LECTURE 9 NOTES
Explain the premotor theory of attention!
- Unable to shift our eye without shifting our attention
- We can shift our attention without moving our eyes.
- Was proposed by vincellati. He stated shifts of attention are occulomotor programs. You shift your attention at the time
when the occulomotor program is ready to be executed..takes some time to do some planning and process.
- At the time when the program is ready so eye can movie to target of interest, that the point when u shift your attention
- Attention precedes eye movt. shift of attention occurs before eye movt.
- Eye movt may or may not occur. difference between overt and covert attention
- Overt: makes eye movt.overt behaviour reflecting shift of attention
- Covert : if u dont move your eyes. Its possible because the occulomotor program may not be executed. Maynot be passed
on to neural structure that are involved in controlling muscles.
~premotor theory predicts close relationship between shifts of attention and eyemovts.
- i.e the macaque stimulation of FEF to see response in V4.
Amplitude: magnitude.diff between compressed regions with the less dense region.
Intensity – physical measure
Decibels : p/p 0
Standard pressure is chosen to be level of minimal hearing. arbitrary reference.
6 is twice as loud as something else.12,18.increases by doubling(x2) in terms of energy.
Intensity is related but NOT equal to loudness!
The relationship is not straightforward.
Intensity- has a big range
Difference between rustling of leaves and jet taking off—130 decibels
For frequency, its not such a big range.
Beats per second: Hz.
Pitch and frequency relationship is not direct because we first have to process the frequency.
Interactions between frequencies and amplitude
-similar to CSF of vision
-interms of temporal frequencies
-here measured as thresholds.
As a funcn of frequency, our aud range is complex
20 Hz: low frequency, inorder to be perceived, the sound pressure level has to be high.
cannot be heard unless they are very intense.
Thresholds are the lowest at frequencies above 2000 Hz to 10, 000 Hz
As frequencies increase, we can’t perceive them anymore.
Frequencies between 20 and 20, 000 hz is our auditory range and it dependent on our age.
You are not as loud as some music when speaking or as low as some music.
Sounds above 110 Hz can damage the eardrums.
Sine wave and complex waves
Complex waves – can be expresses as some compositions of any type of sine waves
Sine waves- building blocks of sound.
A complex sound can be represented by any set of simple sine waves.
Bars at each frequency. The length of bar is decreasing.meaning their power is decreasing.
The bottom spectrum tells u that the A + B function graph or the squre graph is composed of 5 frequencies.
Vs single sine wave: only one frequency Harmonic spectrum:
The frequency increase by multiples of fundamental frequency.
Usually the first bar
How do we still perceive it to be the same pitch?
-because we perceive the pitch of the sound to be similar to the fundamental frequency
The frequencies of sounds is way more but we just notice the fundamental frequency consciously.
Neurons are selective and have specific tuning frequency.
Place code: because of the PHYSICAL PROPERTIES of the membrane.diff parts of the membrane are flexible to varying degree.
Because the haircells are attached to the organ of corti, u always have movt in neighboring regions.There is a limitation to how
selective these movts can be. As when the organ of corti moves, nei