Premotor cortex of monkeys: set- and movement-related activity reflecting amplitude and direction of wrist movements

Abstract

1. Neuronal activity was recorded from the premotor cortex (PM) of Japanese monkeys while they performed hand movements with different amplitudes and directions. On each behavioral trial, two instructions were given sequentially: 1) an amplitude instruction (large or small) and 2) a direction instruction (flexion or extension). The onset of movement was triggered by a visual signal after a delay period. 2. Among various kinds of task-related neuronal activity recorded in the PM, two types were selected for study: 1) set-related activity, sustained activity change during the delay period that followed presentation of instruction signals (IS); and 2) movement-related activity, activity change immediately before and during movement, which followed the trigger signal (TS) presentation. 3. Thirty-two of 101 set-related neurons showed activity change after presentation of the first IS (Delay 1 set-related activity), when they were instructed in either amplitude or direction, but not both. All of the set-related neurons showed activity modulation after presentation of the second IS (Delay 2 set-related activity). When neurons showed both Delay 1 and Delay 2 set-related activity, they were usually more active during Delay 2, i.e., when the monkeys had received both amplitude and directional ISs. A majority of neurons with Delay 2 set-related activity (64%) showed relation to both movement amplitude and direction. Twenty-eight percent of the neurons showed relation to either amplitude or direction, but not both. These findings seem consistent with a view that serial, rather than parallel, processes of motor programming operate in preparation of intended movements. 4. A majority of PM neurons with movement-related activity (51%) showed activity change related to both the direction and amplitude of movement. Forty-two percent showed selective relation to either direction or amplitude. These findings support a view that PM contributes to the control of limb movements. 5. Histological reconstruction showed that a vast majority of PM set-related neurons were located in the dorsal aspect of the PM (PMd), medial to the arcuate spur and lateral to the superior precentral sulcus. In contrast, movement-related neurons were distributed in two distinct foci: one in the ventral aspect of the PM (PMv), immediately caudal to the genu of the arcuate sulcus and lateral to the spur of the sulcus; and the other in the PMd, overlap;ing the location of set-related neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Dissociating the Role of Ventral and Dorsal Premotor Cortex in Precision Grasping

“…The role of F2 has never been investigated in a grip-lift task. Most data about F2 concern reaching movements and support the classical view that F2 codes for the direction and amplitude of reaching movements (Kurata, 1993;Jeannerod et al, 1995;Scott et al, 1997;Messier and Kalaska, 2000).…”

The Role of the Monkey Dorsal Pontine Nuclei in Goal-Directed Eye and Hand Movements

“…It seems more plausible that the two studies tapped functionally distinct types of HMR neurons in the DPN, contributing to different aspects of forearm movements and arguably dependent on different sources of cerebrocortical input. Cortical activity related to wrist movement has been described in a number of areas, among them primary motor cortex and premotor cortex (Kurata, 1993;Riehle and Requin, 1995;Kakei et al, 1999Kakei et al, , 2001, projecting to more ventral parts of the PN (Brodal, 1978;Schmahmann et al, 2004a) not explored in the present study. A more likely source of HMR information in the DPN are axons originating from various posterior parietal areas, known to project to the dorsal parts of the PN, that contains neurons activated by hand reaches like area 5 (Ashe and Georgopoulos, 1994;Johnson et al, 1996;Scott et al, 1997;Hamel-Pâquet et al, 2006), area 7a (MacKay, 1992;Snyder et al, 1997;Merchant et al, 2004;BattagliaMayer et al, 2007), or the parietal reach area PRR (Batista and Andersen, 2001;Calton et al, 2002;Snyder et al, 2006).…”

Basal ganglia network mediates the control of movement amplitude

“…The ®rst hypothesis, recently endorsed by Berardelli et al (2001), proposes that BG output reinforces the cortical mechanisms that prepare the commands to move. Compelling support for this model can be found in neurophysiological data suggesting that: (i) motor and premotor cortical areas are involved in the planning of movement amplitude (Fu et al, 1993(Fu et al, , 1995Kurata, 1993;Messier & Kalaska, 2000); and (ii) the activity of these areas is signi®cantly disordered in PD patients during the performance of various motor tasks (for a review see Berardelli et al, 2001). A second hypothesis, not necessarily incompatible with this central view, is the idea that movement extent depends on the appropriate tuning of spinal circuits, such as presynaptic inhibition of the Ia monosynaptic re¯ex in the antagonist muscles prior to movement onset.…”