Multiple Demand Network - Connectome Guide

Multiple Demand Network (MD)

Why we think these networks are worth considering in decision making:

Damage to the MD network has been shown in several studies to correlate with the degree of decline in higher cognitive function.

Evidence that these networks are responsible for useful function in humans:

Multiple demand network encompasses lateral prefrontal cortex (LPFC) in inferior fontal sulcus (IFS), the anterior insula/frontal operculum (AI/FO), the dorsal anterior cingulate/presupplementary motor area (ACC/pre-SMA), a small region in the anterior frontal cortex (AFC), and the intraparietal sulcus (IPS).¹

Lateral studies demonstrated an extended multiple demand network demonstrated including the areas bilateral pre-SMA/MCC, aINS, MFG/IFG for higher cognitive functions.²

These networks are reported to be involved in a variety of cognitive demands including novelty, perceptual difficulty, response conflict and different memory types.

Stimulation of MD with rTMS in healthy participants improve both the accuracy and response times during the first stages of learning pseudoword-object matching whereas a similar improvement was not found for established vocabulary.³

Consequences of damage to this network:

Structural brain damage: Lesions restricted to the components of this network have shown to be predictive of fluid intelligence deficits whereas lesions outside these regions were not predictive even though they are located in the similar parts of the cortex.⁴ Several behavioral and neuroimaging studies suggested an important role for MD in recovery from aphasia.⁵ Studies revealed a direct causal relation between MD and novel vocabulary learning. In line with this, post stroke studies show that recovery from language deficits can be predicted by the strength of activity in the MD.⁶

Mental Illness: Conducting a meta analysis with 5493 patients and 5728 control participants, McTeague et al (2017) identified a common pattern of impaired activity that parallels the MD observed in intact cognition.⁷ In their study, they included imaging studies investigated different tasks performed by patients with schizophrenia, bipolar or unipolar depression, anxiety disorders and substance use disorders.

a9-46v

ᐅ Summary

Area a9-46v (anterior 9-46 ventral): part of the lateral frontal lobe regions. Like Area 46, plays a role in goal-directed higher- order cognitive processes. The mid- DLPFC, which includes areas 9-46 and 46, is also involved in the conscious, active control of planned behavior.

ᐅ Where is it?

Area a9-46v (anterior 9-46 ventral) is located at the anterior portior of the middle frontal gyrus.

ᐅ What are its borders?

Area a9-46v borders area 46 posteriorly, and area 9-46d medially. Its lateral border is mainly with area p47r and a slight contribution with IFSa. Its anterior limit forms a wedge with areas p10p and a47r.

ᐅ What are its functional connections?

Area a9-46v demonstrates functional connectivity to area 46, 9-46d, p9-46v, a10p, p10p, 6ma, i6-8, a47r, p47r, 8C, and IFSa in the dorsolateral frontal lobe, areas 8BM, and a32prime in the medial frontal lobe, area 11L in the orbitofrontal region, area TE1p in the temporal lobe, area AVI in the insula, areas LIPd, PF, IP1, and IP2 in the parietal lobe, and areas 7pm, 31a, and RSC in the medial parietal lobe .

ᐅ What are its white matter connections?

Area a9-46v is structurally connected to local parcellations. White matter tracts from this parcellation are highly variable. Short association bundles connect with 8C, 9-46d, 46, IFSa and p47r.

ᐅ What is known about its function?

Area 9-46d, like Area 46, plays a role in goal-directed higher-order cognitive processes. The mid-dorsolateral prefrontal cortex, which includes areas 9-46 and 46, is also involved in the conscious, active control of planned behavior.

a9-46v_a

A: lateral-medial

a9-46v_b

B: anterior-posterior

a9-46v_c

C: superior-inferior

a9-46v_dti

DTI image

p9-46v