906 resultados para Lacunar upper cortex


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This study examined muscle strength, muscle performance, and neuromuscular function during contractions at different velocities across maturation stages and between sexes. Participants included pre-pubertal, late-pubertal and adult males and females. All completed 8 isometric and 8 isokinetic leg extensions at two different velocities. Peak torque (PT), rate of torque development (PrTD), electromechanical-day (EMD), rate of muscle activation (Q30), muscle activation efficiency and coactivation were determined. Sex, maturity, and velocity main effects were found in PT and PrTD, reflecting greater values in men, adults, and isometric contractions respectively. When values were normalized to quadriceps cross-sectional area (qCSA), there was still an increase with maturity. EMD decreased with maturity. Adults had greater activation efficiency than children. Overall, differences in muscle size and neuromuscular function failed to explain group differences in PT or PrTD. More research is needed to investigate why adults may be affected to a greater extent by increasing movement velocity.

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The medial prefrontal cortex (mPFC) is involved in performance-monitoring and has been implicated in the generation of several electrocortical responses associated with self-regulation. The error-related negativity (ERN), the inhibitory Nogo N2 (N2), and the feedback-related negativity (FRN) are event-related potential (ERP) components which reflect mPFC activity associated with feedback to behavioural (ERN, N2) and environmental (FRN) consequences. Our main goal was to determine whether or not rnPFC activation varies as a function of motivational context (e.g., those involving performance-related incentives) or the use of internally versus externally generated feedback signals (i.e., errors). Additionally, we assessed medial prefrontal activity in relation to individual differences in personality and temperament. Participants completed a combination of tasks in which performance-related incentives were associated with task performance and feedback generated from internal versus external responses. MPFC activity was indexed using both ERP scalp voltage peaks and intracerebral current source density (CSD) of dorsal and ventral regions. Additionally, participants completed several questionnaires assessing personality and temperament styles. Given previous studies have shown that enhanced mPFC activity to loss (or negative) feedback, we expected that activity in the mPFC would generally be greater during the Loss condition relative to the Win condition for both the ERN and N2. Also, due to the evidence that the (vmPFC) is engaged in arousing contexts, we hypothesized that activity in the ventromedial prefrontal cortex (vmPFC) would be greater than activity in the dorsomedial prefrontal cortex (dmPFC), especially in the Loss condition of the GoNogo task (ERN). Similarly, loss feedback in the BART (FRN) was expected to engage the vmPFC more than the dmPFC. Finally, we predicted that persons rating themselves as more willing to engage in approach-related behaviours or to exhibit rigid cognitive styles would show reduced activity of the mPFC. Overall, our results emphasize the role of affective evaluations of behavioural and environmental consequences when self-regulating. Although there were no effects of context on brain activity, our data indicate that, during the time of the ERN and N2 on the MW Go-Nogo task and the FRN on the BART, the vrnPFC was more active compared to the dmPFC. Moreover, regional recruitment in the mPFC was similar across internally (ERN) and externally (FRN) generated errors signals associated with loss feedback, as reflected by relatively greater activity in the vmPFC than the dmPFC. Our data also suggest that greater activity in the mPFC is associated with better inhibitory control, as reflected by both scalp and CSD measures. Additionally, deactivation of the subgenual anterior cingulate cortex (sgACC) and lower levels of self-reported positive affect were both related to increased voluntary risk-taking on the BART. Finally, persons reporting higher levels of approach-related behaviour or cognitive rigidity showed reduced activity of the mPFC. These results are in line with previous research emphasizing that affect/motivation is central to the processes reflected by mediofrontal negativities (MFNs), that the vmPFC is involved in regulating demands on motivational/affective systems, and that the underlying mechanisms driving these functions vary across both individuals and contexts.

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Exposure to chronic stress can alter the structure and function of brain regions involved in learning and memory, and these effects are typically long-lasting if the stress occurs during sensitive periods of development. Until recently, adolescence has received relatively little attention as a sensitive period of development, despite marked changes in behaviour, heightened reactivity to stressors, and cognitive and neural maturation. Therefore, the purpose of the present study was to investigate the long-term effects of chronic stress in adolescence on two spatial learning and memory tasks (Morris water maze and Spatial Object Location test) and on a working memory task (Delayed Alternation task). Male rats were randomly assigned to chronic social instability stress (SS; daily 1 hour isolation and subsequent change of cage partner between postnatal days 30 and 45) or to a no-stress control group (CTL). During acquisition learning in the Morris water maze task, SS rats demonstrated impaired long-term memory for the location of the hidden escape platform compared to CTL rats, although the impairment was only seen after the first day of training. Similarly, SS rats had impaired long-term memory in the Spatial Object Location test after a long delay (240 minutes), but not after shorter delays (15 or 60 minutes) compared to CTL rats. On the Delayed Alternation task, which assessed working memory across delays ranging from 5 to 90 seconds, no group differences were observed. These results are partially in line with previous research that revealed adult impairment on spatial learning and memory tasks after exposure to chronic social instability stress in adolescence. The observed deficits, however, appear to be limited to long-term memory as no group differences were observed during brief periods of retention.

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Minutes, accounts and other records, 1812-1816, of an association formed at York, to alleviate distress in Upper Canada resulting from war with United States.

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Inscribed on cover: Falconbridge 1919. Previous owner's name inscribed on front flyleaf and stamped on various pages. "Reprinted from the Journal of Negro History, vol. iv, no.4, October, 1919" - cover.

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The earlier Journals of the House of Assembly are to be found in: Ontario. Bureau of Archives. Report of the Bureau of Archives for the Province of Ontario (where they have been printed due to their non-existence in their original form.).

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George Upper is a Niagara area artist. His limited edition prints feature local scenes, many from Port Dalhousie, Ontario.

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A grant of land to Ann Cook of the Township of Crowland. The land is situated in the township of Wainfleet, in the County of Lincoln, in the district of Niagara. Ann Cook is granted 200 acres in lot no. 32 in the 4th concession in Wainfleet. One of the signatures on the document is illegible but other signatures include: Prideaux Selby, auditor general on April 15, 1812. This is the date that the document was entered into the auditor’s office. Isaac Brock has signed in the upper left hand corner as “Isaac Brock President” which refers to the fact that he was President administering the Government of Upper Canada and Major General commanding the forces within the province. It is also signed on the left hand side by John Macdonell (who is buried at Brock’s Monument). At the time, he was the attorney general.

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The origins of Upper Lakes Shipping can be traced back to 1931, when Gordon Leitch, the general manager of Toronto elevators, sent Captain Bruce Angus to scout for potential ships that could be used to transport grain. The ship Sarnian was purchased as a result. It soon became apparent that more ships would be needed by the business, and Leitch subsequently partnered with James Norris of the Norris Grain Company, in order to transport their products more economically. The Upper Lakes and St. Lawrence Transportation Company (which later become known as Upper Lakes Shipping), was incorporated in 1932. In 1956, the company bought Port Weller Dry docks. At this point, the company began constructing new vessels designed to meet specific freight and classification needs.

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A summons "in the court of Requests - Upper Canada" Niagara District Division for a debt of three pounds, one shillings and six pence. Summons to appear before the Court of Requests, Robert Osborn vs. John Shadwick, signed by Walter Sumner, clerk of the court, 1841.

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Composite of the Woodruff Family of St. Davids, Upper Canada. This composite contains 6 4 ½ cm x 4 cm black and white photographs which include: Samuel DeVeaux Woodruff (1819-1904) [the birth and death dates listed on this composite are 1827-1912, but these are actually his wife’s dates] son of William Woodruff. Joseph Woodruff (1820-1882) [1820-1886] son of William Woodruff. Helena Woodruff (1828-1892) daughter of William Woodruff. Julia Woodruff (1825-1870) daughter of William Woodruff. Dr. William Woodruff (1830-1908) son of William Woodruff. Margaret Clements [Clement] Woodruff (1794-1882) wife of William Woodruff

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A Woodruff family genealogy in ten chapters. The chapters are titled: The Five New England Generations, Ezekiel's Seven Children, The Upper Canada Descendants, In Retrospect, Niagara (Newark), St. Davids, The War of 1812-1814, Some More Recent Portraits, Sources and References, Appendix. The first page of the book is inscribed "Best Wishes to Margaret and Percy from Norris", Oct. 5, 1959.

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Indenture between Harmonius Vanalstine of Thorold Township and Joseph Upper of Thorold Township regarding 98 acres in Lot no. 7 in the 1st Concession in the Township of Crowland - instrument no. 3469. This was listed in book A, folio 88, 89. September 11, 1851.