The American crow (Corvus brachyrhynchos) is believed to practice facial discrimination and incorporate past experiences in its reaction to individuals. To test this neural integration of perception and memory, a pilot study performed by Dr. Marzluff and his colleagues used PET imaging methods in conjunction with an avian MRI to create a global map of the bird’s brain after performing a visual, analytical task. The initial results suggest that individual crows incorporate memory and activate distinct brain regions while evaluating different stimuli, specifically familiar human faces previously associated with either capture (dangerous mask) or feeding (caring mask). Regions of high activity were correlated with high 18F-FDG intake, a radioactively labeled glucose injected into the bird prior to a conducting the scan. These experiments are now being expanded to determine if there are different pathways for fear responses between threats such as humans and natural predators. I have exposed crows to a natural danger stimulus, a taxidermy mount of a common predator, the Red-tailed Hawk. My hypothesis is that the hawk treatment should prompt more of an innate reaction instead of the processing of contextual information; therefore more activity should be centered in the midbrain instead of the striatum and nidopallium. The second objective of this study was to find a difference in brain activity between memory storage and memory retrieval. To accomplish this, I have exposed crows to a novel person and a novel person holding a taxidermy mounted “dead” crow. The brains maps of differential activity from these treatments should highlight the fear learning pathway. My data can help distinguish the facial neural processing from that of a broader perception of danger and promote translational research by allowing parallel analyses of physiological and operative processes of the human and animal brain.

The purpose of this study is to investigate whether cortisol levels and heart rate correlate with different types of music. Previous studies have shown that music can raise or lower the “stress” hormone, cortisol. This project examines how (1) the tempo of music and (2) the lyrics in music might modify cortisol levels. The first study focuses on the tempo of music by using music without words. I hypothesize that faster tempos will raise cortisol levels while slower music will lower them. The second study focuses on the lyrics of music examining whether cortisol levels will vary depending on the message and meaning of the lyrics. To test these hypotheses, 60-70 participants will be split into two groups. The first group will include 30 individuals listening to slow for 20 minutes and then after an hour break listening to fast music. The second group will include 30 individuals listening to music with happy lyrics a and then after an hour break listening to music with angry lyrics. Participants will collect saliva specimens before, during, and after listening to music. . There are many studies and theories as to why music is so important for humans yet the biological connection to music is not simple or well understood. This study examining how cortisol and heart rate react to music can not only help identify biologically, physiologically based stress reduction protocols but may provide insight into why music is so important for humans.

Zoos generate both interest in and money to support conservation efforts. Acting as educational resources and providing visual access to species from around the world, it is important that zoos monitor the behavior of their animals to assess welfare and ensure well-being. There is evidence to suggest that various forms of enrichment can affect the activity patterns of animals in zoos. Enrichment devices, such as specialized hanging feeders, have been found to promote species-typical naturalistic behaviors, such as higher instances of foraging and less inactivity. Studies were conducted to assess the behavioral patterns and exhibit use of different species at the Woodland Park Zoo: the elephants; the Sumatran tigers; the sun, sloth, and grizzly bears; the Humboldt penguins; and the hippopotamuses. Over the course of three years, with over sixty trained research assistants, thousands of data points were collected through scan-sampling techniques on P.D.A.'s. Through statistical analysis, the division of time animals spend on different activities and different regions of their exhibits can be combed for any unnatural patterns or irregularities. Once patterns in the data are established, enrichment opportunities can be discussed in order to ensure that the zoo offers the most beneficial treatment of the animals as possible. In the case of the Humboldt penguins, the data led to a weekly live feeding, during which live trout were released into the penguin enclosure in hopes of encouraging more activity in the water. 

Over 800,000 Americans suffer a stroke each year, making this neurological disease the leading cause of long-term adult disability in the United States. Treatments for stroke are limited, and effective interventions given post-stroke are sorely needed. An ischemic stroke occurs when blood flow to the brain is interrupted, resulting in inadequate oxygen delivery to brain cells. The immune response may contribute to ischemic brain injury as the blood brain barrier becomes compromised and allows for interactions between once-segregated central nervous system antigens and lymphocytes from the body. This interaction can activate lymphocytes and the development of autoimmune responses to brain antigens. These responses are regulatory responses which may be neuroprotective. We have found, however, that a systemic inflammatory stimulus at the time of stroke predisposes the development of detrimental TH1 type immune response. We previously demonstrated that a TH1 response to the antigen myelin basic protein (MBP) is associated with worse clinical outcome. My project involves investigating the cellular immune mechanism by which MBP-specific cells with a TH1 phenotype are capable of worsening cerebral injury when adoptively transferred into naïve animals at stroke onset. In our model, we induced a stroke in ‘donor’ Lewis rats using middle cerebral arterial occlusion and injected lipopolysaccharide to induce the TH1 immune response. Lymphocytes from ‘donor’ spleens were then fluorescently labeled and transferred to ‘recipient’ rats. Using immunocytochemistry, we have tracked the migration of these ‘donor” cells in the brains of ‘recipient’ animals. Prior to adoptive transfer the immune response to MBP was quantified using ELISPOT assay. These data will help us understand if the development of a TH1 response to MBP is merely a marker for worse clinical outcome or mediates this worse outcome.

In primates, ventral striatum contains many reinforcement sites. These sites, when stimulated with electrical current, mimic behavioral reinforcement. Monkeys trained to perform behavioral tasks will often work solely for stimulation at these sites without food reward. Using these sites, we can further understand the plasticity of the brain by altering neural activity through conditioned changes in connectivity. We implanted moveable stimulating electrodes near the nucleus accumbens. Reinforcement sites are identified by whether stimulation elicits reinforcement behavior. This is done by the use of alternating reinforced and non-reinforced trials (R/NR) while the monkey performs a simple manual force step-tracking program by controlling a cursor’s movement on a computer screen with forces generated with their wrist. Their objective is to move the cursor into different boxes representing different wrist forces. During each R period, the monkey receives electrical stimulation at the potential reinforcement site for every completed trial. During NR periods, however, the monkey has the opportunity to work but no stimulation is given for completed trials. If the number of completed trials is significantly higher during R periods than NR periods, a reinforcement site has been found. We next condition single neuron firing rates using this reinforcing stimulation. Chronically implanted micro-wires record discriminated neuron activity from primary motor cortex. We determine the cell’s baseline firing rate and trigger stimulation of the reinforcement site on action potentials that exceed this rate-threshold. Our objective is to train the monkey to increase the cell’s activity for reinforcing stimulation in set time periods. This experiment enables us to condition volitional control of brain activity to manipulate neural prosthetics and restore motor function in paralyzed patients. Since this conditioning can also be done with an autonomous brain-computer interface, this paradigm can be extended to freely behaving monkeys and has the potential to be applied to humans.

Thanks to advances in safety equipment and emergency care, most spinal cord injuries that occur in people today are incomplete, leaving a portion of the spinal cord neural tissue intact. Further, recent research has shown that there is plasticity and axonal sprouting following injury, expanding the possibilities for rehabilitation from what was once considered a permanent and unrecoverable injury. Our goal is to enhance this process and work towards functional recovery. Dopamine, a powerful neurotransmitter involved in processes such as learning, memory and motivation, plays an integral role in brain plasticity. We are currently testing whether pairing dopamine release with functional movements can increase plasticity of the remaining active pathways and lead to increased functional recovery following an injury in the same way that it can form powerful associations between behaviors and reward sensations. Recently concluded tests followed the recoveries of two rats which received dopamine-releasing electrical brain stimulation paired with functional movements of an impaired limb following identical unilateral cervical spinal cord injuries. These rats activated the stimulation by using their impaired forelimb to push a lever which activated their medial forebrain bundle, a key pathway in the mesocorticolimbic dopamine system. One of these animals showed a significant recovery, nearly to full pre-injury movement capability, and much greater than control animals that received no dopamine stimulation (results in the second animal were inconclusive). Ongoing experiments will compare animals receiving dopamine-releasing stimulation paired with movement of the injured limb to control animals where phasic dopamine release is uncorrelated with movement. These experiments may lead directly to novel methods for promoting nervous system recovery from injury by using dopaminergic pathways to promote and reinforce neural plasticity. This may lead to therapies which allow people with incomplete spinal cord injuries to improve functional motor skills.