Recipients were killed at the age of 1.6–11.8 months. Frozen sections were analysed by confocal immunohistochemistry for the donor cell label hPAP and synaptic markers. Vibratome slices were stained for hPAP, and processed for electron microscopy. Visual responses were recorded by electrophysiology from the superior colliculus (SC) in 12 rats at the age of 5.3–11.8 months. All recorded transplanted rats had restored or preserved visual responses in the SC corresponding to the transplant location in the retina, with thresholds between −2.8 and −3.4 log cd/m2. No such responses were found in age-matched S334ter-3 rats without
transplants, or in those with sham surgery. Donor cells and processes were identified in the host by light and electron microscopy. Transplant processes penetrated the inner host retina
in spite of occasional glial barriers between transplant and host. Labeled neuronal processes Gefitinib concentration were found in the host inner plexiform layer, and formed apparent synapses with unlabeled cells, presumably of host origin. In conclusion, synaptic connections between graft and host cells, together with visual responses from corresponding locations www.selleckchem.com/products/nu7441.html in the brain, support the hypothesis that functional connections develop following transplantation of retinal layers into rodent models of retinal degeneration. “
“The inter-play between changes in beta-band (14–30-Hz) cortical rhythms and attention during somatosensation Thiamine-diphosphate kinase informs us about where and when relevant processes occur in the brain. As such, we investigated the effects of attention on somatosensory evoked and induced responses using vibrotactile stimulation and magnetoencephalographic recording.
Subjects received trains of vibration at 23 Hz to the right index finger while watching a movie and ignoring the somatosensory stimuli or paying attention to the stimuli to detect a change in the duration of the stimulus. The amplitude of the evoked 23-Hz steady-state response in the contralateral primary somatosensory cortex (SI) was enhanced by attention and the underlying dipole source was located 2 mm more medially, indicating top-down recruitment of additional neuronal populations for the functionally relevant stimulus. Attentional modulation of the somatosensory evoked response indicates facilitation of early processing of the tactile stimulus. Beta-band activity increased after vibration offset in the contralateral primary motor cortex (MI) [event-related synchronization (ERS)] and this increase was larger for attended than ignored stimuli. Beta-band activity decreased in the ipsilateral SI prior to stimulus offset [event-related desynchronization (ERD)] for attended stimuli only. Whereas attention modulation of the evoked response was confined to the contralateral SI, event-related changes of beta-band activity involved contralateral SI–MI and inter-hemispheric SI–SI connections.