While multiple step saccades (MSS) are occasionally reported in the healthy population, they are more evident in patients with Parkinson's disease (PD). Therefore, MSS has been suggested as a biological marker for the diagnosis of PD. However, the lack of clarity on the neural mechanism underlying the generation of MSS largely impedes their application in the clinic. We have proposed recently that MSS are triggered by the discrepancy between desired and executed saccades. Accordingly, brain regions involved in saccadic planning and execution might play a role in the generation of MSS. To test this hypothesis, we explored the role of the prefrontal (PFC) and posterior parietal cortex (PPC) in generating MSS by conducting two experiments: electroencephalographic recording and single-pulse transcranial magnetic stimulation in the PFC or PPC of humans while participants were performing a gap saccade task. We found that the PFC and PPC are involved in the generation of MSS.
Humans ; Parietal Lobe/physiology* ; Saccades/physiology* ; Prefrontal Cortex/physiology* ; Male ; Transcranial Magnetic Stimulation ; Female ; Electroencephalography ; Adult ; Young Adult

The dorsal and ventral visual streams have been considered to play distinct roles in visual processing for action: the dorsal stream is assumed to support real-time actions, while the ventral stream facilitates memory-guided actions. However, recent evidence suggests a more integrated function of these streams. We investigated the neural dynamics and functional connectivity between them during memory-guided actions using intracranial EEG. We tracked neural activity in the inferior parietal lobule in the dorsal stream, and the ventral temporal cortex in the ventral stream as well as the hippocampus during a delayed action task involving object identity and location memory. We found increased alpha power in both streams during the delay, indicating their role in maintaining spatial visual information. In addition, we recorded increased alpha power in the hippocampus during the delay, but only when both object identity and location needed to be remembered. We also recorded an increase in theta band phase synchronization between the inferior parietal lobule and ventral temporal cortex and between the inferior parietal lobule and hippocampus during the encoding and delay. Granger causality analysis indicated dynamic and frequency-specific directional interactions among the inferior parietal lobule, ventral temporal cortex, and hippocampus that varied across task phases. Our study provides unique electrophysiological evidence for close interactions between dorsal and ventral streams, supporting an integrated processing model in which both streams contribute to memory-guided actions.
Humans ; Male ; Female ; Adult ; Young Adult ; Hippocampus/physiology* ; Memory/physiology* ; Parietal Lobe/physiology* ; Temporal Lobe/physiology* ; Visual Perception/physiology* ; Electrocorticography ; Visual Pathways/physiology* ; Electroencephalography

Recent work in decision neuroscience suggests that visual saliency can interact with reward-based choice, and the lateral intraparietal cortex (LIP) is implicated in this process. In this study, we recorded from LIP neurons while monkeys performed a two alternative choice task in which the reward and luminance associated with each offer were varied independently. We discovered that the animal's choice was dictated by the reward amount while the luminance had a marginal effect. In the LIP, neuronal activity corresponded well with the animal's choice pattern, in that a majority of reward-modulated neurons encoded the reward amount in the neuron's preferred hemifield with a positive slope. In contrast, compared to their responses to low luminance, an approximately equal proportion of luminance-sensitive neurons responded to high luminance with increased or decreased activity, leading to a much weaker population-level response. Meanwhile, in the non-preferred hemifield, the strength of encoding for reward amount and luminance was positively correlated, suggesting the integration of these two factors in the LIP. Moreover, neurons encoding reward and luminance were homogeneously distributed along the anterior-posterior axis of the LIP. Overall, our study provides further evidence supporting the neural instantiation of a priority map in the LIP in reward-based decisions.
Animals ; Macaca mulatta/physiology* ; Parietal Lobe ; Neurons/physiology* ; Saccades ; Reward ; Photic Stimulation

Working memory (WM) refers to the process of temporally maintaining and manipulating input information. WM is the global workspace of cognitive functions, however, with severely restricted capacity and precision. Previous cognitive and computational models discussed the methods of calculating capacity and precision of WM and the reason why they are so limited. It still remains debated which model is the best across all datasets, and whether there exists upper limits of items. Besides, sensory cortices and the frontal-parietal loop are suggested to represent WM memorandum. Yet recently, the sensory recruitment hypothesis that posits an important role of sensory cortices in WM is strongly argued. Meanwhile, whether the prefrontal cortex shows sustained activity or bursting γ oscillations is intensely debated as well. In the future, disentangling the contribution to WM of feedforward γ vs feedback α/β oscillations, and/or dopamine vs serotonin systems, is critical for understanding the neural mechanisms underlying WM. It will further do help to recognize the basis for the psychiatric (e.g. schizophrenia) or neurological (e.g. Alzheimer's disease) disorders, and potentially to develop effective training and intervening methods.
Cognition ; Humans ; Memory, Short-Term ; Models, Neurological ; Parietal Lobe ; physiology ; Prefrontal Cortex ; physiology

Evolutionary psychology holds such an opinion that negative situation may threaten survival, trigger avoidance motive and have poor effects on the human-body function and the psychological quality. Both disgusted and sad situations can induce negative emotions. However, differences between the two situations on attention capture and emotion cognition during the emotion induction are still not well known. Typical disgusted and sad situation images were used in the present study to induce two negative emotions, and 15 young students (7 males and 8 females, aged 27 ± 3) were recruited in the experiments. Electroencephalogram of 32 leads was recorded when the subjects were viewing situation images, and event-related potentials (ERP) of all leads were obtained for future analysis. Paired sample t tests were carried out on two ERP signals separately induced by disgusted and sad situation images to get time quantum with significant statistical differences between the two ERP signals. Root-mean-square deviations of two ERP signals during each time quantum were calculated and the brain topographic map based on root-mean-square deviations was drawn to display differences of two ERP signals in spatial. Results showed that differences of ERP signals induced by disgusted and sad situation images were mainly manifested in T1 (120-450 ms) early and T2 (800-1,000 ms) later. During the period of T1, the occipital lobe reflecting attention capture was activated by both disgusted and sad situation images, but the prefrontal cortex reflecting emotion sense was activated only by disgusted situation images. During the period of T2, the prefrontal cortex was activated by both disgusted and sad situation images. However, the parietal lobe was activated only by disgusted situation images, which showed stronger emotional perception. The research results would have enlightenment to deepen understanding of negative emotion and to exploredeep cognitive neuroscience mechanisms of negative emotion induction.
Adult ; Attention ; Brain Mapping ; Cognition ; Electroencephalography ; Emotions ; Evoked Potentials ; Female ; Humans ; Male ; Occipital Lobe ; physiology ; Parietal Lobe ; physiology ; Prefrontal Cortex ; physiology

This study sought to reveal the difference of brain functions at resting-state between subjects with sub-health and normal controls by using the functional magnetic resonance imaging (fMRI) technology. Resting-state fMRI scans were performed on 24 subjects of sub-health and on 24 healthy controls with gender, age and education matched with the sub-health persons. Compared to the healthy controls, the sub-health group showed significantly higher regional homogeneity (ReHo) in the left post-central gyrus and the right post-central gyrus. On the other hand, the sub-health group showed significantly lower ReHo in the left superior frontal gyrus, in the right anterior cingulated cortex and ventra anterior cingulate gyrus, in the left dorsolateral frontal gyrus, and in the right middle temporal gyrus. The Significant difference in ReHo suggests that the sub-health persons have abnormalities in certain brain regions. It is proved that its specific action and meaning deserves further assessment.
Brain ; physiology ; physiopathology ; Brain Mapping ; Case-Control Studies ; Cerebral Cortex ; Frontal Lobe ; Gyrus Cinguli ; Humans ; Magnetic Resonance Imaging ; Parietal Lobe

The present study investigated the characteristic of semantic cognition of Uyghur-Chinese bilinguals. The event-related potentials (ERP) technique was used to explore the characteristic of N400 wave and topographic map of difference-waves with "picture-word" semantic priming paradigm. There were significant semantic priming effects on two languages. The average amplitude of N400 was similar in two languages, while average amplitudes of three electrodes (F3, F4, PZ) in Chinese were negative than others. Meanwhile, the activation of topographic map of Uyghur was almost in all regions except occipital lobe, and the degree of activation of Chinese was less than Uyghur, but the activation in parietal and bilateral frontal lobes was higher. In conclusion, the present study suggests that two languages of Uyghur-Chinese bilinguals are all sensitive to semantic priming. The bilateral frontal and parietal lobes participate in language switching. Semantic cognition of two languages in Uyghur-Chinese late non-proficient bilinguals is both completed by bilateral cerebral hemispheres. We have not found obvious lateralization on two languages of Uyghur-Chinese bilinguals.
Asian Continental Ancestry Group ; China ; Cognition ; Evoked Potentials ; Frontal Lobe ; physiology ; Humans ; Language ; Parietal Lobe ; physiology ; Semantics

To investigate the neuronal mechanism of retrieval of long-term digital memory in healthy volunteers, functional magnetic resonance imaging (fMRI) technique was used in the study. Twenty-two right-handed volunteers were subjected to a long-term digital memory test with block-design. The memory task and control task were adopted in the experiment alternatively. The fMRI data were recorded by a Siemens 1.5T MR machine and analyzed by SPM99. The activated brain regions were shown in the Talairach coordinate. The results showed that the Brodmann's area (BA) 9 region in left middle frontal gyrus was the most activated cortex during the long-term digital memory task. The left medial frontal gyrus, left inferior frontal gyrus, right inferior frontal gyrus, cingulate gyrus, left inferior parietal lobule, left superior parietal lobule, right superior parietal lobule, right middle temporal gyrus, left lingual gyrus, left middle occipital gyrus, right middle brain, cerebellum and right caudate nucleus tail were also involved. The activation in cortices showed obvious left predominance. It is suggested that a series of brain regions with left predominance are involved in long-term digital memory. Left lateral frontal cortex would be the most important structure for information extraction, while the other cortices and their connections may be important for processing and long-term storage of digital information.
Adolescent ; Brain ; physiology ; Female ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Memory, Long-Term ; physiology ; Parietal Lobe ; physiology ; Young Adult

AIMTo study the effect of Nociceptin/orphanin FQ (N/OFQ) on transient outward potassium (I(A)) in rat cerebral cortical neurons and its kinetic mechanism.

METHODSThe effects of N/OFQ on I(A) were investigated by using the whole cell patch clamp technique in acutely dissociated rat cerebral cortical neurons.

RESULTS(1) At the voltage of + 60 mV, 0.1 micromol/L N/OFQ made I(A) decreased from (5356.1 +/- 361.6) pA to (4113.3 +/- 312.7) pA (P < 0.01, n = 10) and the percent inhibition was 23.2% +/- 2.2%. (2) (N/OFQ made I-V curve of I(A) decreased significantly (P < 0.01, n = 10).(3) 0.1 micromol/L N/OFQ shifted the activation curve of I(A) to positive potential from (-9.2 +/- 2.5)mV to (30.6 +/- 3.7) mV (P < 0.01, n = 8) and changed the slope factor(kappa) of the activation curve from (20.4 +/- 2.3) mV to (22.6 +/- 2.1) mV (P > 0.05, n = 8). (4) 0.1 micromol/L N/OFQ caused a significant hyperpolarizing shift of the inactivation curve from (-64.1 +/- 3.2) mV to (-55.9 +/- 1.9) mV (P < 0.05, n = 5), without significant effect on kappa of the inactivation curve.

CONCLUSION0.1 micromol/L N/OFQ has a significant inhibition on I(A) and shift the activation and inactivation curve to depolarization in cerebral parietal cortical neurons of rats.

Animals ; Cerebral Cortex ; physiology ; Female ; Male ; Neurons ; physiology ; Opioid Peptides ; physiology ; Parietal Lobe ; physiology ; Potassium Channel Blockers ; Potassium Channels ; physiology ; Rats ; Rats, Wistar

In the past two decades, pain perception in the human brain has been studied with EEG/MEG brain topography and PET/fMRI neuroimaging techniques. A host of cortical and subcortical loci can be activated by various nociceptive conditions. The activation in pain perception can be induced by physical (electrical, thermal, mechanical), chemical (capsacin, ascoric acid), psychological (anxiety, stress, nocebo) means, and pathological (e.g. migraine, neuropathic) diseases. This article deals mainly on the activation, but not modulation, of human pain in the brain. The brain areas identified are named pain representation, matrix, neuraxis, or signature. The sites are not uniformly isolated across various studies, but largely include a set of cores sites: thalamus and primary somatic area (SI), second somatic area (SII), insular cortex (IC), prefrontal cortex (PFC), cingulate, and parietal cortices. Other areas less reported and considered important in pain perception include brainstem, hippocampus, amygdala and supplementary motor area (SMA). The issues of pain perception basically encompass both the site and the mode of brain function. Although the site issue is delineared to a large degree, the mode issue has been much less explored. From the temporal dynamics, IC can be considered as the initial stage in genesis of pain perception as conscious suffering, the unique aversion in the human brain.
Brain ; physiology ; Brain Mapping ; Brain Stem ; physiology ; Cerebral Cortex ; physiology ; Humans ; Magnetic Resonance Imaging ; Pain Perception ; physiology ; Parietal Lobe ; physiology ; Prefrontal Cortex ; physiology