CHOLINERGIC MODULATION OF THALAMIC INPUT INTO THE CINGULATE CORTEX

This research demonstrates cholinergic modulation of thalamic input into the limbic cortex. A projection from the mediodorsal thalamus (MD) to the anterior cingulate cortex was defined anatomically and physiologically. Injections of horse-radish peroxidase into the anterior cingulate cortex labels neurons in the lateral, parvocellular, region of MD. Electrical Stimulation of this area produces a complex field potential in the anterior cingulate cortex which was further characterized by current density analysis and single cell recordings.^ The monsynaptic component of the response was identified as a large negative field which is maximal in layer IV of the anterior cingulate cortex. This response shows remarkable tetanic potentiation of frequencies near 7 Hz. During a train of 50 or more stimuli, the response would grow quickly and remain at a fairly stable potentiated level throughout the train.^ Cholinergic modulation of this thalamic response was demonstrated by iontophoretic application of the cholinergic agonist carbachol decreased the effectiveness of the thalamic imput by rapidly attenuation the response during a train of stimuli. The effect was apparently mediated by muscarinic receptors since the effect of carbachol was blocked by atropine but not by hexamethonium.^ To determine the source of the cingulate cortex cholinergic innervation, lesions were made in the anterior and medial thalamus and in the nucleus of the diagonal band of Broca. The effects of these lesions on choline acetyltranferase activity in the cingulate cortex were determined by a micro-radio-enzymatical assay. Only the lesions of the nucleus of the diagonal band significantly decreased the choline acetyltransferase activity in the cingulate cortex regions. Therefore, the diagonal band appears to be a major source of sensory cholinergic innervation and may be involved in gating of sensory information from the thalamus into the limbic cortex. Attempts to modulate the cingulate response to MD stimulation with electrical stimulation of the diagonal band, however were not successful.^

Illustrated Catalogue of Standard Surgical Instruments and Allied Lines

Section "A": Dissecting and Post-Mortem Instruments Diagnostic Instruments and Apparatus Microscopes and Microscopic Accessories Laboratory Apparatus and Glass Ware Apparatus for Blood and Urine Analysis Apparatus for Phlebotomy, Cupping and Leeching Apparatus for Infusion and Transfusion Syringes for Aspiration and Injection Osteological Preparations Section "B": Anaesthetic, General Operating, Osteotomy, Trepanning, Bullet, Pocket Case, Cautery, Ligatures, Sutures, Dressings, Etc. Section "B" continued Section "C": Eye, Ear, Nasal, Dermal, Oral, Tonsil, Tracheal, Laryngeal,Esophageal, Stomach, Intestinal, Gall Bladder Section "C": continued Section "D": Rectal, Phimosis, Prostatic, Vesical, Urethral, Ureteral, Instruments Section "E": Gynecic, Hysterectomy, Obstetrical, Instrument Satchels, Medicine Cases Section "F": Electric Cautery Transformers, Electro-Cautery Burners and Accessories, Electric Current Controllers, Electro-Diagnostic Outfits, Electrolysis Instruments Electro-Therapeutic Lamps, Faradic Batteries, Galvanic Batteries Section "G": Office Furniture, Office Sterilizing Apparatus, Hospital Supplies, Surgical Rubber Goods, Sick Room Utensils, Invalid Rolling Chairs, Invalid Supplies Section "H": Artificial Limbs, Deformity Apparatus, Fracture Apparatus, Splints, Splint Material, Elastic Hosiery, Abdominal Supporters, Crutches, Trusses, Suspensories, Etc. Index