Alterations in the processing of non-drug-related affective stimuli in abstinent heroin addicts.

Long-term exposure to drug may alter the neural system associated with affective processing, as evidenced by both clinical observations and behavioral data documenting dysfunctions in emotional experiences and processing in drug addicts. Although many imaging studies examined neural responses to drug or drug-related cues in addicts, there have been few studies explicitly designed to reveal their neural abnormalities in processing non-drug-related natural affective materials. The present study asked abstinent heroin addicts and normal controls to passively view standardized affective pictures of positive, negative, or neutral valence and compared their brain activities with functional MRI. Compared to normal controls, addicts showed reduced activation in right amygdala in response to the affective pictures, consistent with previous reports of blunted subjective experience for affective stimuli in addicts. Furthermore, in two visual cortical areas BA 19 and 37, while the controls showed greater responses to positive pictures than to negative ones replicating literature findings, the addicts showed the opposite pattern. The results reveal a complex pattern of altered processing of non-drug-related affective materials in addicts showing both heightened and blunted neural responses in different brain regions and for different stimulus valence. The present study highlights the importance of brain imaging research on drug addicts' processing of affective stimuli in understanding disruptions in their emotion circuitry.

Peripheral pulmonary nodules: relationship between multi-slice spiral CT perfusion imaging and tumor angiogenesis and VEGF expression.

BACKGROUND: The aim of this study is to investigate the relationship between 16-slice spiral CT perfusion imaging and tumor angiogenesis and VEGF (vascular endothelial growth factor) expression in patients with benign and malignant pulmonary nodules, and differential diagnosis between benign and malignant pulmonary nodules. METHODS: Sixty-four patients with benign and malignant pulmonary nodules underwent 16-slice spiral CT perfusion imaging. The CT perfusion imaging was analyzed for TDC (time density curve), perfusion parametric maps, and the respective perfusion parameters. Immunohistochemical findings of MVD (microvessel density) measurement and VEGF expression was evaluated. RESULTS: The shape of the TDC of peripheral lung cancer was similar to those of inflammatory nodule. PH (peak height), PHpm/PHa (peak height ratio of pulmonary nodule to aorta), BF (blood flow), BV (blood volume) value of peripheral lung cancer and inflammatory nodule were not statistically significant (all P > 0.05). Both showed significantly higher PH, PHpm/PHa, BF, BV value than those of benign nodule (all P < 0.05). Peripheral lung cancer showed significantly higher PS (permeability surface) value than that of inflammatory nodule and benign nodule (all P < 0.05). BV, BF, PS, MTT, PH, PHpm/PHa, and MVD among three groups of peripheral lung cancers were not significantly (all P > 0.05). In the case of adenocarcinoma, BV, BF, PS, PHpm/PHa, and MVD between poorly and well differentiation and between poorly and moderately differentiation were statistically significant (all P < 0.05). The peripheral lung cancers with VEGF positive expression showed significantly higher PH, PHpm/PHa, BF, BV, PS, and MVD value than those of the peripheral lung cancer with VEGF negative expression, and than those of benign nodule with VEGF positive expression (all P < 0.05). When investigating VEGF negative expression, it is found that PH, PHpm/PHa, and MVD of inflammatory nodule were significantly higher than those of peripheral lung cancer, PS of inflammatory nodule were significantly lower than that of peripheral lung cancer (all P < 0.05). PH, PHpm/PHa, BF, and BV of benign nodule were significantly lower than those of inflammatory nodule (all P < 0.05), rather than PS and MTT (mean transit time) (all P > 0.05). PH, PHpm/PHa, BV, and PS of benign nodule were significantly lower than those of peripheral lung cancer (all P < 0.05). In the case of VEGF positive expression, MVD was positively correlated with PH, PHpm/PHa, BF, BV, and PS of peripheral lung cancer and PS of benign nodule (all P < 0.05). CONCLUSION: Multi-slice spiral CT perfusion imaging closely correlated with tumor angiogenesis and reflected MVD measurement and VEGF expression. It provided not only a non-invasive method of quantitative assessment for blood flow patterns of peripheral pulmonary nodules but also an applicable diagnostic method for peripheral pulmonary nodules.

Similar brain activation patterns for writing logographic and phonetic symbols in Chinese.

This event-related functional MRI study examined the neural correlates for Chinese writing, by comparing the writing of logographic characters and that of pinyin, a phonetic notation system for Chinese characters. The temporal profile of the activations indicated that the middle frontal gyrus, superior parietal lobule, and posterior inferior temporal gyrus reflected more central processes for writing. Although pinyin writing elicited greater activity overall than character writing, the critical finding is that the two types of symbols recruited essentially the same brain regions. The results were compared with studies in Japanese showing dissociation between logographic kanji and phonetic kana writing and frequency of use was suggested to be an important factor in accounting for result differences across the two writing systems.

Peripheral lung cancer: relationship between multi-slice spiral CT perfusion imaging and tumor angiogenesis and cyclin D1 expression.

The aim of this study was to investigate the relationship between 16-slice spiral CT perfusion imaging and tumor angiogenesis and cyclin D1 expression in patients with peripheral lung cancer. Fifty-eight patients with peripheral lung cancer underwent 16-slice spiral CT perfusion imaging. The CT perfusion imaging was analyzed for time density curve (TDC), perfusion parametric maps, and the respective perfusion parameters. Correlation between the respective perfusion parameters and immunohistochemical findings of microvessel density measurement and cyclin D1 expression was evaluated.

Changes of dopamine transporter function in striatum during acute morphine addiction and its abstinence in rhesus monkey.

BACKGROUND: Although dopamine transporter (DAT) is essential for addiction, the effect of additive drugs on DAT function is still controversial, especially for opiates. We investigated the functional changes of dopamine transporter in striatum of rhesus monkeys during acute morphine injection and its abstinence. METHODS: Four rhesus monkeys, 6 to 9 years old, two male and two female, were examined for 12 days. Single photon emission computed tomography (SPECT) was performed with (99)T(cm)-TRODAT-1 as the radiopharmaceutical dopamine transporter agent during different stages of acute morphine injection and its abstinence. The ratios of SPECT signal between striatum and cerebellum (ST/CB) were calculated. RESULTS: The ST/CB ratio declined significantly on the first day of morphine injection and continued declining with more morphine injections. After abstinence, the ratio increased with time, but was still significantly lower on the 5th day of abstinence than the normal level. CONCLUSIONS: In rhesus monkey, acute morphine injection has both rapid and lasting effects on DAT by downregulating its function. The decline was partially reversible following morphine abstinence. The results suggest that striatum is one effective target of morphine and that the DAT function in striatum is one indicator for morphine addiction.

Continuous representation of human portraits and natural scenery in human ventral temporal cortex: evidence from functional magnetic resonance imaging.

BACKGROUND: Functional magnetic resonance imaging (fMRI) has become a powerful tool for tracking human brain activity in vivo. This technique is mainly based on blood oxygenation level dependence (BOLD) contrast. In the present study, we employed this newly developed technique to characterize the neural representations of human portraits and natural sceneries in the human brain. METHODS: Nine subjects were scanned with a 1.5 T magnetic resonance imaging (MRI) scanner using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence while they were visually presented with 3 types of white-black photographs: natural scenery, human portraits, and scrambled nonsense pictures. Multiple linear regression was used to identify brain regions responding preferentially to each type of stimulus and common regions for both human portraits and natural scenery. The relative contributions of each type of stimulus to activation in these regions were examined using linear combinations of a general linear test. RESULTS: Multiple linear regression analysis revealed two distinct but adjacent regions in both sides of the ventral temporal cortex. The medial region preferentially responded to natural scenery, whereas the lateral one preferentially responded to the human portraits. The general linear test further revealed a distribution gradient such that a change from portraits to scenes shifted areas of activation from lateral to medial. CONCLUSIONS: The boundary between portrait-associated and scenery-associated areas is not as clear as previously demonstrated. The representations of portraits and scenes in ventral temporal cortex appear to be continuous and overlap.

Neural correlates of regulation of positive and negative emotions: an fmri study.

Regulation of emotion is important for adaptive social functioning and mental well-being. This functional magnetic resonance imaging study identified neural correlates of regulation of positive or negative emotion. Twelve healthy female Chinese participants performed the experimental task that required them to simply view emotional pictures or to regulate their emotions induced by these pictures while their brain activities were monitored by a 1.5 T MRI scanner. The neuroimaging findings indicate that the left superior and lateral frontal regions (BA8/9) are common neural correlates of regulation of both emotions. For regulation of positive or negative emotion, changes of BOLD responses in the prefrontal regions and the left insula are associated with regulation of positive emotion; whereas activity of the left orbitofrontal gyrus, the left superior frontal gyrus, and the anterior cingulate gyrus appears to be involved in regulation of negative emotion. According to the participants' self-report, they appeared to be more effective in regulating positive than negative emotions, which may relate to the distinct patterns of neural activity associated with regulation of the specific emotion. As a conclusion, our findings suggest that there are shared as well as valence-specific neurocognitive mechanisms underlying regulation of positive and negative emotions. Enhanced knowledge about the neural mechanisms of emotion regulation helps improve understanding of the complex interplay of emotion and cognition underlying human behaviors.

Verbal working memory deficits in abstinent heroin abusers.

BACKGROUND: A prevailing belief is that opioids tend not to impair cognitive performance in opioid-dependent users. However, the impact of heroin abuse on verbal memory, especially on working memory, is not well studied and the results available are inconsistent. OBJECTIVE: This study was carried out to test the hypothesis that abstinent heroin abusers have intact working memory capacity. METHODS: N-back task and backward digit span task were used to measure the verbal working memory capacity in 28 abstinent heroin abusers and 25 controls matched for age, education level and gender. Forward digit span task was used as a control task to measure short-term memory capacity. RESULTS: Compared with the control subjects, heroin abusers showed normal backward/forward digit spans but significant performance impairment in the n-back task. CONCLUSION: Abstinent heroin abusers have intact short-term memory capacity but impaired verbal working memory capacity.

Auditory evoked potentials recorded in monkeys with hallucinatory-like behaviors induced by bromocriptine.

Objective Bromocriptine and other dopamine D2 receptor agonists can affect a range of behaviors in nonhuman primates, particularly those behaviors associated with motor and mental function, such as suppressant behaviors and hallucinatory-like behaviors in monkeys. Besides bromocriptine, the dysfunction of the rapid eye movement sleep (REM) mechanism may also contribute to hallucinations. Dissociation of wakefulness, REM, and non-REM (NREM) can cause a series of psychotic symptoms. Methods We simultaneously recorded auditory evoked potentials (AEP) from five cerebral regions in monkeys during normal and psychotomimetic states to investigate and compare state-dependent changes in AEP. Results Phase reversal of peak-to-baseline amplitude of 250 ms component (PBA250) in dorsolateral prefrontal cortex was common characteristic of hallucinatory-like and REM, and that hallucinatory-like and REM shared the equivalent modulatory orderliness of the PBA250 in dorsolateral prefrontal cortex. This result suggests that hallucinatory-like and REM share an equivalent electrophysiological modulatory in dorsolateral prefrontal cortex. Conclusion These results reveal that emergence of the N250 in dorsolateral prefrontal cortex is an exclusive marker that may help to discern whether hallucinatory-like behaviors is exhibited, which suggests that dorsolateral prefrontal cortex may be the most pivotal region for exhibition of hallucinatory-like behaviors.