NE101 Lecture Notes

Anterior pituitary hypothalamic releasing hormones eg

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Anterior pituitary Hypothalamic releasing hormones (e.g., CRH ) released into portal vessels by neurosecretory cells. Induce pituitary endocrine cells to release their own hormones (e.g., ACTH ) into bloodstream. Case Study: Hormonal Modulation of Behavior – Oxytocin/Vasopressin and Affiliative Behavior Oxytocin and vasopressin Close structural similarity (probably evolved from common ancestor via gene duplication). CNS: neuromodulators of reproductive behavior (and social behavior in general). Periphery: oxytocin – maternal physiology (uterine contractions, milk letdown reflex); vasopression – Vasopressin in voles Vasopressin receptors are distributed differently in the brains of polygynous meadow voles and monogamous prairie voles. Polygynous meadow moles expressing more receptors (after viral gene transfer, “+AAV” in figures)
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behave more like monogamous prairie voles (prefer spending time with one partner) correlation between social behavior and expression of vasopressin receptors Monogamous prairie voles spend even more time with mate when given vasopressin Mice (normally polygynous) given vasopressin react like prairie voles if they are transgenically expressing prairie vole vasopressin receptors in their brains. November 5, 2012: Sensory Systems Sensation: transduction (body translation) of outside stimuli into action potentials Perception: organization and interpretation of the action potentials Sensation and perception are the same for all sensory modalities (sight, hearing, taste, touch) Two general principles of sensory systems function all sensory systems are organized hierarchically parallel processing Information can be processed bottom-up and top-down Labelled line principle: Sensory organs and cells respond selectively to different stimuli – specialized to process specific information that they were built to respond to. Example: visual cells: respond to wavelengths auditory cells: respond to pressure waves Receptors need to code and decode information Recruitment: increase stimulus intensity, more and more sensory receptors are activated Temporal summation: increase in intensity → more action potentials Lateral inhibition: absolutely essential to all sensory modalities – neuron sending an inhibitory connection to a downstream neuron positive signal to the middle neuron – negative signal to the peripheral neurons allows peripheral modulation to occur Central modulation: Receptive field: Part of the external world that the receptor responds to higher the density of neurons/receptors, the greater the acuity, the smaller the receptive field VISION bipolar cells and horizontal cells provide the lateral inhibition center-surround: photoreceptors affect the excitatory/inhibitory state of a ganglion cell center-on – excitatory ganglion cell is activated surround off – inhibitory
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Anterior pituitary Hypothalamic releasing hormones eg CRH...

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