Week 6.4 Flashcards
Where are implicit and explicit memories stored?
- implicit: more diffusely (cerebellum and striatum)
- explicit: medial temporal lobe
Something will stay in your short-term memory for as long as you ___.
rehearse it
The process of transferring immediate to short-term memory is called what?
working memory
Where does the transfer of information from working memory to long-term memory occur?
in the limbic circuits
Working memory is mediated by what brain region?
the dorsolateral prefrontal cortex
Long-term memory can be relatively unaffected even if ___ of the cortex has been damaged.
25%, they are resistant because they are stored in a network
Which memory system depends on the intactness of the cortex?
working memory
Long term potentiation is mediated by what NT system?
NMDA receptors and glutamate
What is memory consolidation?
the process that strengthens a memory after it’s initial acquisition
The memory circuit is named what?
the Papez circuit
What brain region is involved in short-term memory?
the Papez circuit
What sort of damage is required to disrupt short-term memory?
bilateral damage to the Papez circuits
How can we test working memory?
- digit span
- 5-7 unrelated word or numbers
- repeat a brief story
Orientation to time and place is a test of what kind of memory?
short-term
How can we test short-term memory?
- orientation to time and place
- remember a word list for three minutes
What are some etiologies for isolated amnestic syndromes?
- large frontal lesion
- midline thalamic lesion
- basilar occlusion
- thiamine deficiency
- anoxia
What is “hollywood” amnesia?
a psychogenic memory loss in which short-term memory is preserved but long-term memory is severely compromised
What kind of memory problems are common with normal aging?
- forget specific dates and names
- remember what they forgot
- can accurately track ongoing events
- memory deficit is inconsistent
- remote memories are forgotten more than recent
What sorts of memory are affected in the early and late stages of Alzheimer’s disease?
- early: short-term memory
- late: working and long-term memory
Trauma will most often affect what kind of memory?
short-term memory
What is anterograde amnesia?
the inability to form new memories
What is retrograde amnesia?
the inability to retrieve formerly learned information
Wernicke’s encephalopathy is due to what?
thiamine deficiency
Which brain regions are selectively vulnerable to thiamine deficiency?
- dorsal medial thalamic nuclei
- maxillary bodies
What are the features of Korsakoff’s psychosis?
- anterograde and retrograde amnesia
- confabulation
What is the most common cause of confabulation amongst alcoholics?
Korsakoff’s psychosis
What cell types comprise the taste bud?
- taste receptor cells
- supporting cells
- basal cells
Which categories of taste are mediated by direct ionic channels?
- salty
- sour
Which categories of taste are mediated by second messenger systems?
- sweet
- bitter
- umami
Which cranial nerves supply gustatory afferents?
CN VII, IX, X
Which brainstem nuclei mediates taste?
the solitary nucleus
Describe the pathway of taste afferents into the CNS.
- CN VII, IX, X
- rostral half of solitary nucleus
- thalamus
- inferior lateral somatosensory cortex
What kind of receptors bind olfactants and mediate smell?
g-protein coupled receptors
Olfactory receptor cells project where?
to glomeruli in the olfactory bulb where they synapse onto mitral cells
What is special about olfactory cells?
they are neurons, thus demonstrating one case of adult neurogenesis
The olfactory tract is formed by axons from what cell population?
mitral cells
Describe the direct pathway for olfactory receptor information into the cortex.
- olfactory receptor cell
- mitral cell in the olfactory bulb
- piriform cortex
- orbitofrontal cortex
Name the four major functions of the limbic system.
- Homeostasis
- Olfaction
- Memory
- Emotions and Drives
What brain structure projects to and passes memories into the cortex?
the hippocampus
Olfactory information enters the hippocampus via what route?
directly through the entorhinal cortex rather than passing through the thalamus
Describe the three layers of the dentate gyrus.
- innermost polymorphic
- granule cell layer
- outermost molecular
What is the perforant pathway?
projections from the entorhinal cortex to granule cells in the dentate gyrus
What are mossy fibers?
projections from dentate granule cells to hippocampal pyramidal cells
What are the three layers of the hippocampus?
- polymorphic
- pyramidal
- molecular
Pyramidal cells in the hippocampus receive input from what two sources?
- mossy fibers
- perforant path fibers
Where do hippocampal pyramidal cells project?
out of the hippocampus via the fornix
The amygdala has what three major regions?
- central
- corticomedian
- basolateral
What is the role of the central amygdala?
- autonomic control
The central amygdala receives input form the ___ and projects to the ___.
- viscerosensory relay nuclei
- hypothalamus and brainstem ANS nuclei
What is the role of the corticomedian amygdala?
feeding and sexual activity
The corticomedian amygdala receives input form the ___ and projects to the ___.
- olfactory bulb and piriform cortex
- septum and hypothalamus
What is the role of the basolateral amygdala?
interpret the emotional importance of events
The basolateral amygdala receives input from the ___ and projects to the ___.
- neocortical sensory association cortex
- hypothalamus, nucleus accumbens, orbitofronal cortex
The hypothalamus has descending input onto what two other systems?
- the pituitary
- sympathetic preganglionic neurons
What are the four functions of the hypothalamus?
- homeostasis
- endocrine
- autonomic
- limbic
What are the two systems through which the hypothalamus controls the pituitary?
- neurohypophyseal
- tuberoinfundibular
Describe the neurohypophyseal system.
neurons form the supraoptic and paraventricular nuclei project to the posterior pituitary and release oxytocin and vasopressin
Describe the tuberoinfundibular system.
neurons from the arcuate and periventricular nuclei project to the anterior pituitary and release releasing factors
Name four homeostatic functions of the hypothalamus.
- feeding/eating
- temperature regulation
- circadian rhythm
- thirst/body fluid
What part of the hypothalamus is activated by heat and which is activated by cold?
- anterior nucleus by heat
- posterior nucleus by cold
What hypothalamic nuclei is responsible for the body’s temperature set point?
the pre-optic nucleus
Which hypothalamic nuclei sense satiety and hunger?
- ventromedial: satiety
- lateral: hunger
A lesion of the ventromedial hypothalamic nuclei will result in what?
an overabundance of feeding activity
What are leptins?
hormones released by adipose tissue to reduce appetite
What is ghrelin?
a hormone produced in the gastric mucosa to stimulate apetite
What hypothalamic nucleus controls circadian rhythm?
the suprachiasmatic nucleus
Which hypothalamic nucleus releases vasopressin?
the supraoptic nucleus
Which hypothalamic nucleus regulates the autonomic nervous system?
paraventricular neurons
Name four places the hypothalamus receives input from?
- retina
- fornix
- amygdala
- medial forebrain bundle
