Hippocampus Psychopathology

HM had ____________ regions of the hippocampus left after his surgery.

posterior

HM’s short term memory was __________________! What did this show? Which region is in charge of STM?

intact/preserved

Fundamental distinction between short-term and long-term memory!

PFC, still intact and working!

What are the two types of non-declarative memory? Explain them. Did HM have them? What region of brain is responsible for them?

Procedural memory: Learning a sequence of movements or actions. HM had intact procedural memory. Basal ganglia.

Emotional memory: Change in approach or avoidance of earlier stimuli as a result of experience like prefer food. HM had impaired interoception of thirst, hunger, pain.

When presented with an image that is emotionally charged, the ________________ regions become activated relative to neutral stimuli. What’s the driver?

Amygdala, entorhinal cortex, and hippocampus

The amygdala, it drives the entorhinal cortex to encode for emotionally salient info better than neutral ones.

The coupling of the amygdala and entorhinal cortex is predictive of memory performance only for ______________ stimuli

emotional

Explain the amygdala vs. hippocampus lesion study.

They had patients that either had focal amygdala lesions or focal hippocampus lesions. They then tested conditioning (emotional memory) and declarative memory difference between healthy controls, pt. with amygdala lesion, and pt. with hippocampus lesion. For conditioning it was skin conductance to visual and auditory cues with either conditioned or unpaired stimulus. For declarative memory it was learning word lists or images. The findings are that for people with amygdala lesions, they didn’t learn the emotional learning, no diff in skin conductance for conditioned vs. unpaired stimulus, but they learned the declarative memory same level as controls. For people with hippocampus lesions, they learned the physiological response, but not the declarative memory!

How can memory testimony be biased?

By wording/contextual details, can generate false memories!

What is Alzheimer’s Disease characterized by?

Most common form of amnesia/dementia; its about memory loss and cognitive impairments

For people with Alzheimer’s, the ___________________ is atrophied. The ______________ regions are also atrophied.

hippocampus

default mode network

For visuospatial memory and verbal recall memory tasks, the size of the hippocampus is _____________ correlated with better performance of memory.

positively

What is Korsakoff’s Syndrome characterized by? What is the cause?

Anterograde and retrograde amnesia and confabulation… others too.

Caused by thiamine deficiency from malnutrition or severe alcoholism

For people with Korsakoff’s there is _____________________ atrophy.

general atrophy across the entire brain!

For Korsakoff’s, the brain atrophy is even ____________ compared to alcohol use disorder.

worse

What are the mamillary bodies? How are they impacted by Korsakoff’s? Locate them on brain.

2 little balls at the end of the fornix (kind of part of hypothalamus) and projects to the thalamus - middle area of brain like below hypothalamus ish!

Important for encoding memories, they are severely atrophied in Korsakoff’s!!! They connect the hippocampus and amygdala with the thalamus together.

What are the 3 clusters of PTSD symptoms?

1. Re-experiencing

2. Avoidance

3. Hypervigilance

Explain the fear learning paradigm experiment.

2 steps of trials: conditioning and extinction learning. During conditioning there is a light that is paired with a shock. Then, during extinction, light is presented without a shock. There is also a light that is never paired in the first place. Then, recall phase where they are shown light and see if the brain recalled.

During extinction recall, (how well participants remember the extinction), PTSD people: . What activity is this paired with in the brain?

Didn’t unlearn! They dont extinct the conditioning so their skin conductance is still high to that original light!

Less hippocampal activity, cuz never learned in the first place.

Hippocampal activity is ____________ correlated with extinction success for extinction recall.

positively

Stress leads to _________________ brain volume. Explain Cushing’s Syndrome.

reduced

Cushing Syndrome is excessive cortisol (stress related) which leads to reduced brain volume.

Explain the twin study for PTSD:

One twin pair, where one went to Vietnam and developed PTSD, while the other didn’t. Both had smaller HPC!

The other twin pair, where one went to Vietnam and didn’t develop PTSD, other didn’t too.

Diff is that for the twin pair w/out PTSD, their HPC volume larger!!

Suggests that reduced hippocampal volume is a predisposition risk factor for PTSD!

For MDD, there is _____________ in hippocampal volume.

reductions