Figure 1. Effect of trans-ACPD on the oscillatory properties of TC neurons in the cat LGN.
A1. Intracellular recording of a cat LGN TC neuron in control conditions showing different types of activity depending on the level of injected d.c. current. In the absence of injected d.c. current the neuron displays rhythmic LTCP-mediated bursts at ~1 Hz (i.e. δ oscillation, bottom trace). When the neuron is depolarized it initially becomes silent (middle trace) and then exhibits tonic firing (top trace). A2. 100 μM trans-ACPD expands the oscillatory repertoire of the neuron so that it includes a slow oscillation (3rd and 4th traces from the top) and HT bursting (top trace). Note that the neuron is now depolarized so that HT bursting becomes the spontaneous activity in the absence of injected d.c. current. Unless otherwise stated all dotted lines in A1 and A2 indicate −60 mV. B. Voltage response of the neuron depicted in A to a range of injected current steps before (1) and after (2) trans-ACPD application. Note the appearance of a distinctly non-linear membrane charging pattern in B2 which encompasses a marked inflection point (). In this and subsequent figures some action potentials have been truncated for clarity.