Forebrain & Limbic System Flashcards
Parts of Diencephalon
Thalamus
Hypothalamus
Epithalamus
Subthalamus
Parts of limbic system
Hippocampus
Hypothalamus
Amygdala
Gateway to the cortex
Thalamus
Anterior division of thalamic nuclei
Anterior Nucleus (AN)
Medial division of thalamic nuclei
Dorsomedial (DM) aka Medial Dorsal (MD)
Lateral division of thalamic nuclei
Dorsal tier: Lateral Dorsal (LD), Lateral Posterior (LP), Pulvinar
Ventral tier: Ventral Anterior (VA), Ventral Lateral (VL), Ventral Posterior Lateral (VPL) and medial (VPM), Medial and Lateral Geniculates (MGN, LGN)
Intralaminar division of thalamic nuclei
Centromedian
Parafascicular
Other division of thalamic nuclei
Reticular nucleus and midline nuclei
All thalamic nuclei consist of?
What’s the exception?
All consist of: Projection neurons (provide output from thalamus) and interneurons (inhibitory)
Exception: Reticular Nucleus
3 Categories of Thalamic Nuclei
Based on patterns of outputs and specific inputs
- Relay Nuclei
- Association Nuclei
- Intralaminar & Midline Nuclei
Receive well defined specific input from a subcortical source and project to a well-defined area of cortex
Relay Nuclei
Receive specific inputs from association cortex
Association nuclei (ex: prefrontal cortex and project back)
Recieve distinct set of specific inputs (Basal ganglia, limbic structures and project to corex, basal ganglia and limbic structures
Intralaminar and midline nuclei
Important source of regulatory input to thalamus with no projections to cortex
Reticular Nucleus
Input and output of Reticular Nucleus
Input: Cortex and Thalamus
Output: Inhibitory axons to Thalamus
Sensory Relay Nuclei
VPL and VPM
Motor Relay Nuclei
VA and VL
Limbic Relay Nuclei
Anterior and LD
Main Association Nuclei of Thalamus
DM and Pulvinar
Prefrontal association nuclei
DM
*foresight and affect
Parietal-occipital-temporal association nuclei
Pulvinar-LP complex
*Function largely unknow, may be involved in visual perception or attention
What fibers pass through internal capsule (IC)?
Thalamocortical and corticothalamic fibers
Almost all fibers going to and from the cortex
Collects and forms cerebral peduncle down which corticopontine, corticobulbar and corticospinal fibers descend
5 parts of internal capsule
- *Based on relationship to lenticular nucleus**
1. Anterior limb
2. Posterior limb
3. Genu
4: Retrolenticular
5. Sublenticular
Critical in autonomic, endocrine, emotional and somatic functions; maintains physiological range
Hypothalamus
3 main types of connections in hypothalamus
- Interconnected with limbic system
- Output to pituitary
- Interconnects visceral/ somatic nuclei
Autonomics of Hypothalamus
- Anterior Hypothal
- Posterior Hypothal
- Stimulation of anterior produces parasympathetic effects
* slow HR, constrict pupil, peristalsis, salivation - Stimulation of posterior produces sympathetic effects
* increases HR and BP, dilate pupils
Hypothalamic Inputs (2 general areas)
- Parts of the forebrain, especially limbic system
* autonomic/somatic aspects of emotional states - Brainstem and Spinal Cord
* Concey Visceral and sensory info
Limbic System bridges…
autonomic/ voluntary responses to environmental changes
Amygdala is responsible for…
Emotional responses
Hippocampus is resposible for…
learning and memory
3 distinct zones of hippocampus
- Dentate Gyrus
- Hippocampus Proper (Cornu Ammonis)
- Subiculum (transition between hippocampus froper and parahippocampal cortex)
Left anterior hippocampus and dorsolateral prefrontal cortex functions
encode novel material involving language
Right hippocampus and inferior parietal lobe function
engaged in spatial tasks like driving a car
Left anterior hippocampus is more active when…
material is new
*as repetition makes material more familiar, activity shifts posteriorly
3 nuclear groups of amygdala and their pathways/ functions
- medial= olfaction
- Central= hypothalamus, PAG; emotional responses
- Basolateral= cortex, central nuclei; emotional responses
