Farm practices and their effects on farm earnings

Includes bibliographical references

Methodological Issues in Biased Policing Research with Applications to the Washington State Patrol

Racial profiling violates the United States Constitution’s premise that all people are equal under the law, as well as the Fourth Amendment’s guarantee that people should be free from unreasonable searches and seizures. Racial profiling has been found to result from individual officer racism or stereotyping, from institutionalized biases, and from the organizational culture of law enforcement agencies. We begin this Article by discussing the history of racial profiling before proceeding to consider various studies from a select number of American jurisdictions. We then examine important methodological and theoretical issues in conducting research on racial profiling and racially biased policing, including a detailed discussion of our research with the Washington State Patrol (WSP). These issues are important to consider because if studies of racial profiling are not based on sound scientific principles, then those who deny the existence of the problem can attribute revelations of bias to faulty research methodology. The Article concludes with a response to the critiques of our methodology and conclusions presented by Professors Mario Barnes and Robert Chang

Methodological Issues in Biased Policing Research with Applications to the Washington State Patrol

Racial profiling violates the United States Constitution’s premise that all people are equal under the law, as well as the Fourth Amendment’s guarantee that people should be free from unreasonable searches and seizures. Racial profiling has been found to result from individual officer racism or stereotyping, from institutionalized biases, and from the organizational culture of law enforcement agencies. We begin this Article by discussing the history of racial profiling before proceeding to consider various studies from a select number of American jurisdictions. We then examine important methodological and theoretical issues in conducting research on racial profiling and racially biased policing, including a detailed discussion of our research with the Washington State Patrol (WSP). These issues are important to consider because if studies of racial profiling are not based on sound scientific principles, then those who deny the existence of the problem can attribute revelations of bias to faulty research methodology. The Article concludes with a response to the critiques of our methodology and conclusions presented by Professors Mario Barnes and Robert Chang

Cellular Classes in the Human Brain Revealed In Vivo by Heartbeat-Related Modulation of the Extracellular Action Potential Waveform

Determining cell types is critical for understanding neural circuits but remains elusive in the living human brain. Current approaches discriminate units into putative cell classes using features of the extracellular action potential (EAP); in absence of ground truth data, this remains a problematic procedure. We find that EAPs in deep structures of the brain exhibit robust and systematic variability during the cardiac cycle. These cardiac-related features refine neural classification. We use these features to link bio-realistic models generated from in vitro human whole-cell recordings of morphologically classified neurons to in vivo recordings. We differentiate aspiny inhibitory and spiny excitatory human hippocampal neurons and, in a second stage, demonstrate that cardiac-motion features reveal two types of spiny neurons with distinct intrinsic electrophysiological properties and phase-locking characteristics to endogenous oscillations. This multi-modal approach markedly improves cell classification in humans, offers interpretable cell classes, and is applicable to other brain areas and species

Distinct roles of dorsal and ventral subthalamic neurons in action selection and cancellation

The subthalamic nucleus (STN) supports action selection by inhibiting all motor programs except the desired one. Recent evidence suggests that STN can also cancel an already selected action when goals change, a key aspect of cognitive control. However, there is little neurophysiological evidence for dissociation between selecting and cancelling actions in the human STN. We recorded single neurons in the STN of humans performing a stop-signal task. Movement-related neurons suppressed their activity during successful stopping, whereas stop-signal neurons activated at low-latencies near the stop-signal reaction time. In contrast, STN and motor-cortical beta-bursting occurred only later in the stopping process. Task-related neuronal properties varied by recording location from dorsolateral movement to ventromedial stop-signal tuning. Therefore, action selection and cancellation coexist in STN but are anatomically segregated. These results show that human ventromedial STN neurons carry fast stop-related signals suitable for implementing cognitive control

Examining the Relationship of Substance Use and Sexual Orientation

In this paper we examine the effects of self-reported sexual orientation on substance abuse. Using data on a random sample of 6713 individuals in Washington State, this study examines causes and correlates of substance use by sexual minorities, an at-risk and treatment underserved population. Logistic regression results indicate homosexual orientation is a significant positive predictor of past year marijuana use, past year hard drug use, past year binge drinking, and lifetime alcohol addiction. Bisexual orientation is a significant predictor of past year marijuana use, past year hard drug use, and past year binge drinking. Potential causal mechanisms for these elevated patterns of substance use are discussed

Extent of single-neuron activity modulation by hippocampal interictal discharges predicts declarative memory disruption in humans

Memory deficits are common in epilepsy patients. In these patients, the interictal EEG commonly shows interictal epileptiform discharges (IEDs). While IEDs are associated with transient cognitive impairments, it remains poorly understood why this is. We investigated the effects of human (male and female) hippocampal IEDs on single-neuron activity during a memory task in patients with medically refractory epilepsy undergoing depth electrode monitoring. We quantified the effects of hippocampal IEDs on single-neuron activity and the impact of this modulation on subjectively declared memory strength. Across all recorded neurons, the activity of 50 of 728 neurons were significantly modulated by IEDs, with the strongest modulation in the medial temporal lobe (33 of 416) and in particular the right hippocampus (12 of 58). Putative inhibitory neurons, as identified by their extracellular signature, were more likely to be modulated by IEDs than putative excitatory neurons (19 of 157 vs 31 of 571). Behaviorally, the occurrence of hippocampal IEDs was accompanied by a disruption of recognition of familiar images only if they occurred up to 2 s before stimulus onset. In contrast, IEDs did not impair encoding or recognition of novel images, indicating high temporal and task specificity of the effects of IEDs. The degree of modulation of individual neurons by an IED correlated with the declared confidence of a retrieval trial, with higher firing rates indicative of reduced confidence. Together, these data link the transient modulation of individual neurons by IEDs to specific declarative memory deficits in specific cell types, thereby revealing a mechanism by which IEDs disrupt medial temporal lobe-dependent declarative memory retrieval processes

Cellular Classes in the Human Brain Revealed In Vivo by Heartbeat-Related Modulation of the Extracellular Action Potential Waveform

Determining cell types is critical for understanding neural circuits but remains elusive in the living human brain. Current approaches discriminate units into putative cell classes using features of the extracellular action potential (EAP); in absence of ground truth data, this remains a problematic procedure. We find that EAPs in deep structures of the brain exhibit robust and systematic variability during the cardiac cycle. These cardiac-related features refine neural classification. We use these features to link bio-realistic models generated from in vitro human whole-cell recordings of morphologically classified neurons to in vivo recordings. We differentiate aspiny inhibitory and spiny excitatory human hippocampal neurons and, in a second stage, demonstrate that cardiac-motion features reveal two types of spiny neurons with distinct intrinsic electrophysiological properties and phase-locking characteristics to endogenous oscillations. This multi-modal approach markedly improves cell classification in humans, offers interpretable cell classes, and is applicable to other brain areas and species

Cognitive boundary signals in the human medial temporal lobe shape episodic memory representation

While experience unfolds continuously, memories are organized as a set of discrete events that bind together the “where”, “when”, and “what” of episodic memory. This segmentation of continuous experience is thought to be facilitated by the detection of salient environmental or cognitive events. However, the underlying neural mechanisms and how such segmentation shapes episodic memory representations remain unclear. We recorded from single neurons in the human medial temporal lobe while subjects watched videos with different types of embedded boundaries and were subsequently evaluated for memories of the video contents. Here we show neurons that signal the presence of cognitive boundaries between subevents from the same episode and neurons that detect the abstract separation between different episodes. The firing rate and spike timing of these boundary-responsive neurons were predictive of later memory retrieval accuracy. At the population level, abrupt neural state changes following boundaries predicted enhanced memory strength but impaired order memory, capturing the behavioral tradeoff subjects exhibited when recalling episodic content versus temporal order. Successful retrieval was associated with reinstatement of the neural state present following boundaries, indicating that boundaries structure memory search. These findings reveal a neuronal substrate for detecting cognitive boundaries and show that cognitive boundary signals facilitate the mnemonic organization of continuous experience as a set of discrete episodic events