Sigmund Hsiao

Brain activities associated with gaming urge of online gaming addiction.

The aim of this study was to identify the neural substrates of online gaming addiction through evaluation of the brain areas associated with the cue-induced gaming urge. Ten participants with online gaming addiction and 10 control subjects without online gaming addiction were tested. They were presented with gaming pictures and the paired mosaic pictures while undergoing functional magnetic resonance imaging (fMRI) scanning. The contrast in blood-oxygen-level dependent (BOLD) signals when viewing gaming pictures and when viewing mosaic pictures was calculated with the SPM2 software to evaluate the brain activations. Right orbitofrontal cortex, right nucleus accumbens, bilateral anterior cingulate and medial frontal cortex, right dorsolateral prefrontal cortex, and right caudate nucleus were activated in the addicted group in contrast to the control group. The activation of the region-of-interest (ROI) defined by the above brain areas was positively correlated with self-reported gaming urge and recalling of gaming experience provoked by the WOW pictures. The results demonstrate that the neural substrate of cue-induced gaming urge/craving in online gaming addiction is similar to that of the cue-induced craving in substance dependence. The above-mentioned brain regions have been reported to contribute to the craving in substance dependence, and here we show that the same areas were involved in online gaming urge/craving. Thus, the results suggest that the gaming urge/craving in online gaming addiction and craving in substance dependence might share the same neurobiological mechanism.

The characteristics of decision making, potential to take risks, and personality of college students with Internet addiction

This study aimed to identify risk factors involved in Internet addiction. A total of 216 college students (132 males and 84 females) were given the following: (a) the diagnostic interview for Internet addiction, (b) the Iowa gambling test for decision-making deficits, (c) the Balloon Analog Risk Test (BART) to assess risk-taking tendencies, and (d) the Tridimensional Personality Questionnaire (TPQ) for personality characteristics. The results revealed the following: (a) 49% of males and 17% of females were addicted, (b) the addicted students tended to select more advantageous cards in the last 40 cards of the Iowa test, indicating better decision making, (c) no difference was found for the BART, indicating that addicted subjects were not more likely to engage in risk-taking behaviors and (d) TPQ scores showed lower reward dependence (RD) and higher novelty seeking (NS) for the addicts. Their higher performance on the Iowa gambling test differentiates the Internet addiction group from the substance use and pathologic gambling groups that have been shown to be deficient in decision making on the Iowa test. Thus, students that fit these characteristics should be closely monitored to prevent Internet addiction.

Anxiety- and depressive-like responses and c-fos activity in preproenkephalin knockout mice: oversensitivity hypothesis of enkephalin deficit-induced posttraumatic stress disorder.

The present study used the preproenkephalin knockout (ppENK) mice to test whether the endogenous enkephalins deficit could facilitate the anxiety- and depressive-like symptoms of posttraumatic stress disorder (PTSD). On Day 1, sixteen wildtype (WT) and sixteen ppENK male mice were given a 3 mA or no footshock treatment for 10 seconds in the footshock apparatus, respectively. On Days 2, 7, and 13, all mice were given situational reminders for 1 min per trial, and the freezing response was assessed. On Day 14, all mice were tested in the open field test, elevated plus maze, light/dark avoidance test, and forced swim test. Two hours after the last test, brain tissues were stained to examine c-fos expression in specific brain areas. The present results showed that the conditioned freezing response was significant for different genotypes (ppENK vs WT). The conditioned freezing effect of the ppENK mice was stronger than those of the WT mice. On Day 14, the ppENK mice showed more anxiety- and depressive-like responses than WT mice. The magnitude of Fos immunolabeling was also significantly greater in the primary motor cortex, bed nucleus of the stria terminalis-lateral division, bed nucleus of the stria terminalis-supracapsular division, paraventricular hypothalamic nucleus-lateral magnocellular part, central nucleus of the amygdala, and basolateral nucleus of the amygdala in ppENK mice compared with WT mice. In summary, animals with an endogenous deficit in enkephalins might be more sensitive to PTSD-like aversive stimuli and elicit stronger anxiety and depressive PTSD symptoms, suggesting an oversensitivity hypothesis of enkephalin deficit-induced PTSD.

Analysis of nocifensive behavior induced in rats by C02 laser pulse stimulation

To characterize nocifensive behavior, a laser beam was applied to the hind footpad of nonanesthetized and unrestrained rats and the reaction pattern was analyzed. Fifty-four rats were divided into nine groups of six animals, and each group was given one of nine combinations of laser stimuli: intensity of 4, 8 or 12 W and duration of 10, 30, or 50 ms. A single pulse was applied to a 0.13 cm2 area of right or left footpad and the trial was repeated 20 times with 3 min between trials. The behavior was videotaped and reviewed for a period of 2 min following each stimulation. It seemed to consist of eight discrete responses, and each response was scored for whether it occurred and for its summed duration per trial. The component responses and the behavior as a whole were characterized by their sensitivity in terms of the level of energy required to attain 50% of the maximum response, and their linear or quadratic trends with increasing stimulus energy. The most sensitive index of pain stimulation was the composite score, followed by foot jumping, foot elevation, body movements, licking, and then foot movements. As stimulus energy increased, rats exhibited a greater number of different responses and a greater frequency of each component response. The results suggest that a pool of hierarchically organized responses in the nocifensive motor system are recruited partially or wholly by nociceptive stimuli of varying intensity.

Infrared irradiation has potential antidepressant effect

PURPOSE Light therapy was only partially effective in treatment of depression when compared with summers sunlight. The antidepressant effect of infrared irradiation was evaluated using an experimental animal model. METHODS Seventeen mice were randomly assigned to the exposure group (n = 9) and the control group (n = 8). The mice in the exposure group received infrared irradiation for 60 min daily during the study period of 4 weeks. The two groups were given forced swim test once a week to evaluate depression with the measurement of the immobility time. RESULTS We found that the exposure group showed a tendency of less immobility time by the end of the 3rd week when compared with the control group, and at the end of 4th week the difference reached a statistical significance (t(15) = 2.873; p = 0.012). CONCLUSIONS The result indicates that the immobility time in forced swim test, the sign of depression, can be reduced after prolonged (4 weeks) exposure to infrared irradiation in the animal model. The result suggests that a continuous application of infrared irradiation has antidepressant effect.

Neural substrates of fear conditioning, extinction, and spontaneous recovery in passive avoidance learning: a c-fos study in rats.

Extinguishing fear conditioning and preventing the return of fear are the goal in the treatment of anxiety disorders. However, the neural substrates that mediate fear conditioning, extinction, and spontaneous recovery (i.e., the return of fear) remain uncertain. We utilized the aversive passive avoidance learning paradigm and Fos-like immunoreactivity to elucidate this issue. Exception for naïve rats that did not receive any treatment served as the control group, the other rats were subjected to three sessions of context/footshock (0.5 mA, 2s) pairings followed by 12 extinction sessions (context-no footshock). After the last extinction test, these rats were assigned to one of three groups reflecting the number of resting days before the test session (context-no footshock): Day 8, Day 9, and Day 10 groups. Only the Day 10 group exhibited spontaneous recovery during the test session. Fos-like immunoreactivity associated with fear conditioning was seen in the amygdala and cingulate cortex area 1 (Cg1). The extinction of fear was seen to be related to Cg1, cingulate cortex area 2 (Cg2), piriform cortex (Pir), and entorhinal cortex (Ect). Spontaneous recovery was seen to be related to amygdala, Pir, and Ect. The present findings indicate that the brain substrates of fear acquisition, extinction and spontaneous recovery have different ensembles of brain activations. These differences suggest that different brain targets may be considered for fear extinction and for avoiding the return of fear in anxiety disorders.

Paradoxical simultaneous occurrence of amphetamine-induced conditioned taste aversion and conditioned place preference with the same single drug injection: A new “pre- and post-association” experimental paradigm

The paradoxical phenomenon of co-existing physically aversive and psychologically rewarding effects of drugs is a crucial issue for drug addiction. The present study employed a new experimental paradigm to test whether the rewarding and aversive properties of amphetamine (AMPH) can exist simultaneously. Rats were given a 15 min period of exposure to saccharin injected with 0.15M NaCl or 1.5mg/kg AMPH and then were confined to one compartment of a test box for 30 min. After three paired and unpaired cycles, the aversive and rewarding effects were assessed. A reduction in consumption of the paired flavored solution provided evidence of avoidance while preference for the AMPH injection context provided evidence of rewarding effects. The present findings demonstrate that the development of AMPH-induced rewarding and aversive effects depends on the particular behavioral conditions and support both the task-dependent drug effects hypothesis and the reward comparison hypothesis. The formation of associations with stimuli that comes before (pre) vs. after (post) the unconditioned stimulus and the role of the dopaminergic system in such associations are discussed.

Dose-dependent dissociable effects of haloperidol on locomotion, appetitive responses, and consummatory behavior in water-deprived rats

UNLABELLED We studied whether a cascade of different phases of ingestive behavior were governed by different doses of the dopamine D2 receptor system. A wide spectrum of doses (0, 0.025, 0.05, 0.1, 0.2, and 0.4mg/kg) of a D2 receptor antagonist, haloperidol, were administered to 6 groups of water-deprived rats. 45min following administration of the drug a 15min water intake session was allowed to assess the effect on (a) locomotion, (b) appetitive response and (c) consummatory responses. The procedure was repeated for 5days. RESULTS The doses of 0.025 to 0.1mg/kg had no effects on any measured behavior compared with the control group. The 0.2mg/kg dose induced catalepsy during sessions 3 and 5 and impaired consummatory (decreased lick numbers and intake volume) behaviors during sessions 1-5. The 0.4mg/kg dose affected appetitive behavior (increased latency to contact the water tube) during session 2 and consummatory behavior during all five water sessions. The 0.2mg/kg dose appeared to dissociate appetitive and consummatory behavior, and the 0.4mg/kg dose locomotor activity and motivational behavior (including consummatory and appetitive responses). These results, that the three elements of ingestive behavior (locomotion, appetitive responses, and consummatory behavior) have different sensitivity to haloperidol, suggest that separable D2 mechanisms are involved in governing the ingestive behavior.

Neural Substrates of Amphetamine-Induced Behavioral Sensitization: Unconditioned (Zero Context) and Conditioned (Switch versus Same Context) Components in c-fos Overexpression

The neural substrates of the unconditioned and conditioned components of amphetamine (AMPH)-induced behavioral sensitization remain unknown. The present study examines the brain activation of rats in response to an AMPH challenge with augmented locomotion in groups receiving chronic AMPH under chloral hydrate anesthetization (i.e., the ‘zero context’) or when tested in the ‘same context’ as a chronic treatment, or when tested in a ‘different context’. The neural activations of the three groups reveal fairly consistent patterns: (a) The substantia nigra is activated in the same context condition and the pure AMPH effect (i.e., the zero context with the unconditioned component), but not in the switch context condition. (b) The ventral pallidum showed Fos expression in the switch context and the same context, but not in the zero context condition. (c) The other nuclei, including the medial prefrontal cortex, nucleus accumbens, caudate putamen, medial thalamus, hippocampus, amygdala, and ventral tegmental area, are activated in all contextual conditions and the pure AMPH effect (the zero context). The context exerts definable effects on the mesocorticolimbic dopamine system on AMPH-induced behavioral sensitization. (d) The ventral pallidum and the substantia nigra activations dissociate the unconditioned component from the conditioned component in behavioral sensitization. Further studies are needed to determine how these two nuclei mediate the effect in terms of primary and conditioned rewards.

The Functional Significance of Affect Recognition, Neurocognition, and Clinical Symptoms in Schizophrenia

Objectives The complex relationship and exact extent of the contribution of plausible indictors to social functional outcome in schizophrenia remain unclear. The present study aimed to explore the functional significance of clinical symptoms, neurocognition, and affect recognition simultaneously in schizophrenia. Methods The clinical symptoms, basic neurocognition, facial emotion recognition, and social functioning of 154 subjects, including 74 with schizophrenia and 80 nonclinical comparisons, were assessed. Results We observed that various subdomains of social functioning were extensively related to general intelligence, basic neurocognition, facial emotion recognition, and clinical symptoms, with different association patterns. Multivariate regression analyses revealed that years of education, age, sustained attention, working memory, and facial emotion recognition were significantly associated with global social functioning in schizophrenia. Conclusion Our findings suggest that affect recognition combined with nonsocial neurocognition demonstrated a crucial role in predicting global social function in schizophrenia.