A reward increases running-wheel performance without changing cell proliferation, neuronal differentiation or cell death in the dentate gyrus of C57BL/6 mice

Abstract

A reward increases running-wheel performance without changing cell proliferation, neuronal differentiation or cell death in the dentate gyrus of C57BL/6 mice Klaus, F; Hauser, T; Slomianka, L; Amrein, I; Lipp, H P Klaus, F; Hauser, T; Slomianka, L; Amrein, I; Lipp, H P (2009). A reward increases running-wheel performance without changing cell proliferation, neuronal differentiation or cell death in the dentate gyrus of C57BL/6 mice. A reward increases running-wheel performance without changing cell proliferation, neuronal differentiation or cell death in the dentate gyrus of C57BL/6 mice Abstract Exercise is one of the best-known stimulators of adult hippocampal neurogenesis, but it is not known if voluntary changes in the intensity of exercise are accompanied by changes in neurogenesis. In this study we investigated whether a reward influences the performance in a running wheel and the rate of cell proliferation, neuronal differentiation and cell death in C57BL/6 mice. Mice had free access to a running wheel during the first week of the experiment. In the second week, animals were rewarded for their performance and compared to normal voluntary running and control mice. A reward significantly increased the performance by 78% when compared to the non-rewarded performance of the first week.The performance of the non-rewarded runners remained relatively constant. Fourteen days of exercise significantly increased cell proliferation by 27% and the number of doublecortin immunoreactive cells by 46%. A reward and the associated increase of performance did not modulate proliferation, cell death or the number of cells entering the neuronal lineage. We suggest that, in C57BL/6 mice, either exercise increases adult hippocampal neurogenesis to a ceiling value, which is reached by a performance at or below the level achieved by voluntary wheel running, or that a possible positive effect of increased running-wheel activity is balanced by stress resulting from rewarded running, which is no longer performed on a strictly voluntary basis. We suggest that, in C57BL/6 mice, either exercise increases adult hippocampal neurogenesis to a ceiling value, which is reached by a performance at or below the level achieved by voluntary wheel running, or that a possible positive effect of increased is balanced by stress resulting from rewarded running, which is no longer performed on a strictly voluntary basis.

Different regulation of adult hippocampal neurogenesis in Western house mice (Mus musculus domesticus) and C57BL/6 mice

“…The increase in the number of immature neurons is much higher in C57BL/6 mice than in house mice. Consistent with previous studies [2, 19], no correlations were found between AHN and performance.…”

“…Although AHN has been described in humans [15], it is not clear if behaviors that modulate AHN in laboratory rodents should do so in humans because of differences in both genetics and motivation for running. In laboratory mice, an increase in performance in expectation of a reward is not associated with an increase in AHN [2], suggesting that psychological states during exercise and the underlying motivation are factors in the regulation of AHN. This idea is supported by the finding that positive effects of forced treadmill running on AHN are lost if the speed or duration is increased beyond a certain level [16].…”

A morphologically distinct granule cell type in the dentate gyrus of the red fox correlates with adult hippocampal neurogenesis

“…In addition, a series of frozen sections was stained with Giemsa solution following an adjusted protocol to visualize pyknotic cells (Klaus et al, 2009). Sections were mounted and dried over night at room temperature.…”

The neuroprotective effects of voluntary exercise in a restraint stress model

“…There are some types of behaviour that activate the HPA axis but are associated with enhanced rates of adult neurogenesis. For instance, physical exercise augments cell proliferation, neuronal differentiation and the survival of new neurons in the dentate gyrus of the adult mouse 39,40 and rat 41,42 . Thus it is possible that by employing voluntary exercise before stress induction the model in this study did not entirely eliminate the level of stress signals, but extensively activated neurogenesis as an adaptive response to cellular stress.…”