Organiser: Lianne Robinson, University of Aberdeen, UK
Apathy is one of the earliest and most common behavioural and psychological symptoms in dementia and neurodegenerative diseases including Alzheimer’s disease (AD), frontotemporal dementia (FTD) and Parkinson’s disease (PD). It is also associated with other diseases including Huntington’s, major depressive disorder and negative symptoms of schizophrenia. In patients, apathy can include symptoms of loss of motivation, initiative, and interest, listlessness, and indifference, flattening of emotions, absence of drive and passion. Researchers have later refined this to a reduction in goal direct behaviours. Apathy assessment in human patients has centred on using clinical scales and questionnaires to assess symptoms including reduced social interactions and changes in activities and emotions. In addition, objective/measurable behavioural tests of reward-based decision-making tasks and assessments of executive function have also been utilised with studies revealing that apathy is related to executive dysfunction (disrupted abstract thinking, planning and performing of complex tasks). Unfortunately, the behavioural tests used to assess apathy in patients do not lend themselves to be directly translated to animals. Furthermore, considering the multi-dimensional aspects of apathy and the close link with depression/anhedonia there is a challenge to back translate apathy like behaviour observed in human patients to animal models.
Behavioural tests to assess apathy-like behaviour in animals have focussed on tests that measure reduced goal directed behaviour (effort-based tasks including progressive ratio reinforcement test) and reward-based activity, altered social interactions, reduced exploration/spontaneous activity similar to observations in clinical trials, or a decline in species-specific behaviours including nest building and burrowing. Such species-specific behaviours are seen as indicators of impaired motivation to perform daily life activities and are reminiscent of the reduced activities of daily living (ADLs) observed in patients with apathy.
This symposium will bring together researchers working within the field of apathy to discuss how different behavioural methods can be utilised to assess apathy-like behaviour in rodent models, these translational approaches are necessary to advance our understanding of mechanisms underlying apathy and guide future therapeutic interventions.