Functional architecture of the cortico-basal ganglia circuitry during motor task execution: correlations of strength of functional connectivity with neuropsychological task performance among female subjects.

The primary aim of this study was to enhance our understanding of the functional architecture of the cortico-basal ganglia circuitry during motor task execution. Twenty right-handed female subjects without any history of neuropsychiatric illness underwent fMRI at 3 T. The activation paradigm was a complex motor task completed with the nondominant hand. Analyses of functional connectivity strength were conducted for pairs of structures in input, intrinsic, and output segments of the circuitry. Next, connectivity strengths were correlated with results of neurocognitive testing conducted outside of the scanner, which provided information about both motor and cognitive processes. For input pathways, results indicate that SMA-striatum interactions are particularly relevant for motor behavior and disruptions may impact both motor and cognitive functions. For intrinsic pathways, results indicate that thalamus (VA nucleus) to striatum feedback pathway appears to have an important role during task execution and carries information relevant for motor planning. Together, these findings add to accumulating evidence that the GPe may play a role in higher order basal ganglia processing. A potentially controversial finding was that strong functional connectivity appears to occur across intrinsic inhibitory pathways. Finally, output (thalamus to cortex) feedback was only correlated with motor planning. This result suggests circuit processes may be more relevant for future behaviors than the execution of the current task.

Age-related changes of the functional architecture of the cortico-basal ganglia circuitry during motor task execution.

Normal human aging is associated with declining motor control and function. It is thought that dysfunction of the cortico-basal ganglia circuitry may contribute to age-related sensorimotor impairment, however the underlying mechanisms are poorly characterized. The aim of this study was to enhance our understanding of age-related changes in the functional architecture of these circuits. Fifty-nine subjects, consisting of a young, middle and old group, were studied using functional MRI and a motor activation paradigm. Functional connectivity analyses and examination of correlations of connectivity strength with performance on the activation task as well as neurocognitive tasks completed outside of magnet were conducted. Results indicated that increasing age is associated with changes in the functional architecture of the cortico-basal ganglia circuitry. Connectivity strength increased between subcortical nuclei and cortical motor and sensory regions but no changes were found between subcortical components of the circuitry. Further, increased connectivity was correlated with poorer performance on a neurocognitive task independently of age. This result suggests that increased connectivity reflects a decline in brain function rather than a compensatory process. These findings advance our understanding of the normal aging process. Further, the methods employed will likely be useful for future studies aimed at disambiguating age-related versus illness progression changes associated with neuropsychiatric disorders that involve the cortico-basal ganglia circuitry.

An fMRI study of sex differences in brain activation during object naming.

We present a neuroimaging experiment that examines whether males and females use distinct brain systems while performing a confrontational naming task, with specific attention to the possibility of laterality differences, as suggested by some theories of sex differences in language processing. We further address whether sex-based differences in functional brain organization might interact with object category distinctions, given that previous behavioral studies have shown some consistent processing differences between the sexes with respect to tools versus plants. Functional magnetic resonance imaging (fMRI) data were collected from 26 participants (13 males and 13 females). Main effect and interaction analyses reveal no discernable laterality differences between the sexes. All other results, however, were consistent with previous object-naming studies. Global effects revealed dominant foci in fusiform gyrus, left posterior middle temporal gyrus, left basal ganglia/thalamus, left middle/inferior frontal gyri, left frontal operculum, left supplementary motor area/dorsal anterior cingulate, and left pre-central gyrus. Main contrasts for tools versus plants were likewise consistent with previous fMRI studies. Although men and women showed no discernable activation differences, hemispheric or otherwise, when collapsed across object categories, sex-by-category analyses showed selective activation for females in dorsal anterior cingulate gyrus and left posterior middle temporal gyrus for tools, and selective activation for males in left posterior middle temporal gyrus for plants. We discuss the relevance of these sex-by-category effects to previous behavioral findings and theories that relate to vocabulary differences between the sexes.

Undergraduate students survey their peers on mental health: Perspectives and strategies for improving college counseling center outreach.

Objective: The purpose of the study was to examine student perspectives about college mental health including the primary mental health issues affecting students, common college student stressors, student awareness of campus mental health resources, and mental health topics students want more information about. Participants: Participants were 822 undergraduate and graduate students enrolled in a private university. The study was conducted during September 2016. Methods: As part of a public health course in program planning, undergraduate students surveyed their peers about their experience with mental health and mental health resources. Results: Stress was perceived as the largest mental health issue. Students most wanted more information about school/work/life balance followed by stress management. Electronic newsletters, social media, and on-campus seminars were the top strategies that students suggested as ways to reach them. Conclusions: The results provide student perspectives on mental health that may be useful in developing effective outreach efforts.

Striatal and cortical midline activation and connectivity associated with suicidal ideation and depression in bipolar II disorder.

BACKGROUND: Considerable evidence implicates dysfunction of striatal and cortical midline structure (CMS) circuitry in mood disorders. Whether such aberrations exist in bipolar II depression is unknown. METHODS: Sixteen unmedicated subjects with bipolar II depression and 19 healthy controls were studied using functional MRI and a motor activation paradigm. Analyses of both activation and functional connectivity were conducted. RESULTS: A history of suicidal ideation (SI) was negatively correlated with activation of the left putamen while depression severity was positively correlated with activation of the left thalamus. The superior bilateral putamen was simultaneously correlated with depression severity and anti-correlated with SI. Striatal functional connectivity was altered with the bilateral CMS and right inferior parietal lobule. Depression severity was correlated with strength of connectivity between the bilateral striatum and the right lingual gyrus and left cerebellum. LIMITATIONS: Only males experiencing an episode of major depression were studied. CONCLUSIONS: Striatal and CMS circuit abnormalities likely contribute to the neurobiology of bipolar II depression. Altered connectivity of the striatum may directly impact depression severity. Further, dissociable components of activation associated with depression severity and suicidal ideation may exist. Finally, the motor activation paradigm used in this study appears to be a useful probe of some neural processes underlying bipolar II depression.

Aberrant emotional processing in posterior cortical midline structures in bipolar II depression.

Bipolar II depression is a serious and disabling illness associated with significant impairment and high rates of suicide attempts. However, mechanisms underlying emotional dysregulation in this condition are poorly characterized. The goal of this work was to investigate one component of emotional processing in this disorder, brain activation associated with exposure to emotional faces. Functional MRI was used to study 16 unmedicated male subjects with bipolar II depression and 19 healthy male controls. The activation paradigm exposed subjects to happy, fearful and neutral faces. The two key findings of this study were as follows. First, bipolar subjects demonstrated significantly decreased activation in response to happy facial expression in the left posterior cortical midline structures (CMS) and frontal cortex. Second, depression severity was positively correlated with activation of the posterior CMS and other regions. Our results suggest that mechanisms involving CMS dysfunction may play a role in the neurobiology of bipolar II depression as has been demonstrated for unipolar illness. Further investigations of CMS function in bipolar spectrum disorders are warranted.