Application of Tuning Cruves lecture, given by Tyler Coye

1. APPLICATIONS OF TUNING CURVES
IN NEUROSCIENCE
Tyler Coye
Alfred University

2. NEUROSCIENCE
A branch of science that deals with the anatomy, physiology, biochemistry,
or molecular biology of nerves and nervous tissue and especially their
relation to behavior and learning
-Merriam-Webster
Dictionary
http://upload.wikimedia.org/wikipedia/commons/d/db/Structural.gif

3. TUNING CURVE
Tuning curves are widely used to characterize the
responses of sensory neurons to external stimuli.
http://www.cogsci.bme.hu/~ikovacs/latas2005/prepI_3_1_files/c_fig6.jpg

4. NEURON CELLS
 A neuron is an electrically
excitable cell that processes
and transmits information by
electrical and chemical
signaling.
 There are several stimuli that
can activate a neuron leading
to electrical activity, including
pressure, stretch, chemical
transmitters, and changes of
the electric potential across
the cell membrane.
http://upload.wikimedia.org/wikipedia/en/a/a6/Chemical_synapse_schema.jpg

5. NEURON RECORDING
 Single-Cell Recording is a technique used in research to
observe changes in voltage or current in a neuron.
 Microelectrode is inserted into the skull and into a neuron in
the area of the brain that is of interest.
http://www.cogsci.bme.hu/~ikovacs/latas2005/prepI_3_1.html

6. GAUSSIAN TUNING CURVE
0
10
20
30
40
50
60
-60 -40 -20 0 20 40 60
F(Hz)
S (orientation angle in degrees)

7. APPLICATION OF THE GAUSSIAN TUNING CRUVE
 Modeling neuron activation in the primary visual cortex (V1) of a cat
shown bars of light that moved across the receptive field of a cell at
different angles.
(Data points from Henry et al., 1974)

8. COSINE TUNING CURVE

9. APPLICATION OF THE COSINE TUNING GURVE
Applied to the primary motor cortex of a monkey that performed an arm-
reaching task.
(Data points from Georgopulos et al,

10. SIGMOIDAL TUNING CURVE
0
5
10
15
20
25
30
35
40
-1.5 -1 -0.5 0 0.5 1 1.5
F(Hz)
S (retinal disparity in degrees)

11. APPLICATION OF THE SIGMOIDAL TUNING CURVE
 Applied to data gathered from V1 neuronal activation of a cat shown
separate bars of light in each eye.
(Data points from Poggio and Talbot,

12. DESCRIBING A STIMULUS

13. WEBER-FECHNER LAW
Ernst
Weber
http://en.wikipedia.org/wiki/File
:Ernst_Heinrich_Weber.jpg
Gustav Theodor
Fechner
http://en.wikipedia.org/wiki/File
:Gustav_Fechner.jpg
Question:
A blind man is holding a weight. The weight
is gradually increased over time. What is the
smallest incrememental change that can be
made in the amount of weight being held
before the man perceives the difference?
Weber found that the smallest noticeable
difference was proportional to the initial
value of the weight.
dp : differential change in perception,
dS: differential increase in the stimulus,
S: stimulus at an instant in time.
K: is an experimentally determined factor.

14. WEBER-FECHNER LAW
We know that
Integrating we get
Where C is a constant. Setting p (perception) equal to 0 and
solving for C we get
Because perception is 0, S0 is the threshold below which a
stimulus is not perceived. Finally, through substitution we
get

15. STEVEN’S POWER LAW
Stevens, S. S. (1957)
Stanley Smith Stevens proposed the more
mathematically plausible power-law relation of
sensation to intensity.
I: Intensity of the stimulus
ψ(I) :psychophysical function relating to the Intensity
of the sensation evoked by the stimulus
a: exponent which is stimulation-dependent
For example: when sensation is heaviness
and stimulation is weight, a=1.45.
K: constant which is stimulation and units-dependent.

16. THE END