Electrical stimulation of one SCN produced responses in the contralateral SCN with a short delay (approximately 5 ms) and Ca2+-dependence that are consistent with action potential-mediated chemical synaptic transmission. Patch-clamp recordings of stimulated cells revealed excitatory postsynaptic inward-currents (EPSCs), which were sufficient in magnitude to elicit action potentials. Electrical stimulation evoked tetrodotoxin-dependent Ca2+ transients in about 30% of all contralateral SCN neurons recorded. The responding neurons were widely distributed within the SCN with a highest density in the posterior SCN. EPSCs and Ca2+ responses were significantly

reduced after application of a glutamate receptor antagonist. Application of antagonists for receptors of other candidate Crizotinib ic50 transmitters inhibited the Ca2+ responses in some of the cells but overall the impact of these antagonists was variable. 5-FU in vitro In a functional assay, electrical stimulation of the SCN produced phase shifts in the circadian rhythm in the frequency of multiunit activity rhythm in the contralateral SCN. These phase shifts were blocked by a glutamate receptor antagonist. Taken together, these results implicate glutamate as a transmitter required for

communication between the left and right SCN. “
“Brain cholinergic modulation is essential for learning-induced plasticity of the auditory cortex. The pedunculopontine tegmental nucleus (PPTg) is an important cholinergic nucleus in the brainstem, and appears to be involved in learning and subcortical plasticity. This study confirms the Tau-protein kinase involvement of the PPTg in the plasticity of the auditory cortex in mice. We show here that electrical stimulation of the PPTg paired with a tone induced drastic changes in the frequency

tunings of auditory cortical neurons. Importantly, the changes in frequency tuning were highly specific to the frequency of the paired tone; the best frequency of auditory cortical neurons shifted towards the frequency of the paired tone. We further demonstrated that such frequency-specific plasticity was largely eliminated by either thalamic or cortical application of the muscarinic acetylcholine receptor antagonist atropine. Our finding suggests that the PPTg significantly contributes to auditory cortical plasticity via the auditory thalamus and cholinergic basal forebrain. “
“Investigations of adult neurogenesis in recent years have revealed numerous differences among mammalian species, reflecting the remarkable diversity in brain anatomy and function of mammals. As a mechanism of brain plasticity, adult neurogenesis might also differ due to behavioural specialization or adaptation to specific ecological niches.