What We do

We take an evolutionary and comparative approach to sensory neuroscience. Our research focuses on behavioral and neural plasticity induced by injury and noxious sensations. We work primarily with cephalopod molluscs, whose complex brains and behaviors provide novel insights into the evolution and function of nociception and pain.


The Crook lab has a dual mission. First, we conduct excellent, ethical research into the sensory physiology of pain. Second, we provide exceptional research training for future leaders in the health science industry.


Our mission


Our work includes studies of neural plasticity, nociception and the higher cognitive experience of pain. Our research examines conserved mechanisms of neural plasticity involved in learning, memory, pain and affective states, contrasting cellular and behavioural changes after injury that vary among invertebrate and vertebrate animals.  

Generally we seek to understand how and why mechanisms of neural plasticity might be conserved across taxonomically diverse species with vastly different brains and behaviours, and how different selective pressures drive the evolution of these mechanisms in distantly related species.


Our research

In our current research we use neurophysiological and behavioural techniques to examine nociception (detecting noxious or unpleasant stimuli) nociceptive sensitization, and pain in invertebrates.

Sensitization resulting from tissue injury or from noxious stimuli can be expressed both as changes to the neurons that detect these stimuli, and as a change to the animal’s behaviour. By studying both nociceptors and the behaviours they influence, we aim to understand how sensitisation might function to provide a fitness benefit for affected animals.


 Nociception or Pain?

Invertebrate animals are used widely in scientific research, but unlike vertebrate animals, their use is generally loosely regulated. This is based partly on the historical and still prevalent view that invertebrate animals lack sufficient neural complexity to experience pain, distress or other negative affective states when subjected to the same experimental manipulations that might cause pain in mammals or other vertebrates.

However, we still know very little about how invertebrates respond to noxious sensations. Many scientists think invertebrates are capable only of nociception (reflexive avoidance that involves no cognitive awareness), whereas others think they might experience pain (a negative emotional state associated with noxious sensations).

Distinguishing nociception and pain experimentally requires a good understanding of sensory physiology and neurobiology, which is still largely missing for cephalopods.

As concern for the welfare of invertebrates increases, there is a critical need for careful study of the way invertebrates process and respond to potentially noxious and injurious stimuli.

Parts of our work aim to clarify how cephalopods respond to different types of sensory stimuli, so that we and others can assess objectively whether cephalopods experience the emotional, subjective aspect that defines pain, or whether their responses are the result of reflexes that do not encompass emotional states.


Cephalopod anesthesia: Science Magazine, Discover Magazine

Pain in invertebrates: New ScientistWashington PostLATimes

Nociception in cephalopods: BrainFactsJEBNeuroDojo

Squid iridescence:  LiveScienceHouston ChronicleHuffington Post

There are signs of change, too: Cephalopods at least now get some protection, in some parts of the world. “We are broadening our understanding of both pain and nociception,” Crook says.
“How can this not be interesting, even to the skeptics?”
— Tamar Stelling, New Scientist Magazine