Anatomical Modularity of Verbal Working Memory? Functional Anatomical Evidence from a Famous Patient with Short-Term Memory Deficits.

Cognitive skills are the emergent property of distributed neural networks. The distributed nature of these networks does not necessarily imply a lack of specialization of the individual brain structures involved. However, it remains questionable whether discrete aspects of high-level behavior might be the result of localized brain activity of individual nodes within such networks. The phonological loop of working memory, with its simplicity, seems ideally suited for testing this possibility. Central to the development of the phonological loop model has been the description of patients with focal lesions and specific deficits. As much as the detailed description of their behavior has served to refine the phonological loop model, a classical anatomoclinical correlation approach with such cases falls short in telling whether the observed behavior is based on the functions of a neural system resembling that seen in normal subjects challenged with phonological loop tasks or whether different systems have taken over. This is a crucial issue for the cross correlation of normal cognition, normal physiology, and cognitive neuropsychology. Here we describe the functional anatomical patterns of JB, a historical patient originally described by Warrington et al. (1971), a patient with a left temporo-parietal lesion and selective short phonological store deficit. JB was studied with the H2(15)O PET activation technique during a rhyming task, which primarily depends on the rehearsal system of the phonological loop. No residual function was observed in the left temporo-parietal junction, a region previously associated with the phonological buffer of working memory. However, Broca's area, the major counterpart of the rehearsal system, was the major site of activation during the rhyming task. Specific and autonomous activation of Broca's area in the absence of afferent inputs from the other major anatomical component of the phonological loop shows that a certain degree of functional independence or modularity exists in this distributed anatomical-cognitive system

Social Science and Neuroscience beyond Interdisciplinarity: Experimental Entanglements

This article is an account of the dynamics of interaction across the social sciences and neurosciences. Against an arid rhetoric of ‘interdisciplinarity’, it calls for a more expansive imaginary of what experiment – as practice and ethos – might offer in this space. Arguing that opportunities for collaboration between social scientists and neuroscientists need to be taken seriously, the article situates itself against existing conceptualizations of these dynamics, grouping them under three rubrics: ‘critique’, ‘ebullience’ and ‘interaction’. Despite their differences, each insists on a distinction between sociocultural and neurobiological knowledge, or does not show how a more entangled field might be realized. The article links this absence to the ‘regime of the inter-’, an ethic of interdisciplinarity that guides interaction between disciplines on the understanding of their pre-existing separateness. The argument of the paper is thus twofold: (1) that, contra the ‘regime of the inter-’, it is no longer practicable to maintain a hygienic separation between sociocultural webs and neurobiological architecture; (2) that the cognitive neuroscientific experiment, as a space of epistemological and ontological excess, offers an opportunity to researchers, from all disciplines, to explore and register this realization

Optimized EPI for fMRI studies of the orbitofrontal cortex: compensation of susceptibility-induced gradients in the readout direction

Object Most functional magnetic resonance imaging (fMRI) studies record the blood oxygen leveldependent (BOLD) signal using gradient-echo echo-planar imaging (GE EPI). EPI can suffer from substantial BOLD sensitivity loss caused by magnetic field inhomogeneities. Here, BOLD sensitivity losses due to susceptibility- induced gradients in the readout (RO) direction are characterized and a compensation approach is developed