A consideration of the cortical projections to the hippocampus provides a number of candidate regions that might provide distal sensory information needed for allocentric processing. Prominent among the input regions are the entorhinal cortex, the perirhinal cortex, the postrhinal cortex, and the retrosplenial cortex. A review of these sites reveals the surprising fact that in spite of their an...

Grid cells in the entorhinal cortex represent an animal's current location during navigation. A new study indicates that grid cells in humans also represent information about imagined movement and spatial orienting, suggesting that the entorhinal network has a flexible role in spatial representation.

UNLABELLED Medial entorhinal cortex (MEC) grid cells exhibit firing fields spread across the environment on the vertices of a regular tessellating triangular grid. In rodents, the size of the firing fields and the spacing between the firing fields are topographically organized such that grid cells located more ventrally in MEC exhibit larger grid fields and larger grid-field spacing compared wi...

resolution, FOV of 24 cm, 62.5 kl-Iz acquisition bandwidth, 4ram slice thickness, 17 sagittal slices). Two different memory tasks were employed: A) Identification of in-/outdoor scenes, B) Comparison of left/right picture sizes. A stimulus-block paradigm with 30 seconds on (task A) and 30 seconds off (task B) were repeated for 4 cycles and followed by a 6 rain resting paradigm in a 10-minute-to...

The verrucae areae entorhinalis (VAE) are a characteristic feature of the human brain that occupy the anterior and posterolateral parts of the parahippocampal gyri and correspond to the islands of layer II neurons. We analyzed VAE in 60 neurologically normal subjects ranging from 23 to 85 years of age using a casting method. In 10 of these subjects the total number of neurons in the entorhinal ...

Acquisition and extinction of the conditioned emotional response (CER) was studied in 24 male hooded rats which, prior to training, received small electrolytical lesions in the dorsal hippocampus, the ventral hippocampus, the entorhinal cortex, or were given sham operations. The rate of the on-going bar-pressing behavior for food pellets was highest in rats with lesions in the ventral hippocamp...

Episodic memory requires associations of temporally discontiguous events. In the entorhinal-hippocampal network, temporal associations are driven by a direct pathway from layer III of the medial entorhinal cortex (MECIII) to the hippocampal CA1 region. However, the identification of neural circuits that regulate this association has remained unknown. In layer II of entorhinal cortex (ECII), we ...

The semaphorins are the largest family of repulsive axon guidance molecules. Secreted semaphorins bind neuropilin receptors and repel sensory, sympathetic and motor axons. Here we show that CA1, CA3 and dentate gyrus axons from E15-E17 mouse embryo explants are selectively repelled by entorhinal cortex and neocortex. The secreted semaphorins Sema III and Sema IV and their receptors Neuropilin-1...