Integration of Motor and Visual Information in the Parietal Area 5 During Locomotion

Abstract

The parietal cortex receives both visual- and motor-related information and is believed to be one of the sites of visuo-motor coordination. This study for the first time characterizes integration of visual and motor information in activity of neurons of parietal area 5 during locomotion under conditions that require visuo-motor coordination. The activity of neurons was recorded in cats during walking on a flat surface-a task with no visuo-motor coordination required (flat locomotion), walking along a horizontal ladder or a series of barriers-a task requiring visuo-motor coordination for an accurate foot placement on surface that is heterogeneous along the direction of progression (ladder and barriers locomotion), and walking along a narrow pathway-a task requiring visuo-motor coordination on surface homogeneous along the direction of progression (narrow locomotion). During flat locomotion, activity of 66% of the neurons was modulated in rhythm of stepping, usually with one peak per cycle. During ladder and barrier locomotion, the proportion of rhythmically active neurons significantly increased, their modulation became stronger, and the majority of neurons had two peaks of activity per cycle. During narrow locomotion, however, the activity of neurons was similar to that during flat locomotion. We concluded that, during locomotion, parietal area 5 integrates two types of information: signals about the activity of basic locomotion mechanisms and signals about heterogeneity of the surface along the direction of progression. We describe here the modes of integration of these two types of information during locomotion.

Long-Lasting Working Memories of Obstacles Established by Foreleg Stepping in Walking Cats Require Area 5 of the Posterior Parietal Cortex

“…Recent studies have reported a role of the parietal cortex of the cat during complex walking and reaching tasks (Fabre and Buser, 1981;Beloozerova and Sirota, 2003;, so it is reasonable to consider whether the loss of memory after a lesion in area 5 is attributable to a disruption of neuronal systems involved in the basic motor control of stepping over obstacles in the absence of delays. We believe this to be unlikely.…”

Precise rhythmicity in activity of neocortical, thalamic and brain stem neurons in behaving cats and rabbits

“…The database for this study was a subset from the databases used for our previously published studies [6,7,8,9,49,50,60]. The selection of the neurons and neuronal populations for this study was based on the duration of available spike trains (4000-65000 spikes).…”

“…The procedures of surgical preparation of the animals were described previously [7,50,52]. Surgery was performed under isoflourane (cats, 2-5%), halothane (cats, 1-2%), or pentobarbital sodium (rabbits, 25-35 mg/kg) anesthesia using aseptic procedures.…”

“…The crosspieces of the horizontal ladder were flat and 5 cm wide, and they were spaced 25 cm apart (Fig. 1A, see also [7]). A series of barriers consisted of five barriers 4.5 cm high and 2 cm thick placed 43 cm apart (Fig.…”

“…The relation of spike activity of these neuronal populations to locomotion and respiration we have described in a series of separate reports: [6] -cat ventrolateral thalamus; [7] -cat parietal cortex; [9,60] -cat motor cortex; [8] -rabbit motor cortex; [49,50] -cat respiratory medulla. The database for this study was a subset from the databases used for the above published studies.…”