We have recorded the firing activities of hippocampal pyramidal cells throughout the classical conditioning of eyelid responses in alert cats. Pyramidal cells (n = 220) were identified by their antidromic activation from the ipsilateral fornix and according to their spike properties. Upper eyelid movements were recorded with the search coil in a magnetic field technique. Latencies and firing pr...

1. We compared gamma-aminobutyric acid (GABA)-mediated responses of identified pyramidal cells and fast spiking interneurons in layer V of visual cortical slices from young rats (P11-14). 2. The frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) was similar in pyramidal cells and interneurons (1.7 vs. 1.9 Hz). For events with 10-90% rise times less than 0.9 ms, no significant di...

Axon sprouting and synaptic reorganization in the hippocampus are associated with the development of seizures in temporal lobe epilepsy. Synaptic interactions among CA1 pyramidal cells were examined in fragments of hippocampal slices containing only the CA1 area from saline- and kainate-treated rats. Glutamate microapplication to the pyramidal cell layer increased excitatory postsynaptic curren...

Introduction: Many studies have shown that amygdala kindling produces synaptic potentiation by induction of changes in the neuronal electrophysiological properties and inward currents both in epileptic focus and in the areas which are in connection with the epileptic focus and have important role in seizure development and progression such as hippocampal CA1 region. However, cellular mechani...

The sequence of changes in single neuron activity in the CA1 area of the rabbit hippocampus was examined during daily sessions (80 trials/session) of hippocampally dependent nonspatial trace eyeblink (i.e., nictitating membrane response) conditioning. Each trial for trace conditioned animals (n = 7) consisted of a tone conditioned stimulus (CS; 6 kHz; 90 dB, 100 ms) followed by a 500-ms silent ...

The temporary interaction of distinct gamma oscillators effects binding, association, and information routing. How independent gamma oscillations are generated and maintained by pyramidal cells and interneurons within a cortical circuit remains unknown. We recorded the spike timing of identified parvalbumin-expressing basket cells in the CA1 hippocampus of anesthetized rats and simultaneously d...

Functional and molecular changes associated with pathophysiological conditions are relatively easily detected based on tissue samples collected from patients. Population specific cellular responses to disease might remain undiscovered in samples taken from organs formed by a multitude of cell types. This is particularly apparent in the human cerebral cortex composed of a yet undefined number of...

The immunohistochemical localization of manganese superoxide dismutase (Mn-SOD), nitric oxide synthase (NOS) and calcium (Ca) binding proteins; calbindin-D28K (Calb) and parvalbumin (Parv), was investigated in the rat hippocampus by using a double immunostaining method and an enzyme histochemical staining method. These substances showed considerable regional immunoreactivities in the hippocampu...

Medial entorhinal cortex (MEC) plays an important role in physiological processes underlying navigation, learning, and memory. Excitatory cells in the different MEC layers project in a region-specific manner to the hippocampus. However, the intrinsic microcircuitry of the main excitatory cells in the superficial MEC layers is largely unknown. Using scanning photostimulation, we investigated the...

In an effort to determine if sex differences exist in the morphologic characteristics of pyramidal cells and granule cells of the hippocampal formation and whether sex plays a role in determining thyroid hormone sensitivity of these neuronal populations, we used single-section Golgi impregnation to examine the effects of neonatal thyroid hormone administration on hippocampal cells from the brai...