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I C Whitfield

Publications and source records attributed to I C Whitfield.

At least 19 recordsLinked to original sources
PubMed1981

Theory and experiment in so-called pulse-interval pitch.

Moore [1980] has criticised the conclusions of Whitfield [1979] who used an alternating pulsatile stimulus [Seebeck, 1843], and found that the predominating interpulse intervals produced in a single auditory nerve fibre did not correspond to the perceived pitch. Moore's criticism depends on an assumption he makes that is not in fact borne out by the experiments.

Animals↗
PubMed1980

Auditory cortex and the pitch of complex tones.

Two cats were trained to discriminate between rising and falling pitch sequences generated by complex tones. The finding of Heffner and Whitfield [J. Acoust. Soc. Am. 59, 915-919 (1976)], that the intact animals respond to the fundamental pitch rather than to the harmonic content, was confirmed. After bilateral ablation of auditory cortex this was no longer the case. The animals lost their initial training, but could be retrained to respond to the complex tone sequences; however, they now required to be separately trained to each complex tone and did not exhibit transfer between tone pairs that had similar pitch shift but different harmonic composition. The results suggest that cats without auditory cortex respond only to the individual frequencies of the complex and are unable to detect the overall pitch to which those complexes normally give rise.

Animals↗
PubMed1979

The object of the sensory cortex.

The phenomenon of "transfer" is used to draw attention to the point that whereas the brain stem animal can solve a variety of individual problem ad hoc, only the intact animal appears to be able to use the result of one problem to solve a closely related problem. It is suggested that this is because information is organized in the cortex as objects and concepts, rather than as a set of more or less elaborate features. The shortcomings of a hierarchical system of feature detectors as a model of cortical organization are examined, and compared with a distributive model. It is pointed out that our ways of thinking about complex tones--e.g. their pitch and harmonic structure--is related to the fact that sound suffers a Fourier transform at the cochlea, and it is this transform which is represented in the brain stem. It is suggested that an analogous integral transform may equally naturally represent the data as "objects" in the cortex. The resistance of such transforms to degradation by ablation, and the implication for single neurone behaviour are discussed.

Acoustic Stimulation↗
PubMed1978

Some further observations on the effects of unilateral cortical ablation on sound localization in the cat.

It has previously been shown that unilateral ablation of the whole auditory cortex in the cat disrupts the precedence effect, and also interferes with the ability of the normal animal to discriminate in the Y-maze between a single sound on one side and a double sound consisting of a signal on both left and right sides. The present work has confirmed these effects and has shown that both can be obtained with lesions confined to AI and AII. The "one-versus-two" deficit has invariably been seen in all the animals studied, but a proportion of animals do not show the precedence effect deficit. It has been confirmed that the apparent sucess of some animals can be due to the training effect of the one-versus-two paradigm, as was proposed in the earlier paper; however it has also been shown that this cannot be explanation in all cases. It has been demonstrated that cats are able to localize sound behind them with some success; turning around in the start box to reverse right and left space is therefore a possible strategy for overcoming a unilateral deficit. However, even with the head "fixed" in the forward-facing position, one animal was still able to run well above chance. The size of the lesion does not appear to be a correlate of the performance level.

Animals↗