Introduction: The nucleus accumbens is involved in various functions ranging from motivation and reward to feeding and drug addiction. Some researchers have also suggested that this region has some roles in consciousness. In the present study, the effect of electrical stimulation and lesion of nucleus accumbens on Electroencephalogram waves (EEG) of addict and non-addict rats was investigated. ...

Intrinsic rhythmic electrical activity in the brain, such as the hippocampal theta rhythm, might serve important roles in normal cognition. Lesions to the medial septal nuclei, or to the fimbria/fornix, disrupt the hippocampal theta rhythm and lead to memory impairment. We have superimposed an artificial stimulating rhythm to the hippocampus of rats with prior lesion of the fornix, during testi...

Neural networks underlying visual perception exhibit oscillations at different frequencies (e.g.,). But how these map onto distinct aspects of visual perception remains elusive. Recent electroencephalography data indicate that theta or beta frequencies at parietal sensors increase in amplitude when conscious perception is dominated by global or local features, respectively, of a reversible visu...

A previous paper [2] presented a model (UCPF-HC) of the hippocampus as a unitary coherent particle filter, which combines the classical hippocampal roles of associative memory and spatial navigation, using a Bayesian filter framework. The present paper extends this model to include online learning of connections to and from the CA3 region. Learning in the extended neural network is equivalent t...

OBJECTIVE Scopolamine, a muscarinic receptor antagonist, can produce temporary cognitive impairments as well as electroencephalographic changes that partially resemble those observed in Alzheimer's disease. In order to test the sensitivity of spectral power and hemispheric coherence to changes in cholinergic transmission, we evaluated quantitative magnetoencephalogram (MEG) after intravenous in...

OBJECTIVE Chronic renal failure frequently causes uremic encephalopathy with impairment of various cognitive functions, but the pathophysiology of uremic syndrome is complex and poorly understood. In this study, we wished to establish a reliable tool and monitor system to evaluate the central nervous system dysfunction of patients with uremic encephalopathy. METHODS A group of 31 patients wit...

The spike timing of spatially tuned cells throughout the rodent hippocampal formation displays a strikingly robust and precise organization. In individual place cells, spikes precess relative to the theta local field potential (6-10 Hz) as an animal traverses a place field. At the population level, theta cycles shape repeated, compressed place cell sequences that correspond to coherent paths. T...

The hippocampal theta rhythm is a prominent oscillation in the field potential observed throughout the hippocampus as a rat investigates stimuli in the environment. A recent computational model [Hasselmo, M. E., Bodelon, C., & Wyble, B. P. (2002a). A proposed function for hippocampal theta rhythm: separate phases of encoding and retrieval enhance reversal of prior learning. Neural Computation, ...

It is a prominent idea that cognitive control mediates conflict adaptation, in that response conflict in a previous trial triggers control adjustments that reduce conflict in a current trial. In the present EEG study, we investigated the dynamics of cognitive control in a response-priming task by examining the effects of previous trial conflict on intertrial and current trial oscillatory brain ...