Conditional Selection of Contra- and Ipsilateral Forelimb Movements by the Dorsal Premotor Cortex in Monkeys

Abstract

Kurata K. Conditional selection of contra-and ipsilateral forelimb movements by the dorsal premotor cortex in monkeys. J Neurophysiol 103: 262-277, 2010. First published November 4, 2009 doi:10.1152/jn.91241.2008. It has been suggested that the dorsal premotor cortex (PMd) may contribute to conditional motor behavior. Thus when a selection is instructed by arbitrary conditional cues, it is possible that the unilateral PMd affects behavior, regardless of which arm, contra-or ipsilateral, is to be used. We examined this possibility by recording neuronal activity and injecting muscimol into the caudal PMd (PMdc) of monkeys while they were performing a reaching task toward visuospatial targets with either the right or left arm, as instructed by low-frequency or high-frequency tone signals. Following the injection of a small amount of muscimol (1 L; 5 g/L) into the unilateral PMdc, monkeys exhibited two major deficits in behavioral performance: 1) erroneous selection of the arm not indicated by the instruction (selection errors) and 2) no movement initiation in response to a visuospatial target cue serving as a trigger signal for reaching within the reaction time limit (movement initiation errors). Errors were observed following unilateral muscimol injection into both right and left PMdc, although selection errors occurred with significantly greater frequency in the arm contralateral to the injection site. By contrast, movement initiation errors were more commonly observed in left-arm trials, regardless of whether the right or left PMdc was inactivated. Notably, errors rarely occurred following a ventral PM muscimol injection. These results suggest that the left and right PMdc cooperate to transform conditional sensory cues into appropriate motor output and can affect both contra-and ipsilateral body movement.

Mossy fibers in the cerebellar hemisphere show delay activity in a delayed response task

“…In the cerebro-cerebellar loop, delay period activities were observed in M1/PM (Tanji and Evarts, 1976;Weinrich and Wise, 1982;Kurata and Wise, 1988;Crammond and Kalaska, 1994;Kakei et al, 1999Kakei et al, , 2001Nakayama et al, 2008;Kurata, 2010), in putative PN (as MFs, present study) and in the motor thalamus (Kurata, 2005) during an arm movement task. We also observed delay activity of DN neurons in the same task used here (unpublished observations).…”

“…Indeed, we found that there were common features in the delay activity of M1/PM neurons and the MFs. First, as observed in PM and M1 (Tanji and Evarts, 1976;Weinrich and Wise, 1982;Kurata and Wise, 1988;Crammond and Kalaska, 1994;Nakayama et al, 2008;Kurata, 2010), most MFs had delay activity triggered by instruction cue presentation. Second, many MFs showed modulation changes that started more than 1000 ms after instruction cue presentation, i.e., after the earliest timing of go signal.…”

“…delay period activity (Tanji and Evarts, 1976;Weinrich and Wise, 1982;Kurata and Wise, 1988;Crammond and Kalaska, 1994;Kakei et al, 1999Kakei et al, , 2001Nakayama et al, 2008;Kurata, 2010). This activity is thought to be involved in motor planning and/or preparation for upcoming movement (Hoshi and Tanji, 2002).…”

Population coding of grasp and laterality-related information in the macaque fronto-parietal network

“…Indeed, a number of studies have probed how neural circuits represent laterality of reaching movements in macaque monkeys. Integration of arm specific and arm independent information has been found in the posterior parietal cortex [1][2][3] , premotor cortex [4][5][6][7][8][9] , and primary motor cortex (M1) [10][11][12] , although the outputs from M1 have been identified as mostly contra-lateral 13,14 .…”

“…Neural activity in these areas is strongly modulated by visual object properties 17,18 , extrinsic goals 19 , performed grip types 20,21 , and preparatory activity in these areas can be used to decode the visual properties of objects and complex hand shapes required to grasp a diverse range of objects [22][23][24] , as well as predict reaction times 25 . Although laterality has been studied in ventral premotor cortex, these studies either employed no delay period 26 , simple movements 10 , or required only reaching movements 6,7,27 . Additionally, to our knowledge, no electrophysiological studies of laterality have been undertaken in AIP.…”