Analysis of lesions in patients with unilateral tactile agnosia using cytoarchitectonic probabilistic maps

Abstract

We propose a novel methodical approach to lesion analyses involving high-resolution MR images in combination with probabilistic cytoarchitectonic maps. 3D-MR images of the whole brain and the manually segmented lesion mask are spatially normalized to the reference brain of a stereotaxic probabilistic cytoarchitectonic atlas using a multiscale registration algorithm based on an elastic model. The procedure is demonstrated in three patients suffering from aperceptive tactile agnosia of the right hand due to chronic infarction of the left parietal cortex. Patient 1 presents a lesion in areas of the postcentral sulcus, Patient 3 in areas of the superior parietal lobule and adjacent intraparietal sulcus, and Patient 2 lesions in both regions. On the basis of neurobehavioral data, we conjectured degradation of sequential elementary sensory information processing within the postcentral gyrus, impeding texture recognition in Patients 1 and 2, and disturbed kinaesthetic information processing in the posterior parietal lobe, causing degraded shape recognition in the patients 2 and 3. The involvement of Brodmann areas 4a, 4p, 3a, 3b, 1, 2, and areas IP1 and IP2 of the intraparietal sulcus was assessed in terms of the voxel overlap between the spatially transformed lesion masks and the 50%-isocontours of the cytoarchitectonic maps. The disruption of the critical cytoarchitectonic areas and the impaired subfunctions, texture and shape recognition, relate as conjectured above. We conclude that the proposed method represents a promising approach to hypothesis-driven lesion analyses, yielding lesion-function correlates based on a cytoarchitectonic model. Finally, the lesion-function correlates are validated by functional imaging reference data.

Lesions to Primary Sensory and Posterior Parietal Cortices Impair Recovery from Hand Paresis after Stroke

“…This kind of task is typically performed with highly coordinated finger movements that are tightly adapted to the object explored (transitive movements). Lesion studies in stroke patients support these regional differences in tactile processing and finger movements: patients with circumscribed lesions in area 2 present severe deficits in discriminating object texture, whereas those with damage to hIP1/hIP2 evidence impaired recognition of three-dimensional shape [6]. Patients with lesion in the parietal lobe show disrupted exploratory finger movements, a gradual decrease in frequency and regularity together with a gradual increase in exploration space depending from the lesion location in its anterior or posterior portion [29].…”

The parietal cortices participate in encoding, short-term memory, and decision-making related to tactile shape

“…L, left; R, right; S1, primary somatosensory cortex; V1, primary visual cortex. 2001Binkofski et al 1999;Bohlhalter et al 2002;Grefkes et al 2002;Hömke et al 2009;Miquée et al 2008;Peltier et al 2007;Reed et al 1996;Seitz et al 1991). Our study contributes to that important previous research by separately analyzing the phases of sensory encoding, short-term memory, and decision-making and contrasting these processes against a control task that had the same cognitive components.…”

“…A strong functional relationship thus exists between the motor and somatosensory areas that participate in exploring the shape of objects contacted with the hand, as has been conclusively demonstrated by numerous investigations (Gardner et al 2007b;Miquée et al 2008;Reed et al 2004;Stoeckel et al 2003). In addition to sensory and motor areas, the association cortices in the parietal lobe have been consistently identified as important nodes in the processing of tactile shape (Binkofski et al 1999;Bohlhalter et al 2002;Hömke et al 2009;Reed et al 1996;Seitz et al 1991), with special relevance for somatic sensory encoding (Gardner et al 2007c;Stoesz et al 2003;Van Boven et al 2005), kinesthetic perception (Fiehler et al 2008), attention (Burton et al 1999, and hand movements (Chen et al 2009;Culham and Valyear 2006;Gardner et al 2007a;Naito and Ehrsson 2006). An important remaining question, however, is whether specific circuits exist within sensory, motor, and association areas that specialize in analyzing the three-dimensional (3D) shape of objects (Bodegård et al 2001), and if so, how specific these circuits are for the different phases of tactile processing such as sensory encoding, short-term memory, and decision-making (Hartmann et al 2008;Hernández et al 2010;Li Hegner et al 2007;Stoeckel et al 2004;Zhou and Fuster 1996).…”

Peripheral Homonymous Hemianopia

“…The map of Horton and Hoyt predicted that the scotomas would begin around 10°from fixation, the refined map of Wong and Sharpe predicted that the scotomas would be located at 15°, and Holmes map predicted that the scotomas would be located at 25°. This methodical approach has been previously used in studies investigating the anatomy of the pupillary light reflex pathway (30), the functional topography of early periventricular lesions in regard to cerebral palsy and reorganization of language (31), the topography of unilateral tactile agnosia (32), and the involvement of damaged white matter fiber tracts in acute spatial neglect (33). In order to exactly localize the brain lesion onto the visual pathway (optic radiation and primary visual cortex) and to investigate its relation to the functional (perimetric) outcome, we used a lesion analysis that combined established reconstruction techniques (17) with the stereotaxic probabilistic cytoarchitectonic atlas developed by the Jülich group (13)(14)(15)(16).…”