When the brain is split, is space still unified?

How does the brain keep track of relevant spatial locations when the eyes move? In extrastriate, parietal and frontal cortex, and in the superior colliculus, neurons update stimulus representations in conjunction with eye movements. This updating reflects a transfer of visual information, from neurons that encode a salient location before the saccade, to neurons that encode the location after the saccade. Copies of the oculomotor command - corollary discharge signals - likely initiate this transfer. Spatial updating, or remapping, is thought to contribute to the maintenance of stable spatial representations as the eyes move. We investigated the circuitry that supports spatial updating in the primate brain. Our central hypothesis was that the forebrain commissures provide the primary route for remapping spatial locations across visual hemifields, which entails the interhemispheric transfer of visual information. Further, we hypothesized that these commissures provide the primary route for corollary discharge signals, generated in one hemisphere, to initiate spatial updating in the opposite hemisphere. We tested these hypotheses by measuring spatial behavior and neural activity in two split-brain macaques. In behavioral experiments, we observed striking initial impairments in the monkeys' ability to update stimuli across visual hemifields. Surprisingly, however, we found that both animals were ultimately capable of performing these across-hemifield sequences. Both monkeys readily performed the same spatial task when updating required an interhemispheric transfer of corollary discharge signals, suggesting that these signals are transferred via subcortical pathways in the normal monkey. In physiological experiments, we found that neurons in lateral intraparietal cortex of the split-brain monkey can remap stimuli across visual hemifields, albeit with a reduction in the strength of remapping activity. These neurons were robustly active when within-hemifield updating was initiated by a saccade into the opposite hemifield. Our findings suggest that both visual and corollary discharge signals from opposite hemispheres can converge to update spatial representations in the absence of the forebrain commissures. These investigations provide new evidence that a unified and stable representation of visual space is supported by a redundant circuit, comprised of cortical as well as subcortical pathways, with a remarkable capacity for reorganization

Roundtable Discussion Examining Ritual, Technology, and Community in Urban Communication

Pervasive technologies that now exist in the urban setting have greatly improved the ability to connect on a macro-level, but have minimized the intimate shared experience of community on a micro level. This paper explores how technology has changed rituals within the global community and has contributed new methods to the process of human interaction. Technology’s influence on civic engagement, business meetings, shopping and socializing are examined to assess the impact technology has on human connections

The zebrafish xenograft platform-A novel tool for modeling KSHV-associated diseases

Kaposi\u27s sarcoma associated-herpesvirus (KSHV, also known as human herpesvirus-8) is a gammaherpesvirus that establishes life-long infection in human B lymphocytes. KSHV infection is typically asymptomatic, but immunosuppression can predispose KSHV-infected individuals to primary effusion lymphoma (PEL); a malignancy driven by aberrant proliferation of latently infected B lymphocytes, and supported by pro-inflammatory cytokines and angiogenic factors produced by cells that succumb to lytic viral replication. Here, we report the development of the firs

A Forty-Year-Old Woman with a History of Psychosis and a Seizure Disorder

In this issue of the Journal, we are introducing a new section. the Interdisciplinary Case Conference. Our goal will be to present psychiatric patients in whom pathology is demonstrable not only by interview, but also by physical examination,laboratory studies. and radiographic imaging techniques

Explaining disappearances as a tool of political terror

Despite the widespread use of disappearances as a central tool of terror in recent decades, little is known about the emergence of the phenomenon or its underlying rationale. We argue that growing international accountability norms, coupled with the improved quality of reporting human rights abuses, paradoxically reshaped the repressive strategies of certain regimes and pushed them to deploy more clandestine and extrajudicial forms of repression, predominantly disappearances. We also explore the timing of disappearances: when a state decides to deploy a particular instrument of terror can greatly benefit our understanding of why it was used. We show that repressive regimes tend to use disappearances in the first period after a coup, taking advantage of the general confusion and opacity to secure strategic benefits and protect the regime from external scrutiny and future accountability. Our findings contribute to the growing literature on human rights and political repression by highlighting an ‘unintended consequence’ of international accountability norms: repressive regimes turn to clandestine crimes

Comparison of neuropsychological functioning in Alzheimer's disease and frontotemporal dementia

Compared the archival neuropsychological data of 15 frontotemporal dementia (FTD) patients (mean age 63.9 yrs), 16 Alzheimer's disease (AD) patients (mean age 70.3 yrs), and 16 controls were compared. Controls outperformed both patient groups on measures of verbal and nonverbal memory, executive ability, and constructional skill, with AD patients showing more widespread memory decline. Patient groups differed only in nonverbal memory, with FTD patients performing significantly better than AD patients. Patient groups also differed in pattern of performance across executive and memory domains. Specifically, AD patients exhibited significantly greater impairment on memory than executive tasks, whereas the opposite pattern characterized the FTD group. Findings suggest that examination of relative rankings of scores across cognitive domains, in addition to interpretation of individual neuropsychological scores, may be useful in differential diagnosis of FTD vs AD

Complementary and alternative medical therapy utilization by people with chronic fatiguing illnesses in the United States

<p>Abstract</p> <p>Background</p> <p>Chronic fatiguing illnesses, including chronic fatigue syndrome (CFS), pose a diagnostic and therapeutic challenge. Previous clinical reports addressed the utilization of health care provided to patients with CFS by a variety of practitioners with other than allopathic training, but did not examine the spectrum of complementary and alternative medicine (CAM) therapies used. This study was designed to measure CAM therapy use by persons with fatiguing illnesses in the United States population.</p> <p>Methods</p> <p>During a random-digit dialing survey to estimate the prevalence of CFS-like illness in urban and rural populations from different geographic regions of the United States, we queried the utilization of CAM including manipulation or body-based therapies, alternative medical systems, mind-body, biologically-based, and energy modalities.</p> <p>Results</p> <p>Four hundred forty fatigued and 444 non-fatigued persons from 2,728 households completed screening. Fatigued subjects included 53 persons with prolonged fatigue, 338 with chronic fatigue, and 49 with CFS-like illness. Mind-body therapy (primarily personal prayer and prayer by others) was the most frequently used CAM across all groups. Among women, there was a significant trend of increasing overall CAM use across all subgroups (p-trend = 0.003). All categories of CAM use were associated with significantly poorer physical health scores, and all but one (alternative medicine systems) were associated with significantly poorer mental health scores. People with CFS-like illness were significantly more likely to use body-based therapy (chiropractic and massage) than non-fatigued participants (OR = 2.52, CI = 1.32, 4.82). Use of body-based therapies increased significantly in a linear trend across subgroups of non-fatigued, prolonged fatigued, chronic fatigued, and CFS-like subjects (p-trend = 0.002). People with chronic fatigue were also significantly more likely to use body-based therapy (OR = 1.52, CI = 1.07, 2.16) and mind-body (excluding prayer) therapy than non-fatigued participants (OR = 1.73, CI = 1.20 – 2.48).</p> <p>Conclusion</p> <p>Utilization of CAM was common in fatiguing illnesses, and was largely accounted for by the presence of underlying conditions and poor physical and mental health. Compared to non-fatigued persons, those with CFS-like illness or chronic fatigue were most likely to use body-based and mind-body therapies. These observations have important implications for provider education programs and development of intervention strategies for CFS.</p

Quantum entanglement and disentanglement of multi-atom systems

We present a review of recent research on quantum entanglement, with special emphasis on entanglement between single atoms, processing of an encoded entanglement and its temporary evolution. Analysis based on the density matrix formalism are described. We give a simple description of the entangling procedure and explore the role of the environment in creation of entanglement and in disentanglement of atomic systems. A particular process we will focus on is spontaneous emission, usually recognized as an irreversible loss of information and entanglement encoded in the internal states of the system. We illustrate some certain circumstances where this irreversible process can in fact induce entanglement between separated systems. We also show how spontaneous emission reveals a competition between the Bell states of a two qubit system that leads to the recently discovered "sudden" features in the temporal evolution of entanglement. An another problem illustrated in details is a deterministic preparation of atoms and atomic ensembles in long-lived stationary squeezed states and entangled cluster states. We then determine how to trigger the evolution of the stable entanglement and also address the issue of a steered evolution of entanglement between desired pairs of qubits that can be achieved simply by varying the parameters of a given system.Comment: Review articl