Canine Biology
Hormones
Responsible for moods, The Pituitary gland produces the hormones controlled by the information passed on from the hypothalamus. The Hypothalamus stimulates behaviours based on what the dog has sensed by linking to the nervous system and produces the ‘releasing hormones’ to tell the Pituitary gland to secrete them.
Limbic system
The dogs Limbic system consists of the cerebral cortex which is responsible for controlling memory, attention, perception, awareness, language and thinking, the hippocampus which is responsible for long and short term memory and the hypothalamus which controls the hormones via the cerebral cortex. These all influence the dogs behaviour, motivation and emotion through learned experiences and expectation of rewards therefore being the decision maker for the dog and whether he is to ignore commands or obey instructions.
The Olfactory bulb
Is a structure located in the forebrain of vertebrates and involved in sense of smell. It receives neural input about odours detected by cells in the nasal cavity and it sends information to the amygdol, the orbitofrontal cortex and the hippocampus where it plays a role in emotion, memory and learning. The functions of the olfactory bulb can be used to discriminate between odours, filtering and enhancing sensitivity of odours but more importantly increasing higher brain activity and arousal connected with odours. This information is also directly sent on to the brain limbic system where they influence emotions and thought and are connected to eating, drinking and sexual behaviour are forming smell memories that last for life.
The dog has around 220 million scent receptors, a huge comparison to a predicted 5 million in humans.
Other sensory receptors
Vibrissae are the small hairs around a dogs eyes, around their mouth and under their jaws that sense shapes and textures of objects as well as detecting air flow helping the dog to become aware of his surroundings and also protect himself.
The brain
The hippocampus is the most important part of the limbic system and mainly responsible for long and short term memory and the connection between the two as well as an association with emotions and learning. It is located in the limbic system and it sends information to the amygdala which indicates fear and is interconnected with other parts of the limbic system such as the entorhinal cortex, the cingulate, temporal, orbital, and olfactory cortices which are all working together to regulate behaviour and emotions based on sensory input and integrating them with past positive and negative learned memories to determine future actions such as remembering not to sniff a bee or that sitting on command means getting a food treat.
Sensory social brain development
Without touch puppies do not develop neural pathways, long term memory can be effected and the stress hormone glucocorticoid is released eventually shrinking the hippocampus as well as causing an exaggerated response to stress. A pup who experienced touch deprivation will end up less less reactive to social engagement and less confident. This puppy can develop behavioural issues into adulthood such as a disconnection with their owner and being insubordinate resulting in the owner being unable to train their dog as they haven’t learnt the neural connections and developed emotional memories to value a reward.