Frontal Lobe

Dissociations in the recognition of specific classes of words have been documented in brain-injured populations. These include deficits in the recognition and production of morphologically complex words as well as impairments specific to particular syntactic classes such as verbs. However, functional imaging evidence for distinctions among the neural systems underlying these dissociations has been inconclusive. We explored the neural systems involved in processing different word classes in a functional Magnetic Resonance Imaging study, contrasting four groups of words co-varying morphological complexity (simple, monomorphemic words vs complex derived or inflected words) and syntactic class (verbs vs nouns/adjectives). Subtraction of word from letter string processing showed activation in left frontal and temporal lobe regions consistent with prior studies of visual word processing. No differences were observed for morphologically complex and simple words, despite adequate power to detect stimulus specific effects. A region of posterior left middle temporal gyrus showed significantly increased activation for verbs. Post hoc analyses showed that this elevated activation could also be related to semantic properties of the stimulus items (verbs have stronger action associations than nouns, and action association is correlated with activation). Results suggest that semantic as well as syntactic factors should be considered when assessing the neural systems involved in single word comprehension.

It is commonly found that memory for context declines disproportionately with aging, arguably due to a general age-related deficit in associative memory processes. One possible mechanism for such deficits is an age-related reduction in available processing resources. In two experiments we compared the effects of aging to the effects of division of attention in younger adults on memory for items and context. Using a technique proposed by Craik (1989), linear functions relating memory performance for items and their contexts were derived for a Young Full Attention group, a Young Divided Attention group, and an Older Adult group. Results suggested that the Old group showed an additional deficit in associative memory that was not mimicked by divided attention. It is speculated that both divided attention and aging are associated with a loss of available processing resources that may reflect inefficient frontal lobe functioning, whereas the additional age-related decrement in associative...

OBJECTIVE Symptoms of borderline personality disorder (BPD) may reflect distinct breakdowns in the integration of posterior and frontal brain networks. We used a high temporal resolution measure (40-Hz gamma phase synchrony) of brain activity to examine the connectivity of brain function in BPD. METHODS Unmedicated patients with BPD (n = 15) and age-and sex-matched healthy control subjects (n = 15) undertook a task requiring discrimination of salient from background tones. In response to salient stimuli, the magnitude and latency of peak gamma phase synchrony for early (0-150 ms post stimulus) and late (250-500 ms post stimulus) phases were calculated for frontal and posterior regions and for left and right hemispheres. We recorded skin conductance responses (SCRs) and reaction time (RT) simultaneously to examine the contribution of arousal and performance. RESULTS Compared with controls, patients with BPD had a significant delay in early posterior gamma synchrony and a reduction in...

Development of affective decision-making was studied in 48 children at two ages (3 and 4 years) using a simplified version of the Iowa Gambling Task (). On each of 50 trials, children chose from 1 of 2 decks of cards that, when turned, displayed happy and sad faces, corresponding to rewards (candies) won and lost, respectively. Cards in 1 deck offered more rewards per trial, but were disadvantageous across trials due to occasional large losses; cards in the other deck offered fewer rewards per trial, but were advantageous overall. On later trials, 4-year-olds made more advantageous choices than 3-year-olds, and 4-year-olds made more advantageous choices than would be expected by chance, whereas 3-year-olds made more disadvantageous choices than would be expected by chance. These findings, which were especially pronounced for girls, indicate that affective decision-making develops rapidly during the preschool period, possibly reflecting the growth of neural systems involving orbitofr...

Abstract: Frontal lobe functions include a range of cognitive, emotional, and social abilities that enable goal-directed behavior. Although a number of studies have plotted the development of frontal lobe functions in childhood, few have extended into the adolescent years. There is also little information on which cognitive and emotional components of frontal functioning may be correlated. The aims of this study were to identify and compare age effects on different components of frontal functioning in childhood and adolescence and to examine whether abstract reasoning skills were associated with levels of emotional intelligence and social sensitivity. Twenty children (ages 9-18) were recruited from the local community for a study of normal adolescent brain development. All subjects were free of psychiatric or developmental disorders, as determined by a structured interview. Subjects completed a comprehensive neuropsychological test battery, as well as self-report measures of social sensitivity (anxiety) and emotional intelligence. Significant age effects were found for measures of abstract reasoning, response inhibition, and attentional set shifting. Levels of social anxiety increased moderately with age, although not significantly at this sample size. Abstract reasoning skills correlated positively with levels of social anxiety but not emotional intelligence. The pattern of results suggests differential developmental trajectories across various cognitive and emotional domains of frontal lobe functioning in childhood and adolescence. Increased abstract reasoning ability may be associated with increased vulnerability to social anxiety during this period.

This article provides current information relevant to school social workers who serve students with obsessive-compulsive disorder (OCD), including how OCD is defined in children and adolescents, the impact of OCD on schooling, issues in identifying students with OCD, and effective interventions. The authors offer suggestions for collaboration among school personnel and families and for linking school with home. Finally, they present recommendations for educating peers of students with OCD.(Contains 2 tables.)

Despite the widespread abuse of marijuana, knowledge about its effects in the human brain is limited. Brain glucose metabolism with and without Δ 9 tetrahydrocannabinol (THC) (main psychoactive component of marijuana) was evaluated in eight normal subjects and eight ...

Aggressive behavior in dementia is a major clinical management problem. Postmortem brain tissue was obtained from 24 patients with Alzheimer disease (AD) and 25 comparison cases. [3H] Prazosin binding to alpha1-AdR was determined. Aggressive behavior was significantly correlated with alpha1-adrenoceptor number in patients with AD (R(s)=0.454, N=24). Furthermore, patients receiving ongoing neuroleptics had significantly higher Bmax for [3H] prazosin (21 +/- 2, N=9) than those who were not (16 +/- 1, N=15). Upregulation of alpha1-AdR is associated with aggressive behavior and chronic treatment with neuroleptic medication.

Just about one and one-half centuries ago, Paul Broca identifi ed the posterior third left frontal convolution of the human brain as a critical area for speech production. Although years of cerebrovascular accident localization studies partially confi rmed Broca’s claim, recent years have seen a clarifi cation and expansion of the role Broca’s area plays in serial processing of language and speech as well as a probable role in nonlinguistic processing. This article will review some of the more recent anatomical and physiological research, including lesion studies, imaging research, and interoperative electrocortical stimulation studies. The article will summarize the research on the role of the human inferior frontal gyrus in lexical, phonologic, and grammatical production, the so-called “mirror mechanism” and other aspects of cognitive processing and motor execution. Key words: aphasia, Broca, executive function, motor cortex, neuroplasticity, prefrontal cortex

The prefrontal cortex (PFC) subserves cognitive control: the ability to coordinate thoughts or actions in relation with internal goals. Its functional architecture, however, remains poorly understood. Using brain imaging in humans, we showed that the lateral PFC is organized as a cascade of executive processes from premotor to anterior PFC regions that control behavior according to stimuli, the present perceptual