Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Dissociable neural mechanisms supporting visual short-term memory for objects

Abstract

Using visual information to guide behaviour requires storage in a temporary buffer, known as visual short-term memory (VSTM)1, that sustains attended information across saccades and other visual interruptions. There is growing debate on whether VSTM capacity is limited to a fixed number of objects2,3 or whether it is variable4,5. Here we report four experiments using functional magnetic resonance imaging that resolve this controversy by dissociating the representation capacities of the parietal and occipital cortices. Whereas representations in the inferior intra-parietal sulcus (IPS) are fixed to about four objects at different spatial locations regardless of object complexity, those in the superior IPS and the lateral occipital complex are variable, tracking the number of objects held in VSTM, and representing fewer than four objects as their complexity increases. These neural response patterns were observed during both VSTM encoding and maintenance. Thus, multiple systems act together to support VSTM: whereas the inferior IPS maintains spatial attention over a fixed number of objects at different spatial locations, the superior IPS and the lateral occipital complex encode and maintain a variable subset of the attended objects, depending on their complexity. VSTM capacity is therefore determined both by a fixed number of objects and by object complexity.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Example trials from experiments 1, 2 and 4.
Figure 2: Results from experiments 1, 2 and 4.
Figure 3: Results from experiment 3.

References

  1. Phillips, W. A. On the distinction between sensory storage and short-term visual memory. Percept. Psychophys. 16, 283–290 (1974)

    Article  Google Scholar 

  2. Pashler, H. Familiarity and visual change detection. Percept. Psychophys. 44, 369–378 (1988)

    CAS  Article  Google Scholar 

  3. Luck, S. J. & Vogel, E. K. The capacity of visual working memory for features and conjunctions. Nature 390, 279–281 (1997)

    ADS  CAS  Article  Google Scholar 

  4. Xu, Y. Encoding colour and shape from different parts of an object in visual short-term memory. Percept. Psychophys. 64, 1260–1280 (2002)

    Article  Google Scholar 

  5. Alvarez, G. A. & Cavanagh, P. The capacity of visual short-term memory is set both by visual information load and by number of objects. Psychol. Sci. 15, 106–111 (2004)

    CAS  Article  Google Scholar 

  6. Fuster, J. M. & Jervey, J. P. Neuronal firing in the inferotemporal cortex of the monkey in a visual memory task. J. Neurosci. 2, 361–375 (1982)

    CAS  Article  Google Scholar 

  7. Goldman-Rakic, P. S. in Handbook of Physiology: The Nervous System, Higher Functions of the Brain (eds Mountcastle, V. B., Plum, F. & Geiger, S. R.) 373–417 (American Physiological Society, Bethesda, Maryland, 1987)

    Google Scholar 

  8. Miller, E. K., Erickson, C. A. & Desimone, R. Neural mechanisms of visual working memory in prefrontal cortex of the macaque. J. Neurosci. 16, 5154–5167 (1996)

    CAS  Article  Google Scholar 

  9. Cohen, J. D. et al. Temporal dynamics of brain activation during a working memory task. Nature 386, 604–608 (1997)

    ADS  CAS  Article  Google Scholar 

  10. Courtney, S. M., Ungerleider, L. G., Keil, K. & Haxby, J. V. Transient and sustained activity in a distributed neural system for human working memory. Nature 386, 608–611 (1997)

    ADS  CAS  Article  Google Scholar 

  11. Desimone, R. Neural mechanisms for visual memory and their role in attention. Proc. Natl Acad. Sci. USA 93, 13494–13499 (1996)

    ADS  CAS  Article  Google Scholar 

  12. Smith, E. E. & Jonides, J. Neuroimaging analyses of human working memory. Proc. Natl Acad. Sci. USA 95, 12061–12068 (1998)

    ADS  CAS  Article  Google Scholar 

  13. Pessoa, L., Gutierrez, E., Bandettini, P. A. & Ungerleider, L. G. Neural correlates of visual working memory: fMRI amplitude predicts task performance. Neuron 35, 975–987 (2002)

    CAS  Article  Google Scholar 

  14. Curtis, C. E. & D'Esposito, M. Persistent activity in the prefrontal cortex during working memory. Trends Cogn. Sci. 9, 415–423 (2003)

    Article  Google Scholar 

  15. Jonides, J., Lacey, S. C. & Nee, D. E. Processes of working memory in mind and brain. Curr. Dir. Psychol. Sci. 14, 2–5 (2005)

    Article  Google Scholar 

  16. Pasternak, T. & Greenlee, M. W. Working memory in primate sensory systems. Nature Rev. Neurosci. 6, 97–107 (2005)

    CAS  Article  Google Scholar 

  17. Todd, J. J. & Marois, R. Capacity limit of visual short-term memory in human posterior parietal cortex. Nature 428, 751–754 (2004)

    ADS  CAS  Article  Google Scholar 

  18. Todd, J. J. & Marois, R. Posterior parietal cortex activity predicts individual differences in visual short-term memory capacity. Cogn. Affect Behav. Neurosci. 6, 144–155 (2005)

    Article  Google Scholar 

  19. Vogel, E. K. & Machizawa, M. G. Neural activity predicts individual differences in visual working memory capacity. Nature 428, 748–751 (2004)

    ADS  CAS  Article  Google Scholar 

  20. Malach, R. et al. Object-related activity revealed by functional magnetic resonance imaging in human occipital cortex. Proc. Natl Acad. Sci. USA 92, 8135–8139 (1995)

    ADS  CAS  Article  Google Scholar 

  21. Grill-Spector, K., Kushnir, T., Edelman, S., Itzchak, Y. & Malach, R. Cue-invariant activation in object-related areas of the human occipital lobe. Neuron 21, 191–202 (1998)

    CAS  Article  Google Scholar 

  22. Kourtzi, Z. & Kanwisher, N. Cortical regions involved in perceiving object shape. J. Neurosci. 20, 3310–3318 (2000)

    CAS  Article  Google Scholar 

  23. Grill-Spector, K., Kushnir, T., Hendler, T. & Malach, R. The dynamics of object-selective activation correlate with recognition performance in human. Nature Neurosci. 3, 837–843 (2000)

    CAS  Article  Google Scholar 

  24. Awh, E. & Jonides, J. Overlapping mechanisms of attention and spatial working memory. Trends Cogn. Sci. 10, 433–437 (1999)

    Google Scholar 

  25. Cowan, N. The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behav. Brain Sci. 24, 87–114 (2001)

    CAS  Article  Google Scholar 

  26. Talairach, J. & Tournoux, P. Co-Planar Stereoaxis Atlas of the Human Brain (transl. Rayport, M) (Thieme Medical, New York, 1988)

    Google Scholar 

  27. Sereno, M. I., Pitzalis, S. & Martinez, A. Mapping of contralateral space in retinotopic coordinates by a parietal cortical area in human. Science 294, 1350–1354 (2001)

    ADS  CAS  Article  Google Scholar 

  28. Kanwisher, N. & Wojciulik, E. Visual attention: insights from brain imaging. Nature Rev. Neurosci. 1, 91–100 (2000)

    CAS  Article  Google Scholar 

  29. Corbetta, M. & Shulman, G. L. Control of goal-directed and stimulus-driven attention in the brain. Nature Rev. Neurosci. 3, 215–229 (2002)

    Article  Google Scholar 

  30. Culham, J. C. et al. Attention response functions: Characterizing brain areas using fMRI activation during parametric variations of attentional load. Neuron 32, 737–745 (2001)

    CAS  Article  Google Scholar 

Download references

Acknowledgements

We thank D. Widders for assistance in MRI scanning, and S. J. Luck and R. Marois for comments on earlier versions of this manuscript. This research was supported by an NIH grant to M.M.C. and in part by an NSF grant to Y.X.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Yaoda Xu.

Ethics declarations

Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Methods

This file describe the details of the experimental design. (DOC 33 kb)

Supplementary Figure

Illustrates the localizer scans used in the study. (PDF 1208 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Xu, Y., Chun, M. Dissociable neural mechanisms supporting visual short-term memory for objects. Nature 440, 91–95 (2006). https://doi.org/10.1038/nature04262

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature04262

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing