Perception of odor-induced tastes following insular cortex lesion.

Lesions of the insula can affect olfaction and gustation. Here, we examined the effect of insula lesions on taste and taste-like experiences generated via smelling (i.e., odor-induced tastes) in patients with focal insula lesions and intact olfaction. From a set of 16 patients with lesions to the insula, we found 7 (6 with right-sided lesions) who performed normally on various olfactory measures. These were compared to 42 normal control subjects on tests of gustatory and odor-induced taste perception as well as control measures. The patients were impaired relative to controls on most gustatory measures. They were also impaired on tests of odor-induced taste perception, primarily for stimuli presented on the left side. Examining cases individually revealed evidence of a dissociation: two patients exhibited no impairment in odor-induced taste perception in spite of gustatory deficits. Together, these findings suggest that the insula mediates taste recognition, hedonics, and intensity judgments as well as odor-induced taste perception. However, the areas responsible for aspects of taste perception and those responsible for odor-induced taste do not fully overlap each other and they are also independent of olfactory areas.

Transfalciform greater omental herniation.

Internal herniae are rare, those involving the falciform ligament even rarer. To the best of our knowledge, there have been approximately 20 cases of herniae involving the falciform ligament previously reported. Of these cases, only one previously reported case involves herniation of the greater omentum through the falciform ligament. We present a second case of an adult man who presented with a 48-hour history of epigastric pain and was found on contrast multidetector CT to have a strangulated transfalciform greater omental hernia. The hernia was repaired laparoscopically and the patient recovered uneventfully.

The nature of facial expression recognition deficits following orbitofrontal cortex damage.

OBJECTIVE: Orbitofrontal cortex (OFC) damage has been associated with facial expression recognition deficits in some, but not all, previous studies. The pattern of performance of a group of patients with OFC damage was assessed across a series of facial expression recognition tasks. We aimed to determine whether some tasks were more sensitive at detecting deficits than others. METHOD: Seven patients with damage to the OFC, 6 control patients with frontal lesions that spared the OFC, and a group of healthy controls completed a series of facial expression recognition tasks including 2 labeling tasks and 2 matching tasks. RESULTS: The OFC patient group demonstrated impaired labeling of negative facial expressions (i.e., anger, disgust, fear, and sadness) shown for a short time (500 ms) relative to the comparison groups. When facial expressions were shown for a longer time (5,000 ms), the OFC patient group's performance did not differ significantly from either comparison group. The OFC patient group was impaired when matching subtle, low intensity negative facial expressions, but not when matching high intensity, prototypical facial expressions. CONCLUSIONS: The pattern of performance across tasks revealed that only certain facial expression recognition tasks appear to be sufficiently sensitive to detect deficits in patients with OFC damage. These findings have important implications for the assessment of facial expression recognition difficulties in patients with OFC damage and more broadly, for special populations.

The lateralization of gustatory function and the flow of information from tongue to cortex.

Controversy surrounds whether crossed and/or uncrossed fibers carry taste information from tongue to cortex and whether there is hemispheric specialization for gustatory processing. The current study examined these issues in 14 patients with unilateral insula lesions, seven with right-sided and seven with left-sided damage, and in 42 healthy controls. Two tasks were carried out, with tastants applied unilaterally to the tongue tip: (1) taste discrimination; and (2) stimulus sampling followed by judgments of quality, intensity, hedonics and name-recognition, for sweet, salty, bitter and sour tastants. Controls were better at discriminating tastants applied to their right tongue tip relative to their left, and better at taste quality judgments when tastants were applied to their left tongue tip relative to their right. Insula lesions to the left or right side resulted in bilateral impairments in discrimination, quality judgments and naming, when compared to controls. However, the Left insula group was poorer on tasks involving salt, and for ipsilateral hedonic judgments, relative to controls and the Right insula group. These findings are consistent with gustatory information ascending from tongue to cortex both ipsilaterally and contralaterally, and provide preliminary support for hemispheric gustatory specialization.

Orbitofrontal cortex lesions result in abnormal social judgements to emotional faces.

Facial expressions of emotion display a wealth of important social information that we use to guide our social judgements. The aim of the current study was to investigate whether patients with orbitofrontal cortex (OFC) lesions exhibit an impaired ability to judge the approachability of emotional faces. Furthermore, we also intended to establish whether impaired approachability judgements provided to emotional faces emerged in the presence of preserved explicit facial expression recognition. Using non-parametric statistics, we found that patients with OFC lesions had a particular difficulty using negative facial expressions to guide approachability judgements, compared to healthy controls and patients with frontal lesions sparing the OFC. Importantly, this deficit arose in the absence of an explicit facial expression recognition deficit. In our sample of healthy controls, we also demonstrated that the capacity to recognise facial expressions was not significantly correlated with approachability judgements given to emotional faces. These results demonstrate that the integrity of the OFC is critical for the appropriate assessment of approachability from negatively valenced faces and this ability is functionally dissociable from the capacity to explicitly recognise facial expressions.