand individual differences. There is significantly stronger functional connectivity between the left DLPFC and posterior cingulate cortex (PCC) under sad mood than that under happy mood. The increased connectivity strength was positively correlated with subjects' emotional arousability. The increased positive correlation between the left DLPFC and PCC under sad relative to happy mood might reflect an increased processing of negative emotion-relevant stimuli. The easier one was induced by strong negative emotion (higher emotional arousability), the greater the left DLPFC-PCC connectivity was indicated, the greater the instability of the intrinsic rsFC was shown.
Adult ; Affect ; Amygdala ; physiology ; Attention ; Gyrus Cinguli ; physiology ; Humans ; Magnetic Resonance Imaging ; Prefrontal Cortex ; physiology ; Young Adult

This study was aimed to optimize the methods of magnetic resonance spectroscopy (MRS) to improve its quality in amygdala. Forty-three volunteers were examined at right and left amygdala using stimulated-echo acquisition mode (STEAM), and point-resolved spectroscopy series (PRESS) with and without saturation bands. The Cr-SNR, water-suppression level, water full width at half maximum (FWHM) and RMS noise of three sequences were compared. The results showed that (1) the Cr-SNR and water-suppression lelvel of PRESS with saturation bands were better than that of PRESS without saturation bands and STEAM (P<0.001); (2) the left and right RMS noise was significantly different both using PRESS with saturation bands and using STEAM (P<0.05); (3) there was a positive, significant correlation between Cr-SNR and voxel size (P<0.05). Therefore, PRESS with saturation bands is better than PRESS without saturation bands or STEAM for the spectroscopy of amygdala. It is also useful to make the voxel as big as possible to improve the spectral quality.
Adult ; Algorithms ; Amygdala ; metabolism ; physiology ; Artifacts ; Female ; Humans ; Magnetic Resonance Spectroscopy ; methods ; Male ; Pattern Recognition, Automated ; standards ; Young Adult

BACKGROUNDStereotactic surgery has been used to treat heroin abstinence in China since 2000 by ablating the amygdaloid nucleus (AMY) and the nucleus accumbens (NAc), which also provides opportunity to identify the relationship between these nuclei and addiction. Our study aimed to explore the physiological and psychological effects of electrically stimulating the AMY and the NAc in heroin addicts after detoxification by observing changes of heart rate, arterial pressure and occurrence of euphoria similar to heroin induced euphoria.

METHODSA total of 70 heroin addicts after detoxification were recruited, and 61 of them were eligible to be given stereotactic surgery for heroin abstinence. The operation was carried out after determining the coordinates of all target nucleuses, and stimulation was performed at the AMY and the NAc solely or jointly. Heart rate, arterial pressure and occurrence of euphoria similar to heroin induced euphoria were recorded and analyzed.

RESULTSThe average heat rate was (66 ± 10) beats/min before electric stimulation, and significantly increased to (84 ± 14) beats/min during stimulation, and changed to (73 ± 12) beats/min 10 minutes after stimulation. There was a significant elevation of the average arterial pressure from 83 mmHg before stimulation to 98 mmHg during the stimulation, and it then decreased to 90 mmHg after stimulation. Forty-three of the 61 patients showed intense euphoria similar to heroin induced euphoria. The largest number (118/186) of euphoric responses occurred when the AMY and the NAc were stimulated at the same time. Odds ratio was 5.4 (95%CI: 2.4 - 11.9, P < 0.0001) to quantify the association. Results from a Logistic regression model showed a positive correlation between unilateral stimulation of either the AMY or NAC and induction of euphoria (OR > 1), especially when the left AMY or left NAc was stimulated (P < 0.05).

CONCLUSIONSOur data are consistent with existing results that the AMY and the NAc are related to addiction. Different roles in drug dependence would be suggested according to the location of the AMY and NAc.

Adolescent ; Adult ; Amygdala ; surgery ; Blood Pressure ; physiology ; China ; Electric Stimulation ; methods ; Female ; Heart Rate ; physiology ; Heroin Dependence ; physiopathology ; psychology ; surgery ; Humans ; Inactivation, Metabolic ; Male ; Nucleus Accumbens ; surgery ; Radiosurgery ; methods ; Young Adult

OBJECTIVETo examine the role of glutaminergic neurons in the transmission and integration of the sweat taste information in the brain stem and the amygdala.

METHODSConscious Sprague-Dawley rats were subjected to oral sweet taste or water (control) stimulations. The activated neurons were identified by detecting c-Fos expression in taste-related brain areas, and the glutaminergic neurons by detecting vesicular glutamate transpoter-3 (VGLUT3).

RESULTSCompared with control group, the rats with oral sucrose solution stimulation exhibited significantly increased c-Fos-expressing and double-labeled neurons in the nucleus of the solitary tract (NST), the parabrachial nucleus (PBN) and the amygdala.

CONCLUSIONNeurons in the NST, PBN and amygdala are activated after oral sweet taste stimulation. The sweet taste perception at different levels in the CNS is partly mediated by glutamate.

Amygdala ; physiology ; Animals ; Brain Stem ; physiology ; Glutamic Acid ; metabolism ; Male ; Neurons ; metabolism ; physiology ; Proto-Oncogene Proteins c-fos ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Solitary Nucleus ; cytology ; physiology ; Sucrose ; administration & dosage ; metabolism ; Taste Perception ; physiology ; Vesicular Glutamate Transport Proteins ; metabolism

OBJECTIVETo study the effect of maternal isolation stress on the epilepsy susceptibility in young rats and the possible mechanism.

METHODSSixty Sprague-Dawley young rats were randomly divided into a normal control and two maternal isolation groups that were subjected to maternal isolation for 15 min or 3 hrs daily on postnatal days 2-17. On postnatal day 18, an amygdala kindling test was performed to induce seizures. The expression of GABA(A) receptor α₁ in the hippocampus was determined by immunohistochemisty.

RESULTSThe weights were reduced, the threshold of amygdala kindling and the stimulation number for full kindling decreased significantly, and seizures were more severe in the maternal isolation 3 hrs group compared with the normal control group. The expression of GABA(A) receptor alpha(1) in the hippocampus CA1 area in the maternal isolation 3 hrs group decreased significantly compared with that in the normal groups. There were no significant differences in the aspects above mentioned between the maternal isolation 15 min and normal control groups.

CONCLUSIONSThe stress of early daily maternal isolation for 3 hrs may affect adversely brain development and increase epilepsy susceptibility in young rats. The decreased expression of GABA(A) receptor α₁ in the hippocampus may contribute to the potential mechanism.

Amygdala ; physiology ; Animals ; Disease Susceptibility ; Epilepsy ; etiology ; Female ; Hippocampus ; chemistry ; Kindling, Neurologic ; Maternal Deprivation ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Receptors, GABA-A ; analysis ; Stress, Psychological ; complications

AIMTo Investigate the effect of glutamate (Glu) and gamma-aminobutyric acid(GABA) in orbitofrontal cortex (OFC) on regulation of gastric motility.

METHODSUsing microinjection in OFC,together with lesion of related nucleus,and recording the intragastric pressure(IGP).

RESULTS(1) Microinjection of Glu in OFC caused a significant reduce of the amplitude of gastric motility, this effect could be reverse by lesion of amygdala, while lesion of LC had no influence on the effect of Glu. (2) microinjection of GABA in OFC could increase the amplitude of gastric motility significantly,and lesion of LC could abolish this effect,while lesion of amygdala could enhance the effect of GABA more.

CONCLUSIONMicroinjection of Glu in OFC may enhance the normal inhibitory effect of amygdale on gastric motility, and the effect of microinjection of GABA in OFC on gastric motility is closely related with LC.

Amygdala ; physiology ; Animals ; Female ; Frontal Lobe ; metabolism ; physiology ; Gastrointestinal Motility ; drug effects ; Glutamic Acid ; pharmacology ; Locus Coeruleus ; physiology ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; pharmacology

OBJECTIVETo investigate the effects of amygdala kindled seizures on memory retention of passive-avoidance test in rats.

METHODSChronic kindled seizures were achieved by daily application of electric stimulations on amygdala until the occurrence of 3 consecutive convulsive seizures. Then a passive-avoidance test was performed to measure memory retention ability in rats; another group of rats received an electric stimulation on amygdala 5 min before the training trail to observe the effects of acute seizure attack on memory retention ability.

RESULTIn the training trail and the 1st day of the test trail, there was no difference in the latency to enter dark compartment between chronic kindled seizure group and its corresponding control group. However, the latency significantly increased at the 5 th day of test trail. In addition, the latency of acute seizure attack group rats significantly decreased at the 1 st day and 5 th day of test trail.

CONCLUSIONChronic amygdala kindled seizures increase memory retention of passive-avoidance test in rats, and acute seizure attack impairs this action.

Amygdala ; physiology ; Animals ; Avoidance Learning ; Electric Stimulation ; Kindling, Neurologic ; physiology ; Male ; Memory ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Seizures ; physiopathology

OBJECTIVETo investigate the difference in the brain activation patterns of males and females during video sexual stimulation by functional magnetic resonance imaging (fMRI).

METHODSThe participants were 20 adult males and 20 adult females, all healthy, right-handed, and with no history of sexual function disorder and physical, psychiatric or neurological diseases. Blood-oxygen-level-dependent fMRI was performed using a 1.5 T MR scanner. Three-dimensional anatomical image of the entire brain were obtained by using a T1-weighted three-dimensional anatomical image spoiled gradient echo pulse sequence. Each person was shown neutral and erotic video sequences for 60 s each in a block-study fashion, i.e. neutral scenes--erotic scenes--neutral scenes, and so on. The total scanning time was approximately 7 minutes, with a 12 s interval between two subsequent video sequences in order to avoid any overlapping between erotic and neutral information.

RESULTSThe video sexual stimulation produced different results in the men and women. The females showed activation both in the left and the right amygdala, greater in the former than in the latter ([220.52 +/- 17.09] mm3 vs. [155.45 +/- 18.34] mm3, P < 0.05), but in the males only the left amygdala was activated. The males showed greater brain activation than the females in the left anterior cingulate gyrus ([420.75 +/- 19.37] mm3 vs. [310.67 +/- 10.53] mm3, P < 0.05), but less than the females in the splenium of the corpus callosum ([363.32 +/- 13.30] mm3 vs. [473.45 +/- 14.92] mm3, P < 0.01).

CONCLUSIONBrain activation patterns of males and females during video sexual stimulation are different, underlying which is presumably the difference in both the structure and function of the brain between men and women.

Adult ; Amygdala ; physiology ; Brain ; physiology ; Brain Mapping ; Coitus ; physiology ; Corpus Callosum ; physiology ; Female ; Gyrus Cinguli ; physiology ; Humans ; Magnetic Resonance Imaging ; Male ; Sex Factors