Panpan Hu

Selective attention deficits in early and moderate stage Parkinson's disease.

Patients with Parkinsons disease (PD) often show impaired performance on visuospatial attentional tasks. The objective of the study was to examine the attentional function of PD patients performing the attentional network test (ANT). We used the ANT to compare PD patients with healthy controls with respect to the efficiency of 3 anatomically defined attentional networks: the alerting, orienting, and executive control networks. We found that PD patients showed a selective abnormality in the orienting network. Although the alerting and executive control networks apparently remained unaffected, the efficiencies of these networks in patients with PD negatively correlated with the Hoehn-Yahr stage. The results supported the idea that the orienting processes may be more dynamic in PD than in non-PD individuals.

Time-based prospective memory impairment in patients with thalamic stroke.

The role of the thalamus in memory is potentially very complex. However, most studies on the memory impairments of thalamic lesions have focused on retrospective memory, rarely on prospective memory. To explore the effect of thalamic lesions on event-based prospective memory (EBPM) and time-based prospective memory (TBPM), respectively, and to verify the hypothesis that the thalamus is involved in the prospective memory, EBPM and TBPM tasks were administered to 18 thalamic stroke patients and 18 age- and education-matched healthy controls. In the EBPM task, subjects were asked to perform an action whenever particular words were presented. In the TBPM task, subjects were asked to perform an action at certain times. Compared with the performance of healthy controls on EBPM and TBPM tasks (EBPM, 4.3 +/- 1.5; TBPM, 5.4 +/- 1.0), there was a significant difference in the performance of thalamic stroke patients in the TBPM tasks (2.4 +/- 1.6), but no difference was found in EBPM tasks (3.7 +/- 1.1). These results may indicate that the thalamus is involved in PM and particularly in TBPM.

Evidence for progressive brain abnormalities in early schizophrenia: a cross-sectional structural and functional connectivity study.

It has long been debated whether a progressive process is involved in schizophrenia. The aim of the current study was to determine whether a progressive process was involved in patients with early schizophrenia, who were drug naive or had received short-term minimal antipsychotic treatment to avoid the distortion through medication effects. Twenty-eight patients with schizophrenia with illness-duration of up to 3 years and twenty-six matched healthy controls were recruited. Structural and functional brain networks were examined based on diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI). The intergroup differences and correlation with illness duration in the patient group were surveyed. The schizophrenic patients showed lower fractional anisotropy (FA) values in the corpus callosum and corona radiata. Negative correlations of illness duration with FA values were observed in similar regions. During functional analysis, reduced functional connectivity between bilateral temporoparietal-junction (TPJ) and the posterior cingulate cortex (PCC) were found in the default mode network (DMN) in schizophrenic patients. In addition, the left TPJ showed gradually weaker functional connectivity with PCC and the medial prefrontal cortex (MPFC) in DMN as the duration of schizophrenia increased. The results suggested that early in the disease process patients have decreased connectivity in both structural and functional networks and that the weaker structural and functional connectivity negatively correlated with illness duration, which provided evidence for progressive brain abnormalities in early schizophrenia.

Selective impairment of attention networks in breast cancer patients receiving chemotherapy treatment

Complaints about attention disorders are common among breast cancer survivors who have undergone chemotherapy treatment. However, it is not known whether these complaints indicate a global attention deficit or the selective impairment of attention networks.

Attention network impairments in patients with focal frontal or parietal lesions

Recently, research on attention has focused on 3 networks that are linked to separate brain regions, i.e. orienting, alerting, and executive control. The attention network test (ANT) is one of the methods to measure the three attention functions. However, neuropsychological investigations have not examined the anatomical disassociation of different attention networks with the same task. We compared the efficiencies of the 3 networks between brain-damaged patients (27 frontal lesions, 20 temporal lesions, and 21 parietal lesions) and healthy controls (N=58) with ANT. Comparing the brain damaged group with the normal controls, a reduced efficiency of the executive network was found in patients with frontal lobe and parietal lobe injuries, and there was also a deficit in the orienting network in patients with parietal lobe injuries. Analysis of lateralization indicated the right hemisphere superiority to the alerting system. The present study found that the three attentional networks were selectively impaired following brain damage which affected different areas in the brain.

Selective Impairment of Attentional Networks of Alerting in Wilson's Disease

Wilsons disease (WD) is typically affected by attention, which is one of the cognitive domains. The Attention Network Test (ANT) was developed to measure the functioning of the following three individual attentional networks: orienting, alerting, and executive control. The ANT has been used in a variety of neuropsychiatric conditions; however, it has not been used in WD. The aim of this study was to investigate the attentional function of WD patients, and 35 patients with early and moderate neurological WD, as well as 35 gender-, age-, and education-matched healthy controls performed the ANT. Remarkable differences between the patients and healthy controls were observed in the alerting network (p = 0.007) in contrast the differences in the orienting (p = 0.729) and executive control (p = 0.888) networks of visual attention. The mean reaction time in the ANT was significantly longer in the WD patients than in the controls (p<0.001, 0.001). In the WD patients, there was an effect specifically on the alerting domain of the attention network, whereas the orienting and executive control domains were not affected.

Effects of painful stimulation and acupuncture on attention networks in healthy subjects

Pain is a subjective sensory and emotional experience, and it has been reported that many different brain regions are regulated by pain, and that pain can impact attention. Acupuncture is an important treatment component of Chinese traditional medicine, and has been used for thousands of years to treat a wide variety of conditions. Although several studies have shown that acupuncture improves consciousness, the precise impact of both acupuncture and painful stimulation on attention is unclear. Are all of the attention networks modulated, or do these stimuli act on a specific network? Is the effect of painful stimulation similar to that of acupuncture? We administered the attention network test to 30 participants (15 males) to investigate the relative efficiencies of three independent attention networks (alerting, orienting, and executive control networks) under three conditions: baseline, after painful stimulation, and after acupuncture. The degree of pain experienced was assessed on a horizontally oriented visual analogue scale. The results showed that painful stimulation and acupuncture had similar effects on the orienting and executive control networks; however, there was a significantly different effect between the three conditions on the alerting network. In conclusion, (1) painful stimulation can selectively impact attention; (2) acupuncture can also selectively impact attention; i.e., both have selective influences on the alerting and executive control networks, but not on the orienting network; (3) the effects of acupuncture and painful stimulation are not identical. The mechanisms by which painful stimulation and acupuncture influence attention warrant further research.

How does emotional context modulate response inhibition in alexithymia: electrophysiological evidence from an ERP study.

Background Alexithymia, characterized by difficulties in identifying and describing feelings, is highly indicative of a broad range of psychiatric disorders. Several studies have also discovered the response inhibition ability impairment in alexithymia. However, few studies on alexithymic individuals have specifically examined how emotional context modulates response inhibition procedure. In order to investigate emotion cognition interaction in alexithymia, we analyzed the spatiao-temporal features of such emotional response inhibition by the approaches of event-related potentials and neural source-localization. Method The study participants included 15 subjects with high alexithymia scores on the 20-item Toronto Alexithymia Scale (alexithymic group) and 15 matched subjects with low alexithymia scores (control group). Subjects were instructed to perform a modified emotional Go/Nogo task while their continuous electroencephalography activities were synchronously recorded. The task includes 3 categories of emotional contexts (positive, negative and neutral) and 2 letters (“M” and “W”) centered in the screen. Participants were told to complete go and nogo actions based on the letters. We tested the influence of alexithymia in this emotional Go/Nogo task both in behavioral level and related neural activities of N2 and P3 ERP components. Results We found that negatively valenced context elicited larger central P3 amplitudes of the Nogo–Go difference wave in the alexithymic group than in the control group. Furthermore, source-localization analyses implicated the anterior cingulate cortex (ACC) as the neural generator of the Nogo-P3. Conclusion These findings suggest that difficulties in identifying feelings, particularly in negative emotions, is a major feature of alexithymia, and the ACC plays a critical role in emotion-modulated response inhibition related to alexithymia.

Impairment of conflict processing in alexithymic individuals.

Alexithymia is characterized by difficulties in identifying and describing feelings and in distinguishing between feelings and bodily sensations. Several researchers have examined the impairment of executive functioning in alexithymia; however, only a few studies have been specifically concerned with conflict processing in alexithymia. Utilizing the attention network test (ANT), we investigated whether alexithymia is related to or independent of executive function, especially with respect to conflict processing. Participants included 33 subjects with high alexithymia scores on the 20-item Toronto Alexithymia Scale (TAS-20) and 30 matched subjects with low alexithymia scores. On the ANT, we found a significant difference between the two groups in conflict processing, and no significant difference in alerting and orienting dimensions. These findings suggested that subjects with high alexithymia scores have selective impairment in conflict processing.

Difference in the binocular rivalry rate between depressive episodes and remission.

Binocular rivalry refers to a phenomenon in which, when different images are presented to each eye simultaneously, perception alternates spontaneously between monocular views rather than being a superposition of the two images. Recently, the involvement of serotonin systems has been reported to be related to the phenomenon. There is abundant evidence for abnormalities of the serotonin systems in depression and the antidepressants that enhance 5-HT transmission, which in turn improves mood and behavior. However, the available data with respect to rivalry rates in depression are less clear. Therefore, we aimed to explore whether perceptual rivalry was affected by a dysfunctional serotonin system in patients with depression and whether there was a rivalry rate difference between episode and remission states in depression patients. Twenty-eight patients with depression and 30 healthy controls were recruited in the study. We assessed the rivalry rate and the 17-item Hamilton Depression Rating Scale (HAMD) in patients with depression during clinical episode and remission states. The results suggested that alternation rates for patients during episodes were significantly slower than during remission and than in healthy controls. Also, alternation rates for patients during remission were slower than in healthy controls. These results may provide further clues to serotonergic neural systems contributing to the dynamics of perception rivalry and may foster enlightenment regarding the field of binocular rivalry in psychiatric disorders other than bipolar disorder.