Biology subjects

Laakso, H.

Publications and source records attributed to Laakso, H..

3 recordsLinked to original sources

bioRxiv2025

Simultaneous zero echo time fMRI of rat brain and spinal cord

PurposeFunctional assessments of the central nervous system (CNS) are essential for many areas of research. Functional MRI (fMRI) typically targets either the brain or the spinal cord, but usually not both, due to the obstacles associated with simultaneous image acquisitions from distant fields of view (FOVs) with conventional MRI. In this work, we establish a novel MRI approach that enables artefact-free, quiet, simultaneous fMRI of both brain and spinal cord, avoiding the need for dynamic shimming procedures. MethodsWe utilized zero echo time (TE) Multi-Band-SWeep Imaging with Fourier Transformation (MB-SWIFT) technique at 9.4T in a simultaneous dual-FOV configuration and two separate radio frequency (RF) transmit-receive surface coils. The first coil covered the rat brain, while the second was positioned approximately at the T13-L1 level of the rat"s spinal cord with copper shielding to minimize the coupling between the RF coils. Eight Sprague-Dawley rats were used for hindlimb stimulation fMRI studies. ResultsRobust and specific activations were detected in both the brain and spinal cord during hind paw stimulation at individual and group levels. The results established the feasibility of the novel approach for simultaneous functional assessment of the lumbar spinal cord and brain in rats. ConclusionThis study demonstrated the feasibility of a novel dual-FOV fMRI approach based on zero-TE MB-SWIFT and set the stage for translation to humans. The methodology enables comprehensive functional CNS evaluations of great value in different conditions such as pain, spinal cord injury, neurodegenerative diseases, and aging.

neuroscience↗

bioRxiv2024

Steroid receptor-assisted loading modulates transcriptional responses in prostate cancer cells

Steroid receptors are involved in a wide array of crosstalk mechanisms that regulate diverse biological processes, with significant implications in diseases, particularly in cancers. In prostate cancer, indirect crosstalk between androgen receptor (AR) and glucocorticoid receptor (GR) is well-documented, wherein AR suppression by antiandrogen therapy leads to elevated GR levels, enabling GR to compensate for and replace AR signaling. However, the existence and impact of direct chromatin crosstalk between AR and GR in prostate cancer have remained elusive. Our genome-wide investigations reveal that AR activation significantly expands GR chromatin binding. Mechanistically, AR induces remodeling of closed chromatin sites, facilitating GR binding to inaccessible sites. Importantly, coactivation of AR and GR results in distinct transcriptional responses at both the cell population and single-cell levels. Intriguingly, pathways affected by these transcriptional changes are generally associated with improved patient survival. Thus, the direct crosstalk between AR and GR yields markedly different outcomes from the known role of GR in circumventing AR blockade by antiandrogens.

genomics↗

bioRxiv2021

Whole-brain studies of spontaneous behavior in head-fixed rats enabled by zero echo time MB-SWIFT fMRI

Understanding the link between the brain activity and behavior is a key challenge in modern neuroscience. Behavioral neuroscience, however, lacks tools to record whole-brain activity in complex behavioral settings. Here we demonstrate that a novel Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) functional magnetic resonance imaging (fMRI) approach enables whole-brain studies in spontaneously behaving head-fixed rats. First, we show anatomically relevant functional parcellation. Second, we show sensory, motor, exploration, and stress-related brain activity in relevant networks during corresponding spontaneous behavior. Third, we show odor-induced activation of olfactory system with high correlation between the fMRI and behavioral responses. We conclude that the applied methodology enables novel behavioral study designs in rodents focusing on tasks, cognition, emotions, physical exercise, and social interaction. Importantly, novel zero echo time and large bandwidth approaches, such as MB-SWIFT, can be applied for human behavioral studies, allowing more freedom as body movement is dramatically less restricting factor.

neuroscience↗