INF5470 Fall 2011 Lecture 2: Neurophysiology in a Nutshell Content - PowerPoint PPT Presentation

INF5470 — Fall 2011 Lecture 2: Neurophysiology in a Nutshell

Content Overview Methods Known Properties Weekly Task Lecture 2: Neurophysiology in a Nutshell 2

Content Overview Methods Known Properties Weekly Task Lecture 2: Neurophysiology in a Nutshell 3

Overview method test subjects observation area temp. res. spat. res. Psycho-physics alert humans cm 2 EEG alert humans patches of brain surface ms 5mm 3 fMRI and PET alert humans brain cross-sections 40ms 0.1 3 mm 3 Extra Cellular Electrode alert test animals neighbourhood of neurons µ s 10 3 µ m 3 Intra Cellular Electr. anesthetized test animals, one neuron µ s slice preparations Fluorescent Tracers anesthetized test animals, a dendritic tree ? < µ m slice preparations Lecture 2: Neurophysiology in a Nutshell 4

Content Overview Methods Known Properties Weekly Task Lecture 2: Neurophysiology in a Nutshell 5

Psychophysics (1/3) Measuring human performance in special tasks in order to make conclusions on physiology. Examples: ◮ reaction times in deciding whether there is food in a picture. ◮ optical illusions ◮ attention tasks: http://viscog.beckman.uiuc.edu/flashmovie/15.php Lecture 2: Neurophysiology in a Nutshell 6

Psychophysics (2/3) (Do you spot an animal?) Lecture 2: Neurophysiology in a Nutshell 7

Psychophysics (3/3) Lecture 2: Neurophysiology in a Nutshell 8

EEG (1/2) Electro-encephalogram: Surface electrodes on skin, measuring correlated activity of a population of neurons. Lecture 2: Neurophysiology in a Nutshell 9

EEG (2/2) Lecture 2: Neurophysiology in a Nutshell 10

fMRI and PET (1/2) fMRI (functional magnet resonance imaging)and PET (positron emission tomography) measure indicators of neuron activity like increased bloodflow and oxygene consumption Lecture 2: Neurophysiology in a Nutshell 11

fMRI and PET (2/2) Lecture 2: Neurophysiology in a Nutshell 12

Extra Cellular Electrodes/Field Potentials Electrodes in the brain tissue that record field potentials caused by the surrounding neurons. Reconstruction methods are sometimes able to isolate activity of individual neurons. Lecture 2: Neurophysiology in a Nutshell 13

Intra Cellular Electrodes Sharp electrodes and patch clamp electrodes observe activity inside a neuron Lecture 2: Neurophysiology in a Nutshell 14

Imaging with Fluorecent Tracers For example two photon microscopy to observe dynamics of chemicals, e.g. calcium Lecture 2: Neurophysiology in a Nutshell 15

Left out here: Methods in Neuroanatomy Lecture 2: Neurophysiology in a Nutshell 16

Content Overview Methods Known Properties Weekly Task Lecture 2: Neurophysiology in a Nutshell 17

Brain Parts Lecture 2: Neurophysiology in a Nutshell 18

Cortical Regions (1/3) Lecture 2: Neurophysiology in a Nutshell 19

Cortical Regions (2/3) Lecture 2: Neurophysiology in a Nutshell 20

Cortical Regions (3/3) Lecture 2: Neurophysiology in a Nutshell 21

Orgaization within cortical regions (1/3) Ocular dominance patterns Lecture 2: Neurophysiology in a Nutshell 22

Orgaization within cortical regions (2/3) Ocular dominance patterns Lecture 2: Neurophysiology in a Nutshell 23

Orgaization within cortical regions (3/3) Orientation selection patterns Lecture 2: Neurophysiology in a Nutshell 24

Cortical Layers and Microcolumns(1/3) Lecture 2: Neurophysiology in a Nutshell 25

Cortical Layers and Microcolumns(2/3) Lecture 2: Neurophysiology in a Nutshell 26

Cortical Layers and Microcolumns(3/3) Lecture 2: Neurophysiology in a Nutshell 27

Neurons and Synapses More about those in dedicated lectures Lecture 2: Neurophysiology in a Nutshell 28

Weekly Task 1. Occular dominance patterns form a kind of a Zebra pattern on V1 with two exceptions: a region close to the center and a region at the outskirts is uniformly dominated by input from just one eye. Do you have an explanation? 2. According to the hierarchy of cortical regions in cat cortex assembled by van Essen etal. it catches the eye that quantitatively there are more recurrent connections than feed forward connections in the cortex. Can you speculate on the significane of this fact? Why could that be? Lecture 2: Neurophysiology in a Nutshell 29