ABSTRACT
Studies have shown that spatial attention remarkably affects the trial-to-trial response variability shared between neurons. Difficulty in the attentional task adjusts how much concentration we maintain on what is currently important and what is filtered as irrelevant sensory information. However, how task difficulty mediates the interactions between neurons with separated receptive fields (RFs) that are attended to or attended away is still not clear. We examined spike count correlations between single-unit activities recorded simultaneously in the primary visual cortex (V1) while monkeys performed a spatial attention task with two levels of difficulty. Moreover, the RFs of the two neurons recorded were non-overlapping to allow us to study fluctuations in the correlated responses between competing visual inputs when the focus of attention was allocated to the RF of one neuron. While increasing difficulty in the spatial attention task, spike count correlations were either decreased to become negative between neuronal pairs, implying competition among them, with one neuron (or none) exhibiting attentional enhancement of firing rate, or increased to become positive, suggesting inter-neuronal cooperation, with one of the pair showing attentional suppression of spiking responses. Besides, the modulation of spike count correlations by task difficulty was independent of the attended locations. These findings provide evidence that task difficulty affects the functional interactions between different neuronal pools in V1 when selective attention resolves the spatial competition.
Subject(s)
Animals , Attention/physiology , Macaca mulatta , Neurons/physiology , Photic Stimulation , Primary Visual Cortex , Visual Cortex/physiologyABSTRACT
Objective To study the relationship between chromosomal abnormality and Y chromosome microdeletions and male infertility. Methods Lymphocytes were cultured from peripheral blood of 1975 male infertility patients and stained with Giemsa. The chromosomes were analyzed under microscope. Y chromosome specific sequence tags (STS) were selected, then the Y chromosome microdeletions in AZF regions were screened by polymerase chain reaction (PCR) in azoospermia and oligozoospermia patients. Results There were 305 cases of detected chromosomal abnormalities (15.44%) in the 1975 cases. There were 101 cases (5.11 %) with autosome abnormalities which clinically manifested as oligozoospermia and teratospermia. There were 204 cases (10. 33%) of sexual chromosome abnormalities and the patients were mainly characterized with Klinefelter's syndrome. Y chromosome microdeletions were detected in 109 (14.97 %) of the 728 cases of azoospermia or oligozoospermia. The most common microdeletion of Y chromosome was AZFc (62.39%) and these patients were characterized with azoospermia and oligozoospermia. Five patients (4. 59%) who suffered Y chromosome microdeletion in AZFa region and AZFb region were characterized with azoospermia. Fifteen cases (13.76%) with microdeletion in AZFb region and AZFc region were mainly characterized with azoospermia. There were 6 cases (5. 50 % ) of microdeletion in AZFa, AZFb and AZFc regions,these patients were all characterized with azoospermia. Conclusions Both Chromosome abnormalities and Y chromosome microdeletions are important causes for male infertility.
ABSTRACT
Purpose To evaluate the clinical effects of early lamellar corneoscleral transplantation in the management of severe alkali-burned eye. Methods The patients compatible with the Ⅲ or Ⅳ grades of Roper-Hall's standards were diveded into operating group and control group according to the post-burning interval which was less than 2 weeks or more.Depending on the presence or absence of scleral nacrosis,the patients in operating group were given a lamellar corneoscleral transplantation or a lamellar keratoplasty.The patients in control group did not receive any operation.The medication was the same in the two groups. Results During the following-up of 6 to 24 months,most cases in operating group had significantly improved vision postoperatively,less inflammatory congestion,lower incidence of corneal ulcertion,and less neovasculerization.No perforation occurred in any case of the operating group.Whilst in the control group,ulcerative perforation occurred in 6 of 10 eyes,leucoma accompanied by severe panus in 6 eyes,symblepharon in 5 eyes. Conclusions Debridement with early lamellar corneoscleral transplantation can effectively decrease the occurrence of corneal perforation,prevent symblepharon,shorten the time of inflammation,and improve visual acuity.