PSYC100 Lecture Notes - Lecture 6: Auditory Cortex, Optic Nerve, Dominant Wavelength
PSYCH100 - FOUNDATIONS OF PSYCHOLOGY
Wk. 6 – Sensation
Sensory systems
Translate info from the external world into neural acticity
Encoding
Process of translating physical properties of a stimulus > pattern of nerve cell
activity
Specific energy doctrine – each sensory system will produce cosed for only
that one sense
Temporal code – rate or timing of firing
Spatial code – location of neurons that are firing
Hearing
Sound
Repetitive fluctuation in the pressure of a medium like air
Vibrating objects create the fluctuations in air pressure
A repetitive fluctuation in pressure is a wave
Characteristics of Sound
Amplitude (intensity)
Difference in air pressure from base to peak of wave
Loudness (dB)
Wavelength
Distance from one wave peak to the next
Frequency
Number of complete waveforms per 1 second
Hertz/Hz
Pitch
Humans 20-20,000Hz
Absolute pitch (identifying specific frequencies and the note they represent)
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Timbre
Quality of sound
Distinguishes different types of sound production
Auditory Pathways
Auditory nerve > thalamus > auditory cortex
Areas of auditory cortex specialised
E.g. frequency vs. location, voice vs. music.
Cells in the auditory cortex have preferred frequencies
Frequency map
Locating sounds
Interaural time difference (ITD)
Interaural intensity difference (IID)
Binaural Cues
Binaural cues refer to when both ears are actively used to locate the source of the
sound.
There are two types of binaural cues:
Interaural time difference (ITD)
Sounds coming from the right will reach the right ear before the left ear
This difference in timing between the two ears gives the indication that the
sound is coming from the right
Vice Versa for sound on the left.
Interaural intensity difference (IID)
Sounds coming from the right will be louder in the right ear than the left ear
This difference in loudness (intensity) between the two ears gives the
indication that the sound is coming from the right
Vice Versa for sound on the left.
Coding Intensity and Pitch
Intensity = temporal code
Faster firing rate = louder
Pitch
Place theory – different frequencies cause the basilar membrane to peak at
different positions
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Translate info from the external world into neural acticity. Process of translating physical properties of a stimulus > pattern of nerve cell activity. Specific energy doctrine each sensory system will produce cosed for only that one sense. Temporal code rate or timing of firing. Spatial code location of neurons that are firing. Repetitive fluctuation in the pressure of a medium like air. Vibrating objects create the fluctuations in air pressure. A repetitive fluctuation in pressure is a wave. Difference in air pressure from base to peak of wave. Distance from one wave peak to the next. Number of complete waveforms per 1 second. Absolute pitch (identifying specific frequencies and the note they represent) Auditory nerve > thalamus > auditory cortex. E. g. frequency vs. location, voice vs. music. Cells in the auditory cortex have preferred frequencies. Binaural cues refer to when both ears are actively used to locate the source of the sound.
