Unit study of monkey frontal cortex: active localization of auditory and of visual stimuli

Abstract

The influence of sound localization behavior on unit activity in the frontal cortex of awake rhesus monkeys was examined by comparing responses under three behavioral conditions: auditory localization, during which a response was required to the location of a sound (broad-band noise) source; auditory detect, during which a response was required to indicate the occurrence of the sound regardless of location; visual localization, during which no sounds were presented and a response was required to the location of a visual stimulus; and nonperform, presentation of auditory stimuli as in the first two conditions, but with the animal sitting passively. Extracellular microelectrode recordings were made in the periarcuate region and dorsal and ventral prefrontal areas near the principal sulcus. Four monkeys were used with a total of 498 cells studied. Of the total population, only five cells were found to have characteristics similar to those of auditory units in the primary auditory cortex and the surrounding belt area. More typically, units were found that had strong short-latency responses specific to the auditory and/or visual localization tasks. These units had no or weak responses when the same sound stimuli were presented in the auditory detect task or when a monkey received the sound stimuli in a nonperforming condition. Two regions were identified, one medial and/or posterior to the arcuate sulcus, in Brodmann's area 6; the second included parts of areas 8 and 9 within the genu of the arcuate sulcus. Units from these regions are referred to, respectively, as the postarcuate and the prearcuate populations. Both populations responded predominantly during active localization behavior. Sixty-two percent of the postarcuate population responded during auditory localization, 32% responded during auditory detect, and only 18% responded to acoustic stimuli presented in the nonperforming condition. In the prearcuate population percentages in these three conditions were 35, 25, and 12%, respectively. For visual localization, 54% in the postarcuate population responded, whereas 42% in the prearcuate responded. Spatial tuning of units during auditory localization was similar to that seen in units of the primary auditory cortex, with the greatest percentages of units responding to stimuli contralateral to the recording site. Similar tuning was observed for the visual localization task as well. Similarities in spatial tuning between the auditory and visual localization conditions were examined to assess the "bimodal" nature of the units.(ABSTRACT TRUNCATED AT 400 WORDS)

On the Anticipatory Precue Activity in Motor Cortex

“…Furthermore, Wise and collaborators (Mauritz and Wise, 1986;Vaadia et al, 1988;di Pellegrino and Wise, 1993a) described an anticipatory activity in PMd preceding relevant sensory cues, even when the movement was to be executed after a subsequent delay of up to several seconds. Such anticipatory activity was also reported in other areas, including parietal area 5 (MacKay and Crammond, 1987), the frontal cingulate cortex (Niki and Watanabe, 1979), the dorsal prefrontal cortex (Vaadia et al, 1986;Niki and Watanabe, 1987), and M1 (Crammond and Kalaska, 1996;Fig. 3 in Roux et al, 2003).…”

“…The primary motor cortex (M1) and dorsal premotor cortex (PMd) are activated during movement execution (Weinrich et al, 1984(Weinrich et al, , 1985Requin, 1989, 1995;Crammond and Kalaska, 1996), but also beforehand, as the animal prepares to move (Wise and Mauritz, 1985;Wise and Kurata, 1989;Shen and Alexander, 1997a,b;Riehle, 2005), and after the presentation of relevant visual cues (Godschalk et al, 1981;Vaadia et al, 1986;Riehle and Requin, 1989;Miller et al, 1992;Boussaoud and Wise, 1993a,b;Kalaska, 1996, 2000;Yamagata et al, 2009). Furthermore, Wise and collaborators (Mauritz and Wise, 1986;Vaadia et al, 1988;di Pellegrino and Wise, 1993a) described an anticipatory activity in PMd preceding relevant sensory cues, even when the movement was to be executed after a subsequent delay of up to several seconds.…”

Development of Multidimensional Representations of Task Phases in the Lateral Prefrontal Cortex

“…A somatosensory region in the ventral LPFC of humans (Kostopoulos et al, 2007) in which neurons reflect the frequency of vibrotactile stimuli has been identified (Romo et al, 1999). Wide regions in the LPFC receive specific inputs from auditory areas in the superior temporal cortex (Hackett et al, 1999;Romanski et al, 1999a,b), and functional specialization has been demonstrated between the dorsal and the ventral LPFCs (Vaadia et al, 1986;Romanski et al, 1999b;Kikuchi-Yorioka and Sawaguchi, 2000;Romanski and Goldman-Rakic, 2002;Cohen et al, 2004;Sugihara et al, 2006;Russ et al, 2008;Cohen et al, 2009). In the current study, we observed a widespread distribution of auditory neurons without a clear functional segregation, which was reasonable because we asked the animals to detect the onset of a simple auditory signal.…”

Parietofrontal Circuits for Action and Space Perception in the Macaque Monkey

“…The SEF is an oculomotor field that can be identified with intracortical microstimulation and that, anatomically, is richly connected with the frontal eye field (FEF). The remaining part of F7 is scarcely excitable and has been object of few functional studies (Vaadia et al, 1986;di Pellegrino and Wise, 1991;Fuji et al, 2000). Some F7 neurons have visual responses even when the stimulus is not instructing a subsequent movement.…”