Left Hemisphere Specialization for Language in the Newborn

Differential Effects of Unilateral Lesions on Language Production in Children and Adults

“…To account for these longstanding and well-documented facts, it seems reasonable to hypothesize that the left side of the human brain contains some kind of specialized organ for language and speech (Fodor, 1983;Newmeyer, 1997;Pinker, 1994; Rice, 1996), one that should be observable in its approximate adult form at birth, not unlike the liver or the heart. This hypothesis is buttressed by studies showing that adult-like structural asymmetries between the left and right sides of the brain are evident at and before birth (Witelson & Pallie, 1973), and by electrophysiological studies showing that the left side of the brain is significantly more active in response to complex auditory stimuli (including speech) in the human infant (Molfese & Segalowitz, 1988).…”

“…To account for these longstanding and well-documented facts, it seems reasonable to hypothesize that the left side of the human brain contains some kind of specialized organ for language and speech (Fodor, 1983;Newmeyer, 1997;Pinker, 1994; Rice, 1996), one that should be observable in its approximate adult form at birth, not unlike the liver or the heart. This hypothesis is buttressed by studies showing that adult-like structural asymmetries between the left and right sides of the brain are evident at and before birth (Witelson & Pallie, 1973), and by electrophysiological studies showing that the left side of the brain is significantly more active in response to complex auditory stimuli (including speech) in the human infant (Molfese & Segalowitz, 1988).In view of all these facts, it is difficult to understand why adults and children who acquired unilateral brain injuries early in life perform so well on language tasks (Bates, 1999;Bates, Vicari, & Trauner, 1999;Eisele & Aram, 1995;Elman et al, 1996;Feldman, Holland, Kemp, & Janosky, 1992; Nass, in press;Stiles, Bates, Thal, Trauner, & Reilly, 1998;Vargha-Khadem, Isaacs, & Muter, 1994;Vicari et al, 2000). In fact, in the absence of confounding factors (e.g., intractable seizures-Vargha-Khadem, Isaacs, van der Werf, Robb, & Wilson, 1992), children with early left-hemisphere injuries almost always go on to acquire language abilities within the normal or low-normal range.…”

Planum Temporale and Heschl Gyrus Volume Reduction in Schizophrenia: A Magnetic Resonance Imaging Study of First-Episode Patients

“…[1][2][3][4][5] Several studies have reported abnormalities in portions of the superior temporal gyrus (STG) in patients diagnosed as having schizophrenia, [1][2][3] including planum temporale (PT) and Heschl gyrus (HG) (primary auditory cortex). [6][7][8][9][10][11][12][13][14] The impetus for much of this work is based on the role that the left (dominant) hemisphere PT plays in language processing [15][16][17] and the role that the HG plays in the initial processing of auditory information. [1][2][3] DeLisi et al 10 measured length of the sylvian fissure and reported asymmetry differences in patients with first-episode schizophrenia compared with controls.…”

Regional differentiation of neuron morphology in human left and right hippocampus: comparing normal to schizophrenia

“…see Rosene and Van Hoesen, 1987 , an approach which ignores the issue of left᎐right asymmetries Ž in the human brain Geschwind and Levitsky, 1968;Witelson and Pallie, 1973;Wada and Davies, . 1977;Turkewitz, 1988 .…”