Archives Italiennes De Biologie最新文献

Spatial reference memory in rodents is commonly performed in the Morris Water Maze (MWM). The use of control groups on this task is essential in order to subtract brain activity not related to learning. To study the functional contribution of selected brain areas, we assessed neuronal metabolic activity thorough quantitative cytochrome c oxidase histochemistry. This technique allows the measurement of the oxidative metabolism responsible for ATP production. Our objective is to analyse if the swimming control group is an optimal control for the evaluation of spatial reference memory task. To do so, we explore the behaviour in the MWM and the neuronal metabolic activity of motor cortex and its layers, in addition to hippocampus. For this purpose, three groups of Wistar rats were used: reference memory group, swimming control, and cage control. The behavioural results show significant differences between the experimental group and the swimming control group in time spent in the quadrants and swimming speed. In addition, higher neuronal hippocampal metabolic activity (CA1 subfield) was found in the experimental when compared to both controls. However, there are no differences in the motor cortex neuronal metabolic activity of the groups. Therefore, we can assume that the swimming control group effectively isolates the motor activity during the swim and the behavioural results are due to the hippocampal activity related to learning itself and not the physical activity performed in the labyrinth.

Age-related macular degeneration represents the main retinal disorder leading to irreversible blindness in people over the age of 50 in the Western World. Here we describe a case report, which suggest that specific nutraceutical compounds may exert beneficial effects on the progression of dry age-related macular degeneration (AMD), an eye disease with no approved treatment or cure. Specific antioxidants, such as lutein, resveratrol and Vaccinium Myrtillus, which are known to reduce the risk of developing AMD, when co-administered alone, were supplemented to diet of an informed patient suffering from dry AMD. The case report indicates an improvement of visual acuity and a long lasting decrease in druse volume and number. The concomitant intake of lutein, resveratrol and Vaccinium Myrtillus when administered for six months produced a marked decrease in the drusen observed at OCT at the 6-month follow-up. At this time interval, the patient experienced a noticeable improvement in visual acuity, a decrease in eye strain, more color contrast, higher visual definition. The case report indicates the potential benefit for a non-invasive treatment with improved quality of vision in dry AMD. A larger population followed over a long-term period is warranted. The support of nutraceuticals could therefore offer a new non-invasive, adverse effect-free which may restore the pathology affecting the cross talk between choroid and retinal cells. The results of this case report are discussed within the frame of molecular mechanisms synergizing site-specifically at the anatomical border between the outer retina and inner choroid.

There is evidence showing that increasing the vertical dimension of occlusion, or interocclusal distance, reduces pain symptoms in patients with temporomandibular disorders (TMD) and bruxism. The mechanism underlying the analgesic effect is still under investigation. Some researchers propose either a gate mechanism or the activation of the trigemino-cardiac reflex. In this study, sensory and pain thresholds changes in the mandibular district have been evaluated in twenty healthy subjects immediately after 5 minutes of mandibular stretching at maximum opening of the jaw. Results showed a 60% increment in sensory threshold and a 70% increment in pain threshold (p<0.001) compared with the baseline values. The magnitude of the analgesic effect seems proportional to the extent of mandibular opening. These and similar results are discussed as for the implication in the treatment of TMD related symptoms.

Imitation is a basic human ability, present early in life. Previous studies on control subjects and callosotomized patients showed that imitation occurred mainly in mirror-mode in both groups (60% controls, 66% patients) when they imitate without instructions (free sessions). In contrast, when asked to use the same or opposite limb as the model (driven sessions), controls used anatomical mode (93%), callosotomized patients mainly mirror strategy (61%). It has been suggested that callosotomized subjects prefer the mirror mode because of an impaired capacity for mental rotation, likely due to the lack of the corpus callosum (CC). The present research investigated the imitation strategies used by schizophrenic patients, who also could present anomaly in the interhemispheric connections. Fifteen hospitalized patients with diagnosis of schizophrenia participated in the study. They were asked to imitate upper limb intransitive meaningful and meaningless gestures performed by a model in a video. The results were compared with those from 20 healthy individuals. In driven imitation, controls answered in anatomical mode (95% of the responses), versus 63% of patients' responses. In free imitation sessions the answers in anatomical mode decreased to 39% in control subjects and to 46% in schizophrenic patients. In both driven and free imitation, the differences between the two proportions, conditioned to Diagnosis, resulted significantly different. The present data, in line with previous studies on psychotic and neurological patients showing impairments on imitation, suggest that the neural circuitry leading patients to perform differently from controls likely relates with the functional efficiency of the CC.

Emotions are influenced by several individual factors. Hypnotizability - a psychophysiological trait associated with morpho-functional cerebral and cerebellar variations able to sustain differences in interoception and emotion - could be one of them. The aims of the study were to find out possible differences in Interoceptive Awareness (IA) and in the emotional traits sustained by the Behavioral Inhibition/Activation System (BIS/BAS) in participants with high (highs), medium (mediums) and low (lows) hypnotizability and to investigate the association of interoceptive awareness and BIS/BAS related emotional traits as a function of hypnotizability. Thus, IA and BIS/BAS were studied in 284 subjects of both genders by the Multidimensional Assessment of Interoceptive Awareness (MAIA) and by BIS/BAS scales, respectively. Significantly lower BIS scores (lower inhibitory control/conflict monitoring) in highs and lows with respect to mediums and significantly higher IA (proneness to notice and interpret interoceptive information) in highs with respect to mediums and lows were found. In addition, different correlations between MAIA and BIS/BAS scales were observed in the three groups, indicating different hypnotizability-related associations.The hypnotizability-related relation between interoceptive awareness and emotional traits could be accounted for by different models and their knowledge may be relevant to the science of emotion and to clinical applications.

Parkinson's disease is a neurodegenerative disease with manifestations related to oxidative stress and damage to the skeletal striated musculature. This study evaluated the electromyographic fatigue of the masseter and temporal muscles in individuals with Parkinson's disease. The median frequency of the normotensive electromyographic signal was analyzed in 16 individuals, aged between 50 and 70 years, with Parkinson's disease in stages I and III of the Hoehn and Yahr disability scale (n=8) or without the disease (n=8). The data were tabulated and analyzed statistically (t-test, p .05). Compared with the group without Parkinson's disease, the group with the disease showed an increase in the median frequency, with significant differences for the right masseter (p=.05) and the right temporal (p=.03) muscles. The results suggest that there is a link between Parkinson's disease and functional alterations of the masticatory system, especially when electromyographic fatigue is assessed.

Contextual fear conditioning (CFC) paradigm is routinely used to study fear-based learning in animals and it provides a useful model for understanding fear and anxiety in human. In the present study, such model was used following the previously established CFC protocol, and immunohistochemistry, enzymatic activity and western blotting analysis approaches were used to identify the expression of acid sphingomyelinase (aSMase) and vitamin D receptor (VDR) in prefrontal region brain of rat. Results revealed an increase of aSMase activity in conditioned rats, suggesting an apoptotic condition in such animals. In addition, an increase of density and organization of axonal neurofilaments and of VDR expression has been observed in brain of conditioned rats, supporting an induction of growth and organization of new neurons in prefrontal regions, whose contribution to various aspects of contextual fear learning is still largely unknown.

The objective of the present study was to ascertain masticatory efficiency by evaluating electromyographic activity in the masseter and temporalis muscles in subjects with sleep bruxism of varying severity, as determined by BiteStrip. Thirty-four subjects with sleep bruxism were divided into two groups: a mild sleep bruxism group with a mean (± standard deviation) age of 31.3 ± 6.2 years (n = 15) and a severe sleep bruxism group with a mean age of 29.8 ± 7.1 years (n = 19). Full-night polysomnography (PSG) was performed in eligible subjects. The linear envelope integral was used to determine masticatory efficiency on the basis of the electromyographic signal of the masseter and temporalis muscles during habitual and non-habitual chewing. There was significantly higher (p .05) electromyographic activity in the severe bruxism group than in the mild bruxism group during both peanut chewing in the right (p = .03) and left (p = .03) temporalis muscles and raisin chewing in the right (p = .01) and left (p = .05) temporalis muscles. Furthermore, Parafilm M chewing showed similar results in the right (p = .008) and left (p = .02) temporalis muscles. These results suggested that subjects with severe sleep bruxism had lower masticatory efficiency.

Recording synaptic activity of layer III neurons from motor cortex slices, which was provoked by stimulating layer IV, generated synaptic responses of the field potential (FP) that went from mean 100 μV to 600 μV when the stimulus was increased up to twice the threshold. Administering 100 μM or 200 μM of copper, increased the responses to mean 800 μV and 820 μV, respectively. The response to 200 μM was not significantly greater than that to 100 μM. However, all FP responses were significantly lower to a copper concentration of 500 μM. The basal FP was slowly restored by removing the copper with Krebs-Ringer(K-R), resulting in similar characteristics to those observed before copper administration. Then, neurons were perfused with penicillin (2000 UI) to increase cortical excitability and to assess the depressing effect of high concentrations of copper. Administering 500 μM of copper significantly reduced the activity generated by penicillin, while removing by wash(K-R) penicillin and copper generated FP responses similar to those obtained at baseline. Our data indicate that depending on the concentration, copper can behave as an activating or blocking agent for cortical activity.

Objectives: to update understanding of the effectiveness of transcranial direct current stimulation (tDCS) on motor dysfunction in Parkinson's disease, since the last review was published in 2016.

Methods: in order to identify suitable publications for inclusion, an online search of the Pubmed, Scopus and Cochrane databases was carried out. Searches of relevant full-text articles were performed through specific keywords. The final database check was performed in July 2019. Papers were restricted to studies investigating motor rehabilitative effects of tDCS in adult patients with Parkinson's disease. Studies involving either single or repeated tDCS sessions with a sham or controlled trial type design (which incorporated outcomes on motor performance measures) were considered. As studies varied widely in terms of methodology, a qualitative analysis of the selected studies was performed using the Newcastle-Ottawa Quality Assessment Scale or the Delphi list (depending on the study design).

Results: twenty-nine studies were retained in this systematic review. Of the studies included, fifteen involved single tDCS session (patients = 256) and fourteen involved repeated tDCS sessions (patients = 294). Eight investigations of single tDCS and ten investigations of repeated tDCS demonstrated significant results. Studies involving multi- target stimulation demonstrated significant improvements on mobility (p=0.006), balance (by 50.9%), gait velocity (by 29%), fall reduction (p0.05) compared to mono-target stimulations.

Conclusions: despite increasing evidence that tDCS may improve motor symptoms, the results showed that fully optimized tDCS protocols are not yet established.