Brain oscillations in the theta frequency band (3-8 Hz) have been shown to be critically involved in human episodic memory retrieval. In prior work, both positive and negative relationships between cortical theta power and retrieval success have been reported. This study examined the hypothesis that slow and fast cortical theta oscillations at the edges of the traditional theta frequency band a...

Theta waves in the amygdala are known to be synchronized with theta waves in the hippocampus. Synchronization between amygdala and hippocampal theta waves is considered important for neuronal communication between these regions during the memory-retrieval process. These theta waves are also observed during rapid eye movement (REM) sleep. However, few studies have examined the mechanisms and fun...

Experiments were carried out in urethane-anesthetized rats in order to evaluate the hypothesis that the red nucleus has functional connections with the hippocampal formation. Depth profiles of electrical stimulation in Experiment 1 confirmed that stimulation administered to the red nucleus elicited theta field activity in the hippocampal formation with a linear relationship between stimulus int...

Experiments were carried out in urethane-anesthetized rats to evaluate the hypothesis that the red nucleus has functional connections with the hippocampal formation. Depth profiles of electrical stimulation in experiment 1 confirmed that stimulation administered to the red nucleus elicited theta field activity in the hippocampal formation with a linear relationship between stimulus intensity an...

In this article we give a Galois-theoretic characterization of the canonical theta structure. The Galois property of the canonical theta structure translates into certain p-adic theta relations which are satisfied by the canonical theta null point of the canonical lift. As an application we give a purely algebraic proof of some 2-adic theta identities which describe the set of theta null points...

In this paper, Kolmogorov-Sinai entropy is studied using mathematical modeling of an observer $ Theta $. The relative entropy of a sub-$ sigma_Theta $-algebra having finite atoms is defined and then   the ergodic properties of relative  semi-dynamical systems are investigated.  Also,  a relative version of Kolmogorov-Sinai theorem  is given. Finally, it is proved  that the relative entropy of a...

Hippocampal theta oscillations support encoding of an animal's position during spatial navigation, yet longstanding questions about their impact on locomotion remain unanswered. Combining optogenetic control of hippocampal theta oscillations with electrophysiological recordings in mice, we show that hippocampal theta oscillations regulate locomotion. In particular, we demonstrate that their reg...

The snail Helix nemoralis in negatively geotropic creeping orients upward upon an inclined surface until the angle of the path of progression (theta) is related to the tilt of the surface (alpha) as (Delta sin theta) (Delta sin alpha) = - const.; theta is very nearly a rectilinear function of log sin alpha. The precision of orientation (P.E.(theta)) declines in proportion to increasing sin alph...

Medial septum (MS) plays a critical role in controlling the electrical activity of the hippocampus (HIPP). In particular, theta-rhythmic burst firing of MS neurons is thought to drive lasting HIPP theta oscillations in rats during waking motor activity and REM sleep. Less is known about MS-HIPP interactions in nontheta states such as non-REM sleep, in which HIPP theta oscillations are absent bu...