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<p> Given that mindfulness-based training techniques (MBT) stimulates and pushes one&rsquo;s core cognitive control capacity limits, brain stimulation techniques, such as transcranial direct current stimulation (tDCS), can be used to facilitate the ongoing neural patterns of functional connectivity toward long-lasting neuroplastic change. The current study assessed the combined effects of MBT with right frontal tDCS on cognitive control abilities and their corresponding brain patterns of activation using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). This study found an enhancement in working memory and sustained attention performance along with changes in the attention-related P3 component and its theta and alpha oscillatory profiles recorded by EEG. Furthermore, a reconfiguration in the chronnectome of large-scale resting-state networks was observed using resting-state fMRI, in addition to task-related changes in the polymodal neural architecture associated with encoding and adaptation, which may bridge the necessary connections from near to far transfer gains.</p>

The kindling model of epilepsy in animals has become a widely used tool in the study of convulsive mechanisms. A recent interest in the role of somatostatin (SS) in epileptic brains has produced a small body of literature, but few insights into the function of SS in seizures. Two experiments utilizing a chemical model of kindling were used. Experiment 1 using a high dose of pentylenetetrazol (PTZ) (30mg/kg) and experiment 2 using a subseizure dose of PTZ (20mg/kg). Behavioral results of experiment 1 showed an increase in seizure sensitivity over the 2 month course of the study but failed immunostaining confounded any anatomical localization of SS. Behavioral results of experiment 2 yielded no significant difference between control and experimental animals but showed both qualitative differences and a decreased number of SS cells in the experimental group. The results of these studies make few predictions about the role of SS in seizure activity or in the kindling model of epilepsy and it is painfully obvious that more work needs to be done in this realm.

<p> Background: Each year, nearly &frac12; million youth under 15 years old sustains a traumatic brain injury (TBI). Although racial disparities have not been found in pediatric TBI (Howard, Joseph, &amp; Natale, 2005), the consequences of TBI still remain a serious public health concern. Moderate and severe TBI (msTBI) frequently result in diffuse axonal injury and other white matter damage. The corpus callosum (CC) is particularly vulnerable to injury, though the impact of this damage may not be apparent until several months-to-years following injury. Damage to the CC has been associated with impaired neurocognitive functioning in youth with TBI.</p><p> Method: The investigator for this dissertation study utilized event-related potentials, an electrophysiological measure of neural processing, to measure interhemispheric transfer time (IHTT) as an indicator of CC integrity in 31 youth with msTBI at the chronic phase of recovery (i.e., 13-18 months post injury), compared with 20 healthy control youth. Neurocognitive performance was also examined among these groups.</p><p> Results: At the chronic phase of recovery, TBI group youth overall demonstrated slower IHTTs and worse neurocognitive functioning than youth in the control group. Only a subset of msTBI group children had IHTTs that were outside the range of the healthy controls; however, this impairment in interhemispheric communication was not significantly associated with neurocognitive performance. A pattern of differential impairments emerged between TBI group participants. Chronic-phase outcomes in IHTT were correlated with the presence of neurosurgery at the acute phase of injury. </p><p> Conclusion: Overall, this study demonstrated that msTBI results in longstanding differences in interhemispheric and neurocognitive functioning, but injured children are differentially impacted. Functional reorganization resulting from neuroplasticity may help explain these results among children with slow IHTT but intact neurocognitive functioning. However, interpretations regarding the course of recovery could not be made due to the cross-sectional methodology used in this study. Investigators conducting future studies might explore additional outcomes associated with interhemispheric and neurocognitive functioning following msTBI at the chronic phase of recovery, including corresponding structural and metabolic changes using advanced imaging techniques.</p>

<p> Within the United States, HIV is a growing epidemic that has important neuropsychological and functional consequences. Early detection and treatment of HIV-associated neurocognitive disorder (HAND) is associated with better outcomes. In major metropolitan areas such Los Angeles County, HIV disproportionately impacts the Latino community. For those individuals who are primarily Spanish-speakers, there may be limited access to comprehensive neuropsychological assessment in the preferred language. Consequently, self-reports of cognitive functioning are often relied on to help determine the presence of HAND. However, self-reports of cognitive decline may be influenced by factors such as depressed mood, variable motivation, and culture, raising important validity questions. To date, relatively few studies have focused on the combined use of Spanish-language, self-report measures of cognitive functioning and mood among primarily Spanish-speaking, HIV-positive individuals. The aim of this study was to explore the relationships among self-reported cognitive decline, neuropsychological functioning, and mood symptoms within this population. Archival data from a sample of 100 HIV+, primarily Spanish-speaking adults who participated in the parent study at a major medical center in Los Angeles were examined. Measures included Spanish-language versions of the Beck Depression Inventory, Cognitive Difficulties Scale-Patient Version, Medical Outcomes HIV Health Survey, and an acculturation measure. An array of neuropsychological measures was used to determine the presence of HAND. It was predicted that depressive symptoms would be positively associated with self-reported cognitive decline. This hypothesis was strongly supported by the results of correlational analysis. The results also showed that for individuals with HAND, the difference in BDI scores between participants with cognitive complaints and those without varied depending on whether the MOS-HIV or the CDS was used to assess cognitive complaints. The analyses revealed no significant impact of acculturation on the relationships among cognitive complaints, neuropsychological functioning, and depressive symptoms. The results of the present study highlight the complex relationship between neuropsychiatric and neuropsychological functioning in Spanish-speaking individuals infected with HIV. Clinical implications and limitations of the study are addressed. Future research that incorporates objective measures of neuropsychological functioning, the input of collateral informants, and self-report measures of mood and functional decline is recommended.</p>