How do humans compute approximate number? According to one influential theory, approximate number representations arise in the intraparietal sulcus and are amodal, meaning that they arise independent of any sensory modality. Alternatively, approximate number may be computed initially within sensory systems. Here we tested for sensitivity to approximate number in the visual system using steady state visual evoked potentials. We recorded electroencephalography from humans while they viewed dotclouds presented at 30 Hz, which alternated in numerosity (ranging from 10 to 20 dots) at 15 Hz. At this rate, each dotcloud backward masked the previous dotcloud, disrupting top-down feedback to visual cortex and preventing conscious awareness of the dotclouds' numerosities. Spectral amplitude at 15 Hz measured over the occipital lobe (Oz) correlated positively with the numerical ratio of the stimuli, even when nonnumerical stimulus attributes were controlled, indicating that subjects' visual systems were differentiating dotclouds on the basis of their numerical ratios. Crucially, subjects were unable to discriminate the numerosities of the dotclouds consciously, indicating the backward masking of the stimuli disrupted reentrant feedback to visual cortex. Approximate number appears to be computed within the visual system, independently of higher-order areas, such as the intraparietal sulcus.

Unconscious Number Discrimination in the Human Visual System / Lucero, C.; Brookshire, G.; Sava-Segal, C.; Bottini, R.; Goldin-Meadow, S.; Vogel, E. K.; Casasanto, D.. - In: CEREBRAL CORTEX. - ISSN 1047-3211. - ELETTRONICO. - 30:11(2020), pp. 5821-5829. [10.1093/cercor/bhaa155]

Unconscious Number Discrimination in the Human Visual System

Bottini R.;
2020-01-01

Abstract

How do humans compute approximate number? According to one influential theory, approximate number representations arise in the intraparietal sulcus and are amodal, meaning that they arise independent of any sensory modality. Alternatively, approximate number may be computed initially within sensory systems. Here we tested for sensitivity to approximate number in the visual system using steady state visual evoked potentials. We recorded electroencephalography from humans while they viewed dotclouds presented at 30 Hz, which alternated in numerosity (ranging from 10 to 20 dots) at 15 Hz. At this rate, each dotcloud backward masked the previous dotcloud, disrupting top-down feedback to visual cortex and preventing conscious awareness of the dotclouds' numerosities. Spectral amplitude at 15 Hz measured over the occipital lobe (Oz) correlated positively with the numerical ratio of the stimuli, even when nonnumerical stimulus attributes were controlled, indicating that subjects' visual systems were differentiating dotclouds on the basis of their numerical ratios. Crucially, subjects were unable to discriminate the numerosities of the dotclouds consciously, indicating the backward masking of the stimuli disrupted reentrant feedback to visual cortex. Approximate number appears to be computed within the visual system, independently of higher-order areas, such as the intraparietal sulcus.
2020
11
Lucero, C.; Brookshire, G.; Sava-Segal, C.; Bottini, R.; Goldin-Meadow, S.; Vogel, E. K.; Casasanto, D.
Unconscious Number Discrimination in the Human Visual System / Lucero, C.; Brookshire, G.; Sava-Segal, C.; Bottini, R.; Goldin-Meadow, S.; Vogel, E. K.; Casasanto, D.. - In: CEREBRAL CORTEX. - ISSN 1047-3211. - ELETTRONICO. - 30:11(2020), pp. 5821-5829. [10.1093/cercor/bhaa155]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/287601
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 5
  • Scopus 10
  • ???jsp.display-item.citation.isi??? 10
social impact