Functional properties of neurons in the temporo-parietal association cortex of awake monkey

Abstract

The temporo-parietal association cortex around the caudal end of the Sylvian fissure was studied with the single cell recording technique in three awake behaving Macaca speciosa-monkeys. Of the 197 cells isolated, 5% were active only during the monkey's own movements, mostly during head rotation, and 95% were responsive to sensory stimulation: 54% to auditory stimuli, 24% to somatosensory stimuli, 13% to both of these and 4% to visual stimuli. Some cells, classified as responsive to somatosensory stimuli, were activated only by passive rotation of the head on the cervical axis; it is possible that they were driven by vestibular stimuli. Half of the cells were activated by stimuli on both sides of the monkey, and almost all the rest, only by stimuli on the side contralateral to the hemisphere recorded. Of the acoustically drivable cells, 95% responded to natural sounds, such as, rubbing hands together, rustle of clothes, clicks or jingles (sounds with noise spectrum and rapid intensity transitions). Most of these neurons were also examined with pure tones of 0.2-20 kHz: various inhibitory or excitatory responses were elicited in half of them, usually over a wide range of frequencies. The responses of most acoustically drivable cells (62%) depended on the location of the sound source with reference to the monkey's head so that the maximal response was elicited by sounds with a certain angle of incidence, usually on the contralateral side. The present results suggest that the area studied participates in the analysis of the temporal pattern of a sound, the location of the sound source and in spatial control of head movements.

Selective memory retrieval of auditory what and auditory where involves the ventrolateral prefrontal cortex

“…We next proceeded to test the hypothesis that this ventrolateral prefrontal region may be interacting functionally with the auditory temporal region that is known to play a role in the encoding and retention of auditory stimuli (32,33) and the parietal region that processes spatial information (34)(35)(36). We therefore examined whether there was a significant change in functional connectivity between the midventrolateral prefrontal cortex and the secondary auditory temporal and the posterior parietal region during the active retrieval compared with the recognition control trials.…”

“…There are considerable anatomical data that the midventrolateral prefrontal cortex (and particularly area 45) is extensively connected with the superior temporal gyrus and the nearby dorsal bank of the superior temporal sulcus (through the extreme capsule and the arcuate fasciculus) and also with the inferior parietal lobule (area PG) (via the second branch of the superior longitudinal fasciculus) (14, 16-18, 20, 37). The superior temporal region of the primate brain is critical for the encoding and short-term maintenance of auditory information (32,33,38), whereas the caudal superior temporal gyrus and the adjacent parabelt region in the caudal superior temporal sulcus entering the inferior parietal lobule are involved in the spatial aspects of auditory coding (34,36). Indeed, a recent study using transcranial magnetic stimulation has shown that the caudal part of the superior temporal gyrus, close to the inferior parietal lobule, is involved in auditory localization to a greater extent than the more rostral temporal region (39).…”

Dissociating the Human Language Pathways with High Angular Resolution Diffusion Fiber Tractography

“…It has been shown that different clusters of neurons within the auditory belt region of the superior temporal gyrus respond selectively to auditory stimuli (Rauschecker and Tian, 2000;Tian et al, 2001). For instance, the lateral auditory belt, which is connected to ventrolateral frontal area 45, responds to the type of calls that an animal makes, whereas the more posterior extent of the auditory belt, which is connected to the caudal dorsolateral frontal areas (i.e., area 8 and rostral area 6), is involved in spatially selective auditory stimuli (Leinonen et al, 1980). These findings have led to the proposal that a more anterior section of the auditory belt region may be involved in an anterior auditory object recognition stream and the posterior section in an auditory spatial stream (Rauschecker and Tian, 2000).…”

Body ownership and embodiment: Vestibular and multisensory mechanisms

“…Another vestibular area has been described in the posterior parietal cortex and was activated during caloric and galvanic vestibular stimulations particularly in the intraparietal sulcus [50,85,112] and superior parietal lobule [118]. These regions are likely homologous to monkey area 7 [82] and the ventral and medial intraparietal areas [27,77] receiving vestibular information as well as visual, somatosensory and auditory cues. There is finally evidence of vestibular projections to the primary motor and premotor cortices (including also the frontal eye fields), and to the inferior frontal gyrus, in relation to the vestibular control of motor and oculomotor functions [6,47,50,85,94].…”