The effects of emotional films and subtitle types on eye movement patterns.

BACKGROUND: In Taiwan, the use of subtitle is common in TV programs and movies. However, studies on subtitles mostly focus on foreign language learning and film subtitle translation. Few studies address how subtitle types and emotion-laden films affect the viewers' eye movement patterns. PURPOSE: We aim to examine how the emotion type of film (happy, sad, angry, fear, or neutral) and subtitle type (meaningful subtitle, no subtitle, or meaningless subtitle) affect the dwell times and fixation counts in the subtitle area. METHODS: This study is a 5 (emotion type of film) × 3 (subtitle type) between-participants design. There were 15 participants per condition, resulting in a total of 225 participants. After watching a film, participants filled out a self-reported questionnaire regarding this film. RESULTS: The subtitled films have more fixation counts and dwell time for the meaningful subtitle compared to meaningless subtitle and no subtitle. The dwell time was longer on the subtitle area for the sad film than the neutral and happy films. Also, the dwell time was longer on the subtitle area for the fear film than the happy film. There were more fixation counts on the subtitle area for the sad film than the angry and happy films. CONCLUSIONS: The subtitle meaning is critical in directing overt attention. Also, overt attention directed to the subtitle area is affected by the different emotion types of films.

Assessment of brain connectome alterations in male chronic smokers using structural and generalized q-sampling MRI.

An association has been shown between chronic cigarette smoking and structural abnormalities in the brain areas related to several functions relevant to addictive behavior. However, few studies have focused on the structural alternations of chronic smoking by using magnetic resonance imaging (MRI). Also, it remains unclear how structural alternations are associated with tobacco-dependence severity and the positive/negative outcome expectances. The q-sampling imaging (GQI) is an advanced diffusion MRI technique that can reconstruct more precise and consistent images of complex oriented fibers than other methods. We aimed to use GQI to evaluate the impact of the neurological structure caused by chronic smoking. Sixty-seven chronic smokers and 43 nonsmokers underwent a MRI scan. The tobacco dependence severity and the positive/negative outcome expectancies were assessed via self-report. We used GQI with voxel-based statistical analysis (VBA) to evaluate structural brain and connectivity abnormalities. Graph theoretical analysis (GTA) and network-based statistical (NBS) analysis were also performed to identify the structural network differences among groups. Chronic smokers had smaller GM and WM volumes in the bilateral frontal lobe and bilateral frontal region. The GM/WM volumes correlated with dependence severity and outcome expectancies in the brain areas involving high-level functions. Chronic smokers had shape changes in the left hippocampal head and tail and the inferior brain stem. Poorer WM integrity in chronic smokers was found in the left middle frontal region, the right superior fronto-occipital fasciculus, the right temporal region, the left parahippocampus, the left anterior internal capsule, and the right inferior parietal region. WM integrity correlated with dependence severity and outcome expectancies in brain areas involving high-level functions. Chronic smokers had decreased local segregation and global integration among the brain regions and networks. Our results provide further evidence indicating that chronic smoking may be associated with brain structure and connectivity changes.

Assessment of disrupted brain functional connectome in tuberous sclerosis complex using resting-state fMRI.

ABSTRACT: Tuberous sclerosis complex (TSC) is a rare genetic disorder with multisystem involvement. TSC is characterized by benign hamartomas in multiple organs, including the brain, and its clinical phenotypes may be associated with abnormal functional connections. We aimed to use resting-state functional connectivity to provide findings of disrupted functional brain networks in TSC patients using graph theoretical analysis (GTA) and network-based statistic (NBS) analysis.Forty TSC patients (age = 24.11+/-11.44 years old) and 18 age-matched (25.13+/- 10.01 years old) healthy controls were recruited; they underwent resting-state functional magnetic resonance imaging using a 3T magnetic resonance imaging scanner. After image preprocessing and removing physiological noises, GTA was used to calculate the topological parameters of the brain network. NBS analysis was then used to determine the differences in cerebrum functional connectivity between the 2 groups.In GTA, several topological parameters, including the clustering coefficient, local efficiency, transitivity, and modularity, were better in controls than in TSC patients (P < .05). In NBS analysis, the edges of the brain networks between the groups were compared. One subnetwork showed more edges in controls than in TSC patients (P < .05), including the connections from the frontal lobe to the temporal and parietal lobe.The study results provide the findings on disrupted functional connectivity and organization in TSC patients compared with controls. The findings may help better understand the underlying physiological mechanisms of brain connection in TSC.

Betel Quid Dependence Effects on Working Memory and Remote Memory in Chewers with Concurrent Use of Cigarette and Alcohol.

OBJECTIVE: The current study asked whether BQ dependence level could affect working memory (WM) and remote memory for the chewers with concurrent use of cigarettes and alcohol, a common phenomenon in Taiwan. METHODS: The standardized neuropsychological tests (Wechsler Memory Scale III (WMS-III) and Remote Memory Test) were adopted to address the BQ chewers' verbal WM, spatial WM and remote memory. The Spatial Span Test and the Digit Span Test from WMS-III and the Remote Memory Test were adopted. The Betel Nut Dependency Scale (BNDS), the Fagerstrom Test for Nicotine Dependence (FTND), and the Alcohol Use Disorders Identification Test (AUDIT) were adopted to measure the dependence levels. RESULTS: The BQ dependence level and Last BQ did not affect spatial WM, verbal WM, and remote memory. Last Cigarette is critical in affecting WM; namely, longer interval led to worse performance. Finally, higher alcohol dependence level could lead to better remote memory. CONCLUSIONS: To our knowledge, there are no BQ studies addressing the effects of concurrent use of cigarettes and alcohol on memory. The current results suggest that cigarette smoking and alcohol drinking, rather than BQ chewing, are critical for memory performance.

A CNN-Based Autoencoder and Machine Learning Model for Identifying Betel-Quid Chewers Using Functional MRI Features.

Betel quid (BQ) is one of the most commonly used psychoactive substances in some parts of Asia and the Pacific. Although some studies have shown brain function alterations in BQ chewers, it is virtually impossible for radiologists' to visually distinguish MRI maps of BQ chewers from others. In this study, we aimed to construct autoencoder and machine-learning models to discover brain alterations in BQ chewers based on the features of resting-state functional magnetic resonance imaging. Resting-state functional magnetic resonance imaging (rs-fMRI) was obtained from 16 BQ chewers, 15 tobacco- and alcohol-user controls (TA), and 17 healthy controls (HC). We used an autoencoder and machine learning model to identify BQ chewers among the three groups. A convolutional neural network (CNN)-based autoencoder model and supervised machine learning algorithm logistic regression (LR) were used to discriminate BQ chewers from TA and HC. Classifying the brain MRIs of HC, TA controls, and BQ chewers by conducting leave-one-out-cross-validation (LOOCV) resulted in the highest accuracy of 83%, which was attained by LR with two rs-fMRI feature sets. In our research, we constructed an autoencoder and machine-learning model that was able to identify BQ chewers from among TA controls and HC, which were based on data from rs-fMRI, and this might provide a helpful approach for tracking BQ chewers in the future.

Appetitive Motivation and Regulatory Processes in Adolescent Ketamine Users.

BACKGROUND: Ketamine has remained the most commonly used illicit drug among adolescents in Taiwan. A dual process model proposes that addictive behaviors develop in adolescents as a result of an imbalance between an appetitive, approach-oriented system (implicit and explicit attitudes) and a regulatory executive system (cool and hot executive functions). We aimed to examine the appetitive and regulatory processes in adolescent ketamine users in comparison to matched healthy adolescents. Method: The participants were 30 adolescent ketamine users and 32 nondrug controls, matched with gender, age, education years, and education systems. Both groups completed the affective priming task (APT), the stop-signal task (SST), an Iowa Gambling Task (IGT), and finally a Drug Use Disorders Identification Test: Extended (DUDIT-E). Results: The controls had higher positive and negative outcome expectancy with respect to using ketamine compared to the adolescent ketamine users. There was no significant between-group performance difference in APT. The adolescent ketamine users may have shown marginally poorer performance compared to the controls in hot executive functions (IGT), but their cold executive functions (SST) remained intact. Conclusion: The current study reported that the adolescent ketamine users may not have imbalanced dual processes (biased appetitive motivation and impaired regulatory executive process). A different therapeutic focus on adolescent ketamine users may be developed accordingly. More advocacies on ketamine's aversive outcomes are needed, particularly on campus in order to reduce substance misuse.

Association between functional brain alterations and neuropsychological scales in male chronic smokers using resting-state fMRI.

RATIONALE: Recent studies have demonstrated that cigarette smoking is related to changes in brain structure and function. However, few studies focus on functional brain differences between male chronic smokers and nonsmokers in both local spontaneous activity and whole-brain functional networks. OBJECTIVES: Our study recruited 67 chronic smokers and 43 nonsmokers who underwent functional magnetic resonance imaging (fMRI) scans to investigate functional activity and connectivity alterations in chronic smokers. METHODS: We used the mean fractional amplitude of the low-frequency fluctuation (mfALFF) and mean regional homogeneity (mReHo) methods to investigate resting-state spontaneous activity in chronic smokers and nonsmokers. The graph theoretical analysis (GTA) and network-based statistical (NBS) analysis were also used to investigate functional connectivity alterations. RESULTS: Compared with nonsmokers, chronic smokers exhibited higher activation in the reward system and portions of the prefrontal cortex but lower activation in the default mode networks (DMN) and visual-related regions. In addition, correlation analysis was conducted to assess the associations between neuroimaging findings and the severity of nicotine dependence or expectations of smoking effects. Our results showed that certain brain regions correlated with the Fagerström Test for Nicotine Dependence (FTND), the positive aspect of the Drug Use Disorders Identification Test Extended (DUDIT-E), and the negative aspect of the DUDIT-E, especially in the attentional control networks and hippocampus. The graph theoretical analysis (GTA) results indicated chronic smokers exhibited a trend toward increased assortativity. Our network-based statistical (NBS) analysis revealed reduced functional connections between the subnetwork in the prefrontal cortex, olfactory cortex, angular gyrus, and cingulate gyrus of chronic smokers. CONCLUSIONS: We concluded that chronic smokers have neural adaptations in local spontaneous activity but remain healthy brain functional networks.

Disrupted white matter connectivity and organization of brain structural connectomes in tuberous sclerosis complex patients with neuropsychiatric disorders using diffusion tensor imaging.

OBJECTIVE: Tuberous sclerosis complex (TSC) is a genetic neurocutaneous syndrome with variable and unpredictable neurological comorbidity that includes epilepsy, intellectual disability (ID), autism spectrum disorder, and neurobehavioral abnormalities. The degree of white matter involvement is believed to be associated with the severity of neurological impairment. The goal of the present study was to evaluate diffusion characteristics of tubers, white matter lesions, and brain structural network alterations in TSC patients using diffusion tensor imaging (DTI), graph theoretical analysis (GTA), and network-based statistical (NBS) analysis. MATERIALS AND METHODS: Forty-two patients with a definitive diagnosis of TSC were recruited for this study. All patients underwent brain DTI examination using a 3 T magnetic resonance imaging system. Mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) values, and fractional anisotropy (FA) mapping in 52 tubers and white matter lesions were measured and compared with those of contralateral normal regions. GTA was performed on the inter-regional connectivity matrix, and NBS analysis was used to identify the significance of any connected subnetworks evident in the set of altered connections. For neurological severity subgrouping, a neurological severity score was assigned to TSC patients including those with ID, seizure, autism, and other neuropsychiatric disorders (NPDs). RESULTS: Significantly higher MD, AD, and RD, and lower FA values, were found in TSC lesions compared with those measured in contralateral normal regions for tubers (P < 0.05). GTA and NBS analysis provided better local segregation but worse global integration of the structural network (regular-like network) in TSC patients with ID, seizure, and higher Neurological Severity Score. Disrupted subnetworks in TSC patients with severe status included connections from the frontal lobe to the parietal lobe, temporal lobe to the caudate, and temporal lobe to the insula. DISCUSSION: DTI has the potential to provide valuable information about cytoarchitectural changes in TSC lesions beyond morphological MRI findings alone. Using GTA and NBS, current results provide the information of disrupted white matter connectivity and organization in TSC patients with different neuropsychological impairments.

Attentional Bias, "Cool" and "Hot" Executive Functions in Obese Patients: Roles of Body Mass Index, Binge Eating, and Eating Style.

PURPOSE/BACKGROUND: Obesity is recognized as an important risk factor for many chronic diseases and is a major health issue. The current study examined attentional bias to food and the "cool" (inhibitory control and mental flexibility) and "hot" (affective decision making) executive functions (EFs) in obese patients preparing for bariatric surgery. In addition to body mass index (BMI), this study examined the impact of the binge-eating tendency and eating styles. METHODS: The study population comprised 21 morbidly obese patients preparing to undergo bariatric surgery (BMI ≥30 kg/m) and 21 normal-weight controls (24 kg/m > BMI ≥ 18.5 kg/m). The Visual Probe Task was adopted to examine attentional bias toward food-related cues. The Stop-Signal Task and the Color Trails Test were used to assess inhibitory control and mental flexibility, respectively. The Iowa Gambling Task was administered to assess the affective decision making. RESULTS: (1) The obese patients showed poorer performances on cool EFs (for Color Trails Test, P = 0.016, ηp = 0.136; for Stop-Signal Task, P = 0.049, ηp = 0.093) and hot EF (for Iowa Gambling Task, normal controls showed progressed performance, P = 0.012, ηp = 0.077, but obese patients did not show this progress, P = 0.111, ηp = 0.089) compared with the normal controls; (2) participants with low binge-eating tendency had larger attentional biases at 2000 milliseconds than at 200 milliseconds on food-related cues (P = 0.003, ηp = 0.363); and (3) low-restrained participants exhibited attentional bias toward the low-calorie food cues, compared with the high-restrained group (P = 0.009, ηp = 0.158). CONCLUSIONS: The current study contributes to the development of a different therapeutic focus on obese patients and binge eaters.

Neural response to betel quid cues in chewers: a functional magnetic resonance imaging study.

The World Health Organization regards betel quid (BQ) as a human carcinogen. The current study analyzes whether the BQ cues can elicit activity in the chewers' craving-related brain areas. We adopted a cue-reactivity paradigm to examine the changes in the brain activities. The urge intensity was also included to examine whether it can moderate the brain areas stimulated by BQ cues. Sixteen male BQ chewers and 16 healthy male controls were recruited and analyzed. Four types of cues were adopted: BQ cues, matched food cues, visual control cues, and resting crosshair cued. The most direct and important comparison was between the brain activities elicited by the BQ cues versus those by the food cues. Furthermore, to test the current urge intensity effect, we compared BQ chewers with a strong urge versus those with a weak urge. All of the three-dimension anatomical and multi-slice task-based functional images were acquired using 3 T MRI. We found that (1) the BQ chewers and the healthy controls had similar brain activation patterns when comparing any two cue types, (2) the high-urge (not the low-urge) chewers showed craving-related activations (e.g., anterior cingulate cortex, medial orbitofrontal gyrus, and superior frontal gyrus) in the critical BQ cues vs. the food cue comparisons. (3) The high-urge chewers had larger contrast activations (BQ - Food) in many craving-related brain areas than low-urge chewers did (e.g., frontal gyrus). The urge states endorsed by the chewers can moderate the neural responses to BQ cues. Multisensory cues should be considered to elicit more intense and consistent cravings.

Neural correlates of executive functions in patients with obesity.

Obesity is one of the most challenging problems in human health and is recognized as an important risk factor for many chronic diseases. It remains unclear how the neural systems (e.g., the mesolimbic "reward" and the prefrontal "control" neural systems) are correlated with patients' executive function (EF), conceptualized as the integration of "cool" EF and "hot" EF. "Cool" EF refers to relatively abstract, non-affective operations such as inhibitory control and mental flexibility. "Hot" EF refers to motivationally significant affective operations such as affective decision-making. We tried to find the correlation between structural and functional neuroimaging indices and EF in obese patients. The study population comprised seventeen patients with obesity (seven males and 10 females, BMI = 37.99 ± 5.40, age = 31.82 ± 8.75 year-old) preparing to undergo bariatric surgery. We used noninvasive diffusion tensor imaging, generalized q-sampling imaging, and resting-state functional magnetic resonance imaging to examine the neural correlations between structural and functional neuroimaging indices and EF performances in patients with obesity. We reported that many brain areas are correlated to the patients' EF performances. More interestingly, some correlations may implicate the possible associations of EF and the incentive motivational effects of food. The neural correlation between the left precuneus and middle occipital gyrus and inhibitory control may suggest that patients with a better ability to detect appetitive food may have worse inhibitory control. Also, the neural correlation between the superior frontal blade and affective decision-making may suggest that patients' affective decision-making may be associated with the incentive motivational effects of food. Our results provide evidence suggesting neural correlates of EF in patients with obesity.

'Cool' and 'Hot' executive functions in suicide attempters with major depressive disorder.

RATIONALE: The World Health Organization reports that, by 2030, depression is expected to be the largest contributor to disease burden. Only small proportion of patients with major depressive disorder (MDD) achieves remission and the majority of them do not achieve long-term functional recovery. One of the neuropsychological domains that have been shown to be particularly impaired in depression, is that of executive function (EF). OBJECTIVES: We examined whether the patients with MDD with and without suicide attempts had deteriorated 'cool' EF and 'hot' EF. METHODS: The study population comprised 34 MDD attempters, 36 MDD non-attempters, and 55 healthy controls. We adopted the symmetry span task (SSPAN) to measure the updating and the affective shifting task (AST) to measure the inhibition and set-shifting in general and in response to emotional material. The Iowa gambling task (IGT) was used to examine the affective decision-making ability. RESULTS: After controlling for PHQ-9, Anxiety (HADS), suicidal ideation, education year and gender, we reported that (1) the MDD non-attempters had worse updating than the healthy controls and the MDD attempters; (2) the MDD attempters had worse general inhibition (GI) than the healthy controls and the MDD non-attempters; (3) the MDD non-attempters had worse general set-shifting (GS) than the healthy controls and the MDD attempters; (4) there was no between-group difference in the 'hot' EFs; and (5) MDD attempters with longer durations (over 5 years) since last attempt had worse general inhibition. CONCLUSIONS: The disrupted 'cool' EFs patients with MDD are consistent with previous review and meta-analytic studies. On the other hand, the two groups with MDD performed similarly to the healthy controls in the 'hot' EF.

Mapping brain functional alterations in betel-quid chewers using resting-state fMRI and network analysis.

RATIONALE: The World Health Organization regards betel quid (BQ) as a human carcinogen, and DSM-IV and ICD-10 dependence symptoms may develop with its heavy use. BQ's possible effects of an enhanced reward system and disrupted inhibitory control may increase the likelihood of habitual substance use. OBJECTIVES: The current study aimed to employ resting-state fMRI to examine the hypothesized enhanced reward system (e.g., the basal forebrain system) and disrupted inhibitory control (e.g., the prefrontal system) in BQ chewers. METHODS: The current study recruited three groups of 48 male participants: 16 BQ chewers, 15 tobacco- and alcohol-user controls, and 17 healthy controls. We used functional connectivity (FC), mean fractional amplitude of low-frequency fluctuations (mfALFF), and mean regional homogeneity (mReHo) to evaluate functional alternations in BQ chewers. Graph theoretical analysis (GTA) and network-based statistical (NBS) analysis were also performed to identify the functional network differences among the three groups. RESULTS: Our hypothesis was partially supported: the enhanced reward system for the BQ chewers (e.g., habitual drug-seeking behavior) was supported; however, their inhibitory control was relatively preserved. In addition, we reported that the BQ chewers may have enhanced visuospatial processing and decreased local segregation. CONCLUSIONS: The current results (showing an enhanced reward system in the chewers) provided the clinicians with important insight for the future development of an effective abstinence treatment.

Evaluation of structural connectivity changes in betel-quid chewers using generalized q-sampling MRI.

RATIONALE: Betel quid (BQ) is a common addictive substance in many Asian countries. However, few studies have focused on the influences of BQ on the brain. It remains unclear how BQ can affect structural brain abnormalities in BQ chewers. OBJECTIVES: We aimed to use generalized q-sampling imaging (GQI) to evaluate the impact of the neurological structure of white matter caused by BQ. METHODS: The study population comprised 16 BQ chewers, 15 tobacco and alcohol controls, and 17 healthy controls. We used GQI with voxel-based statistical analysis (VBA) to evaluate structural brain and connectivity abnormalities in the BQ chewers compared to the tobacco and alcohol controls and the healthy controls. Graph theoretical analysis (GTA) and network-based statistical (NBS) analysis were also performed to identify the structural network differences among the three groups. RESULTS: Using GQI, we found increases in diffusion anisotropy in the right anterior cingulate cortex (ACC), the midbrain, the bilateral angular gyrus, the right superior temporal gyrus (rSTG), the bilateral superior occipital gyrus, the left middle occipital gyrus, the bilateral superior and inferior parietal lobule, and the bilateral postcentral and precentral gyrus in the BQ chewers when compared to the tobacco and alcohol controls and the healthy controls. In GTA and NBS analyses, we found more connections in connectivity among the BQ chewers, particularly in the bilateral anterior cingulum. CONCLUSIONS: Our results provided further evidence indicating that BQ chewing may lead to brain structure and connectivity changes in BQ chewers.

Attentional bias to betel quid cues: An eye tracking study.

The World Health Organization regards betel quid as a human carcinogen, and DSM-IV and ICD-10 dependence symptoms may develop with heavy use. This study, conducted in central Taiwan, investigated whether betel quid chewers can exhibit overt orienting to selectively respond to the betel quid cues. Twenty-four male chewers' and 23 male nonchewers' eye movements to betel-quid-related pictures and matched pictures were assessed during a visual probe task. The eye movement index showed that betel quid chewers were more likely to initially direct their gaze to the betel quid cues, t(23) = 3.70, p < .01, d = .75, and spent more time, F(1, 23) = 4.58, p < .05, η2 = .17, and were more fixated, F(1, 23) = 5.18, p < .05, η2 = .18, on them. The visual probe index (response time) failed to detect the chewers' attentional bias. The current study provided the first eye movement evidence of betel quid chewers' attentional bias. The results demonstrated that the betel quid chewers (but not the nonchewers) were more likely to initially direct their gaze to the betel quid cues, and spent more time and were more fixated on them. These findings suggested that when attention is directly measured through the eye tracking technique, this methodology may be more sensitive to detecting attentional biases in betel quid chewers. (PsycINFO Database Record

Spatial short-term memory is impaired in dependent betel quid chewers.

RATIONAL: Betel quid is regarded as a human carcinogen by the World Health Organization. It remains unknown whether chewing betel quid has a chronic effect on healthy betel quid chewers' memory. OBJECTIVES: The present study aims to investigate whether chewing betel quid can affect short-term memory (STM). METHODS: Three groups of participants (24 dependent chewers, 24 non-dependent chewers, and 24 non-chewers) were invited to carry out the matrix span task, the object span task, and the digit span task. All span tasks' results were adopted to assess spatial STM, visual STM, and verbal STM, respectively. Besides, there are three set sizes (small, medium, and large) in each span task. RESULTS: For the matrix span task, results showed that the dependent chewers had worse performances than the non-dependent chewers and the non-chewers at medium and large set sizes. For the object span task and digit span task, there were no differences in between groups. In each group, recognition performances were worse with the increasing set size and showing successful manipulation of memory load. CONCLUSIONS: The current study provided the first evidence that dependent betel quid chewing can selectively impair spatial STM rather than visual STM and verbal STM. Theoretical and practical implications of this result are discussed.

Early attentional bias for negative words when competition is induced.

Previous research (Zeelenberg, Wagenmakers, & Rotteveel, 2006) revealed that emotionally meaningful words were identified significantly better than neutral words, with no difference between positive and negative words. Since in that study only a single target word was displayed at a time, we hypothesized that the equivalent performances for positive and negative words were due to a lack of competition. To test this, in our Experiment 1, we replicated Zeelenberg and colleagues' finding, using emotion-laden Chinese words and the identical data-limited method, which measured the accuracy of a briefly shown target. We then introduced competition in Experiment 2 by simultaneously presenting two words during the target frame, and found evidence for an early attentional bias to negative words. In Experiment 3, we confirmed that the bias in Experiment 2 was not due to the inevitable repetition of stimuli. Taken together, these results support our hypothesis that, in the presence of competition, negative words receive attentional priority and consequently have enhanced perceptual representations.

Measuring attention in a Parkinson's disease rat model using the 5-arm maze test.

Twenty to thirty percent of patients with Parkinson's disease (PD) suffer from not only motor disorder, but also symptoms of dementia, named Parkinson's disease dementia (PDD). Cognitive deficits in PDD include memory, recognition, and attention. Although patients with PDD show fluctuation of internal attention when taking an attentional test, they perform better when provided with an external cue, indicating that they have normal external attention. We examined visuospatial attention in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD animal model using the 5-arm maze test. After an 8-day training period, followed by a 2-day pre-lesion test in the 5-arm maze, male Wistar rats received a microinfusion of MPTP into the substantia nigra pars compacta, while controls underwent a sham operation procedure. Nine days after MPTP lesioning, the rats underwent an open field test, followed by a 2-day post-lesion test in the maze. The results showed that: (1) no motor impairment was observed 9 days after MPTP lesioning; and (2) in the post-lesion 5-arm maze test, cue illumination lasting 0.5s resulted in a decrease in the percentage of correct responses compared to a 2 second cue in both the sham-operated and MPTP-lesioned groups and no difference was observed between these two groups. As far as we are aware, this is the first study examining visuospatial attention in the PD rat model using the 5-arm maze test. These results suggest that, as in patients with PDD, MPTP-induced PD rats show normal external attention function.

Attentional biases for betel nut cues in heavy and light chewers.

The betel nut (Areca catecu) is regarded by the World Health Organization as the fourth most prevalent human carcinogen. Our study aims to investigate whether habitual chewers show bias in their attention toward betel nut usage. In the current study, heavy and light betel nut chewers were instructed to respond to a probe presented immediately after either one of a pair of areca-related picture and non-areca-matched picture. The presentation durations of these pictures were manipulated to investigate attentional biases under awareness threshold (17 ms), in initial orienting (200 ms), and maintenance of attention (2,000 ms). Faster response to the probe replacing the areca-related picture, in comparison with a matched picture, indicated attentional bias. The results showed that neither group showed subliminal attentional biases. Further, heavy chewers, but not light chewers, exhibited supraliminal biases toward betel nut cues in initial orienting of attention and maintained attention. Moreover, attentional bias scores at 2,000 ms were also shown to be positively associated with betel nut craving and dependence. Implications of the current findings are thoroughly discussed in the article.