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Partial dissociation in the neural bases of VSTM and imagery in the early visual cortex.

Saad E, Wojciechowska M, Silvanto J - Neuropsychologia (2015)

Bottom Line: We hypothesized that any differential effect of TMS on VSTM and imagery would indicate that their neuronal bases differ at the level of EVC.The impact of TMS on sensitivity did not differ between VSTM and imagery, but did depend on whether the tasks were carried concurrently or alone.This study shows that neural processes associated with VSTM and imagery in the early visual cortex can be partially dissociated.

View Article: PubMed Central - PubMed

Affiliation: Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, 00076 Espoo, Finland; Institute of Behavioral Sciences, University of Helsinki, 00014 Helsinki, Finland. Electronic address: saad.ely@gmail.com.

No MeSH data available.


Related in: MedlinePlus

Timeline of an experimental trial. At the start of each trial, participants were presented with a cue (a vertical grating). The task involved maintaining the contrast of the grating by holding it in memory and/or forming a conscious mental image of it and maintaining it throughout the maintenance period. TMS pulse train was applied 2.5 s after the onset of the maintenance period. At the end of each trial, participants were asked to judge the test cue contrast relative to VSTM/imagery content (i.e. is the test cue of lower or higher contrast). (A) In “VSTM alone” and “Imagery alone” blocks, the assessment of memory and imagery were carried out in separate blocks. (B) In “concurrent” blocks, participants were informed at the end of the trial whether memory for the original memory cue would be assessed, or whether they should perform the contrast discrimination task relative to their conscious mental image.
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f0005: Timeline of an experimental trial. At the start of each trial, participants were presented with a cue (a vertical grating). The task involved maintaining the contrast of the grating by holding it in memory and/or forming a conscious mental image of it and maintaining it throughout the maintenance period. TMS pulse train was applied 2.5 s after the onset of the maintenance period. At the end of each trial, participants were asked to judge the test cue contrast relative to VSTM/imagery content (i.e. is the test cue of lower or higher contrast). (A) In “VSTM alone” and “Imagery alone” blocks, the assessment of memory and imagery were carried out in separate blocks. (B) In “concurrent” blocks, participants were informed at the end of the trial whether memory for the original memory cue would be assessed, or whether they should perform the contrast discrimination task relative to their conscious mental image.

Mentions: Within the same day of testing, two sub-sessions were carried out for each participant. In session 1, conditions 1 and 2 were run (see Fig. 1A). For both conditions, 2 blocks of 32 trials were run for both TMS conditions (Early Visual Cortex, Sham). In Session 2, condition 3 was run in 4 blocks of 32 trials for both TMS conditions (see Fig. 1B). The order of sessions was counterbalanced, as was the order of blocks within each session. Each block contained Memory/imagery main cues of four different contrasts (0.2, 0.3, 0.4, and 0.5 Michelson contrast). The contrast difference between the test cue and the main cue was either ±0.06 or ±0.09.


Partial dissociation in the neural bases of VSTM and imagery in the early visual cortex.

Saad E, Wojciechowska M, Silvanto J - Neuropsychologia (2015)

Timeline of an experimental trial. At the start of each trial, participants were presented with a cue (a vertical grating). The task involved maintaining the contrast of the grating by holding it in memory and/or forming a conscious mental image of it and maintaining it throughout the maintenance period. TMS pulse train was applied 2.5 s after the onset of the maintenance period. At the end of each trial, participants were asked to judge the test cue contrast relative to VSTM/imagery content (i.e. is the test cue of lower or higher contrast). (A) In “VSTM alone” and “Imagery alone” blocks, the assessment of memory and imagery were carried out in separate blocks. (B) In “concurrent” blocks, participants were informed at the end of the trial whether memory for the original memory cue would be assessed, or whether they should perform the contrast discrimination task relative to their conscious mental image.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542523&req=5

f0005: Timeline of an experimental trial. At the start of each trial, participants were presented with a cue (a vertical grating). The task involved maintaining the contrast of the grating by holding it in memory and/or forming a conscious mental image of it and maintaining it throughout the maintenance period. TMS pulse train was applied 2.5 s after the onset of the maintenance period. At the end of each trial, participants were asked to judge the test cue contrast relative to VSTM/imagery content (i.e. is the test cue of lower or higher contrast). (A) In “VSTM alone” and “Imagery alone” blocks, the assessment of memory and imagery were carried out in separate blocks. (B) In “concurrent” blocks, participants were informed at the end of the trial whether memory for the original memory cue would be assessed, or whether they should perform the contrast discrimination task relative to their conscious mental image.
Mentions: Within the same day of testing, two sub-sessions were carried out for each participant. In session 1, conditions 1 and 2 were run (see Fig. 1A). For both conditions, 2 blocks of 32 trials were run for both TMS conditions (Early Visual Cortex, Sham). In Session 2, condition 3 was run in 4 blocks of 32 trials for both TMS conditions (see Fig. 1B). The order of sessions was counterbalanced, as was the order of blocks within each session. Each block contained Memory/imagery main cues of four different contrasts (0.2, 0.3, 0.4, and 0.5 Michelson contrast). The contrast difference between the test cue and the main cue was either ±0.06 or ±0.09.

Bottom Line: We hypothesized that any differential effect of TMS on VSTM and imagery would indicate that their neuronal bases differ at the level of EVC.The impact of TMS on sensitivity did not differ between VSTM and imagery, but did depend on whether the tasks were carried concurrently or alone.This study shows that neural processes associated with VSTM and imagery in the early visual cortex can be partially dissociated.

View Article: PubMed Central - PubMed

Affiliation: Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, 00076 Espoo, Finland; Institute of Behavioral Sciences, University of Helsinki, 00014 Helsinki, Finland. Electronic address: saad.ely@gmail.com.

No MeSH data available.


Related in: MedlinePlus