Regulation of dopamine release and synthesis is thought to occur via pre-synaptic dopamine(DA) D2 autoreceptors. Selective mapping of autoreceptors in vivo is difficult, as their function is best assessed using dynamic measures of DA release such as microdialysis. We show here that pharmacologic MRI (phMRI) may also prove useful for this purpose. First, we mapped the phMRI response to acute agonism and antagonism of D2 receptors using either quinpirole or eticlopride. These ligands lead to small change in relative cerebral blood volume (rCBV)(<10%) in stiratum (Str), nucleus accumbens (NAcc), and cingulate cortex. We then studied the response to an amphetamine (AMPH) challenge using pre- and post-treatment with eticlopride and quinpirole. Agonism of D2 receptors using quinpirole lead to a large decrease in rCBV changes induced by AMPH in Str and NAcc, but had little effect in frontal cortex (FCtx). Conversely, antagonism of D2 receptors with eticlopride lead to a large potentiation of rCBV changes induced ...

The development of neural substrates for face recognition has been understudied in humans, but with the advent of functional magnetic resonance imaging (fMRI), more studies on this topic are now emerging. However, to our knowledge no studies have examin...

In a study on 20 healthy right-handed volunteers, we used functional magnetic resonance imaging (fMRI) to separate regions involved at various processing levels in the production of speech. SPARSE acquisition of data was used to avoid difficulties assoc...

Functional magnetic resonance imaging (fMRI) was used to explore the neural correlates of semantic judgments to visual Chinese characters in a group of 8-12 year old Chinese children. Forty-eight character pairs were semantically related according to th...

Previous functional magnetic resonance imaging (fMRI) studies did not find differences between visually guided saccade trials and nogo trials, which required subjects to look at a flashed visual stimulus or to inhibit the automatic saccade evoked by a p...

For both theoretical and clinical purposes, it is important to understand the validity of functional magnetic resonance imaging (fMRI) measurements as an indicator of the functional status of underlying brain tissue. One way to test this validity, on a ...

Zebra finch males learn their songs from an adult tutor early in life. Tutor song-induced neuronal activation in the caudomedial nidopallium (NCM) in male zebra finches is related to the strength of song learning. Neurons in the NCM are also responsive to the playback of bird’s own song (BOS) as well as conspecific song. To determine which acoustic features are relevant for song responsiveness in the NCM, we used blood oxygenation level dependent (BOLD) fMRI to investigate the neuronal activation induced by sound presentation. Previous work from our group (Neuroimage, 25, 1242-55) demonstrated that BOLD fMRI is able to reveal brain activity in the NCM upon hearing conspecific song or music. In the present study we measured the BOLD response in Field L and in the NCM in 5 anaesthetized male zebra finches during presentation of BOS, song composed of randomly ordered syllables of the bird’s repertoire, reversed BOS, synthetic sounds with power and spectro-temporal modulation spectra matched to BOS (song rippl...

The cognitive abilities of the Corvidae family of birds are comparable to those of higher mammals. Higher brain functions such as tool-use, logical deduction, long-term facial memory and the use of working memory which these birds exhibit are almost at ...

There is now substantial evidence that mild traumatic brain injury (mTBI) increases the risk of developing post-traumatic stress disorder (PTSD). Although the mechanisms by which risk of PTSD may be increased following mTBI remain unclear, it has been h...

Cerebral microvascular dysfunction significantly contributes to early cognitive impairment and dementia. Here we analyzed blood-brain barrier (BBB) permeability and cerebral blood flow (CBF) in relation to early cognitive decline in APOE3-homozygotes (ε...