Selective reduction in neural responses to high calorie foods following gastric bypass surgery.

OBJECTIVE: To investigate changes in neural activation and desire to eat in response to appetitive cues from pre- to postbariatric surgery for obesity. BACKGROUND: Roux-en-Y gastric bypass (RYGB) is the most common bariatric procedure. However, the mechanisms of action in RYGB are not well understood. A significant proportion of the resulting reduction in caloric intake is unaccounted for by the restrictive and malabsorptive mechanisms and is thought to be mediated by neuroendocrine function. Numerous investigations of postsurgical changes in gut peptides have resulted; however, changes in neural activation after RYGB surgery have not been previously investigated. METHODS: Functional magnetic resonance imaging and verbal rating scales were used to assess brain activation and desire to eat in response to high- and low-calorie food cues in 10 female patients 1-month pre- and post-RYGB surgery. RESULTS: Postsurgical reductions in brain activation were found in key areas within the mesolimbic reward pathway, which were significantly more pronounced in response to food cues that were high (vs. low) in caloric density. These changes mirrored concurrent postsurgical reductions in desire to eat, which were also greater in response to food cues that were high versus low in caloric density (P = 0.007). CONCLUSIONS: Findings support the contention that RYGB surgery leads to substantial changes in neural responses to food cues encountered in the environment, provide a potential mechanism for the selective reduction in preferences for high-calorie foods, and suggest partial neural mediation of changes in caloric intake seen after RYGB surgery.

Analysis of clamping versus cutting of T3 sympathetic nerve for severe palmar hyperhidrosis.

OBJECTIVES: Endoscopic thoracic sympathectomy can predictably eliminate the disabling symptoms of palmar hyperhidrosis. Debate has ensued over competing techniques, in particular, cutting versus clamping of the sympathetic chain. We subjectively assessed the sweat severity in different areas of the body and evaluated changes in the quality of life in patients undergoing either the cutting or clamping technique. METHODS: Patients examined between June 2003 and March 2007 were asked to quantify the severity of their symptoms before and after endoscopic thoracic sympathectomy. The interviews were conducted approximately 1 year after the procedure. Only the patients undergoing sympathectomy at the T3 level for a chief complaint of palmar hyperhidrosis were included in the analysis (n = 152). In 45% of these patients, clamping of the sympathetic chain was performed, and the remaining 55% had the chain cut. RESULTS: After surgery, no patients had continued excessive sweating of the hands. Of all the patients, 95% were satisfied with the results after the cutting procedure and 97% were satisfied after clamping. No difference was seen in any outcome between the patients undergoing clamping versus cutting of the sympathetic chain, including sweating on the hands, face, armpits, feet, trunk, and thighs or in the quality of life. CONCLUSIONS: We found high rates of success and patient satisfaction when T3 sympathectomy was performed for palmar hyperhidrosis, with no differences found between the cutting and clamping techniques.

A case of locked-in syndrome complicated by central deafness.

BACKGROUND: A 53-year-old male with a history of hypertension, diabetes mellitus, and factor V deficiency presented to an emergency room with progressively increasing headache, slurred speech, and left upper extremity weakness. Over the previous 3 months, he had been receiving warfarin for prophylaxis of deep venous thrombosis following knee surgery. After presentation and an initial period of coma, he became tetraplegic and anarthric, requiring intubation and ventilatory assistance. INVESTIGATIONS: Neurological examination, CT scan, electroencephalogram, brainstem auditory and visual evoked potential studies, neuropsychological assessment and functional MRI studies. DIAGNOSIS: Locked-in syndrome following ventral pontine hemorrhage, complicated by central deafness secondary to extension of the lesion to the inferior colliculus. MANAGEMENT: Development of an augmentative communication system designed to exploit the patient's preserved cognitive and motor functions.

Facial emotion recognition after curative nondominant temporal lobectomy in patients with mesial temporal sclerosis.

PURPOSE: The right (nondominant) amygdala is crucial for processing facial emotion recognition (FER). Patients with temporal lobe epilepsy (TLE) associated with mesial temporal sclerosis (MTS) often incur right amygdalar damage, resulting in impaired FER if TLE onset occurred before age 6 years. Consequently, early right mesiotemporal insult has been hypothesized to impair plasticity, resulting in FER deficits, whereas damage after age 5 years results in no deficit. The authors performed this study to test this hypothesis in a uniformly seizure-free postsurgical population. METHODS: Controls (n=10), early-onset patients (n=7), and late-onset patients (n=5) were recruited. All patients had nondominant anteromedial temporal lobectomy (AMTL), Wada-confirmed left-hemisphere language dominance and memory support, MTS on both preoperative MRI and biopsy, and were Engel class I 5 years postoperatively. By using a standardized (Ekman and Friesen) human face series, subjects were asked to match the affect of one of two faces to that of a simultaneously presented target face. Target faces expressed fear, anger, or happiness. RESULTS: Statistical analysis revealed that the early-onset group had significantly impaired FER (measured by percentage of faces correct) for fear (p=0.036), whereas the FER of the late-onset group for fear was comparable to that of controls. FER for anger and happiness was comparable across all three groups. CONCLUSIONS: Despite seizure control/freedom after AMTL, early TLE onset continues to impair FER for frightened expressions (but not for angry or happy expression), whereas late TLE onset does not impair FER, with no indication that AMTL resulted in FER impairment. These results indicate that proper development of the right amygdala is necessary for optimal fear recognition, with other neural processes unable to compensate for early amygdalar damage.

Real-time magnetic resonance imaging for interventional neuroradiological procedures.

Over the last two decades, interventional neuroradiologists have developed powerful techniques for the treatment of cerebrovascular disorders and brain tumors. Current interventional neuroradiological procedures are performed under X-ray fluoroscopy, which has allowed for high temporal and spatial resolution. However, these imaging techniques do not provide the treating physician with vital anatomic and functional information regarding vessel walls and the surrounding brain tissue. Better visualization of vessel structures and real-time information about the state of perfusion and metabolism of the surrounding brain tissue (real-time magnetic resonance arteriography, diffusion and perfusion-weighted imaging, apparent diffusion coefficient maps) would enhance safety and efficacy of neuroendovascular procedures available currently. Recent advances in magnetic resonance hardware and software have permitted significant enhancements in temporal and spatial resolution, which have resulted in the capability of visualizing anatomic structures with real-time fluoroscopy and angiography. This review outlines how real-time magnetic resonance procedures may replace conventional X-ray fluoroscopy in diagnostic and interventional neuroradiology during the next decade.