Forebrain and Limbic System Flashcards
What is the major function of the thalamus?
Major relay station for sensory pathways
What thalamic structure defines the subdivisions of the nuclei? (splits medial and lateral subdivisions)
IML (internal medullary lamina)
Which nucleus is even more lateral to the lateral subdivision?
Reticular nucleus
What is the general theme of most thalamic nuclei?
Sensory input and regulatory input -> interneurons inhibit signal if needed -> projection neurons provide output
Which thalamic nuclei does not follow the typical pattern?
Reticular nucleus
What are the three patterns of thalamic nuclei?
- Relay nuclei
- Association nuclei
- Intralaminar & midline nuclei
Describe the function of a relay nucleus.
Receives specific input from subcortical structure (e.g. medial lemniscus) -> projects to cortex
Describe the function of an association nucleus.
Receives specific input from association cortex (e,g, prefrontal) -> projects back to cortex
Describe the function of an intralaminar or midline nucleus.
Receive specific inputs (basal ganglia, limbic) -> projects to cortex, basal ganglia, and limbic structures
Which thalamic nuclei has no projections to the cortex?
Reticular nucleus
Where does the reticular nucleus receive its input? Output?
In: cortex and thalamus
Out: inhibitory axons to thalamus
What are the relay nuclei for the sensory system?
VPL and VPM (ventral posterolateral and posteromedial nuclei)
What are the relay nuclei for the motor system?
VA and VL (ventral anterior and lateral nuclei)
What are the relay nuclei for the limbic system?
Anterior and lateral dorsal nuclei
What are the two major association nuclei?
DM (dorsomedial nucleus) and Pulvinar nucleus
What is the major function of the DM?
Association for prefrontal: foresight
What structure does nearly all fibers traveling from the thalamus to the cortex and vice versa go through?
Internal Capsule
What are the five parts of the internal capsule?
- Anterior limb
- Genu
- Posterior limb
- Retrolenticular
- Sublenticular
What fibers go through the anterior limb?
Anterior nucleus and DM -> frontal lobe and prefrontal cortex
What fibers go through posterior limb?
- VA/VL -> motor areas
- Motor areas -> brainstem/spinal cord
- VPL/VPN -> somatosensory cortex
The sublenticular part of the internal capsule handles the _______ visual field and the retrolenticular part handles the ______ visual field.
Superior; Inferior
What part of the brain is critical in maintaining physiological homeostasis?
Hypothalamus
What are the three main types of hypothalamic connections?
- Limbic system
- Output to pituitary
- Interconnects visceral and somatic nuclei
Which part of the hypothalamus is a continuation of the reticular formation?
Lateral
Which part of the hypothalamus is a continuation of the periaquaductal gray?
Periventricular
Which part of the hypothalamus contains only nuclei?
Medial
Which neuroendocrine cells end in the posterior lobe?
Magnocellular
Which neuroendocrine cells end in the median eminence?
Parvocellular
Which two nuclei control the posterior pituitary and what do they release?
Paraventricular and Supraoptic; Antidiuretic hormone and oxytocin
Which part of the hypothalamus stimulates parasympathetics? (slow HR, constrict pupils, etc.)
Anterior hypothalamus
Which hypothalamic nucleus stimulates feeding?
Lateral nucleus
Which hypothalamic nucleus stimulates the refusal of food?
Ventromedial nucleus
What is a major difference between males and females “fight or flight” response?
Males: more aggresive (lateral prefrontal cortex)
Females: more social (cingulate gyrus)
Where do input fibers to the hypothalamus conveying visceral and sensory info come from?
Brainstem and spinal cord
Where do input fibers conveying info about emotions come from?
Limbic system
What are the major structures of the limbic system?
- Cingulate gyrus
- Parahippocampal gyrus
- Amygdala
- Hippocampus
The ______ deals with emotional responses, while the ______ deals with learning and memory.
Amygdala; Hippocampus
What is the major afferent pathway into the hippocampus?
Cortex -> Entorhinal cortex -> dentate gyrus -> CA3 -> fimbria and CA1 -> subiculum -> entorhinal cortex -> sensory cortex
Describe the Papez circuit.
Cingulate gyrus -> Entrohinal cortex -> hippocampus -> fornix -> mammilothalamic tract -> anterior nucleus of thalamus -> cingulate cortex
Which part of the hippocampus deals with memory of novel material such as language?
Left anterior
Which part of the hippocampus deals with spatial tasks like driving a car?
Right hippocampus
What is the primary function of the amygdala?
FEAR
Where do afferents into the amygdala come from?
- Sensory association
2. Visual areas
Where do efferents from the amygdala go?
Septal area and hypothalamus -> medial forebrain and central tegmental tract
Which part of the brain may be more active than amygdala with anxiety?
Red nucleus
T/F: Kluver-Bucy syndrome is associated with amygdala damage.
TRUE
Release of dopamine in what area provides a “high” feeling of well being?
Nucleus accumbens (ventral striatum)
