PWS

*maˁmaˁ- - brain (SED I No. 184; Kogan 2005d; Kogan 2011: 220)

Not quite reliable. Scarce attestation only in Ugr., Arb. (phonetically questionable) and MSA. Cf. *muḫḫ- - brain, marrow No. 187. 

Ugaritic
mmˁ - brain (WUS 187)
see discussion of the meaning in SED I No. 184
Arabic
naˁāmat- - brain (of the horse); membrane that surrounds the brain (BK 2 1299)

Dissimilation < *maˁām(-­at)-­ < *maˁmaˁ(-­at)-­? (can n­- < *m­- be influenced by contamination with nuḫḫ-­, naḫāḫat-­ ‘bone marrow’ [ibid. 1219]?). Phonetically quiestionable. 

Mehri
mēma - brain (ML 260)

pl. mōma

Jibbali
maˁ - brain (JL 168)
Harsusi
māmā - brain (HL 87)

pl. mōmet

Soqotri
mímaˁ - brain (CSOL II 536)