Dopamine D3 receptor binding of (18)F-fallypride: Evaluation using in vitro and in vivo PET imaging studies.

Identification of dopamine D3 receptors (D3R) in vivo is important to understand several brain functions related to addiction. The goal of this work was to identify D3R binding of the dopamine D2 receptor (D2R)/D3R imaging agent, (18)F-fallypride. Brain slices from male Sprague-Dawley rats (n = 6) and New Zealand White rabbits (n = 6) were incubated with (18)F-fallypride and D3R selective agonist (R)-7-OH-DPAT (98-fold D3R selective).

Neural correlates of voluntary and involuntary risk taking in the human brain: an fMRI Study of the Balloon Analog Risk Task (BART).

Increasing effort has been devoted to understanding the neural mechanisms underlying decision making during risk, yet little is known about the effect of voluntary choice on risk taking. The Balloon Analog Risk Task (BART), in which subjects inflate a virtual balloon that can either grow larger or explode [Lejuez, C.W.

Minimizing acquisition time of arterial spin labeling at 3T.

An improved arterial spin labeling (ASL) perfusion technique that combines pseudo-continuous labeling and a T2*-insensitive sequence (GRASE) with background suppression was used to acquire perfusion maps in normal volunteers and stroke patients. It is shown that perfusion measurements obtained in less than 1 min of scan time are reproducible, with a coefficient of variation of 7%. The perfusion maps generated from these data can be used to characterize the stroke lesion.

Functional magnetic resonance imaging and working memory in adolescents with gestational cocaine exposure.

Objective: To assess the effect of gestational cocaine exposure on the prefrontal cortex (PFC) with functional magnetic resonance imaging (fMRI).

Study Design: Using an n-back task, we obtained fMRI with a 3T Siemens scanner on 49 adolescents, 25 who were exposed to cocaine and 24 who were not exposed. The primary outcome was PFC activation during task performance.

Hippocampus-specific fMRI group activation analysis using the continuous medial representation.

We present a new shape-based approach for regional group activation analysis in fMRI studies. The method restricts anatomical normalization, spatial smoothing and random effects statistical analysis to the space inside and around a structure of interest. Normalization involves finding intersubject correspondences between manually outlined masks, and it leverages the continuous medial representation, which makes it possible to extend surface-based shape correspondences to the space inside and outside of structures.

Hippocampus-specific fMRI group activation analysis with continuous M-Reps.

A new approach to group activation analysis in fMRI studies that test hypotheses focused on specific brain structures is presented and used to analyze hippocampal activation in a visual scene encoding study. The approach leverages the cm-rep method to normalize hippocampal anatomy and project intra-subject hippocampal activation maps into a common reference space, eliminating normalization errors inherent in whole-brain approaches and guaranteeing that peaks detected in the random effects activation map are indeed associated with the hippocampus. When applied to real fMRI data, the method detects more significant hippocampal activation than the established whole-brain method.