Optical brain imaging

One of the most impactful uses of in vivo optical imaging is functional brain mapping, where researchers visualize how different regions of the brain respond to various stimuli or tasks. By using techniques like calcium imaging, intrinsic optical signal (IOS) imaging, or voltage-sensitive dye imaging (VSDI), scientists can monitor brain activity with high spatial and temporal resolution.

• Sensory processing: Researchers often use optical imaging to explore how the brain processes sensory inputs to delineate how information is encoded in neural circuits.
• Motor and cognitive function: Functional mapping can also reveal the areas involved in motor control and higher cognitive processes.
• Neuronal network activity: Optical techniques enable researchers to monitor not just individual neurons but entire networks, allowing for the investigation of how different regions of the brain interact and coordinate responses.

In vivo optical imaging is a powerful tool for studying how the brain develops over time, from early neuronal migration and synapse formation to the refinement of brain circuits during maturation. It allows for longitudinal studies, where the same animal can be imaged multiple times throughout its development, providing insights into dynamic changes.

• Synaptogenesis and circuit formation: During early development, neurons establish and refine their connections with one another.
• Axonal and dendritic growth: Imaging techniques can track the growth of neuronal processes, like axons and dendrites, to study how they extend to form proper connections.
• Critical periods of development: Optical imaging helps to understand how activity during brain functions, such as vision or language acquisition, shapes long-term neural connectivity and behavior.

Optical imaging has become a cornerstone for studying neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD), as well as amyotrophic lateral sclerosis (ALS).

• Alzheimer’s Disease: In vivo two-photon imaging can be used to monitor the formation of amyloid-beta plaques, one of the pathological hallmarks of Alzheimer’s, in real-time.
• Parkinson’s Disease: In rodent models of PD, optical imaging can assess how dopaminergic circuits are impaired as the disease progresses.
• Huntington’s Disease: Optical imaging allows for observing the spread of these aggregates and how they correlate with changes in neural activity and motor impairments.

Neural plasticity refers to the brain's ability to reorganize and adapt in response to experiences, learning, or injury. In vivo optical imaging is uniquely suited to study this phenomenon, as it can track changes in neural circuits over time.

• Learning and memory: Optical imaging has been widely used to study how neurons encode and store new information during tasks such as spatial navigation or operant conditioning.
• Injury and recovery: In vivo imaging can monitor recover after brain injury by visualizing how surviving neurons sprout new dendrites or axons and form new synapses.
• Experience-dependent plasticity: Optical imaging allows researchers to directly observe how experience-driven plasticity reshapes the structure and function of neural circuits.