Some types of epileptic seizures involve both thalamus and cerebral cortex, while other types can be evoked in the cerebral cortex without thalamic participation. We investigated the possible role of low-threshold spike (LTS) cortical neurons in the genesis of these intracortical seizures. We found LTS cortical neurons in cat area 5}7 in vivo, the properties of which could be modeled based on r...

Cerebellar Purkinje neurons have intrinsic membrane properties that favor burst firing, seen not only during complex spikes elicited by climbing fiber input but also with direct electrical stimulation of cell bodies. We examined the ionic conductances that underlie all-or-none burst firing elicited in acutely dissociated mouse Purkinje neurons by short depolarizing current injections. Blocking ...

Nauhaus I, Nielsen KJ, Callaway EM. Nonlinearity of twophoton Ca imaging yields distorted measurements of tuning for V1 neuronal populations. J Neurophysiol 107: 923–936, 2012. First published November 23, 2011; doi:10.1152/jn.00725.2011.—We studied the relative accuracy of drifting gratings and noise stimuli for functionally characterizing neural populations using two-photon calcium imaging. C...

Synaptic transmission and membrane properties of sympathetic neurons in superior cervical ganglia of spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY), and Sprague-Dawley rats (SD) were investigated in vitro by extracellular and intracellular recording. The sympathetic neurons of SHR showed an atypical loss of spike accommodation. The spike discharge was insensitive to...

Spike-timing-dependent plasticity (STDP) provides a cellular implementation of the Hebb postulate, which states that synapses, whose activity repeatedly drives action potential firing in target cells, are potentiated. At glutamatergic synapses onto hippocampal and neocortical pyramidal cells, synaptic activation followed by spike firing in the target cell causes long-term potentiation (LTP)-as ...

Neuronal firing patterns and frequencies determine the nature of encoded information of the neurons. Here we discuss the molecular identity and cellular mechanisms of spike-frequency adaptation in central nervous system (CNS) neurons. Calcium-activated potassium (KCa) channels such as BKCa and SKCa channels have long been known to be important mediators of spike adaptation via generation of a l...

Dopamine (DA) neurons have been recorded in vivo in four states of activity: hyperpolarized, nonfiring; single spike firing; burst firing; and depolarization inactivation. Nonfiring DA neurons can be made to fire by iontophoretic application of the excitatory substances glutamate and cholecystokinin, or by depolarizing current injection. Spontaneously active DA cells typically fire in a slow (3...

Cooperative regulation of inosiol-1,4,5-trisphosphate receptors (IP(3)Rs) by Ca(2+) and IP(3) has been increasingly recognized, although its functional significance is not clear. The present experiments first confirmed that depolarization-induced Ca(2+) influx triggers an outward current in visual cortex pyramidal cells in normal medium, which was mediated by apamin-sensitive, small-conductance...

We identified Kv3-like high-threshold K+ currents in hypothalamic supraoptic neurons using whole cell recordings in hypothalamic slices and in acutely dissociated neurons. Tetraethylammonium (TEA)-sensitive currents (< 1 mM TEA) evoked from -50 mV were characterized by a large component that inactivated in 10-30 ms, and a smaller, persistent component that inactivated in 1-2 s. I/V relations in...

Bath application of 8-parachlorophenylthio-cyclic GMP (8-pcpt-cGMP) has been shown to increase the number of action potentials per burst in the Aplysia neuron R15. Here we report that 8-pcpt-cGMP can eventually inhibit R15's bursting activity and cause the cell to exhibit slow tonic spiking activity. This action is preceded by decreases in spike frequency and in the amplitude of the interburst ...