Brain and Behavior Final Exam Study Guide (All Resources)

🎥 Tolman's cross maze/ Morris water maze

used to demonstrate that rats are capable of

allocentric navigation.

🎥 Overtrained animals

tend to navigate along habitual routes, ignoring their cognitive

map

🎥 Bilateral lesion/inactivation of the hippocampus

disrupts a rat's capacity for allocentric navigation.

🎥 Humans with hippocampal damage

have trouble learning to navigate through novel environments.

📕⭐️ Place Cell

a type of neuron that increases its firing rate (above the background rate) when the organism is in a specific spatial location, regardless of how the animal is oriented or in which direction it is moving

📕⭐️ Grid Cell

a type of neuron that increases its firing rate (above the background rate) when the organism is in any one of several spatial locations, which are arranged in a hexagonal "grid" pattern

🎥 Very small number

people that have highly

superior autobiographical memory

🎥 ⭐️Patient H.M had his ____,___,___ removed

amygdala, hippocampus, and parts of the adjacent cortices

📕 Place Learning

the process of learning where in space some object is located and how to navigate to that location regardless of one's starting location

📕⭐️ Morris Water Maze

a behavioral test of spatial memory and navigation, in which a rodent is trained to swim to a submerged platform from diverse starting positions; it tests for the presence of a cognitive map

🎥 the hippocampus is reciprocally connected to the

entorhinal cortex, which is reciprocally connected to the

perirhinal/postrhinal cortex, which has reciprocal

connections with many other neocortical areas.

🎥 area CA3 of the hippocampus is an

autoassociative

network that is capable of forming Hebbian cell

assemblies and thus potential memory traces.

🎥 It is hypothesized that reactivation of a hippocampal

cell assembly can

reinstate, at least in part, the pattern

of neocortical activity that occurred during the original

experience, leading to memory recall.

🎥 Information generally flows from

higher order

neocortical areas through the perirhinal/postrhinal and

entorhinal cortices into the hippocampus and back out.

🎥 The hippocampus includes the:

dentate gyrus, CA3, CA1, subiculum

🎥 Hippocampal CA3 neurons receive input through these 3 major pathways

From entorhinal cortex, from the dentate, from other CA3 neurons

🎥 The projection from the entorhinal cortex to neurons in the dentate gyrus and CA3 is called the?

perforant path,

because it "perforates" the boundary between the

dentate and the entorhinal cortex

🎥 Mossy Fiber Pathway

connects the dentate gyrus to CA3. the neurons of CA3 project to CA1 and, via

recurrent collaterals to other CA3 neurons.

🎥 LTP in the CA3-CA3 pathway is _____

Hebbian

📕 Hebb's rule

the idea that synapses are strengthened only when their (presynaptic) activity coincides with postsynaptic activation (depolarization); as a result, neurons that "fire together" tend to become "wired together"

🎥 Hebbian LTP ___

wires co-activated neurons together, so that even a partial stimulus can later (during recall) reactivate the entire cell assembly

🎥 Memory recall activates

a subset of the cortical regions activated during perception

🎥 According to a widely accepted model:

memory formation involves the formation of hippocampal cell assemblies

🎥 Memory Recall Involves:

"reinstatement" of neocortical activity

🎥 During cued recall:

activation of just a few of the previously active

neocortical neurons activates the hippocampal cell assembly, which then "reinstates," at least to some extent, the pattern of neocortical activity that had been active during the original experience.

🎥 According to the standard model of systems consolidation:

repeated reactivation of hippocampal

memory traces leads to the creation of neocortical cell

assemblies that can be activated without the

hippocampus

🎥 Hippocampus lesions:

impair recent memories much more than distant (old) memories. (resulting in a "retrograde amnesia gradient"

🎥 Repeated reactivation of cortical neurons:

generates cortical cell assemblies, which can then be reactivated without involving the hippocampus

🎥 According to the standard model of memory consolidation, repeated reactivation of the neocortical

neurons is thought to :

strengthen the connections

between them, leading to the formation of a neocortical

cell assembly that can then be activated without

involving the hippocampus.

This is often called "systems consolidation"

🎥 Synaptic Consolidation

stabilization of

changes in synaptic strength

🎥 Systems Consolidation

memory traces in

the neocortex can strengthen gradually after the initial coding; once they are strong, those neocortical memory

traces can support memory independently of the

hippocampus

🎥 Auditory fear conditioning:

rats learn to freeze in

response to a tone previously paired with an aversive stimulus. The underlying neural circuits run through the

basolateral and central nuclei of the amygdala

🎥 contextual fear conditioning

animals learn to fear

environments in which bad things happened to them.

Recalling recent, but not old, contextual fear memories requires an intact hippocampus.

🎥 Inactivating the amygdala interferes with:

auditory fear conditioning

🎥 Auditory fear conditioning likely involves

multiple pathways and sites of plasticity

🎥 Contextual fear conditioning involves

Both the amygdala and the hippocampus

📕 Inhibitory avoidance training

a fear learning paradigm in which a subject (typically a rat) is given an electric shock when it enters a distinctive compartment of the experimental apparatus; learning and memory are tested by measuring how long it takes the animal to enter the threat-associated compartment on a subsequent trial

🎥 The neural substrates of memory change as the:

memory consolidates

🎥 CNQX

blocks AMPA-type glutamate receptors

🎥 "conditioned taste aversion"

remembering what made you sick

🎥 Behavioral arousal activates:

the basolateral complex of

the amygdala, which then enhances memories while

they are formed, while they are consolidated, or both

🎥 Norepinephrine in the basolateral amygdala modulates:

memory consolidation

🎥 Lateral amygdala stimulation:

opens the "gate" for information flowing into the hippocampus

🎥 Electrical stimulation of perirhinal area 36:

leads to activity in the dentate gyrus only if the lateral amygdala is stimulated simultaneously

🎥 Some neurons in the basolateral amygdala respond to both:

saccharin and lithium

🎥 In monkeys, object recognition is imparied by:

lesions of the peri- and entorhinl cortices (NOT by lesions of the hippocampus or amygdala)

🎥 Object recognition memory in rodents also depends on the:

perirhinal cortex, rather than the hippocampus, (however hippocampus lesions in rodents do impair spatial memory)

🎥 Visual Spatial Attention

can be voluntary, such when you are searching for a specific object in a cluttered space, or "grabbed" against your will by salient stimuli.

Although spatial attention is often accompanied by

orienting movements, it can also be covert.

🎥 Salient stimuli

may activate neurons in the superior colliculus, which then direct attention toward the stimulus. With strong stimulation, the shift in attention is accompanied by orienting movements to the stimulus location; with weak stimulation, the shift is covert

🎥 Voluntary spatial attention

involves the frontal

eye fields, makes neurons with receptive fields in the

attended area respond more strongly to their preferred stimuli (but not to other stimuli)

📕 Covert spatial attention

a form of visual spatial attention that can be shifted from one location to another without movement of the eyes (or head)

📕 Saliency map

the idea of a map-like neural representation of external space in which each neuron's firing rate correlates with the salience of the stimuli at the encoded location

🎥 "inhibition of return"

decrements the

salience of winning locations, ensuring that attention

does not get stuck.

📕 superior colliculus

a major midbrain region that receives visual as well as auditory information and projects to the pulvinar and brainstem saccade generators; it is called the optic tectum in nonmammalian vertebrates

🎥 critical players in the neural circuits underlying attention:

superior colliculus and pulvinar nucleus (of the

thalamus), which conveys attention-related signals to

the visual cortices

🎥 PEF

parietal eye field

🎥 FEF

frontal eye field (helps direct voluntary spatial

attention.)

🎥 LGN

lateral geniculate nucleus

🎥 frontal eye field (FEF) activity correlates with:

covert voluntary attention

🎥⭐️ Hemispatial neglect is characterized by:

inattention to the left side of objects or the world

🎥⭐️ Hemispatial neglect is generally caused by:

lesion of inferior parietal and/or superior temporal cortex on the right side of the brain

🎥 Wakefulness and behavioral arousal are associated with:

EEG desynchronization (smaller, more irregular EEG traces)

📕⭐️ Locus coeruleus

a small group of neurons near the fourth ventricle that use norepinephrine as their transmitter and project throughout most of the brain; they are involved in regulating behavioral arousal

🎥 REM Sleep

The EEG is as

desynchronized as it is during the waking state, but

muscle tone is minimal.

🎥 Slow-wave sleep

The rhythmic activation of cortical neurons during this results from intrinsic neuronal rhythms as well as looping interactions between the neocortex,

the dorsal thalamus, and the thalamic reticular nucleus.

🎥 Waking from sleep

involves the activation of basal forebrain cholinergic neurons, which receive input from glutamatergic peribrachial neurons, locus coeruleus, and hypocretin neurons in the hypothalamus.

🎥 Loss of hypocretin neurons causes:

narcolepsy

🎥⭐️ Looping connections can generate:

rhythmic oscillations

🎥 Rhythmic oscillations result if the:

thalamocortical neurons

exhibit post-inhibitory

rebound firing

📕⭐️ Frontostriatal system

a set of interconnected brain regions that includes the frontal lobes and the striatum; it is involved in selection of movements, actions, and goals

🎥 the Frontostriatal system also includes dopaminergic neurons in the:

substantia nigra and ventral tegmental area

🎥 core of the Frontostriatal system:

set of topographically arranged positive feedback loops that each contain two inhibitory neurons. Inhibitory connections within the striatum ensure that these loops inhibit each other, setting up a winner-take-all competition

🎥 An indirect side-loop to the direct pathway through the striatum regulates:

behavior selection

🎥 Activating the striatum disinhibits the:

thalamus, Thus, the frontostriatal system contains a positive feedback loop

🎥 Since all the pathways are topographically organized, the frontostriatal

system actually contains a large number of:

parallel positive feedback loops.

📕 ⭐️Indirect pathway

a pathway through the basal ganglia that starts with neurons in the striatum that project to the external segment of the globus pallidus, which projects to the subthalamic nucleus, which projects to the pallidum(Inhibits movement, STOP pathway)

🎥 The striatum recieves dense:

dopaminergic input

🎥 Striatal neurons with different

dopamine receptors project

to:

different targets

🎥 Dopamine stimulates

D1 neurons

🎥 Dopamine inhibits

D2 neurons

🎥 associated with a loss

of dopaminergic neurons in SNc

Parkinson's disease

🎥 involved in learning

what to do when to reach a goal. More formally, it is

involved in instrumental conditioning.

The striatum

🎥 Phasic increases in striatal dopamine levels signal

unexpected rewards or, after training, predict that a

reward is coming soon

🎥 The ventral striatum

involved in the pursuit of

behavioral goals, including drug seeking

🎥 The dorsal striatum

involved in learning motor

habits

🎥 Drug conditioned place preference involves mainly the:

ventral striatum

🎥 involved in a variety of "executive" functions related to goal pursuit

and decision making

The prefrontal cortex i

🎥 Working memory

The temporary storage of information that was just

experienced or retrieved from long-term memory but is no longer

accessible in the external environment

🗣️What's wrong with H.M?

He had bilateral medial temporal lobe surgery (including most of the hippocampus plus nearby regions like the amygdala and adjacent cortices).

🗣️⭐️Anterograde amnesia

severe inability to form new long-term episodic/declarative memories for new life events.

🗣️⭐️Retrograde amnesia

partial loss for a period before surgery (especially the few years before), while many older childhood memories were more preserved.

🗣️⭐️ What attention does

improves performance and is selective (targets specific locations/features), unlike arousal (global).

🗣️⭐️ Voluntary attention

(top-down): goal-driven focusing and searching

🗣️ ⭐️Involuntary attention

(bottom-up): salient stimuli capture attention automatically

🗣️ Parallel search

pop-out, fast, distractors don't slow much.

🗣️ Serial search

item-by-item, slower, more distractors = more time.

🗣️ ⭐️Overt attention

attention shift with eye/head movement

🗣️ ⭐️Covert attention

attention shift without moving eyes; attention can shift before eye movement.

🗣️ ⭐️ Direct Pathway

generally facilitates the selected action. Striatum inhibits pallidum output neurons, which reduces inhibition on the thalamus (disinhibition). The thalamus then excites cortex more strongly, making the selected action more likely (Facilitates movement, GO pathway)

🗣️ ⭐️How do we learn what to do when?

Dopamine signals unexpected reward and shifts toward predicting reward after learning, Dopamine promotes plasticity at corticostriatal synapses, so rewarded actions become more likely in similar contexts. This is instrumental conditioning: learning actions based on outcomes