Pitch Perception

Question 1

Fourier (1822)

Answer 1

Any function can be thought of as a mixture of sine waves

Question 2

o ANSI, 1994

Answer 2

‘the auditory attribute of sound according to which sounds can be ordered on a scale from low to high’

Question 3

Goldstein and Kiang (1968)

Answer 3

Recordings of AN fibres in cats to acoustic stimuli of2 pure tones with which the 2F1-F2 was approximately similar to the CF if the fibre and found that responses locked to individual cycles of the reference combination tone for every fibre and time locked response could be called by adding a combination tone to the stimuli.

Question 4

McAnally and Calford (1989)

Answer 4

): did the same as Goldstein and Kiang (1968) but recoding in the IC of cats an found that missing fundamental could be created in the cochlea as activity is evoked in the population of neurons aby distortion arising from non-linear combination of tones with frequencies outside of neurons response area.
o Not directly recording from the cochlea

Question 5

Cariani and Delgutte (1996)

Answer 5

Recoding of AN fibres in anaesthetised cat while presenting a vowel using a harmonic structure whereby F0 varies and the amplitude varies so peak remains constant. They then autocorrelated for ever 20ms and found that peaks always correlated to F0 and so main conclusion is it is possible to read F0 from the temporal structure of AN fibre responses
o Didn’t link to behaviour, doesn’t tell how brain extracts periodicity or generate a pitch percept.

Question 6

• Oxenham et al (2004)

Answer 6

Found that when presenting the low frequency sinusoids to location sin the cochlea tuned to high frequency regions of the cochlea (transposed stimuli) in human subjects and found that listeners were unable to extract F0 so indicated that temporal information might not be sufficient to provide accurate pitch perception and that tonotopic representation is also crucial

Question 7

• Schreiner and Langmer (1988)

Answer 7

). Single unit and multi unit responses to AMP tones of Cat IC and found there was a topographical districution of BMFs with highest BMFs clustered in the ICc sector and then the progressively lower are increasing distances away producing making iso-contours arranged concentrically
o Only looked at responses at AM tones

Question 8

• Baumann et al (2011)

Answer 8

fMRI in an awake macaque IC in response to broadband noise with AM rates changing and fourth that periodotopic map was observed orthogonal to the tonotopic map with mediodorsal high and lateroventral low so opposite to Schriener and Langer
o Only 3 macaques and 20-30voxels per IC
o The IC is a deep structure so resolution not grand

Question 9

• Schnupp et al (2015)

Answer 9

microelectrode study in gerbil IC in response to pure tones and different periodic sounds and found no consistent periodotopic maps though periodic sounds produced highly reproducible gradients consistent with animals

Question 10

Nelken et al (2008)

Answer 10

Optical imaging of the ferret AC and found no consistent pitch map in AC however gradient for periodicity to different sounds such as click trains and IRN

Question 11

Schulze et al (2002):

Answer 11

Optical imaging and electrophysiological mapping of the gerbil IC in response to AM and found periodicity maps with semicircular gradient superimposed onto the linear tonotopic gradient in the low frequency part of the A1

Question 12

Bendor and Wang (2005)

Answer 12

Recordings from marmoset AC in response to harmonics (some with fundamental missing or just using increasingly high harmonics) and found a pitch area on the low frequency border of area A1 and R. Found pitch selective neuron (though rare) tuned to same FO for pure tones and complex tones, not tuned when tones were unperiodic and salience decreased with increased the irregularity of periodicity, tuned to missing fundamental and not other attributed of sound.

Question 13

Bizley et al (2009)

Answer 13

microelectrode study in ferret AC looking at the representation of pitch, timbre and azimuth location and found that many neurons modulated by F0 of sounds through the primary and secondary cortex. Sound units sensitive to 2 or more stimuli, distributed across the AC but significant difference in average neuronal sensitivity across cortical areas and depth which suggests some level of interaction between attributes during process. No neurons were sensitive to pitch alone but neurons particularly sensitive to periodicity were found more commonly in low frequency parts of AC but not confined to one cortical area

Question 14

• Kadia and Wang (2003):

Answer 14

Microelectrode study in marmosets while playing best frequency with another tome and found the presence of multipeaked neurons in the A1 whereby they preferred the best frequency when it was played along with tone of one harmonic above than below

Question 15

Griffiths et al (2010)

Answer 15

electrophysiological responses of the HG of patients with epilepsy in response to RIN stimuli and found that increasing activity when RIN evoked pitch was presented also an increase in gamma band signal, a signature of pitch perception.

Question 16

• Hall and Plack (2002):

Answer 16

fMRI in human brain using IRN stimuli and found that the lateral HG shoed a stronger response to sounds that evoke a pitch percept however when ptch varied randomly or along a musical scale then it activated higher cortical areas such as the superior temporal gyrus and planum polare

Question 17

• Patterson et al (2002):

Answer 17

Played a range of pitch evoking stimuli presented to the same listeners and recording with the fMRI of human brain and failed to find a overlapping pitch area when a wider set of stimulus used. Although IRNs did differentially activate the lHG. Other pitch evoking stimuli strongly activated other parts of the auditory cortex and not necessarily lHG. The area that most consistently activated by different pitch processing was the planum temporale.