Estrogen has been reported to enhance cocaine sensitization in the female rat, suggesting that brain circuits mediating the rewarding and addictive properties of cocaine are affected by the gonadal steroid. The present study used functional magnetic resonance imaging (fMRI) to investigate the effect of repeated cocaine administration on blood-oxygen-level-dependent (BOLD) signal changes in fully conscious female rats without and with estrogen. Rats were ovariectomized and given subcutaneous Silastic implants without (OVX) or with estradiol benzoate (OVX+EB). Upon recovery, rats were given an i.p. cocaine injection (1 mg/kg) on 7 consecutive days. Functional MRI was performed during injections on days 1 and 7. MR Images were acquired using a 4.7T/40-cm (Oxford magnet Technology, Oxford, UK) horizontal magnet interfaced to a Paravision console (Bruker Medical Instruments, MA, USA). Anatomical data sets were acquired using a fast spin echo (RARE) sequence, (TR=2.5s; TE=56ms; field of view= 3.5x3.5cm; data mat...

Competing cognitive theories of categorical representation are feature-based theory (FT) and structured-representation theory (ST). FT suggests that superordinate categories are represented by a subset of features of basic level categories. In contrast, ST suggests that superordinate representations contain variables not represented in basic level categories. In the present study, we used functional MRI to study neural substrates underlying categorization at basic and superordinate levels. Participants viewed easily-nameable objects and judged whether these objects (e.g. poodle) fit into either basic (e.g. dog) or superordinate (e.g. animal) categories. FT predicts that superordinate categorization should activate a subset of areas activated by basic level categorization, or the same areas at a lower level. ST predicts superordinate categorization should active areas outside those activated by basic level categorization. Preliminary data and analyses are consistent with ST: contrasting different levels of ...

One of the most striking endeavors in neuroscience is the accomplishment of a comprehensive functional representation of the human brain in which models concerning its organization could be derived from neuroimaging data. Many studies have extensively a...

Introduction: Primary progressive aphasia (PPA) is a class of neurological disorders characterized by progressive speech and language deficits, and are associated with different pathologies. As treatment trials are developed, finding reliable methods of...

The rabbit is an ideal animal for fMRI imaging research. It is uniquely tolerant of restraint for prolonged time periods without the need for any anaesthetic to immobilize the animal. The visual pathways and central mechanisms of both pattern and movement vision are well explored. In addition the associative conditioning of the rabbit nictitating membrane has long been a major animal model for studying neural mechanisms of associative learning. The purpose of the present study is to determine the concordance between MRI assessment of the extent of experimentally induced brain lesions with postmortem histological reconstruction of the lesions. Using sterile procedure discrete sections of the corpus callosum were made in the rabbit brain. Assessment of tissue damage was undertaken both after 1 hour and 72 hours following surgery. Magnetic field images (6 Tesla) of lesion damage are described and compared with detailed histological reconstruction for both fiber and cellular damage.

Stress-Induced SP1 and p75NTR Transcription Alberto Ramos, Wai Chi Ho, Stephanie Forte, Kathleen Dickson, Jacqueline Boutilier, Kristy Favell, and Philip A. Barker (see pages [1498–1506][1]) The p75 neurotrophin receptor (p75NTR), normally expressed at low levels in adult tissue, springs to

Computations performed by a given cortical region are a product of its underlying cytoarchitecture and likely sculpted through development. Yet, how does cortical tissue change as brain function and behavior improve from childhood to adulthood? Human hi...

Introduction: White matter hyperintensities (WMH) are frequent in aging individuals and are known to affect cognition, balance, and gait. However, the affects of WMHs on upper-limb performance are unknown. Methods: The KINARM robot was used for 4 upper-...

Intravenous immunoglobulins (IVIg), natural antibodies collected from the plasma of thousands of healthy blood donors, are currently being tested for efficacy in the treatment of Alzheimer’s disease (AD). Its ability to target different pathological mar...

Human brain structure undergoes robust changes over development. Longitudinal structural magnetic resonance (MR) imaging studies are essential to map developmental trajectories of brain structures and understand how brain maturation supports cognitive d...