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. 2010 Oct 19;107(42):18167-72.
doi: 10.1073/pnas.1007277107. Epub 2010 Oct 4.

Prefrontal cortex and basal ganglia contributions to visual working memory

Bradley Voytek  1 , Robert T Knight
Affiliations

Prefrontal cortex and basal ganglia contributions to visual working memory

Bradley Voytek et al. Proc Natl Acad Sci U S A. .

Abstract

Visual working memory (VWM) is a remarkable skill dependent on the brain's ability to construct and hold an internal representation of the world for later comparison with an external stimulus. The prefrontal cortex (PFC) and basal ganglia (BG) interact within a cortical and subcortical network supporting VWM. We used scalp electroencephalography in groups of patients with unilateral PFC or BG lesions to provide evidence that these regions play complementary but dissociable roles in VWM. PFC patients show behavioral and electrophysiological deficits manifested by attenuation of extrastriate attention and VWM-related neural activity only for stimuli presented to the contralesional visual field. In contrast, patients with BG lesions show behavioral and electrophysiological VWM deficits independent of the hemifield of stimulus presentation but have intact extrastriate attention activity. The results support a model wherein the PFC is critical for top-down intrahemispheric modulation of attention and VWM with the BG involved in global support of VWM processes.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Patient lesion reconstruction. Structural MRI slices illustrating the lesion overlap across the two patient groups (color represents number of subjects with a lesion at that voxel). For the PFC group (n = 6), mean lesion volume was 58.6 cm3 and maximal lesion overlap (>50%) was in Brodmann areas 6, 8, 9, and 46 centered in the middle frontal gyrus and including portions of the inferior and middle frontal gyrus in some patients. For the BG group (n = 6), mean lesion volume was 9.7 cm3 and maximal lesion overlap was in the putamen and encompassed the head and body of the caudate as well as the globus pallidus in some patients. All lesions are normalized to the left hemisphere for comparison; however, two patients in each group had right hemisphere lesions. Software reconstructions were performed using MRIcro (53).
Fig. 2.
Fig. 2.
Behavioral paradigm and performance. (A) Diagram of task design. (B) For a patient with a left unilateral PFC lesion, as illustrated here, stimuli that appear in the left visual hemifield are ipsilesional, and the visual information selectively enters the intact cerebral hemisphere, whereas stimuli that appear in the right visual hemifield are contralesional and selectively enter the damaged hemisphere. (C) Plots of average behavior by group and hemifield. Patients with unilateral PFC lesions performed as well as controls when stimuli were presented ipsilesionally but were impaired for contralesional stimuli. In contrast, patients with unilateral BG lesions performed more poorly overall, regardless of the hemifield of stimulus presentation. (*P < 0.05 compared with controls, **P < 0.0005, error bars represent SEM). (D) Control subjects and PFC patients performed equally well across trials. BG patients were significantly impaired in early trials.
Fig. 3.
Fig. 3.
Electrophysiological analyses (group grand averages). (A) Average CDA for control subjects collapsed across hemifield. For controls, CDA amplitude increases with memory load (*main effect of load, P < 0.0005). (B) Summary of CDA findings for ipsilesional stimuli in the two patient groups (shown in detail in C–F) and for left hemifield stimuli for controls. For ipsilesional stimuli (C and E), both controls and the PFC group show a significant effect of memory load on CDA (*P < 0.05, error bars represent SEM) that is not seen in the BG group (ns, not significant). For contralesional stimuli (D and F), the relationship between CDA and load is abolished in both patient groups. Both patient groups generated a sustained negative shift for contralesional stimuli that was not sensitive to VWM load (SI Results).
Fig. 4.
Fig. 4.
Attention-modulated ERPs. N1 amplitudes from the contralateral visual cortex in response to the memory array. In the PFC group there is a significant effect of hemisphere (**P = 0.023) where N1 amplitudes are attenuated for contralesional stimuli and are lower than control amplitudes (*P = 0.003). The BG group shows no such deficit (error bars represent SEM).
See this image and copyright information in PMC

References

    1. Müller NG, Machado L, Knight RT. Contributions of subregions of the prefrontal cortex to working memory: Evidence from brain lesions in humans. J Cogn Neurosci. 2002;14:673–686. - PubMed
    1. Tsuchida A, Fellows LK. Lesion evidence that two distinct regions within prefrontal cortex are critical for n-back performance in humans. J Cogn Neurosci. 2009;21:2263–2275. - PubMed
    1. Rossi AF, Bichot NP, Desimone R, Ungerleider LG. Top down attentional deficits in macaques with lesions of lateral prefrontal cortex. J Neurosci. 2007;27:11306–11314. - PMC - PubMed
    1. Bressler SL. Large-scale cortical networks and cognition. Brain Res Brain Res Rev. 1995;20:288–304. - PubMed
    1. Curtis CE, D'Esposito M. Persistent activity in the prefrontal cortex during working memory. Trends Cogn Sci. 2003;7:415–423. - PubMed

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