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Dr Kristin Hillman Research Interests

Email kristin.hillman@otago.ac.nz 
Tel 64 3 470 3473
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Neural Basis of Effortful Behaviour

 Dr Kristin HillmanCost-benefit decision-making frequently requires an assessment of effort: Am I willing to put in the work required to achieve X?  Our research examines how the brain formulates and eventually executes this decision.

How the brain codes effort-reward information

 To make optimal decisions, your brain must assess whether a certain course of action is going to be ‘worth the effort’.  This requires detecting the amount of effort that is going to be required, and weighing it up against the value of the end reward.  We’ve hypothesized that neurons in a particular region of the prefrontal cortex encode such effort-reward ratios, and signal whether a certain course of action is going to be worth the effort.  By encoding and storing this information, the brain enables us to then make an informed decision as to how we expend effort. 

Individual differences in effort investment

While the brain is capable of encoding effort-reward information and indicating when a course of action is ‘worth it’, individuals are highly variable as to whether they actually execute effortful behaviour.  Some subjects routinely accept high-effort, high-reward challenges, while others routinely avoid them.  Our current research tests whether differences in brain signals – particularly in the prefrontal region that encodes effort-reward information – accounts for individual differences in effortful behaviour.  These projects will help to clarify how the brain drives the decision to engage in and persist in effortful pursuits, and could help to elucidate the cortical components of the proverbial work ethic.

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Publications

Silva, C., Porter, B. S., & Hillman, K. L. (2021). Stimulation in the rat anterior insula and anterior cingulate during an effortful weightlifting task. Frontiers in Neuroscience, 15(202), 643384. doi: 10.3389/fnins.2021.643384

Kaack, I., Chae, J., Shadli, S. M., & Hillman, K. (2020). Exploring approach motivation: Correlating self-report, frontal asymmetry, and performance in the Effort Expenditure for Rewards Task. Cognitive, Affective, & Behavioral Neuroscience. Advance online publication. doi: 10.3758/s13415-020-00829-x

Porter, B. S., Li, K., & Hillman, K. L. (2020). Regional activity in the rat anterior cingulate cortex and insula during persistence and quitting in a physical-effort task. eNeuro, 7(5), ENEURO.0243-20.2020. doi: 10.1523/eneuro.0243-20.2020

Porter, B., & Hillman, K. L. (2019). A novel weight lifting task for investigating effort and persistence in rats. Frontiers in Behavioral Neuroscience, 13, 275. doi: 10.3389/fnbeh.2019.00275

Hillman, K. L., Wall, H. J., Matthews, L. O., Gowing, E. K., & Clarkson, A. N. (2019). Altered hippocampal-prefrontal dynamics following medial prefrontal stroke in mouse. NeuroMolecular Medicine, 21, 401-413. doi: 10.1007/s12017-019-08557-3

Journal - Research Article

Silva, C., Porter, B. S., & Hillman, K. L. (2021). Stimulation in the rat anterior insula and anterior cingulate during an effortful weightlifting task. Frontiers in Neuroscience, 15(202), 643384. doi: 10.3389/fnins.2021.643384

Kaack, I., Chae, J., Shadli, S. M., & Hillman, K. (2020). Exploring approach motivation: Correlating self-report, frontal asymmetry, and performance in the Effort Expenditure for Rewards Task. Cognitive, Affective, & Behavioral Neuroscience. Advance online publication. doi: 10.3758/s13415-020-00829-x

Porter, B. S., Li, K., & Hillman, K. L. (2020). Regional activity in the rat anterior cingulate cortex and insula during persistence and quitting in a physical-effort task. eNeuro, 7(5), ENEURO.0243-20.2020. doi: 10.1523/eneuro.0243-20.2020

Porter, B., & Hillman, K. L. (2019). A novel weight lifting task for investigating effort and persistence in rats. Frontiers in Behavioral Neuroscience, 13, 275. doi: 10.3389/fnbeh.2019.00275

Hillman, K. L., Wall, H. J., Matthews, L. O., Gowing, E. K., & Clarkson, A. N. (2019). Altered hippocampal-prefrontal dynamics following medial prefrontal stroke in mouse. NeuroMolecular Medicine, 21, 401-413. doi: 10.1007/s12017-019-08557-3

Porter, B. S., Hillman, K. L., & Bilkey, D. K. (2019). Anterior cingulate cortex encoding of effortful behavior. Journal of Neurophysiology, 121, 701-714. doi: 10.1152/jn.00654.2018

Laurence, N. C., Labuschagne, L. G., Lura, B. G., & Hillman, K. L. (2015). Regular exercise enhances task-based industriousness in laboratory rats. PLoS ONE, 10(6), e0129831. doi: 10.1371/journal.pone.0129831

Hillman, K. L. (2013). Cost-benefit analysis: The first real rule of fight club? Frontiers in Neuroscience, 7, 248. doi: 10.3389/fnins.2013.00248

Hillman, K. L., & Bilkey, D. K. (2012). Neural encoding of competitive effort in the anterior cingulate cortex. Nature Neuroscience, 15(9), 1290-1298. doi: 10.1038/nn.3187

Hillman, K. L., & Bilkey, D. K. (2010). Neurons in the rat anterior cingulate cortex dynamically encode cost-benefit in a spatial decision-making task. Journal of Neuroscience, 30(22), 7705-7713. doi: 10.1523/JNEUROSCI.1273-10.2010

Hillman, K. L., Lei, S., Doze, V. A., & Porter, J. E. (2009). Alpha-1A adrenergic receptor activation increases inhibitory tone in CA1 hippocampus. Epilepsy Research, 84, 97-109. doi: 10.1016/j.eplepsyres.2008.12.007

Hillman, K. L., Doze, V. A., & Porter, J. E. (2007). α1A-Adrenergic receptors are functionally expressed by a subpopulation of cornu ammonis 1 interneurons in rat hippocampus. Journal of Pharmacology & Experimental Therapeutics, 321, 1062-1068. doi: 10.1124/jpet.106.119297

Jurgens, C. W. D., Hammad, H. M., Lichter, J. A., Boese, S. J., Nelson, B. W., Goldstein, B. L., … Hillman, K. L., … Doze, V. A. (2007). α2A adrenergic receptor activation inhibits epileptiform activity in the rat hippocamal CA3 region. Molecular Pharmacology, 71(6), 1572-1581. doi: 10.1124/mol.106.031773

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Journal - Research Other

Hillman, K. L., & Bilkey, D. K. (2013). Persisting through subjective effort: A key role for the anterior cingulate cortex? Behavioral & Brain Sciences, 36(6), 691-692. doi: 10.1017/S0140525X13001039

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Conference Contribution - Published proceedings: Abstract

Porter, B. S., & Hillman, K. (2019). A novel weight lifting task to investigate persistence in rodents. Proceedings of the Society for Neuroscience Annual Meeting. 241.14/W16. SfN. Retrieved from https://www.sfn.org

Li, K., Porter, B., & Hillman, K. (2019). Local field potential recordings in rat anterior cingulate cortex, anterior insula, and ventral tegmental area during a voluntary effort exertion task. In K. Hillman (Ed.), Proceedings of the 37th International Australasian Winter Conference on Brain Research (AWCBR). (pp. 49). Retrieved from http://www.otago.ac.nz/awcbr

Porter, B. S., Bilkey, D. K., & Hillman, K. L. (2019). Mind over matter: The anterior cingulate cortex's role in driving action towards difficult but worthwhile goals. In K. Hillman (Ed.), Proceedings of the 37th International Australasian Winter Conference on Brain Research (AWCBR). (pp. 26). Retrieved from http://www.otago.ac.nz/awcbr

Hillman, K., & Porter, B. (2019). A novel weight lifting task for investigating effort and persistence in rats. Proceedings of the 39th Australasian Neuroscience Society (ANS) Annual Scientific Meeting. 12624. Retrieved from https://www.ans.org.au

Jaquiery, Z., Wall, H., & Hillman, K. (2017). Regular exercise enhances anterior cingulate-insula coherence in the adult rat brain. Proceedings of the Australasian Neuroscience Society 37th Annual Scientific Meeting. Retrieved from http://ans2017.aomevents.com.au

Hillman, K., & Bilkey, D. (2015). Broadband local field potential characteristics in rat cingulate cortex are predictive of high-effort, goal-directed behaviour. Journal of Neurochemistry, 134(Suppl. 1), (pp. 316-317). doi: 10.1111/jnc.13189

Hillman, K., & Bilkey, D. (2015). Broadband local field potential characteristics in rat cingulate cortex are predictive of high-effort, goal-directed behaviour. Proceedings of the International Behavioral Neuroscience Society (IBNS) 24th Annual Meeting. (pp. 72-73). Retrieved from http://www.ibnsconnect.org/ibns-2015-annual-meeting

Bilkey, D. K., & Hillman, K. L. (2012). Prospective memory during decision-making. Proceedings of the Australian Neuroscience Society (ANS) Annual Scientific Meeting. (pp. 10). Retrieved from http://www.ans.org.au/ans-annual-conference/

Hillman, K., & Bilkey, D. (2011). Competitive effort registers in the rat anterior cingulate cortex as a cost-benefit decision variable. Proceedings of the Society for Neuroscience 41st Annual Meeting. Washington, DC: SfN. Retrieved from http://www.sfn.org/am2011/index.aspx?pagename=abstracts_main

Hillman, K., & Bilkey, D. (2010). Nike says ″Just Do It″: But what does your brain say? New Zealand Medical Journal, 123(1312). Retrieved from http://journal.nzma.org.nz/journal/123-1312/4065/content.pdf

Hillman, K. L., & Bilkey, D. K. (2010). Neurons in the rat anterior cingulate cortex encode integrated effort-reward information in a spatial decision-making task. Proceedings of the 7th Forum of European Neuroscience (FENS). Retrieved from http://fens2010.neurosciences.asso.fr/

Hillman, K. L., & Bilkey, D. K. (2010). Cost-benefit encoding in the anterior cingulate cortex. In B. Leitch (Ed.), Proceedings of the 28th International Australasian Winter Conference on Brain Research. 28, (pp. 58). AWCBR. Retrieved from http://psy.otago.ac.nz/awcbr/Abstracts/Abstracts2010.htm

Bilkey, D. K., & Hillman, K. L. (2009). Neurons in the rat anterior cingulate cortex dynamically encode cost-benefit in both a retro- and prospective manner in a spatial decision-making task. Proceedings of the Society for Neuroscience 39th Annual Meeting. SfN. Retrieved from http://www.abstractsonline.com/plan/AdvancedSearch.aspx

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Conference Contribution - Edited volume of conference proceedings

Hillman, K. (Ed.). (2019). Proceedings of the 37th International Australasian Winter Conference on Brain Research (AWCBR). 45p. Retrieved from http://www.otago.ac.nz/awcbr

Hillman, K. (Ed.). (2018). Proceedings of the 36th International Australasian Winter Conference on Brain Research (AWCBR). AWCBR. 76p. Retrieved from https://www.otago.ac.nz/awcbr

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Conference Contribution - Verbal presentation and other Conference outputs

Hillman, K. L., & Bilkey, D. K. (2013, February). Neural encoding of competitive effort in the anterior cingulate cortex. Verbal presentation at the Australian Neuroscience Society Annual Meeting, Melbourne, Australia.

Hillman, K., & Bilkey, D. (2010, November). Nike says ″Just Do It″: But what does your brain say? Verbal presentation at the Psycolloquy Seminar, Dunedin, New Zealand.

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Awarded Doctoral Degree

Hillman, K. L. (2007). Adrenergic modulation of CA1 neuron activity (PhD). University of North Dakota, Grand Forks, ND. 101p.

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