NPB%20112%2009%20somato%20slides

NPB%20112%2009%20somato%20slides - NPB 112, Fall 2009:...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 NPB 112, Fall 2009: 10-6- 10-8 Outline: I. Sensory physiology: overview (Ch. 9) II. Skin mechanoreceptor types A. Mechanoreceptor B. Thermoreceptors (Ch. 10) 1. Warm receptors 2. Cold receptors C. Nociceptors (pain) 1. A-delta mechanical nociceptor 2. polymodal nociceptor RECEPTOR : specialized neuron or epithelial cell that responds to a specific type or wavelength of environmental energy (process by which environmental energy is transformed by receptor into an electrical signal) ADEQUATE (or appropriate) STIMULUS : type of stimulus energy that activates receptor at the lowest relative intensity
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Some terminology • RECEPTOR: specialized neuron or epithelial cell that responds to a specific type or wavelength of environmental energy • RECEPTIVE FIELD: region on body surface, or area in visual and auditory space, within which an appropriate stimulus activates the receptor (or changes the firing rate of neurons along the sensory pathway) • STIMULUS TRANSDUCTION: process by which environmental energy is transformed by receptor into an electrical signal • ADEQUATE (or appropriate) STIMULUS: type of stimulus energy that activates receptor at the lowest relative intensity • RECEPTOR POTENTIAL (or generator potential): change in receptor membrane potential elicited by appropriate stimulus • THRESHOLD: lowest stimulus intensity evoking a measurable change in receptor membrane potential (or perceived on >50% of trials of repeated stimuli) Sensory systems signal what, where, when, and how much stimulation occurs •Wh a t (modality): accomplished by labeled line (specificity) or some kind of population coding e r e : topographic map in sensory cortex •How mu ch : population and rate coding en (duration): rate of adaptation to stimulus
Background image of page 2
3 WHAT? Johannes Mueller (1826): “law of specific nerve energies” Modality is property of sensory nerve fiber • nerve fiber is activated primarily by a certain type of stimulus energy, and makes specific connections to structures in the brain whose activity gives rise to a specific sensation • Modality is encoded by “labeled line” – Receptor’s afferent fiber is modality-specific line of communication – Activation of sensory neuron naturally or electrically elicits the same sensation – Modality is represented by sensory system , an ensemble of neurons connected to specific receptor class – Submodalities (qualities): can divide modality into constituent qualities based on sensitivity of receptors to specific bandwidths of energy (e.g., somatosensory includes touch, pressure, vibration, pain, itch, temperature, etc.) Sensory Modality Quality (sub-modality) vision color, motion hearing pitch smell > 20 odors (950 genes, 400 functional receptors) taste sweet, sour, salt, bitter, "umami" (MSG, other amino acids) somatic touch-pressure warm-cold flutter-vibration pain, itch, tickle, pleasurable touch?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/14/2009 for the course NPB 33042 taught by Professor Carstens during the Spring '09 term at UC Davis.

Page1 / 37

NPB%20112%2009%20somato%20slides - NPB 112, Fall 2009:...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online