Behavioral rhythms that developed after weaning reflected the phase-shift of clock gene expression rhythm in the SCN. These findings indicate that a daily exposure to an ambient temperature of 10 °C during the neonatal period is
capable of resetting the circadian clock in the SCN, but other factors yet unidentified are also involved in maternal entrainment. “
“The thalamic reticular nucleus (nRt) is an assembly of GABAergic projection neurons that participate in the generation of brain rhythms during synchronous sleep and absence epilepsy. NRt cells receive inhibitory BAY 80-6946 ic50 and excitatory synaptic inputs, and are endowed with an intricate set of intrinsic conductances. However, little is known about how click here intrinsic and synaptic properties interact to generate rhythmic discharges in these neurons. In order to better understand this interaction, I studied the subthreshold responses of nRt cells to time-varying inputs. Patch-clamp recordings were performed in acute slices of rat thalamus (postnatal days 12–21). Sinusoidal current waveforms of linearly changing frequencies were injected into the soma, and the resulting voltage oscillations were recorded. At the resting membrane potential, the impedance profile showed
a characteristic resonance at 1.7 Hz. The relative strength of the resonance was 1.2, and increased with membrane hyperpolarization. Small suprathreshold current injections led to preferred spike generation at the resonance frequency. Bath application of ZD7288 or Cs+, inhibitors of the hyperpolarization-activated Loperamide cation current (Ih), transformed the resonance into low-pass behaviour, whereas the T-channel blockers mibefradil and Ni2+ decreased the strength of the resonance. It is concluded that nRt cells have an Ih-mediated intrinsic frequency preference in the subthreshold voltage range that favours action potential generation in the delta-frequency
“Fixational saccades are small, involuntary eye movements that occur during attempted visual fixation. Recent studies suggested that several cognitive processes affect the occurrence probability of fixational saccades. Thus, there might be an interaction between fixational saccade-related motor signals and cognitive signals. The pedunculopontine tegmental nucleus (PPTN) in the brainstem has anatomical connections with numerous saccade-related and limbic areas. Previously, we reported that a group of PPTN neurons showed transient phasic bursts or a pause in activity during large visually guided and spontaneous saccades, and also showed sustained tonic changes in activity with task context. We hypothesised that single PPTN neurons would relay both fixational saccade-related and task context-related signals, and might function as an interface between the motor and limbic systems.