The role of task-based neural activation research in understanding cognitive deficits in pediatric epilepsy.

Children with epilepsy can experience significant cognitive dysfunction that can lead to academic underachievement. Traditionally believed to be primarily due to the effects of factors such as the chronicity of epilepsy, medication effects, or the location of the primary epileptogenic lesion;, recent evidence has indicated that disruption of cognition-specific distributed neural networks may play a significant role as well. Specifically, over the last decade, researchers have begun to characterize the mechanisms underlying disrupted cognitive substrates by evaluating neural network abnormalities observed during specific cognitive tasks, using task-based functional magnetic resonance imaging (fMRI).

The Timing, Nature, and Range of Neurobehavioral Comorbidities in Juvenile Myoclonic Epilepsy.

Background: Accumulating evidence suggests that considerable cognitive and psychiatric comorbidity is associated with juvenile myoclonic epilepsy, for which the etiology remains controversial. Our goal was to comprehensively characterize the status of multiple neurobehavioral comorbidities in youth with new- or recent-onset juvenile myoclonic epilepsy, before effects of chronic seizures and medications.

Methods: A total of 111 children aged eight to 18 years (41 new- or recent-onset juvenile myoclonic epilepsy and 70 first-degree cousin controls) underwent neuropsychological assessment (attention, executive, verbal, perceptual, speed), structured review of need for supportive academic services, parent reports of behavior and executive function (Child Behavior Checklist and Behavior Rating Inventory of Executive Function), and formal structured psychiatric interview and diagnosis (Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version).

Default mode network deactivation in pediatric temporal lobe epilepsy: Relationship to a working memory task and executive function tests.

Objectives: Children with temporal lobe epilepsy (TLE) exhibit executive dysfunction on traditional neuropsychological tests. There is limited evidence of different functional network alterations associated with this clinical executive dysfunction. This study investigates working memory deficits in children with TLE by assessing deactivation of the default mode network (DMN) on functional Magnetic Resonance Imaging (fMRI) and the relationship of DMN deactivation with fMRI behavioral findings and neuropsychological test performance.

High Sleep Disturbance and Longer Concussion Duration in Repeat Concussions.

: The relationship between repeated concussions and sleep disturbance is yet to be fully understood. The objective of this study was to examine the relationship between sleep disturbance, concussion duration, and repeated concussions by assessing postconcussive symptoms and cognition. : Subjects (ages 13-33 years) underwent postconcussion cognitive function evaluation and reported postconcussion symptoms including severity of disturbed sleep (drowsiness, trouble falling asleep, sleeping more than usual, and sleeping less than usual), mood disturbance (sadness, irritability, nervousness, and emotional lability), and headache.

Executive dysfunction is associated with an altered executive control network in pediatric temporal lobe epilepsy.

Objectives: Children with temporal lobe epilepsy (TLE) exhibit executive dysfunction on traditional neuropsychological tests. However, there is limited evidence of neural network alterations associated with this clinical executive dysfunction. The objective of this study was to characterize working memory deficits in children with TLE via activation of the executive control network on functional magnetic resonance imaging (fMRI) and determine the relationships to fMRI behavioral findings and traditional neuropsychological tests.

Postconcussive Symptoms After Single and Repeated Concussions in 10- to 20-Year-Olds: A Cross-Sectional Study.

The objective was to characterize cognitive deficits and postconcussive symptoms in a pediatric population with no concussion, a single concussion, and ≥2 concussions, using a cross-sectional design. Cognitive function and postconcussive symptoms were assessed in participants (age 10-20) with no concussion (n = 1118), single concussion (n = 368), and repeated (≥2) concussions (n = 252). Analyses were adjusted for age and gender.

Gender differences in sleep symptoms after repeat concussions.

Objectives: There are notable gender differences in concussion as well as sleep. Sleep disturbance is a major symptom of post-concussive syndrome. The interplay between sleep disturbance, concussion, and gender has yet to be examined.

Gender Differences in Concussion and Postinjury Cognitive Findings in an Older and Younger Pediatric Population.

Background: Studies have documented gender differences associated with concussion. The purpose of this study was to determine if these gender differences are also noted within a pediatric population.

Methods: This prospective study analyzed 1971 patients who had completed preconcussion and postconcussion neuropsychological testing within the Washington, DC, area.

Independent and additive contributions of postvictory testosterone and social experience to the development of the winner effect.

The processes through which salient social experiences influence future behavior are not well understood. Winning fights, for example, can increase the odds of future victory, yet little is known about the internal mechanisms that underlie such winner effects. Here, we use the territorial California mouse (Peromyscus californicus) to investigate how the effects of postvictory testosterone (T) release and winning experience individually mediate positive changes in future winning ability and antagonistic behavior.

The nature and extent of cerebellar atrophy in chronic temporal lobe epilepsy.

Purpose: Research indicates that patients with chronic temporal lobe epilepsy (TLE) exhibit cerebellar atrophy compared to healthy controls, but the degree to which specific regions of the cerebellum are affected remains unclear. The purpose of this study was to characterize the extent and lateralization of atrophy in individual cerebellar lobes and subregions in unilateral TLE using advanced quantitative magnetic resonance imaging (MRI) techniques.

Methods: Study participants were 46 persons with TLE and 31 age- and gender- matched healthy controls.

Testosterone release and social context: when it occurs and why.

The functions of rapid increases in testosterone seem paradoxical because they can occur in response to different social contexts, such as male-male aggressive encounters and male-female sexual encounters. This suggests that context may impact the functional consequences of changes in testosterone, whether transient or long term. Many studies, including those with California mice (Peromyscus californicus), have addressed these issues using manipulations and species comparisons, but many areas remain to be investigated.

Weak winner effect in a less aggressive mammal: correlations with corticosterone but not testosterone.

We investigated the existence of the "winner effect" (winning an aggressive encounter following previous victories) and an associated rise in testosterone (T) in the white-footed mouse (Peromyscus leucopus) which generally display low levels of aggression and territoriality. We compared the effect of previously winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter. Although 50% of males were removed during training because of peaceful encounters, the winner effect was weak and not significant.

Winning fights elevates testosterone levels in California mice and enhances future ability to win fights.

The 'winner effect' has been studied in a variety of species, but only rarely in mammals. We compared effects of winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter in the California mouse (Peromyscus californicus). During the training phase, we ensured that resident males won all encounters by staging contests with mildly sedated, smaller intruders.