Receptive “Field” Concept1. Receptive field: Area of retina that, when stimulated with light, changes a cell’s membrane potential;Light always hyperpolarizes photoreceptors, reducing neurotransmitter (glutamate) release1. Off bipolar cells: depolarize during light off periods (dark);On bipolar cells: depolarize during lights on periods (light)Antagonistic center-surround receptive fields1. On-center Bipolar CellsPresence of light on center receptive field = depolarizationPresence of light on surround receptive field = hyper polarizationOff-center Bipolar Cells:Display the reverse responses to light compared to On-center cellsGanglion Cell Receptive Fields1. First cells that produce action potentials and send their axons to brain via Optic nerve;2. On-Center and Off-Center ganglion cells driven by similarly responsive bipolar cells;3. Responsive to differences in illuminationTypes of Ganglion Cells1. M-type (Magno - large) and P-type (Parvo - small) ganglion cellsDifferent in appearance, connectivity, and electrophysiological propertiesColor-Opponent Ganglion Cells“Linked” colors: Center-surround receptive fields responsive to colors (P-type ganglion cells mostly);Red-green opponentsBlue-yellow opponentsVisual Hemifields1. Right and Left Visual HemifieldsLeft hemifield projects to right side of brain and vice versa;Ganglion cell axons from nasal retina cross, temporal retinal axons stay ipsilateralCentral Pathway for Conscious Visual PerceptionRetinal Ganglion cells → Optic Nerve → Optic Tract → Lateral Geniculate Nucleus → Optic radiation → Primary Visual cortex (Occipital lobe)Non-Thalamic Central Visual Pathways1. Hypothalamus (suprachiasmatic nucleus): Biological rhythms, including sleep and wakefulness.Pretectum: Size of the pupil; certain types of eye movement.Superior colliculus: Orients the eyes in response to new stimuli.Lateral Geniculate Nucleus Organization1. Eye segregation into different layers (1-6);2. M-layers (1-2, ventral) derived from M-type ganglion cells;3. P-layers (3-6), dorsal) derived from P-type ganglion cells;4. LGN cells retain characteristic properties of retinal cells projecting to them.Striate (Primary Visual) Cortex Organization1. V1 – recipient of LGN axon terminals2. Neocortex generally divided into 6 layers:Layer V/VI:deepest (output);Layer IV (C): recipient of major LGN inputs (M→α, P→β); Ctr-Srd org;Layer I contains few cells and is next to pia.Striate (Primary Visual) Cortex Organization1. Ocular Dominance ColumnsPresent in layer IV - alternating inputs from two eyes1. (brown one eye, blue other eye; each column ~ 0.5 mm)Striate (Primary Visual) Cortex OrganizationOrientation selective cells:- outside layer IVC;- neighboring patchesrespond to closelyrelated angles;- simple cortical cellsExtra Striate Cortex and Visual InformationDorsal streamAnalysis of visual motion and the visual control of actionVentral streamPerception of the visual world and the recognition of objectsChemical Senses: Taste and SmellSmell = Olfaction - olfactory systemTaste = Gustation - gustatory systemcalled “chemical” senses because their function is to monitor the chemical content of the environment.Flavor of food is a composite of both taste and smell sensation.In many species, including humans, taste (especially of bitterness and sourness) is used to protect against poisoning;NRSC 2100 1st Edition Lecture 18Receptive “Field” Concept1. Receptive field: Area of retina that, when stimulated with light, changes a cell’s membrane potential;– Light always hyperpolarizes photoreceptors, reducing neurotransmitter (glutamate) release1. Off bipolar cells: depolarize during light off periods (dark);• On bipolar cells: depolarize during lights on periods (light)Antagonistic center-surround receptive fields1. On-center Bipolar Cells– Presence of light on center receptive field = depolarization– Presence of light on surround receptive field = hyperpolarization– Off-center Bipolar Cells:– Display the reverse responses to light compared to On-center cellsGanglion Cell Receptive Fields 1. First cells that produce action potentials and send theiraxons to brain via Optic nerve;These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. On-Center and Off-Center ganglion cells driven by similarly responsive bipolar cells;3. Responsive to differences in illuminationTypes of Ganglion Cells1. M-type (Magno - large) and P-type (Parvo - small) ganglion cells– Different in appearance, connectivity, and electrophysiological propertiesColor-Opponent Ganglion Cells“Linked” colors: Center-surround receptive fields responsive to colors (P-type ganglion cells mostly);• Red-green opponents• Blue-yellow opponentsVisual Hemifields1. Right and Left Visual Hemifields– Left hemifield projects to right side of brain and vice versa;– Ganglion cell axons from nasal retina cross, temporal retinal axons stay ipsilateralCentral Pathway for Conscious Visual PerceptionRetinal Ganglion cells → Optic Nerve → Optic Tract → Lateral Geniculate Nucleus → Optic radiation → PrimaryVisual cortex (Occipital lobe)Non-Thalamic Central Visual Pathways1. Hypothalamus (suprachiasmatic nucleus): Biological rhythms, including sleep and wakefulness.– Pretectum: Size of the pupil; certain types of eye movement.– Superior colliculus: Orients the eyes in response tonew stimuli.Lateral Geniculate Nucleus Organization1. Eye segregation into different layers (1-6);2. M-layers (1-2, ventral) derived from M-type ganglion cells;3. P-layers (3-6), dorsal) derived from P-type ganglion cells;4. LGN cells retain characteristic properties of retinal cells projecting to them.Striate (Primary Visual) Cortex Organization1. V1 – recipient of LGN axon terminals2. Neocortex generally divided into 6 layers:– Layer V/VI:deepest (output);– Layer IV (C): recipient of major LGN inputs (M→α, P→β); Ctr-Srd org;– Layer I contains few cells and is next to pia.Striate (Primary Visual) Cortex Organization1. Ocular Dominance Columns– Present in layer IV - alternating inputs from two eyes1. (brown one eye, blue other eye; each column ~ 0.5mm)Striate (Primary Visual) Cortex OrganizationOrientation selective cells: - outside layer IVC; - neighboring patches respond to closely related angles; - simple cortical cellsExtra
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