The brain exhibits organized fluctuations of neural activity, even in the absence of tasks or sensory input. A prominent type of such spontaneous activity is the alpha rhythm, which influences ...perception and interacts with other ongoing neural activity. It is currently hypothesized that states of decreased prestimulus α oscillations indicate enhanced neural excitability, resulting in improved perceptual acuity. Nevertheless, it remains debated how changes in excitability manifest at the behavioral level in perceptual tasks. We addressed this issue by comparing two alternative models describing the effect of spontaneous α power on signal detection. The first model assumes that decreased α power increases baseline excitability, amplifying the response to both signal and noise, predicting a liberal detection criterion with no effect on sensitivity. The second model predicts that decreased α power increases the trial-by-trial precision of the sensory response, resulting in improved sensitivity. We tested these models in two EEG experiments in humans where we analyzed the effects of prestimulus α power on visual detection and discrimination using a signal detection framework. Both experiments provide strong evidence that decreased α power reflects a more liberal detection criterion, rather than improved sensitivity, consistent with the baseline model. In other words, when the task requires detecting stimulus presence versus absence, reduced α oscillations make observers more likely to report the stimulus regardless of actual stimulus presence. Contrary to previous interpretations, these results suggest that states of decreased α oscillations increase the global baseline excitability of sensory systems without affecting perceptual acuity.
Spontaneous fluctuations of brain activity explain why a faint sensory stimulus is sometimes perceived and sometimes not. The prevailing view is that heightened neural excitability, indexed by decreased α oscillations, promotes better perceptual performance. Here, we provide evidence that heightened neural excitability instead reflects a state of biased perception, during which a person is more likely to see a stimulus, whether or not it is actually present. Therefore, we propose that changes in neural excitability leave the precision of sensory processing unaffected. These results establish the link between spontaneous brain activity and the variability in human perception.
Transperineal repair of rectourethral fistula (RUF) following prostate cancer treatment with gracilis muscle flap interposition (GMFI) leads to favourable outcomes, but published data are still ...lacking, notably concerning functional aspects.
To assess surgical and functional outcomes of this treatment of RUF.
A retrospective study was conducted in two referral hospitals including 21 patients who underwent RUF transperineal repair with GMFI between 2008 and 2020.
The standard vertical perineal approach is performed for fistula dissection. Bladder and rectal defects are closed separately. After dissection from its facia, the flap is harvested, preserving its pedicle; it is brought to the perineum and placed between the urethra and the rectum to fully cover the sutures.
Fistula closure (clinical data and postoperative cystography), digestive stoma closure, and complications graded according to the Clavien-Dindo classification were reviewed. Functional results were assessed using the Urinary Symptom Profile (USP) questionnaire, anal incontinence St Mark’s score, Patient Observer Scar Assessment Scale (POSAS) score, and a nonvalidated Likert scale questionnaire assessing issues with lower extremity functionality.
The median (interquartile range) follow-up was 27 (8–47) mo. Fistula closure was successful for 20 patients (95% success). Digestive stoma was closed in 10/12 shunted patients (83%). Two (9%) Clavien-Dindo grade ≥3b complications were reported (one urinoma in a kidney transplant patient and one thigh haematoma evacuation). Eighteen patients (86%) completed the postoperative questionnaire; 11/18 (61%) had significant urinary incontinence. The mean (standard deviation) USP dysuria score was 1/9 (1.2), mean St Mark’s score was 5/24 (5), mean POSAS score was 19/70 (11), mean lower extremity functionality score was 2/20 (4), and mean procedure patient satisfaction score was 9/10 (2). The retrospective design and limited number of patients are the main limitations.
The present study found an excellent success rate and low morbidity for RUF transperineal repair with GMFI. Functional outcomes were satisfactory despite a high urinary incontinence rate.
We performed an analysis of the outcomes of perineal approach surgery with muscle interposition for closing abnormal communication between the bladder and the rectum after prostate cancer treatment. This surgical technique was found to be safe to perform and provides a high success rate, with patients being satisfied despite poor urinary continence outcomes.
Transperineal repair of rectourethral fistula with gracilis muscle flap interposition is a safe surgery with a high success rate. Urinary continence is a serious issue, but patients may be reassured as to the impact on digestive continence, lower extremity functionality, and scar aesthetics.
Objective
To train and to test for prostate zonal segmentation an existing algorithm already trained for whole-gland segmentation.
Methods
The algorithm, combining model-based and deep learning–based ...approaches, was trained for zonal segmentation using the NCI-ISBI-2013 dataset and 70 T2-weighted datasets acquired at an academic centre. Test datasets were randomly selected among examinations performed at this centre on one of two scanners (General Electric, 1.5 T; Philips, 3 T) not used for training. Automated segmentations were corrected by two independent radiologists. When segmentation was initiated outside the prostate, images were cropped and segmentation repeated. Factors influencing the algorithm’s mean Dice similarity coefficient (DSC) and its precision were assessed using beta regression.
Results
Eighty-two test datasets were selected; one was excluded. In 13/81 datasets, segmentation started outside the prostate, but zonal segmentation was possible after image cropping. Depending on the radiologist chosen as reference, algorithm’s median DSCs were 96.4/97.4%, 91.8/93.0% and 79.9/89.6% for whole-gland, central gland and anterior fibromuscular stroma (AFMS) segmentations, respectively. DSCs comparing radiologists’ delineations were 95.8%, 93.6% and 81.7%, respectively. For all segmentation tasks, the scanner used for imaging significantly influenced the mean DSC and its precision, and the mean DSC was significantly lower in cases with initial segmentation outside the prostate. For central gland segmentation, the mean DSC was also significantly lower in larger prostates. The radiologist chosen as reference had no significant impact, except for AFMS segmentation.
Conclusions
The algorithm performance fell within the range of inter-reader variability but remained significantly impacted by the scanner used for imaging.
Key Points
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Median Dice similarity coefficients obtained by the algorithm fell within human inter-reader variability for the three segmentation tasks (whole gland, central gland, anterior fibromuscular stroma)
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The scanner used for imaging significantly impacted the performance of the automated segmentation for the three segmentation tasks
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The performance of the automated segmentation of the anterior fibromuscular stroma was highly variable across patients and showed also high variability across the two radiologists
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Recent research indicates that attentional stimulus selection could be a rhythmic process. In monkey, neurons in V4 and IT exhibit rhythmic spiking activity in the theta range in response to a ...stimulus. When two stimuli are presented together, the rhythmic neuronal responses to each occur in anti-phase, a result indicative of competitive interactions. In addition, it was recently demonstrated that these alternating oscillations in monkey V4 modulate the speed of saccadic responses to a target flashed on one of the two competing stimuli. Here, we replicate a similar behavioral task in humans (7 participants, each performed 4000 trials) and report a pattern of results consistent with the monkey findings: saccadic response times fluctuate in the theta range (6 Hz), with opposite phase for targets flashed on distinct competing stimuli.
High-intensity Focused Ultrasound (HIFU) is a promising treatment modality for a wide range of pathologies including prostate cancer. However, the lack of a reliable ultrasound-based monitoring ...technique limits its clinical use. Ultrasound currently provides real-time HIFU planning, but its use for monitoring is usually limited to detecting the backscatter increase resulting from chaotic bubble appearance. HIFU has been shown to generate stiffening in various tissues, so elastography is an interesting lead for ablation monitoring. However, the standard techniques usually require the generation of a controlled push which can be problematic in deeper organs. Passive elastography offers a potential alternative as it uses the physiological wave field to estimate the elasticity in tissues and not an external perturbation. This technique was adapted to process B-mode images acquired with a clinical system. It was first shown to faithfully assess elasticity in calibrated phantoms. The technique was then implemented on the Focal One® clinical system to evaluate its capacity to detect HIFU lesions in vitro (CNR = 9.2 dB) showing its independence regarding the bubbles resulting from HIFU and in vivo where the physiological wave field was successfully used to detect and delineate lesions of different sizes in porcine liver. Finally, the technique was performed for the very first time in four prostate cancer patients showing strong variation in elasticity before and after HIFU treatment (average variation of <inline-formula> <tex-math notation="LaTeX">33.0 \, \pm \, 16.0 \% </tex-math></inline-formula>). Passive elastography has shown evidence of its potential to monitor HIFU treatment and thus help spread its use.
Objective
To compare complications after implantation of an artificial urinary sphincter (AUS) in patients with or without prior radiotherapy (RT).
Patients and Methods
Between January 2000 and ...December 2011, 160 patients underwent AMS 800 AUS implantation in our institution. We excluded neurological and traumatic causes, implantation on ileal conduit diversion, penoscrotal urethral cuff position and those lost to follow‐up. In all, 122 patients were included in the study, 61 with prior RT and 61 without prior RT. All patients underwent the same surgical technique by two different surgeons. All AUS were implanted with a bulbar urethral cuff position. The mean (range) follow‐up was 37.25 (1–126) months.
Results
In the patients without prior RT and those with prior RT, revision rates were 32.8% vs 29.5%, respectively (P = 0.59). The median time to first revision was 11.7 months. Early complications were similar in the two groups (4.9% vs 6.5%, P = 1). Erosion rates were not significantly different (4.9% vs 13.1%, P = 0.13). However, infection and explantation were more prevalent in patients with prior RT two (3.2%) vs 10 (16.3%), P = 0.018 and three (4.9%) vs 12 (19.6%), P = 0.016, respectively. Finally, continence rates were not significantly different 75.4% (without prior RT) vs 63.9% (with prior RT), P = 0.23.
Conclusion
AUS is the ‘gold standard’ treatment of male urinary incontinence after re‐education failure in patients with or without prior RT. Our experience showed similar functional outcomes in both groups but a higher rate of major complications in the group with prior RT.
In most species, the sense of taste is key in the distinction of potentially nutritious and harmful food constituents and thereby in the acceptance (or rejection) of food. Taste quality is encoded by ...specialized receptors on the tongue, which detect chemicals corresponding to each of the basic tastes (sweet, salty, sour, bitter, and savory 1), before taste quality information is transmitted via segregated neuronal fibers 2, distributed coding across neuronal fibers 3, or dynamic firing patterns 4 to the gustatory cortex in the insula. In rodents, both hardwired coding by labeled lines 2 and flexible, learning-dependent representations 5 and broadly tuned neurons 6 seem to coexist. It is currently unknown how, when, and where taste quality representations are established in the cortex and whether these representations are used for perceptual decisions. Here, we show that neuronal response patterns allow to decode which of four tastants (salty, sweet, sour, and bitter) participants tasted in a given trial by using time-resolved multivariate pattern analyses of large-scale electrophysiological brain responses. The onset of this prediction coincided with the earliest taste-evoked responses originating from the insula and opercular cortices, indicating that quality is among the first attributes of a taste represented in the central gustatory system. These response patterns correlated with perceptual decisions of taste quality: tastes that participants discriminated less accurately also evoked less discriminated brain response patterns. The results therefore provide the first evidence for a link between taste-related decision-making and the predictive value of these brain response patterns.
•Large-scale electrophysiological response patterns code for taste quality in humans•Taste quality is represented early in the central gustatory system•Neural response patterns correlate with subjective perceptual experience
Taste allows discriminating nutritious and harmful food constituents. Crouzet et al. show that the earliest taste-evoked neural responses in the human cortex code for taste quality (e.g., salty or sweet). These neural response patterns were correlated with perceptual decisions, indicating that they form the basis of subjective taste experience.
High-intensity focused ultrasound (HIFU) has been widely used for whole gland ablation with large series. HIFU induces immediate and irreversible coagulative necrosis with sharply delineated ...boundaries making HIFU an attractive treatment option for focal therapy of localized prostate. The treatment can be accurately targeted to a portion of the prostate gland. Unlike radiation, there is no lifetime dose limit, allowing HIFU to be repeated if necessary. Additional radical therapy can be performed involving radical surgery, external beam radiation therapy and cryotherapy. Moreover, HIFU is a minimally invasive therapy that can be performed under spinal anesthesia on an outpatient basis.
Focal therapy is a new treatment modality for localized prostate cancer. Different energy can be employed to achieve focal therapy including HIFU. With a transrectal treatment, HIFU is one of the less invasive focal treatments. A systematic review of the literature has been performed to highlight the results of focal HIFU.
The first published results of focal HIFU are promising. The patient's quality of life and potency are well preserved with good early oncological results.
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