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Albuquerque, NM, United States

Claus E.D.,The Mind Research Network
Alcoholism, clinical and experimental research | Year: 2012

Impulsivity, particularly risk taking, is believed to play a significant role in alcohol use disorders (AUDs). While risk taking has been measured using questionnaires, recent performance-based tasks such as the Balloon Analog Risk Task (BART) have shown considerable promise in understanding risky decision-making processes in drinkers. While the number of studies using the BART has grown significantly over the past decade, the neural mechanisms that underlie risky choices on the BART have only begun to be explored. The current study was designed to assess both the neural mechanisms of risk taking on the BART and to explore relationships between risk taking and hazardous drinking. Seventy-nine individuals with an AUD completed an fMRI compatible version of the BART that required pumping simulated air into risky or nonrisky balloons to earn points on each trial, and deciding when to terminate pumping to earn points accumulated. Hazardous drinking was assessed with the Alcohol Use Disorder Identification Test (AUDIT). Comparison of risky and nonrisky decisions revealed differences in the dorsal anterior cingulate cortex (dACC), anterior insula, and striatum. Comparison of Cashout responses and Explosions revealed increased responses in lateral prefrontal cortex, insula, ACC, and middle temporal gyrus during Explosions and greater response in inferior parietal lobe and caudate during Cashouts. When examining relationships between hazardous drinking and neural measures of risk taking, we found significant negative relationships with insula, striatum, and dACC. The current results suggest that risk taking is associated with increased response in the dACC and anterior insula, regions previously implicated in representing error likelihood and negative outcome magnitudes, respectively. In addition, hazardous drinking was associated with responses in the dACC, possibly suggesting a reduced ability to predict the likelihood of errors and to predict negative outcomes associated with risk taking. Copyright © 2012 by the Research Society on Alcoholism.

Bernard J.A.,University of Colorado at Boulder | Leopold D.R.,University of Colorado at Boulder | Calhoun V.D.,The Mind Research Network | Calhoun V.D.,University of New Mexico | Mittal V.A.,University of Colorado at Boulder
Human Brain Mapping | Year: 2015

Cerebellar morphology and function have been implicated in a variety of developmental disorders, and in healthy aging. Although recent work has sought to characterize the relationships between volume and age in this structure during adolescence, young, and older adulthood, there have been no investigations of regional cerebellar volume from adolescence through late middle age. Middle age in particular has been largely understudied, and investigating this period of the lifespan may be especially important for our understanding of senescence. Understanding regional patterns of cerebellar volume with respect to age during this portion of the lifespan may provide important insight into healthy aging and cognitive function as well as pathology from adolescence into later life. We investigated regional cerebellar volume using a highly novel lobular segmentation approach in conjunction with a battery of cognitive tasks in a cross-sectional sample of 123 individuals from 12 to 65 years old. Our results indicated that regional cerebellar volumes show different patterns with respect to age. In particular, the more posterior aspect of the neocerebellum follows a quadratic "inverse-U" pattern while the vermis and anterior cerebellum follow logarithmic patterns. In addition, we quantified the relationships between age and a variety of cognitive assessments and found relationships between regional cerebellar volumes and performance. Finally, exploratory analyses of sex differences in the relationships between regional cerebellar volume, age, and cognition were investigated. Taken together, these results provide key insights into the development and aging of the human cerebellum, and its role in cognitive function across the lifespan. Hum Brain Mapp 36:1102-1120, 2015. © 2014 Wiley Periodicals, Inc.

Prause N.,The Mind Research Network
Sexual and Relationship Therapy | Year: 2011

Orgasm is assumed to be the height of sexual pleasure, reinforcing the recurrence of sexual behaviors. Surprisingly, data supporting the role of orgasm as a reward in women appear lacking. The most likely psychological function of orgasm in women, consistent with the very limited empirical information, is as a secondary reinforcer. In other words, sexual arousal is the primary reward for sexual behavior in women and orgasm associates sexual arousal with the partner. Data from a small (n = 38 women) pilot are presented to highlight the challenges of studying female orgasm. Challenges include differentiating vaginally- or clitorally-generated orgasms by self-report and the large proportion of women who are unsure if they experience orgasms. Finally, the recent spate of publications purporting to show differences in penile-vaginal intercourse induced orgasms is critiqued in light of the information reviewed. © 2011 Copyright Taylor and Francis Group, LLC.

Vosskuhl J.,University of Oldenburg | Huster R.J.,University of Oldenburg | Huster R.J.,University of Oslo | Huster R.J.,The Mind Research Network | Herrmann C.S.,University of Oldenburg
Frontiers in Human Neuroscience | Year: 2015

Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity. © 2015 Vosskuhl, Huster and Herrmann.

Chen J.,The Mind Research Network
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012

Independent component analysis (ICA), a blind source separation method, has been shown to be a useful approach to identify genetic components representing combined effects from multiple mutations. However, the ICA order selection for genotype data has been a challenge, since a genetic component usually accounts for a small amount of variance of the data, and makes it difficult to distinguish true signals from background. To address this issue, we propose to select ICA order based on consistency and implement three strategies in this study. Simulations demonstrate robust performances of all three strategies where the selected orders lead to optimal results regardless of ICA performances.

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