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

Knowledge about the neuronal dynamics and the projectome are both essential for understanding how the neuronal network functions in concert. However, it remains challenging to obtain the neural activity and the brain-wide projectome for the same neurons, especially for neurons in subcortical brain regions. Here, by combining in vivo microscopy and high-definition fluorescence micro-optical sectioning tomography, we have developed strategies for mapping the brain-wide projectome of functionally relevant neurons in the somatosensory cortex, the dorsal hippocampus, and the substantia nigra pars compacta. More importantly, we also developed a strategy to achieve acquiring the neural dynamic and brain-wide projectome of the molecularly defined neuronal subtype. The strategies developed in this study solved the essential problem of linking brain-wide projectome to neuronal dynamics for neurons in subcortical structures and provided valuable approaches for understanding how the brain is functionally organized via intricate connectivity patterns.
Animals ; Neurons/physiology* ; Mice ; Brain/physiology* ; Mice, Inbred C57BL ; Somatosensory Cortex/physiology* ; Neural Pathways/physiology* ; Hippocampus/physiology* ; Mice, Transgenic ; Male ; Brain Mapping ; Nerve Net/physiology* ; Substantia Nigra/physiology* ; Tomography, Optical/methods*

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

Animals ; Brain Mapping ; Dominance, Cerebral ; Magnetic Resonance Imaging ; Parietal Lobe ; Primates

The incidence of tinnitus is very high, which can affect the patient's attention, emotion and sleep, and even cause serious psychological distress and suicidal tendency. Currently, there is no uniform and objective method for tinnitus detection and therapy, and the mechanism of tinnitus is still unclear. In this study, we first collected the resting state electroencephalogram (EEG) data of tinnitus patients and healthy subjects. Then the power spectrum topology diagrams were compared of in the band of δ (0.5-3 Hz), θ (4-7 Hz), α (8-13 Hz), β (14-30 Hz) and γ (31-50 Hz) to explore the central mechanism of tinnitus. A total of 16 tinnitus patients and 16 healthy subjects were recruited to participate in the experiment. The results of resting state EEG experiments found that the spectrum power value of tinnitus patients was higher than that of healthy subjects in all concerned frequency bands. The
Attention ; Brain ; Electroencephalography ; Humans ; Parietal Lobe ; Tinnitus

Humans ; Pruritus ; Somatosensory Cortex ; Spinal Cord

OBJECTIVE: To investigate association between lesion location on magnetic resonance imaging (MRI) performed after an infarction and the duration of dysphagia in middle cerebral artery (MCA) infarction. METHODS: A videofluoroscopic swallowing study was performed for 59 patients with dysphagia who were diagnosed as cerebral infarction of the MCA territory confirmed by brain MRI. Lesions were divided into 11 regions of interest: primary somatosensory cortex, primary motor cortex, supplementary motor cortex, anterior cingulate cortex, orbitofrontal cortex, parieto-occipital cortex, insular cortex, posterior limb of the internal capsule (PLIC), thalamus, basal ganglia (caudate nucleus), and basal ganglia (putamen). Recovery time was defined as the period from the first day of L-tube feeding to the day that rice porridge with thickening agent was prescribed. Recovery time and brain lesion patterns were compared and analyzed. RESULTS: The mean recovery time of all patients was 26.71±16.39 days. The mean recovery time was 36.65±15.83 days in patients with PLIC lesions and 32.6±17.27 days in patients with caudate nucleus lesions. Only these two groups showed longer recovery time than the average recovery time for all patients. One-way analysis of variance for recovery time showed significant differences between patients with and without lesions in PLIC and caudate (p<0.001). CONCLUSION: Injury to both PLIC and caudate nucleus is associated with longer recovery time from dysphagia.
Basal Ganglia ; Brain ; Caudate Nucleus ; Cerebral Cortex ; Cerebral Infarction ; Deglutition ; Deglutition Disorders ; Extremities ; Gyrus Cinguli ; Humans ; Infarction ; Infarction, Middle Cerebral Artery ; Internal Capsule ; Magnetic Resonance Imaging ; Middle Cerebral Artery ; Motor Cortex ; Prefrontal Cortex ; Somatosensory Cortex ; Thalamus

OBJECTIVE: Dopamine plays a significant role in working memory by acting as a key neuromodulator between brain networks. Additionally, treatment of patients with schizophrenia using amisulpride, a pure dopamine class 2/3 receptor antagonist, improves their clinical symptoms with fewer side effects. We hypothesized that patients with schizophrenia treated with amisulpride and aripiprazole show increased working memory and glucose metabolism compared with those treated with cognitive behavioral therapy (CBT) and aripiprazole instead. METHODS: Sixteen patients with schizophrenia (eight in the amisulpride group [aripiprazole+amisulpride] and eight in the CBT group [aripiprazole+CBT]) and 15 age- and sex-matched healthy control subjects were recruited for a 12-week-long prospective trial. An [18F]-fluorodeoxyglucose-positron emission tomography/computerized tomography scanner was used to acquire the images. RESULTS: After 12 weeks of treatment, the amisulpride group showed greater improvement in the Letter-Number Span scores than the CBT group. Additionally, although brain metabolism in the left middle frontal gyrus, left occipital lingual gyrus, and right inferior parietal lobe was increased in all patients with schizophrenia, the amisulpride group exhibited a greater increase in metabolism in both the right superior frontal gyrus and right frontal precentral gyrus than the CBT group. CONCLUSION: This study suggests that a small dose of amisulpride improves the general psychopathology, working memory performance, and brain glucose metabolism of patients with schizophrenia treated with aripiprazole.
Aripiprazole ; Brain ; Cognition ; Cognitive Therapy ; Dopamine ; Electrons ; Frontal Lobe ; Glucose ; Humans ; Memory, Short-Term ; Metabolism ; Neurotransmitter Agents ; Occipital Lobe ; Parietal Lobe ; Positron-Emission Tomography ; Prefrontal Cortex ; Prospective Studies ; Psychopathology ; Schizophrenia ; Sulpiride

OBJECTIVE: The aims of this study were to investigate the effects of daily low-dose tadalafil on cognitive function and to examine whether there was a change in cerebral blood flow (CBF) in patients with erectile dysfunction (ED) and mild cognitive impairment. METHODS: Male patients aged 50 to 75 years with at least three months of ED (International Index of Erectile Function [IIEF]-5 score ≤ 21) and mild cognitive impairment (Montreal Cognitive Assessment [MoCA] score ≤ 22) were included in the study. The subjects were prescribed a low-dose PDE5 inhibitor (tadalafil 5 mg) to be taken once daily for eight weeks. Changes in MoCA score and single-photon emission computed tomography (SPECT) study between the two time-points were assessed by paired t tests. RESULTS: Overall, 30 male patients were assigned to the treatment group in this study and 25 patients completed the eight-week treatment course. Five patients were withdrawn due to adverse events such as myalgia and dizziness. Mean baseline IIEF and MoCA scores were 7.52 ± 4.84 and 18.92 ± 1.78. After the eight-week treatment, mean IIEF and MoCA scores were increased to 12.92 ± 7.27 (p < 0.05) and 21.8 ± 1.71 (p < 0.05), respectively. Patients showed increased relative regional CBF in the postcentral gyrus, precuneus, and brainstem after tadalafil administration versus at baseline (p < 0.001). CONCLUSION: The results of this prospective clinical study suggest that daily use of tadalafil 5 mg increases some regional CBF and improves cognitive function in patients with ED and mild cognitive impairment.
Brain Stem ; Cerebrovascular Circulation ; Clinical Study ; Cognition ; Dizziness ; Erectile Dysfunction ; Humans ; Male ; Methylenebis(chloroaniline) ; Mild Cognitive Impairment ; Myalgia ; Parietal Lobe ; Perfusion ; Phosphodiesterase Inhibitors ; Prospective Studies ; Somatosensory Cortex ; Tadalafil ; Tomography, Emission-Computed