Environment and experience influence defensive behaviors, but the neural circuits mediating such effects are not well understood. We describe a new experimental model in which either flight or freezing reactions can be elicited from mice by innately aversive ultrasound. Flight and freezing are negatively correlated, suggesting a competition between fear motor systems. An unfamiliar environment ...

Cognitive deficits associated with aging and with neurodegenerative diseases such as Alzheimer's disease have been attributed to degeneration of cholinergic neurons in the basal forebrain. Estrogen is known to provide trophic support to cholinergic neurons, although the mechanisms underlying the actions of estrogen have yet to be determined. Because cholinergic neurons require neurotrophic grow...

Introduction: We previously shown that microinjection of glutamate into the hDB of rat elicited cardiovascular depressive responses. Microinjection of AP5 (an NMDA receptor antagonist, 2.5 mM, 50 nl) and CNQX (an AMPA receptor antagonist, 1 mM, 50 nl) caused no significant changes in the blood pressure and heart rate. Microinjection of bicuculline (BMI: a GABAA receptor antagonist, 1 mM, 50...

Neurons in the rat central nervous system (CNS) were examined for their content of both the acetylcholine-synthesizing enzyme, choline acetyltransferase (ChAT; acetyl-CoA, choline O-acetyl-transferase, EC 2.3.16), and the transmitter-degrading enzyme, acetylcholinesterase (AChE). ChAT was localized immunohistochemically and AChE was localized histochemically in normal, colchicine-treated, or di...

PURPOSE The objective of this study is to compare the physiological capacity and training characteristics of the world's six highest ranked female cross-country skiers (world class (WC)) with those of six competitors of national class (NC). METHODS Immediately before the start of the competition season, all skiers performed three 5-min submaximal stages of roller skiing on a treadmill for mea...

Individual neurons in the medial septum and diagonal band fire in phase with, and appear to act as a 'pacemaker' of, the hippocampal theta rhythm. We investigated the relationships of periodic EEG both among various parts of the septum and with dorsal hippocampal theta recorded concurrently in freely moving rats. Most septal sites showed theta rhythm concurrent with hippocampal theta during loc...

Spontaneous firing and behavior-related changes in discharge profiles of basal forebrain (BF) neurons are well documented, albeit the mechanisms underlying the variety of activity modes and intermodal transitions remain elusive. With the use of cell-attached recordings, this study identifies a range of spiking patterns in diagonal band Broca (DBB) noncholinergic cells of rats and tentatively ca...

The majority of the cortical cholinergic innervation implicated in attention and memory originates in the nucleus basalis of Meynert and in the horizontal limb of the diagonal band nucleus of the basal prosencephalon. Functional alterations in this system give rise to neuropsychiatric disorders as well as to the cognitive alterations described in Parkinson and Alzheimer's diseases. Despite the ...