Lecture 12 Flashcards
olfaction
- primary: pyrifom cortex & amygdala
- secondary: orbitofrontal cortex &thalamus
- 500 types of olfactory receptors
guestation
- taste receptors are not limited to the tong
- two gustation pathways to the brain
- thalamus > S1 and primary gustation cortex
- hypothalamus & amygdala
brain regions involved in motivated behaviour
- hypothalamus + pituitary gland
- limbic system
- frontal lobes
hypothalamic - pituitary gland system operates under limbic system/frontal lobes
regulatory behaviour
- necessary for survival (eating drinking)
- regulated by internal stimuli > homeostatic mechanisms
- controlled by hypothalamus - acts on endocrine and autonomic NS
non-regulatory behaviour
- not necessary for survival
- sinfluened by external stimuli - controlled by sensory systems
- controlled by prefrontal cortex, limbic system and sometimes hypothalamus
hypothalamus regions
- lateral
- medial
- periventricular region
- all containing multiple nuclei
posterior pituitary (neural tissue)
- gets hormones from thalamus, through axons of neurons
- releases hormones into bloodstream through capillaries
anterior pituitary (glandular tissue)
- gets releasing hormones from hypothalamus from capillaries
- then synthesises its own hormones and releases them to the bloodstream
hypothalamic hormone related activity is controlled by:
- feedback loops
- neural regulation
- experience based responses
Eating - control of regulatory behaviour
the summed activity of various hypothalamic neurons constitutes a complex homeostat that controls eating
- lateral hypothal
- ventromedial hypothal
eating - lateral hypothal
stimulation - feeling of hunger (on switch)
- lesions > aphagia (failure to eat)
eating - ventromedial hypothalamus
stimulation - feeling of saturation (off switch)
- lesions - hyperphagia (overeating)
digestive system (enetric nervous system
- pancreas: secretes insulin
- liver: stores glycogen
2 types of sex hormones
- organising effects
- activating effects
organising effects
influence development of foetal brain (prenatal)
- e.g., influence of androgens on development of gender characteristics and masculinisation of the brain
activating effects
influence activities in the adult brain (postnatal)
- females - estrogen
- males - testosterone
effect of sex hormones on hypothalamus
- ventromedial area: copulation behaviour in female rates
- preoptic area: copulation behaviour in male rats
- not sexual motivation
effects of sex hormones on the amygdala
sexual motivation in males probably also in fmeales
effects of sex hormoens on the cortex
- role is not entirely clear - imagery: ventral visual system, planning: frontal lobe
- frontal lesions can lead to disinhibition of sexual behaviour, but also loss of libido.
constructive theory (James-Lange
- the brain interprets autonomic reactions and concocts a story to explain bodily reactions
- see wolf > run > are afraid
- evidence from spinal cord patients (less pain, less emotional intensity)
cannon-bard
i see, i fear, i run (proved to be false because of the speed of the processes)
appraisal theory
emotions involved highly coordinated effects in behaviour, body and brain
these effects are considered either consequences of a central emotional state or part of the emotional experience itself
three main components of emotion
- subjective feeling
- physiological response
- cognition
brain region(s) for subjective feelings
amygdala + prefrontal cortex
brain region(s) for physiological response
hypothalamus
brain region(s) for cognition
cerebral cortex
limbic circuit consists of
- cingulate gyrus (evaluation of reward and punishment)
- hippocampus (memory, spinal navigation)
- amygdala (central role in emotions)
- mammillary nucleus of hypothalamus (memory)
- allocortex
organisation of the limbic circuit
- hippocamp and amygdala and prefrontal C all connected with the hypothal
- mammillary nucleus of the hypothal connects to the anterior thal connected to the cingulate cortex
- cingulate C connects to the hippocamp formation
what does the amygdala do
- recieves input
- evaluates info from emotional and motivational meaning
- projects to hypothal and brainstem
- essential in tuning emotional behaviour and innate behaviours
electrical stimulation of the amygdala
- autonomic responses
- feelings of fear
removal of both amygdalae (in animals)
tameness and loss of fear
indiscriminate eating behaviour
prefrontal cortex
‘rational brake’ on emotional behaviour.
- gets input from all sensory areas and has connections to amyg and hypothal
damage to the prefrontal C
- loss of emotions: flat affect
- inability to recognise emotions in others
- apathy and loss of initiative and motivation
- inability to concentrate, plan and organise
- easily distracted by sensory stimulation
- radical changes in personality
reward system - wanting
- mesolimbic dopamine system
reward system - liking
- likely mediated by small localised set of nuclei controlled by opioid and endocannabinoid systems
