Spared ability to recognise fear from static and moving whole-body cues following bilateral amygdala damage

Bilateral amygdala lesions impair the ability to identify certain emotions, especially fear, from facial expressions, and neuroimaging studies have demonstrated differential amygdala activation as a function of the emotional expression of faces, even under conditions of subliminal presentation, and again especially for fear. Yet the amygdala's role in processing emotion from other classes of stimuli remains poorly understood. On the basis of its known connectivity as well as prior studies in humans and animals, we hypothesised that the amygdala would be important also for the recognition of fear from body expressions. To test this hypothesis, we assessed a patient (S.M.) with complete bilateral amygdala lesions who is known to be severely impaired at recognising fear from faces. S.M. completed a battery of tasks involving forced-choice labelling and rating of the emotions in two sets of dynamic body movement stimuli, as well as in a set of static body postures. Unexpectedly, S.M.'s performance was completely normal. We replicated the finding in a second rare subject with bilateral lesions entirely confined to the amygdala. Compared to healthy comparison subjects, neither of the amygdala lesion subjects was impaired in identifying fear from any of these displays. Thus, whatever the role of the amygdala in processing whole-body fear cues, it is apparently not necessary for the normal recognition of fear from either static or dynamic body expressions.     

Clinical outcome after orbital floor fracture reduction with special regard to patient''s satisfaction

Purpose: Primary reconstruction via transconjunctival approach is a standardized treatment option for orbital floor fractures. The aim of this study was to compare the findings of specific ophthalmologic assessment with the patient''s complaints after fracture reduction. Methods: A retrospective medical chart analysis was performed on patients who had undergone transconjunctival orbital floor fracture reduction for fracture therapy with resorbable foil (ethisorb sheet or polydioxanone foil). A follow-up assessment including ophthalmological evaluation regarding visual acuity (eye chart projector), binocular visual field screening (Bagolini striated glasses test) and diplopia (cover test, Hess screen test) was conducted. Additionally, a questionnaire was performed to assess patients'' satisfaction. Results: A total of 53 patients with a mean follow-up of 23 months (ranging from 11 to 72) after surgical therapy were included. Diplopia was present preoperatively in 23 (43.4%) and reduced in follow-up examination (n=12, 22.6%). Limitations in ocular motility reduced from 37.7% to 7.5%. The questionnaire about the patient''s satisfaction revealed excellent outcomes in relation to the functional and esthetical parameters. Conclusion: Transconjunctival approach is a safe approach for orbital fracture therapy. Postoperative diplopia is nearly never perceptible for the individual and differs to pathologic findings in the ophthalmic assessment.     

Anterior prefrontal cortex contributes to action selection through tracking of recent reward trends

The functions of prefrontal cortex remain enigmatic, especially for its anterior sectors, putatively ranging from planning to self-initiated behavior, social cognition, task switching, and memory. A predominant current theory regarding the most anterior sector, the frontopolar cortex (FPC), is that it is involved in exploring alternative courses of action, but the detailed causal mechanisms remain unknown. Here we investigated this issue using the lesion method, together with a novel model-based analysis. Eight patients with anterior prefrontal brain lesions including the FPC performed a four-armed bandit task known from neuroimaging studies to activate the FPC. Model-based analyses of learning demonstrated a selective deficit in the ability to extrapolate the most recent trend, despite an intact general ability to learn from past rewards. Whereas both brain-damaged and healthy controls used comparisons between the two most recent choice outcomes to infer trends that influenced their decision about the next choice, the group with anterior prefrontal lesions showed a complete absence of this component and instead based their choice entirely on the cumulative reward history. Given that the FPC is thought to be the most evolutionarily recent expansion of primate prefrontal cortex, we suggest that its function may reflect uniquely human adaptations to select and update models of reward contingency in dynamic environments.     

Amygdala damage impairs emotional memory for gist but not details of complex stimuli

Neurobiological studies demonstrate the amygdala's role in emotional memory, and psychological studies suggest a particular pattern: enhanced memory for the gist but not the details of complex stimuli. We hypothesized that these two findings are related. Whereas normal (n = 52) and brain-damaged (n = 22) controls showed the expected enhancement of gist memory when the encoding context was emotional, persons with unilateral damage to the medial temporal lobe including the amygdala (n = 16) did not show this pattern. Furthermore, amygdala volume showed a significant positive correlation with gist memory but not with overall memory. A further study in four subjects with selective medial temporal damage sparing the amygdala, and one with selective damage confined to the amygdala, confirmed the specificity of this effect to the amygdala. The data support a model whereby the amygdala focuses processing resources on gist, possibly accounting for features of traumatic memories and eyewitness testimony in real life.     

Frontofacial advancement by internal distraction devices. A technical modification for the management of craniofacial dysostosis in early childhood

Normal craniofacial growth is characterized by a different growth pattern of neuro- and viscerocranium. In craniofacial dysostosis (CFD) syndromes there is complex disturbance of this physiological growth pattern. Modern surgical management of CFD is staged with respect to the severity of the deformity, the age and the development of the patient. Early single stage management of anterior cranial vault deformity and midfacial retrusion in children affected by syndromic craniosynostosis is possible when anterior cranial vault remodelling is performed together with gradual Le Fort III midfacial advancement. One pair of internal distraction devices, placed in accordance with the midfacial growth vector after initial cranial vault remodelling, can be sufficient for this purpose. Technical aspects of this modified frontofacial advancement procedure are presented and discussed based on a case report with a postoperative follow up time of 50 months.     

Mineralization and mechanical properties of the canine mandible distraction wound following acute molding

To investigate the influence of an acute single step callus manipulation immediately after distraction on mechanical properties and mineralization of the regenerate, custom made distraction devices were bilaterally placed in the mandibular angle of 15 beagle dogs, allowing to simultaneously compress and stretch the regenerate after completed linear distraction. The animals were divided in three groups (n=5): Group 1 and 2 underwent manipulation of the regenerate, group 3 remained in a linear position. After 42 (group1) and 90 (group 2 and 3) days of consolidation the animals were sacrificed. The mechanical properties were assessed in an Instron testframe and bone density quantified by quantitative computed tomography and three- dimensionally assessed (Scion Image processing and analysis software). After 6 weeks of consolidation 25% of the specimens reached a stiffness which was >/=90% of the mean values of the unoperated reference hemi-mandibles. After a 13 week consolidation period, 62.5% were as stiff as the referenced specimens. Manipulated regenerates, allowed to heal under stable conditions for 13 weeks, had the same mechanical properties as specimens that underwent pure linear distraction. A temporary but not significant delay of osseous healing had to be postulated for the stretched zone after 6 weeks, indicating this area to be more critical than the compressed area.     

The neuroanatomical correlates of route learning impairment

Recent functional imaging studies of topographical learning point to the participation of a large network of cortical and subcortical regions. Nevertheless, areas which are crucial remain poorly specified due to the absence of group studies of subjects with focal lesions distributed throughout the brain. We assessed the ability of 127 subjects with stable, focal lesions to learn a complex real-life route, a critical aspect of topographical functioning. Results indicated that impairment in route learning was highly associated with damage to medial occipital and posterior parahippocampal cortices in either hemisphere, the right hippocampus, and the right inferotemporal region. Impairment was seen among 86% of the subjects with damage to any these regions, in contrast to impairment among 31% of subjects with lesions in other regions. The importance of medial occipitotemporal cortices bilaterally and right inferotemporal cortex likely reflects the critical role of the ability to quickly and accurately perceive and learn multiple topographical scenes. The importance of the right (and probably left) posterior parahippocampal gyrus and of the right hippocampus likely reflects their critical, distinctive roles forming an integrated representation of the extended topographical environment (i.e., the appearance of places and spatial relationships between specific places), and consolidating that representation into multifaceted contextual knowledge of the environment.     

Dentoalveolar injury related to general anaesthesia: a 14 years review and a statement from the surgical point of view based on a retrospective analysis of the documentation of a university hospital

Abstract – Introduction: Damage to dentoalveolar structures related to general anaesthesia is a well‐known complication and may represent a relevant morbidity for affected patients. Central documentation of perioperative dentoalveolar injuries was performed since 1990 in the Department of Anaesthesiology and Intensive Care Medicine in cooperation with the Department of Oral and Maxillofacial Surgery at the Charité Universitätsmedizin Berlin, Campus Virchow‐Klinikum. Documentation of perioperative dentoalveolar injury consisted of anaesthesia charts, reports of the anaesthesiologists and consultant maxillofacial surgeons. Materials and methods: Retrospective analysis of the data from 1990 to 2004 was performed according to this documentation with respect to incidence, matter, distribution of dental injury and therapeutic consequences. Results: Within 14 years 82 ‘dental injuries’ with 103 affected teeth were documented in calculated 375 000 general anaesthesias. Incidence of 0.02% was very constant with an average of 5.5 events/year. Eighty‐nine percent of the documented injuries occurred during scheduled operative procedures. Only 32.9% of the injuries took place during endotracheal intubation. In about 50% the injury was not related to intubation or extubation but happened during general anaesthesia. In 80% the dental injury was estimated by the anaesthesiologist as ‘not avoidable’. In 83% pre‐existing affection or structural injury of intraoral tissues was documented, in 32.7% of the affections sufficient therapy could be provided already during inhospital stay. Conclusion: Perioperative dentoalveolar injury is surely an annoying complication of general anaesthesia. However incidence is rare and seems to be unavoidable. Pre‐existing damage to dentoalveolar structures is the main risk for additional injuries related to general anaesthesia. Adequate therapy can be provided by interdisciplinary concepts. There should be a fair balance between the benefit of the surgical procedure and the risk of dental injury related to general anaesthesia. Awareness of the problem and proper documentation are important factors for adequate management in liability cases.     

Processing of facial emotion in the human fusiform gyrus

Electrophysiological and fMRI-based investigations of the ventral temporal cortex of primates provide strong support for regional specialization for the processing of faces. These responses are most frequently found in or near the fusiform gyrus, but there is substantial variability in their anatomical location and response properties. An outstanding question is the extent to which ventral temporal cortex participates in processing dynamic, expressive aspects of faces, a function usually attributed to regions near the superior temporal cortex. Here, we investigated these issues through intracranial recordings from eight human surgical patients. We compared several different aspects of face processing (static and dynamic faces; happy, neutral, and fearful expressions) with power in the high-gamma band (70-150 Hz) from a spectral analysis. Detailed mapping of the response characteristics as a function of anatomical location was conducted in relation to the gyral and sulcal pattern on each patient's brain. The results document responses with high responsiveness for static or dynamic faces, often showing abrupt changes in response properties between spatially close recording sites and idiosyncratic across different subjects. Notably, strong responses to dynamic facial expressions can be found in the fusiform gyrus, just as can responses to static faces. The findings suggest a more complex, fragmented architecture of ventral temporal cortex around the fusiform gyrus, one that includes focal regions of cortex that appear relatively specialized for either static or dynamic aspects of faces.     

Changes in cortical morphology resulting from long-term amygdala damage

The amygdala's contribution to emotion, cognition and behavior depends on its interactions with subcortical and cortical regions. Amygdala lesions result in altered functional activity in connected regions, but it is not known whether there might be long-term structural sequelae as well. We hypothesized that developmental bilateral amygdala lesions would be associated with specific gray matter morphometric abnormalities in the ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC) and the ventral visual stream. We conducted regions of interest and vertex-based analyses of structural MRI data acquired in two patients with long-standing focal bilateral amygdala lesions (S.M. and A.P.), compared to gender- and age-matched healthy comparison subjects. Both patients showed significant proportional increases in gray matter volume of the vmPFC. Cortical thickness was increased in the vmPFC and ACC and decreased in the ventral visual stream. There were no morphometric changes in dorsolateral prefrontal cortex or dorsal visual stream cortices. These findings support the hypothesis that cortical regions strongly connected with the amygdala undergo morphometric changes with long-standing amygdala damage. This is the first evidence in humans of the remote alteration of brain morphology in association with amygdala lesions, and will help in interpreting the structural and functional consequences of amygdala pathology in neuropsychiatric disorders.