activation during task performance. This technology elucidates the unique role of the prefrontal cortex (PFC) in gait control, notably under dual-task (DT) conditions ( Bishnoi et al., 2021 ). The PFC is associated with higher-order executive functions such as working memory and attention ( Shechner & Bar
Tal Krasovsky, Rawda Madi, Eyal Fruchter, Elias Jahjah, and Roee Holtzer
Charles Germain, Alexandra Perrot, Christophe Tomasino, Julien Bonnal, Canan Ozsancak, Pascal Auzou, and Fabrice Prieur
) that showed the prophylactic effects of regular exercise on prefrontal cortex (PFC) ( Colcombe et al., 2003 ), numerous transversal and interventional studies showed that physical activity can optimize the volume, integrity, and brain function of certain areas associated with the performance of
Luca Pollastri, Gabriele Gallo, Milena Zucca, Luca Filipas, Antonio La Torre, Ugo Riba, Luigi Molino, and Elisabetta Geda
been an increasing number of studies that have investigated the effects of anodal tDCS on endurance physical performance. The results are contrasting for all the areas targeted 3 , 4 (primary motor cortex—M1, insular cortex [IC], prefrontal cortex [PFC]), with some studies that showed positive effects
Joel A. Vilensky and Sid Gilman
From the late 1800s until approximately the middle of the 20th century, neurosurgeons made discrete motor cortex lesions in humans in attempts to reduce or eliminate a variety of involuntary movements, resulting mainly from epilepsy. In some cases, the neurosurgeons tested and recorded their patients' ability to perform various movements and to perceive various types of sensory stimuli after the operation. Although these studies have been largely forgotten, they have an immense advantage over primate lesion studies for understanding the function of the motor cortex because the patients were able to attempt to perform complex movements upon request, and to describe their perceptions of cutaneous stimuli, including integrated sensations (e.g., recognition of objects by palpation alone). We provide here a table containing the results of these studies pertaining to sensory deficits. The most consistent and persistent sensory deficits reported relate to object recognition and position sense. This finding is in keeping with recent electrophysiological studies in primates. Our analysis suggests that the “motor” cortex serves important sensory functions; hence, the term sensorimotor cortex, remains appropriate for the primate precentral (and postcentral) cortex.
Katherine G. Holste, Alia L. Yasen, Matthew J. Hill, and Anita D. Christie
The purpose of this study was to assess the effect of a cognitive task on motor cortex excitability and inhibition. Transcranial magnetic stimulation of the motor cortex was performed on 20 healthy individuals (18–24 years; 9 females) to measure motor evoked potentials (MEPs) and cortical silent periods at baseline, during, and following a secondary cognitive task. The MEP amplitude increased from 0.50 ± 0.09–0.87 ± 0.50 mV during a secondary cognitive task (p = .04), and returned to baseline (0.48 ± 0.31 mV; p = .90) posttask. The CSP duration also increased from 93.48 ± 28.76–113.6 ± 33.68 ms (p = .001) during the cognitive task, and returned to baseline posttask (89.0 ± 6.9 ms; p = .88). In the presence of a cognitive task, motor cortex excitability and inhibition were both increased relative to baseline. The increase in inhibition may help to explain the motor deficits experienced while performing a secondary cognitive task.
Gabriele Gallo, Elisabetta Geda, Roberto Codella, Emanuela Faelli, Marco Panascì, Luis Eduardo Ranieri, Luca Pollastri, Stefania Brighenti, Luigi Molino, Ugo Riba, Livio Luzi, Piero Ruggeri, and Luca Filipas
(primary motor cortex, insular cortex, and prefrontal cortex [PFC]) with some studies showing positive effects, 2 – 5 and others no variation, 6 , 7 in performance results. The low focality of traditional tDCS may be responsible for this heterogeneity, producing excitatory or inhibitory effects in other
Leonardo S. Fortes, Maicon R. Albuquerque, Heloiana K.C. Faro, Dalton de Lima-Júnior, Maria E.C. Ferreira, and Sebastião S. Almeida
cortex or dorsolateral prefrontal cortex (DLPFC), a-tDCS improves executive functions (e.g., inhibitory control and attention; Angius et al., 2019 ; Borducchi et al., 2016 ) and well-being in athletes ( Moreira et al., 2021 ). For example, Angius et al. ( 2019 ) found an improvement in Stroop task (i
Nick J. Davey, Steve R. Rawlinson, David W. Maskill, and Peter H. Ellaway
Transcranial magnetic stimulation (TMS) of the motor cortex was used to produce compound motor evoked potentials (cMEPs) in the first dorsal interosseus (FDI) muscle. The size of cMEPs was measured as an index of corticospinal excitability before and after initiation of a simple reaction task (SRT). The SRT, consisting of an abduction of the right index finger against a vertical support in response to a 1 kHz cueing tone, was performed in 6 healthy male subjects. cMEPs were facilitated when timed to occur just before the fastest simple reaction time (fSRT). When the cMEP was placed 15.5 ± 1.5 ms before the fSRT, its amplitude increased to 176 ± 36% of the control response seen in the relaxed state (no SRTs). Facilitation of the cMEP increased to 382 ± 43% of the control when it was placed 11.9 ± 1.5 ms after the fSRT. The facilitation of cMEP responses prior to the SRT is discussed with particular reference to the premovement potential that may be recorded over the cortex prior to a voluntary movement.
Y.L. Lo, H.H. Zhang, C.C. Wang, Z.Y. Chin, S. Fook-Chong, C. Gabriel, and C.T. Guan
In overt reading and singing tasks, actual vocalization of words in a rhythmic fashion is performed. During execution of these tasks, the role of underlying vascular processes in relation to cortical excitability changes in a spatial manner is uncertain. Our objective was to investigate cortical excitability changes during reading and singing with transcranial magnetic stimulation (TMS), as well as vascular changes with nearinfrared spectroscopy (NIRS). Findings with TMS and NIRS were correlated. TMS and NIRS recordings were performed in 5 normal subjects while they performed reading and singing tasks separately. TMS was applied over the left motor cortex at 9 positions 2.5 cm apart. NIRS recordings were made over these identical positions. Although both TMS and NIRS showed significant mean cortical excitability and hemodynamic changes from baseline during vocalization tasks, there was no significant spatial correlation of these changes evaluated with the 2 techniques over the left motor cortex. Our findings suggest that increased left-sided cortical excitability from overt vocalization tasks in the corresponding “hand area” were the result of “functional connectivity,” rather than an underlying “vascular overflow mechanism” from the adjacent speech processing or face/mouth areas. Our findings also imply that functional neurophysiological and vascular methods may evaluate separate underlying processes, although subjects performed identical vocalization tasks. Future research combining similar methodologies should embrace this aspect and harness their separate capabilities.
James Faulkner, Danielle Lambrick, Sebastian Kaufmann, and Lee Stoner
The purpose of this study was to assess the acute effects of posture (upright vs recumbent) during moderate-intensity cycle exercise on executive function and prefrontal cortex oxygenation in young healthy adults.
Seventeen physically active men (24.6 ± 4.3 years) completed 2 30-minute submaximal exercise tests (conditions: upright and recumbent cycle ergometry). Executive function was assessed using the “color” and “word” Stroop task, preexercise (resting) and postexercise. Regional oxygen saturation (rSO2) to the prefrontal cortex was continuously monitored using near-infrared spectroscopy.
Significant improvements in executive function (Stroop color and word tasks) were observed after 30 minutes of exercise for both upright and recumbent cycling (P < .05). However, there were no differences in executive function between cycling conditions (P > .05). A significant increase in rSO2 was recorded immediately postexercise compared with preexercise for both conditions (P < .05), with a trend (P = .06) for higher peak rSO2 following recumbent cycling compared with upright cycling (81.9% ± 6.5% cf 79.7% ± 9.3%, respectively).
Although submaximal cycling exercise acutely improves cognitive performance and prefrontal oxygenation, changes in cognition are not perceived to be dependent on body posture in young, healthy men.