Neural correlates of embodied action language processing: a systematic review and meta-analytic study

Brain Imaging and Behavior - The neural correlates of action language processing are still debated within embodied cognition research and little is known about the flexible involvement of...     

How many forms of perseveration? Evidence from cancellation tasks in right hemisphere patients

Neglect patients' performance during cancellation tasks is characterized by left sided omissions and, in many cases, by the production of inappropriate material of various kinds in the ipsilesional space, e.g. additional marks over already cancelled targets, marks drawn away from targets, scribbles, irrelevant drawings. It is unclear whether these behaviours, which have collectively been called perseverative, are functionally and anatomically connected and whether they correlate with the severity of neglect. Here we report a retrospective study on 33 right brain damaged patients with neglect after right hemisphere lesions in whom we measured the intensity of perseveration of the three following kinds: (1) ‘additional marks' (AM) perseveration where patients cancelled a target with two or more well separated marks; (2) ‘scribble’ perseveration, where patients, instead of cancelling the target with a single pen stroke as required by the task, performed multiple pen strokes without breaking the pen-to-paper contact, with the final product being a scribble; (3) ‘flying marks’ (FM) perseveration where patients produced cancellation marks well away from the targets. We found that AM and FM perseveration correlated with neglect severity, while ‘scribble’ perseveration did not. The lesion-symptom mapping showed three separate anatomical areas in the right hemisphere: ‘scribble’ perseveration was associated with lesions of the orbitofrontal cortex and caudate nucleus; AM perseveration was associated with damage to the rolandic operculum, superior temporal gyrus and inferior frontal gyrus; FM perseveration was associated with damage to the dorsal premotor cortex and the temporal pole. Neglect severity followed damage to a region which grossly corresponds to the sum of the regions associated with AM and FM perseveration respectively. This complex behavioural and anatomical pattern is interpreted in terms of a three-factor model, in which AM perseveration is caused by a deficit of disengagement of attention from the right side (also causing omissions), FM perseveration is caused by directional hypokinesia (also causing left-side omissions), and ‘scribble’ perseveration is the consequence of a failure to inhibit an initiated motor act, which is completely separate (both anatomically and functionally) from the disorder inducing omissions.     

Involvement of PKCα–MAPK/ERK-phospholipase A2 pathway in the Escherichia coli invasion of brain microvascular endothelial cells

Escherichia coli K1 is the most common Gram-negative organism that causes neonatal meningitis following penetration of the blood–brain barrier. In the present study we demonstrated the involvement of cytosolic (cPLA₂) and calcium-independent phospholipase A₂ (iPLA₂) and the contribution of cyclooxygenase-2 products in E. coli invasion of microvascular endothelial cells. The traversal of bacteria did not determine trans-endothelial electrical resistance (TEER) and ZO-1 expression changes and was reduced by PLA₂s siRNA. cPLA₂ and iPLA₂ enzyme activities and cPLA₂ phosphorylation were stimulated after E. coli incubation and were attenuated by PLA₂, PI3-K, ERK 1/2 inhibitors. Our results demonstrate the role of PKCα/ERK/MAPK signaling pathways in governing the E. coli penetration into the brain.     

Dapsone hydroxylamine-mediated alterations in human red blood cells from endometriotic patients

Endometriosis, an estrogen-dependent chronic gynecological disease in women of reproductive age, is characterized by a systemic inflammation status involving also red blood cells (RBCs). In this study, we evaluated how the protein oxidative status could be involved in the worsening of RBC conditions due to dapsone intake in endometriotic women in potential treatment for skin or infection diseases. Blood samples from two groups of volunteers, control group (CG) and endometriosis patient group (PG), were analyzed for their content of band 3 tyrosine phosphorylation (Tyr-P) and high molecular weight aggregate (HMWA) in membranes, and glutathione (GSH) content and carbonic anhydrase (CA) activity in cytosol. In endometriotic patients, RBC showed the highest level of oxidative-related alterations both in membrane and cytosol. More interestingly, the addition of dapsone hydroxylamine (DDS-NHOH) could induce further increase of both membranes and cytosol markers, with an enhancement of CA activity reaching about 66% of the total cell enzyme amount. In conclusion, in PG the systemic inflammatory status leads to the inability of counteracting adjunctive oxidative stress, with a potential involvement of CA-related pathologies, such as glaucoma. Hence, the importance of the evaluation of therapeutic approaches worsening oxidative imbalance present in PG RBC is underlined.     

Corneal Manifestations of Systemic Sclerosis

Purpose: Corneal involvement in systemic sclerosis (SSc) is rare, but due to rich collagen composition cornea is especially vulnerable to connective tissue diseases. Therefore, our aim was to evaluate corneal parameters of SSc patients.

Methods: The study included 32 SSc patients and 39 control subjects with no ocular symptoms or ocular surface disorders. All study participants underwent Pentacam evaluation and objective signs of dry eye disease (DED), and clinical parameters were evaluated.

Results: All pachymetric values, most of the corneal front surface, corneal volume, as well as anterior chamber depth measurements were significantly lower in the SSc group than in the control group (p < 0.05). Significant negative correlation was found between corneal parameters and age on the one hand, and disease duration on the other.

Conclusions: Early recognition of corneal impairment, a possible extraintestinal manifestation of SSc, should be included in the check-up of the disease in order to reduce sight-threatening complications.     

Differential Roles of GABAA Receptor Subtypes in Benzodiazepine-Induced Enhancement of Brain-Stimulation Reward

Benzodiazepines such as diazepam are widely prescribed as anxiolytics and sleep aids. Continued use of benzodiazepines, however, can lead to addiction in vulnerable individuals. Here, we investigate the neural mechanisms of the behavioral effects of benzodiazepines using the intracranial self-stimulation (ICSS) test, a procedure with which the reward-enhancing effects of these drugs can be measured. Benzodiazepines bind nonselectively to several different GABA_A receptor subtypes. To elucidate the α subunit(s) responsible for the reward-enhancing effects of benzodiazepines, we examined mice carrying a histidine-to-arginine point mutation in the α1, α2, or α3 subunit, which renders the targeted subunit nonresponsive to diazepam, other benzodiazepines and zolpidem. In wild-type and α1-point-mutated mice, diazepam caused a dose-dependent reduction in ICSS thresholds (reflecting a reward-enhancing effect) that is comparable to the reduction observed following cocaine administration. This effect was abolished in α2- and α3-point-mutant mice, suggesting that these subunits are necessary for the reward-enhancing action of diazepam. α2 Subunits appear to be particularly important, since diazepam increased ICSS thresholds (reflecting an aversive-like effect) in α2-point-mutant animals. Zolpidem, an α1-preferring benzodiazepine-site agonist, had no reward-enhancing effects in any genotype. Our findings implicate α2 and α3 subunit containing GABA_A receptors as key mediators of the reward-related effects of benzodiazepines. This finding has important implications for the development of new medications that retain the therapeutic effects of benzodiazepines but lack abuse liability.