Neurons get smaller (Stockmeier and colleagues, 2004 as cited in Pittenger et al., 2008). If you are completing a behavioural modification plan with your pet you may feel frustrated if they are not learning new behaviours as quickly as possible – but this can be common. This is why it can be helpful to write a diary entry after a walk or have a traffic light system in your phone calendar about how things are going. Our brains can often cling to the negative (it’s helpful from an evolutionary perspective!)

Memory can be affected by high levels of glucocorticoids (Bodnoff et al., 1995 as cited in Pittenger at al., 2008). They are released by the adrenal glands – these are glands that sit above the kidney and release hormones such as cortisol, and they increase alertness – leading to fight or flight. 

Reference

Bodnoff S, Humphreys A, Lehman J, Diamond D, Rose G, Meaney M(1995). Enduring effects of chronic corticosterone treatment on spatial learning, synaptic plasticity and hippocampal neuropathol-ogy in young and mid-aged rats. J Neurosci 15:61–69.

Pittenger C, Duman RS. Stress, depression, and neuroplasticity: a convergence of mechanisms. Neuropsychopharmacology. 2008 Jan;33(1):88-109.

Stockmeier CA, Mahajan GJ, Konick LC, Overholser JC, Jurjus GJ, Meltzer HY et al (2004). Cellular changes in the postmortem hippocampus in major depression. Biol Psych 56: 640–650.