SummaryAnatomical and physiological experiments have outlined a blueprint for the feed-forward flow of activity in cortical circuits: signals are thought to propagate primarily from the middle cortical layer, L4, up to L2/3, and down to the major cortical output layer, L5. Pharmacological manipulations, however, have contested this model and suggested that L4 may not be critical for sensory responses of neurons in either superficial or deep layers. To address these conflicting models we reversibly manipulated L4 activity in awake, behaving mice using cell-type specific optogenetics. In contrast to both prevailing models, we show that activity in L4 directly suppresses L5, in part by activating deep, fast spiking inhibitory neurons. Our data suggest that the net impact of L4 activity is to sharpen the spatial representations of L5 neurons. Thus we establish a novel translaminar inhibitory circuit in the sensory cortex that acts to enhance the feature selectivity of cortical output.

No abstract

No abstract

Aim Patients undergoing colorectal surgery or those with inflammatory bowel disease (IBD) are particularly at risk for opioid‐related complications and progression to long‐term opioid dependence. The aim of this work is to explore the real‐world possibility of perioperative opioid avoidance in colorectal surgery and IBD. Method We conducted a retrospective analysis of patients aggregated from two prospective studies on multimodal postoperative pain control conducted at a single tertiary referral centre. All patients underwent major colorectal surgery with bowel resection. Patients with chronic preoperative opioid use were excluded. Opioid use was measured in oral morphine equivalents (OME) each postoperative day (POD) and cumulatively for the first 72 h. Results Our cohort of 209 patients included 148 (71%) with IBD and 61 (29%) non‐IBD patients. IBD patients required significantly more opioids cumulatively over the first 72 postoperative hours compared with non‐IBD patients [median OME 77 mg (interquartile range 33–148 mg) vs. 4 mg (interquartile range 17–82 mg), respectively; p = 0.001]. Five percent of IBD patients achieved opioid‐free postoperative pain control during the entire 72 h postoperative period compared with 12% of non‐IBD patients. Only 7% of IBD patients avoided opioid use on POD 1 compared with 20% of non‐IBD patients (p = 0.02); however the number of IBD patients increased to 16% on POD 2 then 40% on POD 3, closely resembling the non‐IBD cohort at 49% (p = 0.22). Conclusion In the era of modern enhanced recovery protocols and minimally invasive techniques, we show that early postoperative opioid avoidance is feasible in a limited number of IBD patients after colorectal surgery.

No abstract

No abstract

No abstract