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Biological Basis of Behavior
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
The frontal lobe is the largest of the brain’s structures. It is the main site of the higher cognitive functions. The frontal lobe is variably divided: one commonly used classification is to divide it into the precentral cortex, then the strip immediately anterior to the central or Sylvian fissure, and the prefrontal cortex, the section extending from the frontal poles to the precentral cortex, including the frontal operculum. The precentral cortex is composed of the primary motor cortex (Brodmann area 4), the premotor cortex, and the supplementary motor (Brodmann area 6). The precentral cortex is involved in voluntary movement, language, and posture and body orientation. The prefrontal cortex is subdivided into several regions, including the dorsolateral, orbitofrontal, ventrolateral, ventromedial, basal, orbital, and frontopolar areas. Each of these areas is suggested to have specialized behavioral functions and has widespread connectivity. Damage to these areas results in characteristic behavioral abnormalities.
What Is Coded in the Primary Motor Cortex?
Published in Alexa Riehle, Eilon Vaadia, Motor Cortex in Voluntary Movements, 2004
Unfortunately, a deep understanding of motor cortex function still eludes us. In what follows, I will deal with the motor cortex proper, i.e., Brodmann area 4, and focus on the control of reaching movements of the upper limb. Also, I will not consider in any detail issues such as how visual signals are integrated into motor behavior, the putative coordinate transformations in other motor areas necessary to convert retinal input into a reference frame meaningful for action, or how the proprioceptive and motor systems interact. I am assuming that the final command for a motor act comes from the motor cortex; this chapter will focus on the properties (characteristics) of such a command.
The Central Nervous System Organization of Behavior
Published in Rolland S. Parker, Concussive Brain Trauma, 2016
Major axonal control of motions descends from the motor cortex, the red nucleus, the pontomedullary reticular formation, and the vestibular nuclei. Two systems perform synergistically. The medial system provides postural control for stance, ambulation, and orientation of the head. Vestibular and reticular nuclei axons descend in ventromedial pathways in the spinal cord. The lateral voluntary system superimposes sophisticated, voluntary movements in response to stimulation from the motor cortex forming the medullary pyramids, decussating, and decussating to the lateral column with the exception of a small minority of uncrossed corticospinal axons (Schieber & Baker, 2000). Premotor areas control high-order aspects of movement. The primary motor cortex then decomposes movement into simple components in a body map that is communicated to the spinal cord for execution. The primary motor cortex (Brodmann area 4; M1) is made up of overlapping areas that control the contrelateral action of single muscles or muscle groups. It receives input from the primary somatosensory cortex (Brodmann areas 1, 2, 3) and from posterior area 5, which with area 7 is involved in integrating multiple sensory modalities for motor planning. Premotor damage causes more complex motor impairment than does damage to the primary motor cortex (Krakauer & Ghez, 2000). The supplementary motor area (premotor) instructs the motor area which neurons to fire and in what order they should be fired in order to achieve a spatial temporal trajectory. The motor areas of the cortex have reciprocal relations with these centers: directly with the thalamic; indirectly from ventral anterior and ventrolateral nuclei, which forward stimuli from the globus pallidus and the cerebellum (which receives information from the pons), and from projections to the supplementary motor cortex, premotor cortex (Brodmann area 6), and primary motor cortex; indirectly via the somatosensory cortex; the posterior parietal cortex relays visual and somatosensory information to the motor areas. Two large subcortical motor systems send output via the thalamus to the cortical motor systems (i.e., the basal ganglia [inhibitory] and the cerebellum [excitatory]) (Schieber & Baker, 2003).
A review of magnetoencephalography use in pediatric epilepsy: an update on best practice
Published in Expert Review of Neurotherapeutics, 2021
Hiroshi Otsubo, Hiroshi Ogawa, Elizabeth Pang, Simeon M Wong, George M Ibrahim, Elysa Widjaja
Movement-related evoked fields (MEF) are generated in brain motor areas prior to movement onset, as the brain prepares to initiate a motor activity [106,107]. Localization of this readiness potential identifies contralateral M1, or primary motor cortex (Brodmann Area 4) on the anterior bank of the central sulcus from hand, foot, mouth, or tongue movements [108]. Typically, these movements involve finger tapping, a repeated contraction, or an isometric movement, which, most importantly, are time-locked to brain activity using either simultaneous electromyogram (EMG) recordings or some sort of light-beam interruption or switch closure [92]. The patient must be awake, alert, cooperative, and able to perform each movement in a fairly consistent fashion. The most challenging factor for adequate performance (and therefore data acquisition) is boredom. These protocols can be conducted in children [109]. Mapping of motor cortex is indicated in patients with cortical malformations [22] or lesions [100,110] in and around the Rolandic cortex.
Regional estimates of cortical thickness in brain areas involved in control of surgically restored limb movement in patients with tetraplegia
Published in The Journal of Spinal Cord Medicine, 2020
Lina Bunketorp Käll, Jan Fridén, Malin Björnsdotter
Cortical thickness processing and analysis was performed using the Freesurfer image analysis suite, which is documented and freely available for download online (http://surfer.nmr.mgh.harvard.edu/). We examined average cortical thickness measures obtained from individual level surface reconstructions for two types of regions of interest (ROIs). First, we examined the anatomically localized primary motor cortex in the FreeSurfer Brodmann Atlas, i.e. Brodmann Area 4 (posterior and anterior portions combined). Since all participants were right-handed, we restricted the analyses to the left hemisphere. Second, we examined ROIs derived from the functionally defined motor cortex area that had regained control of the pinch grip, as described above.32 Here, we used the reported individual coordinates of the primary motor cortex CoGs. ROIs were created as volumetric spheres with a 5 mm radius centered on these coordinates. The spherical ROIs were then converted into each participants’ native cortical surface space ROIs using FreeSurfer, and the average cortical thickness in each ROIs was extracted.
Fluid–structure interaction analysis of cerebrospinal fluid with a comprehensive head model subject to a rapid acceleration and deceleration
Published in Brain Injury, 2018
Figure 10 shows the cortical areas affected by the SPH impulse intensity at the peak velocity. The diffuse pattern of SPH impulse intensity maxima may represent the cortical areas most affected by a concussion. Brodmann’s areas with at least 10% coverage of maximal SPH impulse intensity include 40 (10.1%), 4 (11.7%), 1, 2, 3 (15.3%) and 52 (21.7%). Brodmann area 40, the left supramarginal gyrus, receives input from multiple sensory modalities and supports complex linguistic processes. Lesions here may result Gerstmann syndrome and fluent aphasia, such as Wernicke’s aphasia. Brodmann area 4 is typically associated with motor functions but also plays a supportive role in sensory perception. Lesions in the primary motor cortex may result in paralysis and decreased somatic sensation. Brodmann areas 1, 2 and 3 comprise the postcentral gyrus in the parietal lobe and are primarily associated with somatosensory perception. Lesions in the postcentral gyrus may result in cortical sensory impairments, including loss of fine touch and proprioception. Brodmann area 52, the parainsular, is the smallest of the mentioned areas and has the high percentage of SPH impulse intensity maxima coverage. It joins the insula and the temporal lobe.