Toward a “treadmill test” for cognition: Improved prediction of general cognitive ability from the task activated brain

General cognitive ability (GCA) refers to a trait‐like ability that contributes to performance across diverse cognitive tasks. Identifying brain‐based markers of GCA has been a longstanding goal of cognitive and clinical neuroscience. Recently, predictive modeling methods have emerged that build whole‐brain, distributed neural signatures for phenotypes of interest. In this study, we employ a predictive modeling approach to predict GCA based on fMRI task activation patterns during the N‐back working memory task as well as six other tasks in the Human Connectome Project dataset (n = 967), encompassing 15 task contrasts in total. We found tasks are a highly effective basis for prediction of GCA: The 2‐back versus 0‐back contrast achieved a 0.50 correlation with GCA scores in 10‐fold cross‐validation, and 13 out of 15 task contrasts afforded statistically significant prediction of GCA. Additionally, we found that task contrasts that produce greater frontoparietal activation and default mode network deactivation—a brain activation pattern associated with executive processing and higher cognitive demand—are more effective in the prediction of GCA. These results suggest a picture analogous to treadmill testing for cardiac function: Placing the brain in a more cognitively demanding task state significantly improves brain‐based prediction of GCA.     

Self-Determination Theory and Outpatient Follow-Up After Psychiatric Hospitalization

The objective of this study was to assess whether the constructs of self-determination theory—autonomy, competence, and relatedness—are associated with adherence to outpatient follow-up appointments after psychiatric hospitalization. 242 individuals discharged from inpatient psychiatric treatment within the Veterans Health Administration completed surveys assessing self-determination theory constructs as well as measures of depression and barriers to treatment. Medical records were used to count the number of mental health visits and no-shows in the 14 weeks following discharge. Logistic regression models assessed the association between survey items assessing theory constructs and attendance at mental healthcare visits. In multivariate models, none of the self-determination theory factors predicted outpatient follow-up attendance. The constructs of self-determination theory as measured by a single self-report survey may not reliably predict adherence to post-hospital care. Need factors such as depression may be more strongly predictive of treatment adherence.     

c-Jun N terminal kinases (JNK) are activated in the brain during the pathology of experimental cerebral malaria

The aim of the present electroencephalographic (EEG) study was to investigate neuronal correlates of working memory encoding in a visuo-spatial serial delayed match-to-sample task. A rapid serial visual presentation approach was used to dissociate brain activity related to encoding of visuo-spatial targets and cortical activity evoked by suppression of distracting information. During the task EEG was recorded and steady-state visually evoked potentials (SSVEPs) were calculated. Finally, standardized low-resolution electromagnetic tomography (sLORETA) was used to determine brain regions involved in visuo-spatial working memory encoding. A distributed task-relevant network comprising right temporal, parietal, and occipital areas was identified. Results suggest that activity of this network is amplified during actual encoding of targets into visual working memory, whereas the same network is attenuated in its activation when distracting visual information should be suppressed. Left prefrontal and anterior cingulate cortices do not seem to be involved in encoding of targets but only in suppression of distracting information, likely reflecting activity of an attention-based supervisory system. These results strongly emphasise the linkage between visuo-spatial attention and working memory during amplification of selected and suppression of irrelevant information.     

Altered resting-state amygdala functional connectivity in men with posttraumatic stress disorder

Background

Converging neuroimaging research suggests altered emotion neurocircuitry in individuals with posttraumatic stress disorder (PTSD). Emotion activation studies in these individuals have shown hyperactivation in emotion-related regions, including the amygdala and insula, and hypoactivation in emotion-regulation regions, including the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC). However, few studies have examined patterns of connectivity at rest in individuals with PTSD, a potentially powerful method for illuminating brain network structure.

Methods

Using the amygdala as a seed region, we measured resting-state brain connectivity using 3 T functional magnetic resonance imaging in returning male veterans with PTSD and combat controls without PTSD.

Results

Fifteen veterans with PTSD and 14 combat controls enrolled in our study. Compared with controls, veterans with PTSD showed greater positive connectivity between the amygdala and insula, reduced positive connectivity between the amygdala and hippocampus, and reduced anticorrelation between the amygdala and dorsal ACC and rostral ACC.

Limitations

Only male veterans with combat exposure were tested, thus our findings cannot be generalized to women or to individuals with non–combat related PTSD.

Conclusion

These results demonstrate that studies of functional connectivity during resting state can discern aberrant patterns of coupling within emotion circuits and suggest a possible brain basis for emotion-processing and emotion-regulation deficits in individuals with PTSD.     

A prospective double-blind randomised controlled trial of intraoperative pelvic instillation with bupivacaine for management of pain following laparoscopy and dye

The aim of this randomised, double-blind, placebo-controlled trial was to evaluate the effectiveness of intraperitoneal instillation of bupivacaine following laparoscopy and dye test. Women received either 15 ml of 0.9% saline (n= 42) or 15 ml of 0.5% bupivacaine (n= 43), which was instilled intraperitoneally. Pain and nausea scores were recorded on a visual analogue scale (VAS). Pain perception was no different in the bupivacaine group compared with the control group with median values of VAS at 2 hours (18, 19; P= 0.8), 6 hours (21, 22; P= 0.5), 12 hours (19, 25; P= 0.8), 24 hours (27, 27; P= 0.9) and 48 hours (21, 13; P= 0.26). Women in the bupivacaine group were less nauseated than controls in the immediate postoperative period (with median VAS scores of 0, 8; P value = 0.03 at 2 hours and 0, 7; P= 0.01 at 6 hours).     

Blockade of sensitization to methylphenidate by MK-801: partial dissociation from motor effects

The role of MK-801's locomotor effect in blocking the development of sensitization to methylphenidate was investigated utilizing a computerized locomotor activity monitoring system. After 7 days of acclimation to a 12:12 light-dark cycle (lights on at 07:00), male Sprague-Dawley rats (n=62) were housed in test cages and motor activity was recorded continuously for 16 days. The first 2 days of recording served as a baseline for each rat, and on day 3 each rat received a saline injection. On days 4 to 9 rats were randomly divided into seven groups: Rats received either six daily s.c. injections of methylphenidate (2.5 mg/kg; Group 1), or six daily i.p. injections of 0.30 mg/kg, 0.05 mg/kg MK-801 (Groups 2 and 3, respectively); two MK-801 pre-treatment groups received a single i.p. injection of 0.05, or 0.30 mg/kg MK-801 one hour prior to 2.5 mg/kg methylphenidate (n=8 each) on day 4 followed by five daily injections of 2.5 mg/kg methylphenidate; and finally, two cotreatment groups received a challenge dose of 2.5 mg/kg methylphenidate on day 4 followed by either 0.05 or 0.30 mg/kg MK-801 i.p. one hour prior to 2.5 mg/kg methylphenidate from days 5 to 9. All groups were allowed five days of no treatment before being re-challenged on day 15 with the same treatment they received on day 4. Methylphenidate and 0.30 mg/kg MK-801 sensitized to their own locomotor effects, but 0.05 mg/kg MK-801, which had no acute motor effects, did not. The administration of MK-801 (0.30 mg/kg) prior to methylphenidate either singly on day 4, or coadministered throughout the repeated methylphenidate treatment phase, blocked the development of sensitization to methylphenidate. However, MK-801 at 0.05 mg/kg delayed the development of sensitization when co-administered on days 5 to 9, but a single injection 1 h prior to methylphenidate on day 4 did not prevent sensitization to subsequent methylphenidate administration. In conclusion, MK-801 prevents sensitization to methylphenidate; motor stimulation by MK-801 is not necessary for short-term prevention or delay of sensitization to methylphenidate but may be necessary for a persistent blockade of sensitization.     

Peripheral nerve blocks for intraoperative management in patients with hemophilia A

The use of peripheral nerve blocks as the sole anesthetic, augmented with mild sedation for intraoperative management of surgery on the ankle and knee in two hemophiliac patients, is presented. Peripheral nerve blocks may be safely used for surgery of the extremities in a patient with moderate to severe hemophilia, provided a safe level of Factor VIII is maintained throughout the perioperative period.     

A prospective cohort study investigating the use of a surgical planning tool to improve patient fasting times in orthopaedic trauma

Objectives

To improve surgical planning and reduce fasting times with a tool designed to predict average surgical times for the commonest orthopaedic trauma operations.