INVESTIGATING THE HUMAN FACE PROCESSING NETWORK: INSIGHTS FROM ACQUIRED PROSOPAGNOSIA AND HYPERFAMILIARITY FOR FACES

Human faces provide essential social cues that we interpret rapidly, allowing us to recognize identities, interpret emotions, and gauge familiarity. This thesis explores face processing disruptions in four case studies, each offering new insights into the brain’s face recognition mechanisms. Chapter one presents Annie, a 28-year-old woman who acquired prosopagnosia (face blindness) following COVID-19. After recovering from the severe symptoms of the infection, Annie experienced significant difficulty in recognizing familiar faces and navigating familiar environments. Testing confirmed her impairment in face recognition but showed her preserved cognitive and basic visual processing abilities. Annie was still able to recognize objects and scenes, pointing to a selective impact on face processing. A survey of individuals with long COVID revealed deficits with visual processing, highlighting a need for further exploration of long COVID’s cognitive and perceptual effects. Chapter two thoroughly explores face processing abilities in two participants, Alma-Jean and Rose, who acquired prosopagnosia due to extensive damage to their right temporal lobes. Both participants exhibited severe impairments in face identity recognition while retaining the ability to recognize facial expressions, suggesting a dissociation between identity and expression processing. Alma-Jean also displayed intact facial sex recognition. Our findings provide evidence for separate processing pathways for facial identity and expression, as well as facial identity and sex. Chapter three describes Nell who developed hyperfamiliarity for faces after a severe migraine. Nell experiences false feelings of familiarity with unfamiliar faces, names, and some object categories while retaining accuracy in recognizing actually familiar faces, names, and objects. Her prolonged response times on face tests suggest disruptions in familiarity mechanisms that interfere with processing efficiency. Together, these cases reveal how distinct disruptions in face processing can stem from varied etiologies and increase our understanding of mechanisms underlying the complex neural systems that support social cognition and recognition

WATERMAN FUND ESSAY WINNER: Old Friends in the Alpine: Field Scientists on Vermont\u27s Highest Peak

In this winning essay of the annual contest sponsored by the Waterman Fund, a young scientist meets Bill Howland, who studied the same vegetation in 1991, at their study site high on Vermont’s Mount Mansfield

Skyline Sketches: Survival of the Timid

A mother and daughter retreat in bad weather, showing that timidity saves lives

Skyline Sketches: A Journey through the Boundary Waters

A man who has never canoed paddles through Minnesota’s Boundary Waters

Ecology of Ixodes scapularis Say: Experimental and Observational Studies with Social Perspectives on Ticks and Tick-Borne Diseases

Tick-borne diseases are a growing concern globally. Understanding the factors that influence tick ecology and people’s understanding of that ecology is crucial for developing effective tick management and disease prevention strategies. In this work, I investigated fundamental questions about the ecology of a primary vector of medically important pathogens in the United States, the blacklegged tick Ixodes scapularis Say, and identified common misconceptions about ticks and tick-borne diseases on social media. First, I examined the effects of temperature and moisture stress on the movement of adult female I. scapularis in laboratory experiments. Using a Drosophila Activity Monitor, ticks were exposed to controlled temperatures from 10°C to 25°C and relative humidities of 75%, 84%, and 100%. The probability of tick movement responded independently and non-linearly to both temperature and vapor pressure deficit (VPD), with implications for tick activity under natural conditions. Using field observations collected over five years, I then explored how local environmental conditions influence tick host-seeking activity in Hanover, New Hampshire. I. scapularis activity was best predicted by the sampling date, habitat type (forested, edge, or meadow), and morning minimum VPD. Specifically, more host-seeking adult ticks were collected during early spring and fall, in forest and edge habitats, and when morning conditions were wetter. This fine-scale analysis highlights the importance of season- and habitat-specific strategies for reducing disease risk. Lastly, I explored public perceptions and misinformation about ticks on Facebook, recognizing that public education is a vital component of disease prevention. Misinformation was relatively rare – just 17% of 170 public posts and 2483 comments from summer 2021 contained misinformation – and predominantly related to issues with tick biology and ecology. This study underscores the need for targeted public health campaigns to dispel common misconceptions and inform the public accurately about tick prevention and control. Taken together, this work bridges ecological research and its application to public health. By integrating our understanding of the natural world and how it may change as the anthropogenic footprint increases, my work informs more effective tick management practices and public health education efforts, thereby contributing to the reduction of the burden associated with tick-borne diseases