Caffeine enhances BOLD responses to electrical whisker pad stimulation in rats during alpha‐chloralose anaesthesia

Angiotensin II receptor blockers (telmisartan) prevent rodents from diet-induced obesity and improve their metabolic status. Hyperglycemia and obesity are associated with reduced cerebral blood flow and neurovascular uncoupling which may lead to behavioral deficits. We wanted to know whether a treatment with telmisartan prevents these changes in obesity. We put young mice on high-fat diet and simultaneously treated them with telmisartan. At the end of treatment, we performed laser speckle imaging and magnetic resonance imaging to assess the effect on neurovascular coupling and cerebral blood flow. Different behavioral tests were used to investigate cognitive function. Mice developed diet-induced obesity and after 16, not 8 weeks of high-fat diet, however, the response to whisker pad stimulation was about 30% lower in obese compared to lean mice. Simultaneous telmisartan treatment increased the response again by 10% compared to obese mice. Moreover, telmisartan treatment normalized high-fat diet-induced reduction of cerebral blood flow and prevented a diet-induced anxiety-like behavior. In addition to that, telmisartan affects cellular senescence and string vessel formation in obesity. We conclude, that telmisartan protects against neurovascular unit impairments in a diet-induced obesity setting and may play a role in preventing obesity related cognitive deficits in Alzheimer’s disease.

Download Full-text

Theta-burst TMS of lateral occipital cortex reduces BOLD responses across category-selective areas in ventral temporal cortex

NeuroImage ◽

10.1016/j.neuroimage.2021.117790 ◽

2021 ◽

Vol 230 ◽

pp. 117790

Author(s):

Iris I A Groen ◽

Edward H Silson ◽

David Pitcher ◽

Chris I Baker

Keyword(s):

Temporal Cortex ◽

Occipital Cortex ◽

Bold Responses ◽

Ventral Temporal Cortex ◽

Theta Burst ◽

Lateral Occipital Cortex

Download Full-text

Association Between Brain Activation and Functional Connectivity

Cerebral Cortex ◽

10.1093/cercor/bhy077 ◽

2018 ◽

Vol 29 (5) ◽

pp. 1984-1996 ◽

Cited By ~ 13

Author(s):

Dardo Tomasi ◽

Nora D Volkow

Keyword(s):

Functional Connectivity ◽

Brain Activity ◽

Low Frequency ◽

Brain Activation ◽

Blood Oxygen Level Dependent ◽

Common Source ◽

Functional Connectivity Density ◽

Density Mapping ◽

Human Connectome Project ◽

Bold Responses

Abstract The origin of the “resting-state” brain activity recorded with functional magnetic resonance imaging (fMRI) is still uncertain. Here we provide evidence for the neurovascular origins of the amplitude of the low-frequency fluctuations (ALFF) and the local functional connectivity density (lFCD) by comparing them with task-induced blood-oxygen level dependent (BOLD) responses, which are considered a proxy for neuronal activation. Using fMRI data for 2 different tasks (Relational and Social) collected by the Human Connectome Project in 426 healthy adults, we show that ALFF and lFCD have linear associations with the BOLD response. This association was significantly attenuated by a novel task signal regression (TSR) procedure, indicating that task performance enhances lFCD and ALFF in activated regions. We also show that lFCD predicts BOLD activation patterns, as was recently shown for other functional connectivity metrics, which corroborates that resting functional connectivity architecture impacts brain activation responses. Thus, our findings indicate a common source for BOLD responses, ALFF and lFCD, which is consistent with the neurovascular origin of local hemodynamic synchrony presumably reflecting coordinated fluctuations in neuronal activity. This study also supports the development of task-evoked functional connectivity density mapping.

Download Full-text

ALPHA-CHLORALOSE IMMOBILIZATION OF ROCK DOVES IN OHIO

Journal of Wildlife Diseases ◽

10.7589/0090-3558-35.2.239 ◽

1999 ◽

Vol 35 (2) ◽

pp. 239-242 ◽

Cited By ~ 4

Author(s):

Jerrold L. Belant ◽

Thomas W. Seamans

Keyword(s):

Alpha Chloralose

Download Full-text