SEARCH · PubMed Health

Results for “Dorsolateral Prefrontal Cortex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1986

Physiologic dysfunction of dorsolateral prefrontal cortex in schizophrenia. I. Regional cerebral blood flow evidence.

To evaluate dorsolateral prefrontal cortex (DLPFC) physiology and function simultaneously, 20 medication-free patients with chronic schizophrenia and 25 normal controls underwent three separate xenon Xe 133 inhalation procedures for determination of regional cerebral blood flow (rCBF): first at rest, then while performing an automated version of the Wisconsin Card Sort (WCS), a DLPFC-specific cognitive test, and while performing a simple number-matching (NM) test. During rest, patients had significantly reduced relative, but not absolute, rCBF to DLPFC. During NM, no specific region differentiated patients from controls. During WCS, however, both absolute and relative rCBF to DLPFC significantly distinguished patients from controls. While controls showed a clear increase in DLPFC rCBF, patients did not. The changes were regionally specific, involving only DLPFC. Furthermore, in patients, DLPFC rCBF correlated positively with WCS cognitive performance, suggesting that the better DLPFC was able to function, the better patients could perform. Autonomic arousal measures, the pattern of WCS errors, and results of complementary studies suggest that the DLPFC finding is linked to regionally specific cognitive function and is not a nonspecific epiphenomenon.

Adult↗

PubMed1976

Delayed-matching and delayed-response deficit from cooling dorsolateral prefrontal cortex in monkeys.

The hypothesis that the functional integrity of the dorsolateral prefrontal cortex is important for short-term memory of both spatial and nonspatial information was examined. Monkeys were tested in delayed matching-to-sample (DMS) and delayed-response (DR) tasks with delays of 0-32 sec. Testing was carried out under three different conditions: frontal cooling (FC), parietal cooling (PC), and normal temperature (noncooling, NC). Errors, reaction time, and motor activity were recorded. The proportion of correct responses decreased in NC as a function of the delay. This decrease was significantly accentuated by FC, whereas it was not modified by PC. At each delay, the decrement elicited by FC was as large in DR as in DMS. Reaction time and activity normally increased as a function of delay; these changes were enhanced by FC. The FC-induced decrements in proportion of correct responses suggest a faster loss from short-term memory of both spatial and nonspatial information.

Animals↗

PubMed2001

The role of dorsolateral prefrontal cortex in the preparation of forthcoming actions: an fMRI study.

The dorsolateral prefrontal cortex (DLPFC) plays a key role in working memory (WM). Yet its precise contribution (the storage, manipulation and/or utilization of information for the forthcoming response) remains to be determined. To test the hypothesis that the DLPFC is more involved in the preparation of actions than in the maintenance of information in short-term memory (STM), we undertook a functional magnetic resonance imaging investigation in normal subjects performing two delayed response tasks (matching and reproduction tasks) in a visuospatial task sequence (presentation, delay, response). In the two tasks, the presentation and delay phases were similar, but the expected response was different: in the matching task, subjects had to indicate whether a visuospatial sequence matched the sequence presented before the delay period; in the reproduction task, subjects had to reproduce the sequence and, therefore, to mentally organize their response during the delay. Using a fMRI paradigm focusing on the delay period, we observed a significant DLPFC activation when subjects were required to mentally prepare a sequential action based on the information stored in STM. When subjects had only to maintain a visuospatial stimulus in STM, no DLPFC activation was found. These results suggest that a parietal-premotor network is sufficient to store visuospatial information in STM whereas the DLPFC is involved when it is necessary to mentally prepare a forthcoming sequential action based on the information stored in STM.

Adult↗

PubMed2006

Anomalies of asymmetry of pyramidal cell density and structure in dorsolateral prefrontal cortex in schizophrenia.

BACKGROUND: Studies suggest that neuronal density in left dorsolateral prefrontal cortex is increased in schizophrenia. AIMS: To replicate these findings and extend them to both hemispheres. METHOD: Neuronal density, size and shape were estimated in the prefrontal cortex (Brodmann area 9) of the left and right hemispheres of brains taken post-mortem from 10 people with schizophrenia and 10 without mental illness (6 men, 4 women in both groups). RESULTS: Overall neuronal density (individually corrected for shrinkage) did not differ between the groups. In the control brains, density was generally greater in the left than the right hemisphere, the reverse was seen in the schizophrenia brains; this loss or reversal of asymmetry was most significant in cortical layer 3. Pyramidal neurons in this cell layer were significantly larger on the left and more spherical in shape than on the right side in control brains, but size and shape did not differ between the two sides in schizophrenia. Non-pyramidal and glial cell densities were unchanged. CONCLUSIONS: We failed to find an increase in neuronal density, but found evidence at a cellular level of loss or reversal of asymmetry, consistent with the hypothesis of a primary change in the relative development of areas of heteromodal association cortex in the two hemispheres.

Aged↗

PubMed2004

Late-life depression and microstructural abnormalities in dorsolateral prefrontal cortex white matter.

OBJECTIVE: The purpose of this study was to determine whether microstructural abnormalities in the white matter of the dorsolateral prefrontal cortex are associated with late-life depression. METHOD: Seventeen elderly depressed subjects were compared with 16 elderly subjects who were not depressed. Diffusion tensor imaging was used to measure the fractional anisotropy of the white matter in the dorsolateral prefrontal cortex's superior and middle frontal gyri bilaterally and in the left occipital lobe as a control region. The authors compared results between groups while controlling for age, sex, and comorbid medical disorders. RESULTS: Even after controlling for age, sex, hypertension, and heart disease, the authors found significantly lower fractional anisotropy values in the right superior frontal gyrus white matter of depressed patients than comparison subjects. CONCLUSIONS: Microstructural changes in the white matter of the right superior frontal gyrus are associated with late-life depression. Further work is needed to determine how these changes contribute to depression outcomes.

Aged↗

PubMed1996

Rapid-rate transcranial magnetic stimulation of left dorsolateral prefrontal cortex in drug-resistant depression.

BACKGROUND: Lesion and neuroimaging studies suggest that left prefrontal lobe dysfunction is pathophysiologically linked to depression. Rapid-rate transcranial magnetic stimulation (rTMS) to prefrontal structures has a lateralised effect on mood in normal volunteers, and several preliminary studies suggest a beneficial effect of rTMS on depression. However, adequately controlled studies have not been conducted. METHODS: We have studied the effects of focal rTMS on the depressive symptoms in 17 patients with medication-resistant depression of psychotic subtype. The study was designed as a multiple cross-over, randomised placebo-controlled trial. Sham rTMS and stimulation of different cortical areas were used as controls. FINDINGS: Left dorsolateral prefrontal cortex rTMS resulted in a significant decrease in scores on the Hamilton depression rating scale HDRS (from 25.2 to 13.8) and the self-rated Beck questionnaire BQ (from 47.9 to 25.7). 11 of the 17 patients showed pronounced improvement that lasted for about 2 weeks after 5 days of daily rTMS sessions. No patient experienced any significant undesirable side-effects. INTERPRETATION: Our findings emphasise the role of the left dorsolateral prefrontal cortex in depression, and suggest that rTMS of the left dorsolateral prefrontal cortex might become a safe, non-convulsive alternative to electroconvulsive treatment in depression.

Adult↗

PubMed2004

Depletion of MAP2 expression and laminar cytoarchitectonic changes in dorsolateral prefrontal cortex in adult autistic individuals.

The neuropathological substrates underlying the characteristic clinical phenotype of autism are unknown. Neuroimaging studies have identified a decrease in task-related activation in the dorsolateral prefrontal cortex in autism. In the current study, we have analysed the dorsolateral prefrontal cortex in two adult individuals with a clinical diagnosis of autism, using Nissl staining and MAP2 immunohistochemistry. There was unchanged density of both neuronal and glial cell pools, although the autistic individuals had ill-defined neocortical cellular layers, substantially depleted MAP2 neuronal expression, and reduced dendrite numbers. Further studies on a larger number of individuals with autism are needed to establish the clinical relevance of the described changes, especially to determine whether the loss of dendritic markers is age associated or disease specific.

Adult↗

PubMed2007

Frontoparietal cortical activity of methamphetamine-dependent and comparison subjects performing a delay discounting task.

Relative to individuals who do not have addictive disorders, drug abusers exhibit greater devaluation of rewards as a function of their delay ("delay discounting"). The present study sought to extend this finding to methamphetamine (MA) abusers and to help understand its neural basis. MA abusers (n = 12) and control subjects who did not use illicit drugs (n = 17) participated in tests of delay discounting with hypothetical money rewards. We then used a derived estimate of each individual's delay discounting to generate a functional magnetic resonance imaging probe task consisting of three conditions: "hard choices," requiring selections between "smaller, sooner" and "larger, later" alternatives that were similarly valued given the individual's delay discounting; "easy choices," in which alternatives differed dramatically in value; and a "no choice" control condition. MA abusers exhibited more delay discounting than control subjects (P < 0.05). Across groups, the "hard choice > no choice" contrast revealed significant effects in the ventrolateral prefrontal cortex, dorsolateral prefrontal cortex (DLPFC), dorsal anterior cingulate cortex, and areas surrounding the intraparietal sulcus (IPS). With group comparisons limited to these clusters, the "hard choice > easy choice" contrast indicated significant group differences in task-related activity within the left DLPFC and right IPS; qualitatively similar nonsignificant effects were present in the other clusters tested. Whereas control subjects showed less recruitment associated with easy than with hard choices, MA abusers generally did not. Correlational analysis did not indicate a relationship between this anomaly in frontoparietal recruitment and greater degree of delay discounting exhibited by MA abusers. Therefore, while apparent inefficiency of cortical processing related to decision-making in MA abusers may contribute to the neural basis of enhanced delay discounting by this population, other factors remain to be identified.

Adult↗

PubMed2003

The effects of dentate granule cell destruction on behavioral activity and Fos protein expression induced by systemic MDMA in rats.

In this study, we examined the effect of the s.c. administration of (+/-) 3,4-methylenedioxymethamphetamine (MDMA) or saline on locomotor activity and Fos expression following the bilateral destruction of hippocampal dentate granule cells by colchicine in rats. The lesioned animals, when administered s.c. saline, showed a significantly greater increase in locomotor activity compared to the intact animals, and revealed a marginally significant level of increased locomotor activity compared to the sham-lesioned animals. In addition, when the lesioned animals were given s.c. saline or MDMA, there was a significant increase in Fos expression in the nucleus accumbens core, but not in the medial prefrontal cortex, dorsolateral prefrontal cortex, anterior cingulate cortex, piriform cortex, dorsal striatum, or nucleus accumbens shell, compared to the intact and sham-lesioned animals. Overall, these results suggest that the nucleus accumbens core may be involved in the enhancement of locomotor activity induced by the injection of saline alone (stress loading) or MDMA following bilateral destruction of hippocampal dentate granule cells by colchicine.

Animals↗

PubMed2002

Neuronal activity representing visuospatial mnemonic processes associated with target selection in the monkey dorsolateral prefrontal cortex.

To investigate how visuospatial mnemonic and target selection processes are represented in the dorsolateral prefrontal cortex (PFC), we studied neuronal attributes of the dorsolateral PFC while monkeys were performing oculomotor delayed visual search (ODVS) and oculomotor delayed-response (ODR) tasks. In the ODVS task, the subject made a memory-guided saccade to a remembered target location that had been presented along with distractors before a delay period; in the ODR task, the target was presented without any distractors. A total of 252 neurons in the dorsolateral PFC showed directional delay-period activity and were divided into two groups; neurons that showed directional delay-period activity predominantly in the ODVS task (n=112), and those that showed such activity similarly in both the ODVS and ODR tasks (n=140). These neuronal groups shared similar temporal properties (i.e. onset latency, peak time of delay-period activity) and spatial tuning. Our findings suggest that the dorsolateral PFC contains a particular visuospatial memory system for information selected by target selection (selective attention), and this attention-memory system (or 'memory system for special use') appears to be represented in the dorsolateral PFC, in parallel with a more 'general' memory system that is not specifically associated with target selection.

Action Potentials↗

PubMed2006

Dorsolateral prefrontal cortex and anterior cingulate cortex white matter alterations in late-life depression.

BACKGROUND: The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) are critical for mood regulation. Alterations in the white matter connections of these regions may impair their role in mood regulation and increase the risk of developing depression. This study used diffusion tensor imaging to examine for white matter microstructural abnormalities of these regions and of central white matter structures in late-life depression. METHODS: One hundred six elderly depressed subjects and eighty-four elderly nondepressed subjects underwent clinical assessment and diffusion tensor imaging. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in regions of interest placed in the white matter of the DLPFC, ACC, corpus callosum, and internal capsule. Differences between groups were assessed, controlling for age, sex, and total cerebral volume. RESULTS: After controlling for covariates, depressed subjects had significantly lower FA values in white matter of the right ACC, bilateral superior frontal gyri, and left middle frontal gyrus. There were no significant differences in ADC values. CONCLUSIONS: Lower FA, representing lower tissue organization, is observed in depressed elders in the DLPFC and right ACC. These findings support the hypothesis that altered connectivity between brain regions contributes to the risk of depression.

Aged↗

PubMed2003

Involvement of the dorsolateral prefrontal cortex of monkeys in visuospatial target selection.

To examine the involvement of the dorsolateral prefrontal cortex (PFC) in visuospatial target selection, we induced local, reversible inactivation with muscimol at various sites in the dorsolateral PFC of two rhesus monkeys while they performed oculomotor visual search (OVS) and oculomotor detection (OD) tasks. The OVS task required the subject to select a target stimulus from among distractors and to make a saccade to the target location (target selection was required for correct performance), whereas the OD task only required a saccade to the target (target selection was not required for correct performance). The local injection of muscimol (5 microg, 1 microl) into the dorsolateral PFC induced a specific deficit in the OVS task but not in the OD task. The deficit in the OVS task was characterized by the disordering of saccades for some (mostly a few) particular target locations as well as by prolongation of the time required for the visual search in most cases. The target locations affected by muscimol were biased to the contralateral visual field. Further, the OVS task with "pop-out" and "non-pop-out" conditions was similarly impaired by muscimol injection. These results suggest that the dorsolateral PFC plays a role in target selection in visual space to guide goal-directed motor acts and particular sites are involved in target selection for a particular visuospatial coordinate. Further, this function of the dorsolateral PFC appears to involve both top-down (active) and bottom-up (passive) target-selection/selective attention processes to control interfering information (distractors).

Animals↗

PubMed1985

Reward related neuronal activity in monkey dorsolateral prefrontal cortex during feeding behavior.

Extracellular single neuron activity was recorded in the dorsolateral prefrontal cortex (DL) during bar pressing for food reward. Most of the reward-related neurons were located around the rostral end of the principal sulcus. Neuronal activity was diminished, abolished, or reversed when quinine adulterated food (aversive food) was given as a reinforcement. Cue-related neurons tended to be located more caudally in the DL. The activity of these neurons was not modulated by the nature of the reward as much as that of the reward-related neurons. The results suggest that DL neurons are not functionally homogeneous.

Animals↗

PubMed1986

Role of bar press-related neurons in the dorsolateral prefrontal cortex during task performance by monkey.

Extracellular single neuron activity of the dorsolateral prefrontal cortex (DL) was recorded in the monkey, during bar pressing for reward. The bar press-related neurons which exhibited excitation or inhibition during the bar press period were found to be scattered diffusely in the DL. Activity changes that arose during the bar press period also appeared when the experimenter pressed the bar for the monkey. When delivery of food was delayed for a random time after cue tone on, bar press responses were still confined to the bar press period and did not extend beyond the cue tone. These results, together with the lesion studies, suggest that bar press-related neurons are involved in the animal's concentration during the bar press period.

Action Potentials↗

PubMed2006

Monkey dorsolateral prefrontal cortex sends task-selective signals directly to the superior colliculus.

The dorsolateral prefrontal cortex (DLPFC) has been implicated in the ability to perform complex behaviors requiring the implementation of cognitive control. A central supposition of models of prefrontal function is that the DLPFC engages control by selectively modulating the activity of target structures to which it is connected, but no studies in the primate have directly investigated DLPFC output signals. Here, we recorded the activity of DLPFC neurons identified as sending a direct projection to the superior colliculus, a midbrain oculomotor structure, while monkeys performed alternating blocks of trials in which they had to look toward a flashed peripheral stimulus (prosaccades) and trials in which they had to look away from the stimulus in the opposite direction (antisaccades). We report the first direct evidence that the primate DLPFC sends task-selective signals to a target structure. This supports the notion that the DLPFC orchestrates the activity of other brain areas in accordance with task requirements.

Action Potentials↗

PubMed2003

Cellular pathology in the dorsolateral prefrontal cortex distinguishes schizophrenia from bipolar disorder.

The classification of schizophrenia and bipolar disorder as two separate disease entities has been hotly debated almost from the moment of its inception with Kraepelin's descriptions of "dementia praecox" and "manic-depressive insanity" in 1896. Kraepelin's nosologic distinction was based on clinical observation of symptomatology and outcome, and even today, despite major advances in science and technology, differential diagnosis of psychosis relies on the clinical course of illness. However, new evidence from diverse fields, e.g., genetics, neuropsychology, and brain imaging, have refueled the debate about whether or not schizophrenia and bipolar disorder represent distinct diseases, leading some to postulate that schizophrenia and bipolar disorder represent different manifestations of psychosis along a continuum with schizoaffective disorder representing an intermediate subtype. To this discourse, we add our own recent postmortem anatomic findings indicating that cellular pathology in the dorsolateral prefrontal cortex in schizophrenia and bipolar disorder differs not just in magnitude but also in direction, in laminar scope, and in relative involvement of neuronal and glial cell types. Thus, distinct morphometric alterations in the dorsolateral prefrontal cortex underlie what appear on neuroimaging analysis to be similar abnormalities in structural and metabolic function in the prefrontal cortex, and the diverse cellular pathology in the dorsolateral prefrontal cortex in these two disorders may account for the greater deficit in schizophrenia on cognitive tasks involving memory, problem solving and abstraction.

Bipolar Disorder↗

PubMed2001

Effects of slow rTMS at the right dorsolateral prefrontal cortex on EEG asymmetry and mood.

In a sham-controlled design (n = 12), slow repetitive transcranial magnetic stimulation (rTMS) was applied to the right dorsolateral prefrontal cortex for 20 min, and the subsequent effects on mood and the EEG spectrum were investigated, Analysis revealed a significant left hemisphere increase in EEG theta activity at 25-35 and 55-65 min after stimulation. In addition, participants reported significant decrease in anxiety immediately after stimulation, as well as 35 and 65 min after rTMS. These findings indicate that reductions in anxiety after slow rTMS at the right dorsolateral prefrontal cortex are associated with a contralateral increase in theta activity.

Adult↗

PubMed2006

Dysfunction of dorsolateral prefrontal cortex in antipsychotic-naïve schizophreniform psychosis.

Reports of abnormal activation of the dorsolateral prefrontal cortex (dlPFC) are common in functional neuroimaging studies of schizophrenia, although very few have examined brain activity in patients close to the onset of illness. In this H(2)(15)O PET study, eight young male patients with first-episode schizophreniform psychosis and age-matched control subjects performed a version of the Stroop task that we have previously shown to engage the middle-frontal gyrus. At the time of testing, patients were antipsychotic-naïve and were scanned within 1 week of initial contact with our clinical program. All patients received a later diagnosis of schizophrenia 6 months after participating in the study. Whole-brain (within-group) and region-of-interest (between-group) analyses were carried out and data underwent spatial reproducibility testing. Compared with healthy subjects, patients showed significantly greater reaction-time (RT) interference but normal RT accuracy on the Stroop task. This pattern correlated with significant under-activation of the posterior left middle-frontal gyri in the patient versus control group. These findings support an emerging model of impaired cognitive control in schizophrenia and suggest that there is significant dysfunction of the dlPFC close to the onset of illness that may coincide with, or be modulated by, the transition-to-illness phase.

Adolescent↗