The hippocampus plays a key role in learning and memory. Previous studies suggested that the main types of principal neurons, dentate gyrus granule cells (GCs), CA3 pyramidal neurons, and CA1 pyramidal neurons, differ in their activity pattern, with sparse firing in GCs and more frequent firing in CA3 and CA1 pyramidal neurons. It has been assumed but never shown that such different activity ma...

Chronic restraint stress (CRS) induces the remodeling (i.e. retraction and simplification) of the apical dendrites of hippocampal CA3 pyramidal neurons in rats, suggesting that intrahippocampal connectivity can be affected by a prolonged stressful challenge. Since the structural maintenance of neuronal dendritic arborizations and synaptic connectivity requires neurotrophic support, we investiga...

To investigate the activity of senescence-associated beta-galactosidase (SA-beta-GAL) in the hippocampus of aging rats. Hippocampi of 6-, 18-, and 24-month-old rats were observed by histochemical staining for SA-beta-GAL and cytochemical staining for SA-beta-GAL in cultured hippocampal neurons. The activity of SA-beta-GAL doubled in hippocampal pyramidal cells of the CA3 region in rats between ...

Hippocampal population bursts ("sharp wave-ripples") occur during rest and slow-wave sleep and are thought to be important for memory consolidation. The cellular mechanisms involved are incompletely understood. Here we investigated the cellular mechanisms underlying the initiation of sharp waves using a hippocampal slice model. To this end, we used a combination of field recordings with planar ...

The equilibrium potential for GABA-A receptor mediated currents (EGABA) in neonatal central neurons is set at a relatively depolarized level, which is suggested to be caused by a low expression of K+/Cl- co-transporter (KCC2) but a relatively high expression of Na+-K+-Cl- cotransporter (NKCC1). Theta-burst stimulation (TBS) in stratum radiatum induces a negative shift in EGABA in juvenile hippo...

Baraban, Scott C. and Philip A. Schwartzkroin. Effects of hycampal excitability because each interneuron synapses posmolar solutions on membrane currents of hippocampal interneuonto Ç200 pyramidal neurons (Traub and Miles 1991) . rons and mossy cells in vitro. J. Neurophysiol. 79: 1108–1112, Hippocampal ‘‘mossy’’ cells are another subtype of non1998. Whole cell voltage-clamp recordings in rat h...

Alkondon, Manickavasagom and Edson X. Albuquerque. Nicotinic acetylcholine receptor a7 and a4b2 subtypes differentially control GABAergic input to CA1 neurons in rat hippocampus. J Neurophysiol 86: 3043–3055, 2001. The hippocampus, a limbic brain region involved in the encoding and retrieval of memory, has a well-defined structural network assembled from excitatory principal neurons and inhibit...

High-frequency field ripples occur in the rodent hippocampal formation and are assumed to depend on interneuron type-specific firing patterns, structuring the activity of pyramidal cells. Ripples with similar characteristics are also present in humans, yet their underlying cellular correlates are still unknown. By in vivo recording interneurons and pyramidal cells in the human hippocampal forma...

Maternal immune activation (MIA) resulting from prenatal exposure to infectious pathogens or inflammatory stimuli is increasingly recognized to play an important etiological role in neuropsychiatric disorders with neurodevelopmental features. MIA in pregnant rodents induced by injection of the synthetic double-stranded RNA, Poly I:C, a mimic of viral infection, leads to a wide spectrum of behav...