The Morris water maze task was originally designed to assess the rat's ability learn navigate a specific location in relatively large spatial environment. This article describes new measures that provide information about distribution of search during both training and probe trial performance. basic measure optimizes use computer tracking identify position with respect target location. proximity found be highly sensitive age-related impairment an assessment young aged male Long-Evans rats....

We have divided the cortical regions surrounding rat hippocampus into three cytoarchitectonically discrete regions, perirhinal, postrhinal, and entorhinal cortices. These appear to be homologous monkey parahippocampal, cortices, respectively. The origin of afferents these is well-documented in but less known about them rat. present study investigated origins input perirhinal (areas 35 36) postrhinal cortices lateral medial subdivisions cortex (LEA MEA) by placing injections retrograde...

The cortical regions dorsally adjacent to the posterior rhinal sulcus in rat can be divided into a rostral region, perirhinal cortex, which shares features of monkey and caudal postrhinal has connectional attributes similar parahippocampal cortex. We examined connectivity among (areas 35 36), postrhinal, entorhinal cortices by placing anterograde retrograde tracers all three regions. There is dorsal-to-ventral cascade connections cortices. Dorsal area 36 projects strongly ventral 36, 35....

The role of the postrhinal cortex (POR) and perirhinal (PER) in processing relational or contextual information was examined with Pavlovian fear conditioning. Rats electrolytic neurotoxic lesions POR PER were tested 2 conditioning paradigms. In Experiment 1, produced impairments but not to a phasic auditory conditioned stimulus. Neurotoxic likewise resulted anterograde (Experiment 2) retrograde 3) deficits training context an unsignaled shock paradigm. results suggest that operations...

Abstract Cytoarchitectonic and histochemical analyses were carried out for perirhinal areas 35 36 the postrhinal cortex, providing first detailed cytoarchitectonic study of these regions in rat brain. The rostral border with insular cortex is at extreme caudal limit claustrum, consistent classical definitions dating back to Rose ([ 1928 ] J. Psychol. Neurol. 37:467–624). between cortices angular bundle, as previously proposed by Burwell et al. 1995 Hippocampus 5:390–408). ventral borders...

Spatial and contextual learning are considered to be dependent on the hippocampus, but extent which other structures in medial temporal lobe memory system support these functions is not well understood. This study examined effects of individual combined lesions perirhinal, postrhinal, entorhinal cortices spatial learning. Lesioned subjects were consistently impaired measures fear unimpaired Morris water maze. Neurotoxic perirhinal or postrhinal cortex that previously shown impair...

Abstract We investigated the cortical efferents of parahippocampal region by placing injections anterograde tracers, Phaseolus vulgaris ‐leuccoagglutinin, and biotinylated dextran amine, throughout perirhinal (PER), postrhinal (POR), entorhinal cortices rat brain. The resulting density labeled fibers was evaluated in 25 subregions piriform, frontal, insular, temporal, cingulate, parietal, occipital areas. locations terminal differed substantially depending on whether location injection site...

Studying brain function and its local circuit dynamics requires neural interfaces that can record stimulate the with high spatiotemporal resolution. Optogenetics, a technique genetically targets specific neurons to express light-sensitive channel proteins, provides capability control central nervous system neuronal activity in mammals millisecond time precision. This enables precise optical stimulation of simultaneous monitoring response by electrophysiological means, both vicinity distant...

The posterior parietal cortex (PPC) is an associative neocortical region that integrates multiple streams of information and implicated in spatial cognition decision making. In some cases, however, the PPC not required for these functions. One possibility recruited when complexity high. Yet, few studies function have explicitly manipulated environmental complexity, changes, or temporal structure tasks. To examine whether task recruits function, we tested rats with neurotoxic damage to dorsal...

The perirhinal (PER) and postrhinal (POR) cortices, two components of the medial temporal lobe memory system, are reciprocally connected with hippocampus both directly via entorhinal cortex. Damage to PER or POR before shortly after training on a contextual fear conditioning task causes deficits in subsequent expression fear, implicating these regions acquisition memory. Here, we examined contribution processing remotely learned information. Male Long-Evans rats were trained an unsignaled...

This is the second of two studies detailing subcortical connections perirhinal (PER), postrhinal (POR) and entorhinal (EC) cortices rat. In present study, we analyzed efferents rat PER areas 35 36, POR, lateral medial (LEA MEA). Anterograde tracers were injected into these five regions, resulting density fiber labeling was quantified in an extensive set structures. Density topography quantitatively assessed 36 areas, including olfactory structures, claustrum, amygdala nuclei, septal basal...

In this study the subcortical afferents for rat PER areas 35 and 36, POR, lateral medial entorhinal (LEA MEA) were characterized. We analyzed 33 retrograde tract-tracing experiments distributed across five regions. For each experiment, we estimated total numbers, percentages, densities of labeled cells in 36 structures nuclei septum, basal ganglia, claustrum, amygdala, olfactory structures, thalamus, hypothalamus. found that complement inputs differs regions, especially POR. The receives...

The entorhinal, perirhinal and parahippocampal cortices are anatomically positioned to mediate the bi-directional flow of information between hippocampus neocortex. Consistent with this organization, damage involving region causes significant learning memory impairment in young subjects. Although recent evidence indicates that neuron death is not required account for effects normal aging on memory, other findings suggest changes interactions may play a role. Prompted by background, we tested...