Tag: The Wonders of the Brain

Optical access to auditory cortex for in-vivo two-photon calcium imaging

Presenter(s): Raj Shah—Human Physiology

Faculty Mentor(s): Santiago Jaramillo, Beth McCarry

Session 5: The Wonders of the Brain

In vivo two-photon calcium imaging is a powerful tool that enables measuring activity of hundreds of individual neurons simultaneously . To understand how the brain makes predictions about sounds, we will use this imaging technique to measure how neurons from the auditory cortex of awake mice respond to expected and unexpected sounds . To image activity at the neuronal level, optical access is achieved via implantation of a cranial window . However, the auditory cortex is not easily accessible during surgery due its lateral location and large muscles and arteries around the ears . Here, we report an updated protocol for cranial window implantation over the auditory cortex for use in two-photon calcium imaging . With optical access to the auditory cortex, we are able to use in-vivo two-photon calcium imaging to evaluate sound-evoked responses of hundreds of auditory cortical neurons . These data will allow classifying and mapping the location of neurons that represent either predictions about a stimulus or errors in these predictions .

Effects of Feedback-Related Negativity on Excecutive Function and Development in Preschoolers

Presenter(s): Dakota Paulus—Biology, Biochemistry Minor

Co-Presenter(s): Nisha Sridhar, Katia Pramono

Faculty Mentor(s): Tyson Barker, Leticia Hayes

Session 5: The Wonders of the Brain

Executive function (EF) is a set of higher-order cognitive skills that support early learning and development . EF is highly influenced by environmental factors such as exposure to stress and social interaction . The prefrontal cortex (PFC) is one of the primary neural regions underlying EF . As the PFC develops during early childhood, the brain begins to lay the groundwork for more complex processing . One neural component that supports EF, feedback-related negativity (FRN), is measurable using electroencephalography (EEG), a device that measures the brain’s electrical activity . FRN is observed following both positive and negative feedback and is generated by the PFC . Although FRN is theorized to represent EF, little is known about the FRN development in early childhood: a period of critical EF development .

We predict that children’s FRN will be positively related to a behavioral measure of EF, which was collected during a previous study . Thus, we propose that FRN will reflect an early neural indicator
of EF . Previous research has used tasks without intermittent reinforcement making it difficult to maintain children’s attention . We will be using the Doors Game, which is a novel feedback-based task providing intermittent random reinforcement to children upon their selection between two doors . This task presents the reward immediately alongside feedback, thus it is more age-appropriate due to its ability to sustain their motivation . As feedback processing serves an important role in early childhood development and may serve as a novel indicator of EF, it is a promising area for research .

Determining the role of the pulvinar in visual attentional control

Presenter(s): Emmalyn Leonard—Biochemistry

Faculty Mentor(s): Cristopher Niell, Philip Parker

Session 5: The Wonders of the Brain

Visual attentional control is a behavior that is critical for survival; despite its importance, the specific neural mechanisms underlying the process remain unclear . Upon perception, visual information is routed from the retina through the thalamus, which relays signals to the cortex for further processing . The pulvinar, a nucleus of the thalamus, has strong connections to both visual cortex (V1) and areas involved with attentional control, such as the superior colliculus and prefrontal cortex . The pulvinar has been implicated in attentional control from studies of human patients, as pulvinar lesions are correlated with an inability to ignore distracting visual information during performance of a behavioral task . Studies have also shown that mice are capable of learning similar tasks; given that their visual system is highly analogous to that of humans, mice serve as an optimal model for important behaviors such as visual attentional control . We targeted mouse pulvinar neurons with a GCaMP-expressing virus to allow measurement of brain activity through a cranial window . Utilizing both widefield and two-photon microscopic imaging, we found that axons projecting from the pulvinar to V1 are visually responsive and appear to be organized in a retinotopic manner . Future work on this project will include introduction of a visually guided behavioral task alongside silencing of pulvinar neurons using a DREADDs-expressing virus . We expect to find that, when mouse pulvinar neurons are silenced, important signals for visual attention sent from the thalamus to V1 will be interrupted, resulting in poor performance of a task requiring visual attentional control .

Electrophysiological Patterns of Skilled Motor Movements

Presenter(s): Vanessa Hufnagel—Biology

Faculty Mentor(s): Nicole Swann, Alexander Rockhill

Session 5: The Wonders of the Brain

Proposed future missions to send humans to Mars for long term exploration require the development of improved waste management technology in space and increased reliable energy for running necessary systems . In this study, the potential of methanogenic bacteria from wastewater sludge
to be a source of biomethane in the atmospheric composition of Mars was explored . Bottles of wastewater containing methanogens were prepared anaerobically and sparged with either nitrogen or a martian gas mixture and their biogas production was tracked and compared over time . Research findings proving high survivalbiltiy rates of the bacteria and high metabolic function under these extreme conditions suggest anaerobic digestion of mission waste to be a viable solution for recycling human waste and producing biomethane for the production of energy .

The Relationship Between Cholinergic and Noradrenergic Activity and Behavioral State

Presenter(s): John Francis—Biology

Faculty Mentor(s): Lindsay Collins, David McCormick

Session 5: The Wonders of the Brain

Observable changes in behavior result from complex network activity within the brain . Precise excitation and inhibition of neurons is partially regulated via neuromodulatory systems which regulate the behavior of other neurons, thereby producing observable changes in behavior . I plan to investigate the relationship between activity of two neuromodulatory cell types, cholinergic and noradrenergic neurons, and observable behavior in mice . Acetylcholine (ACh) and noradrenaline (NA) are produced and released by cholinergic and noradrenergic neurons, respectively, and have broad functions throughout the central nervous system . For instance, both ACh and NA neurons are more likely to fire during high arousal state, a physiological measure of alertness and attentiveness which is related to external metrics of brain state, like pupil diameter . My project will investigate the relationship between activity of ACh and NA neurons and arousal-linked behavior in three ways: 1) we will confirm the relationship between ACh and NA activity and arousal previously demonstrated in our lab and expand on this literature by including other behavioral measures such as whisker pad motion and tail motion in our analyses, 2) determine whether changes in ACh and NA activity precede or follow the onset of behavioral events, 3) determine the extent to which ACh or NA provides synchronous signals across the brain during arousal state fluctuations . Using systems neuroscience techniques such as intracranial viral injections, immunohistochemistry, and 2-photon microscopy, this project will further our current understanding of the relationship between ACh and NA activity and observable patterns of behavior in mice .