Neuro 6 - Thalamus and Hypothalamus Flashcards
Where is the thalamus found within the brain?
Right in the middle of the brain just under the posterior half of the corpus callosum
What separates the two halves of the thalamus?
3rd ventricle
Describe the connections of the thalamus with the forebrain.
Each half has ipsilateral connections with the forebrain
What is the main function of the thalamus?
Relay centre between cerebral cortex and rest of CNS
What is the only function not represented within the thalamus?
Olfaction
What is the classification of thalamic nuclei based on and what are the 4 different classes?
The classification is based on the connections of the thalamic nuclei with the cortex
SPECIFIC – connected to primary cortical areas
ASSOCIATION – connected to association cortex
INTRALAMINAR – connected to ALL cortical areas
RETICULAR – not connected to the cortex
Which nuclei connect within the motor cortex?
Ventral lateral
Ventral anterior
Which nuclei relay sensory information from different parts of the body?
Head - Ventral Posteromedial
Below the neck - Ventral Posterolateral
Which nucleus connect with the primary visual cortex?
Lateral geniculate nucleus
Which nucleus is connected with the primary auditory cortex?
Medial geniculate nucles
The association cortex can be divided into three areas based on thalamic function. What are these 3 areas?
Prefrontal cortex
Pareito-temporal-occipital cortex
Cingulate cortex
What do the anterior, lateral dorsal and dorsomedial nuclei connect with?
Prefrontal and cingulate cortex
What do the lateral posterior and pulvinar nucleus connect with?
Prefrontal and parieto-tempero-occipital cortex
What important system are the intralaminar and reticular nuclei a part of?
Reticular activating system - involved in maintaining conciousness
Describe how the reticular nuclei affect cortical activity?
don’t have direct connections with the cortex
but they have widespread intrathalamic connections so can influence the flow of information from other nuclei to the cortex
What is the core of grey matter that runs through the brainstem and is involved in the reticular activating system?
Reticular formation
How do he intralaminar nuclei modulate the activity of the cortex?
The reticular formation projects up to the thalamus to the intralaminar nuclei
have diffuse cortical projections so can modulate cortical activity
What is thalamic syndrome?
syndrome that develops after thalamic stroke
symptoms depend on which part affected
What 3 main changes occur in thalamic syndrome?
1) change in sensation
2) pain - central - non localised
3) emotional disturbance
Describe the location and structure of the hypothalamus.
just below the thalamus and divided by the 3rd ventricle
How is the hypothalamus involved in maintaining homeostasis?
- autonomic nervous system
- endocrine
- behaviour
State some forebrain structures that the hypothalamus has very close connections with?
Olfactory system
Limbic system
List some structures of the limbic system
hippocampus
amygdala
cingulate cortex
septal nuclei
What does the behavioural control exerted by the hypothalamus include?
eating and drinking emotion sexual behaviour circadian rhythm memory
Which nucleus is involved in the circadian rhythm?
Suprachiasmatic nucleus
How is behaviour directed towards our homeostatic goals?
Pleasure centre within the limbic system
when you’ve achieved homeostasis, pleasure centre activity increases
What are the presenting symptoms of hypothalamic tumour?
Polydipsia
Polyuria
Absent menses
What are some later symptoms of hypothalamic tumour?
Rage Inappropriate sexual behaviour memory lapses temperature fluctuation thyroid hyperphagia
