Hippocampal oscillations reflect coordinated neuronal activity on many timescales. Distinct types of GABAergic interneuron participate in the coordination of pyramidal cells over different oscillatory cycle phases. In the CA3 area, which generates sharp waves and gamma oscillations, the contribution of identified GABAergic neurons remains to be defined. We have examined the firing of a family o...

The functional activity of hippocampal neurons is strongly correlated with behavioral performance in a vertebrate model learning system, rabbit eyeblink conditioning. Using this system, we have previously shown that (a) complete removal of the hippocampus blocks acquisition of the conditioned response; (b) a calcium-dependent postsynaptic afterhyperpolarization is reduced in pyramidal cells rec...

The action potential (AP) is a fundamental feature of excitable cells that serves as the basis for long-distance signaling in the nervous system. There is considerable diversity in the appearance of APs and the underlying repolarization mechanisms in different neuronal types (reviewed in Bean BP. Nat Rev Neurosci 8: 451-465, 2007), including among pyramidal cell subtypes. In the present work, w...

Buhler, A. V. and T. V. Dunwiddie. 7 nicotinic acetylcholine receptors on GABAergic interneurons evoke dendritic and somatic inhibition of hippocampal neurons. J Neurophysiol 87: 548–557, 2002; 10.1152/jn.00316.2001. GABAergic interneurons in the hippocampus express high levels of 7 nicotinic acetylcholine receptors, but because of the diverse roles played by hippocampal interneurons, the impac...

Bibbig, Andrea, Roger D. Traub, and Miles A. Whittington. Long-range synchronization of and oscillations and the plasticity of excitatory and inhibitory synapses: a network model. J Neurophysiol 88: 1634 –1654, 2002; 10.1152/jn.00064.2002. The ability of oscillating networks to synchronize despite significant separation in space, and thus time, is of biological significance, given that human ac...

Five pyramidal cells from the posteromedial barrel subfield of mouse SmI cortex were labeled by Golgi impregnation and then gold-toned and de-impregnated (Fairen, Peters & Saldanha, 1977). Subsequently, 40 to 70 pm-long segments of their apical dendrites occurring in layer IV were graphically reconstructed from serial thin sections to determine the distribution of their synapses. Thalamocortica...

Pyramidal neurons in layer 5 of the neocortex can be differentiated into 3 cell subtypes: 1) short regular spiking (SH), 2) tall regular spiking (TR), and 3) tall burst spiking (TB), based on their morphological and electrophysiological properties. We characterized the functional excitatory local input to these 3 cell subtypes in rat primary visual cortex using laser-scanning photostimulation. ...

The behaviour-contingent rhythmic synchronization of neuronal activity is reported by local field potential oscillations in the theta, gamma and sharp wave-related ripple (SWR) frequency ranges. In the hippocampus, pyramidal cell assemblies representing temporal sequences are coordinated by GABAergic interneurons selectively innervating specific postsynaptic domains, and discharging phase locke...

The neonatal period is critical for seizure susceptibility, and neocortical networks are central in infantile epilepsies. We report that application of 4-aminopyridine (4-AP) to immature (P6-P9) neocortical slices generates layer-specific interictal seizures (IISs) that transform after recurrent seizures to ictal seizures (ISs). During IISs, cell-attached recordings show action potentials in in...