Physical activity and cognitive brain function in learning

Physical activity refers to body movement that is produced by the contraction of the Skeletal Muscle and that increases energy expenditure. It includes activities in the workplace around the house and during leisure time (Pesce et al, 2021). Exercise is the link between our brain and learning (Ratey and Hagerman (2008), this theory was researched by Hillman, Erickson, and Kramer (2008) who reviewed several meta-analyses, and indicated that in all of the studies they reviewed physical activity had a positive effect on cognition. According to Ratey & Hagerman, (2008) physical activity impacts the learner on three different levels; firstly it is said to improve alertness, attention, and motivation; second, it prepares and encourages nerve cells to bind to one another, which is the cellular basis for logging in new information; and finally it spurs the development of new nerve cells from stem cells in the hippocampus. Silverman and Deuster (2014) have also suggested that regular physical activity affects the following biological pathways: (i) optimization of neuroendocrine and physiological responses to psychosocial and physical stressors; (ii)action as a buffer against stress and stress-related (iii) promotion of an anti-inflammatory state; and (iv) enhancement of neuroplasticity and growth factor expression. Ratey and Hagerman (2008) mention that exercise directly influences learning by improving the brain’s potential to tune in and process new information via the increased glutamate that is signaled between synapses. And the greater this signaling process the greater the swelling of the synapses creating a stronger connection. This process is termed long-term potentiation (LTP). It has been suggested by Koch and Hasbrouck, (2013) that physical activity triggers the brain to increase and improve the function of neurons by releasing the neurotransmitters: serotonin, norepinephrine, and dopamine which play a vital role in regulating brain chemistry and behavior (Berg, 2010). Physical activity activates these natural motivators in the brain elevating and balancing our neurotransmitters as well as enhancing the connection between their neurons (Trudeau & Shephard, 2009). In accordance, physical activity increases synaptic efficacy following an increase of synaptic traffic from the hippocampal long-term potentiation (Trudeau and Shephard, 2009), which “binds” cells and retains memory formation, giving weight to a strong indicator of a psychological perspective of the benefits of physical activity has on learning and memory (Ratey and Hagerman, 2008). As previously mentioned physical activity triggers the brain to increase and improve the function of neurons by releasing the neurotransmitters: serotonin, norepinephrine, and dopamine, the importance of these neurotransmitters is that Serotonin controls mood, anger, aggression, and become impulsive, Dopamine triggers feeling satisfied and motivation where Norepinephrine influences attention, perception, and arousal (Martini, Timmons, & Tallitsch, 2009), all of vital importance to the optimal brain chemistry that wakeups and increase the energy level in the learning individual and helps improve information storage, retrieval, and learning behaviors. In addition, Ratey & Hagerman (2008) state that about 80 percent of the signaling in the brain is carried out by two neurotransmitters that balance each other’s effect: glutamate stirs up activity to begin the signaling cascade, and gamma-aminobutyric acid (GABA) clamps down on activity. According to Adaes (2018) in the brain, groups of neurons (nerve cells) form neural circuits to carry out specific small-scale functions (e.g., formation and retrieval of memory). These neural circuits interconnect with each other to form large-scale brain networks, which carry out more complex functions (e.g., hearing, vision, movement). To get the individual nerve cells to work together across these networks some type of communication between them is needed and one way it is accomplished is by chemical messenger molecules called neurotransmitters (Zhou, 2014). Glutamate plays a prominent role in neural circuits involved with synaptic plasticity, the ability for strengthening or weakening of signaling between neurons over time to shape learning and memory. It’s a major player in the subset of plasticity called long-term potentiation (LTP). The glutamatergic system is paramount for fast signaling and information processing in neuronal networks. Glutamate signaling is critical in brain regions, including the cortex and hippocampus, which are fundamental for cognitive function. Glutamate receptors are widely expressed throughout the CNS, not only in neurons but also in glial cells (Purvis, 2011). In addition to the improved functioning of the neurotransmitters, physical activity also directly influences the hormonal system by releasing the hormones IGF 1 (insulin-like growth factor), VEGF (vascular endothelial growth factor), and FGF-2 (fibroblast growth factor) (Berg, 2010). When the working muscles contract there is a release IGF-1, which in turn is released in your brain activating learning and transferring short-term memories into long-term memories (Ratey & Hagerman, 2008). It has been suggested that when FGF-2 is released in the brain during physical activity there is an impact upon long-term potentiation which aids the tissues within the brain to grow (Trudeau & Shephard, 2009). In relationship with the above hormones, physical activity triggers the input of movement to the hippocampus causing it to release BDNF (Brain-derived neurotrophic factor (Mallory, 2006) though Irisin which is cleaved from fibronectin type III domain containing 5 (FNDC5), a transmembrane precursor protein expressed in muscle under the control of PGC-1α (Moon et al, 2013). FNDC5 is also known to be profoundly expressed in many regions of the brain, including cerebellar Purkinje cells, the hypothalamus, and the hippocampus, a region of the brain involved in memory and spatial awareness (Wrann, et al,2013). Sattelmair & Ratey (2009) refer BDNF as to a “MiracleGro” due to its ability in creating new cells within the hippocampus, the region of the brain that builds and maintains our cells as well as sorting and grouping together information to form new neuronal connections (Trudeau & Shephard, 2009). It is now known that neurogenesis occurs in the hippocampus and the layer of cells surrounding the lateral cerebral ventricles (the subventricular zone) and that exercise stimulates this proliferation (Van Praag, 1999). These cells are sometimes referred to as endogenous stem cells. According to Berg (2010), BDNF is a very important protein ingredient in sprouting new dendrites needed for learning to occur and is a crucial biological link between thoughts, emotions, and movement and plays an important role in the homeostatic function and survival of the neurons; particularly in synaptic plasticity and neurogenesis (Pesce et al, 2021).