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Simulating stimulus- and TMS-induced interference in short-term memory using a model of prefrontal cortex

Scalar short-term memory (STM) tasks are those in which the to-be-remembered property of a stimulus can be represented as a scalar quantity – for example, the frequency of a tactile vibration or an auditory pure tone, or the duration or amplitude of a stimulus. Scalar STM tasks have been studied extensively using single-cell methods [13], and have proven to be useful model systems for examining behavioural aspects of short-term memory [46] and developing computational models [710]. In two studies [11, 12], we applied a model of prefrontal cortex [9] to experimental datasets [5, 13].

In Study 1, we simulated the effects of presenting an irrelevant (distractor) stimulus to experimental subjects during the maintenance period of a vibrotactile scalar STM task by assuming the stimulus was encoded into memory, intruding into the PFC memory store. We were able to replicate previous experimental results [5], and our results also suggested that distractors were only encoded into memory on approximately 50% of trials, consistent with experimental indications that activity in sensory cortex may be inhibited during memory maintenance in order to protect the contents of memory against interference [6, 14].

In Study 2, we simulated a previous vibrotactile scalar STM study in which TMS was applied to somatosensory cortex during the maintenance period of the memory task, resulting in decreased performance [13]. We were able to replicate experimental results by assuming that TMS produced increased, noisy neural activity in sensory cortex, which then degraded the contents of the PFC memory store through feedforward interference.


  1. 1.

    Romo R, Brody CD, Hernández A, Lemus L: Neuronal correlates of parametric working memory in the prefrontal cortex. Nature. 1999, 399: 470-473. 10.1038/20939.

  2. 2.

    Romo R, Salinas E: Flutter discrimination: Neural codes, perception, memory and decision making. Nat Rev Neurosci. 2003, 4: 203-218. 10.1038/nrn1058.

  3. 3.

    Lemus L, Hernández A, Romo R: Neural encoding of auditory discrimination in ventral premotor cortex. Proc Nat Acad Sci. 2009, 106: 14640-14645. 10.1073/pnas.0907505106.

  4. 4.

    Harris JA, Harris IM, Diamond ME: The topography of tactile working memory. J Neurosci. 2001, 21: 8262-8269.

  5. 5.

    Bancroft T, Servos P: Distractor frequency influences performance in vibrotactile working memory. Exp Brain Res. 2011, 208: 529-532. 10.1007/s00221-010-2501-2.

  6. 6.

    Bancroft TD, Servos P, Hockley WE: Mechanisms of interference in vibrotactile working memory. PLoS ONE. 2011, 6: e22518-10.1371/journal.pone.0022518.

  7. 7.

    Machens CK, Romo R, Brody CD: Flexible control of mutual inhibition: A neural model of two-interval discrimination. Science. 2005, 307: 1121-1124. 10.1126/science.1104171.

  8. 8.

    Deco G, Rolls ET: Decision-making and Weber's law: A neurophysiological model. Eur J Neurosci. 2006, 24: 901-916. 10.1111/j.1460-9568.2006.04940.x.

  9. 9.

    Miller P, Wang XJ: Inhibitory control by an integral feedback signal in prefrontal cortex: A model of discrimination between sequential stimuli. Proc Nat Acad Sci. 2006, 103: 201-206. 10.1073/pnas.0508072103.

  10. 10.

    Verguts T: How to compare two quantities? A computational model of flutter discrimination. J Cog Neurosci. 2007, 19: 409-419. 10.1162/jocn.2007.19.3.409.

  11. 11.

    Bancroft TD, Hockley WE, Servos P: Irrelevant sensory stimuli interfere with working memory storage: Evidence from a computational model of prefrontal neurons. Cogn Affect Behav Neurosci. 2013, 13: 23-34. 10.3758/s13415-012-0131-9.

  12. 12.

    Bancroft TD, Hogeveen J, Hockley WE, Servos P: TMS-induced neural noise in sensory cortex interferes with short-term memory storage. Front Comput Neurosci. 2014

  13. 13.

    Harris JA, Miniussi C, Harris IM, Diamond ME: Transient storage of a tactile memory trace in primary somatosensory cortex. J Neurosci. 2002, 22: 8720-8725.

  14. 14.

    Linke AC, Vicente-Grabovetsky A, Cusack R: Stimulus-specific suppression preserves information in auditory short-term memory. Proc Nat Acad Sci. 2011, 108: 12961-12966. 10.1073/pnas.1102118108.

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Correspondence to Tyler D Bancroft.

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  • Prefrontal Cortex
  • Computational Model
  • Memory Task
  • Neural Activity
  • Pure Tone