PSYC 309 Final 1

Brain Systems Perception, Attention, Memory

What is contralateral control?

Right hemisphere controls the left side of the body, and vice versa

What is localization of function?

hypothesis that different functions of thought are performed in different locations in the brain

Functions and productions of the brainstem

controls automatic life-support functions; breathing, heart rate, swallowing, sleep cycles.

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produces serotnin, norepinephrine, etc.

Functions of cerebellum

balance and coordination of voluntary movements

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damage to it causes difficulty in coordination

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important role in high-level cognitive tasks like learning and memory

Components and functions of midbrain

Superior and inferior colliculus

Shallow layers: relay centers for sensory information entering the brain

Deep layers: motor activity, including eye movement

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Damage can cause problems in hearing, seeing, and motor control

Function of forebrain

regulates higher mental processes and enables people to engage in complex learning, memory, thought, and language

Components and functions of diencephalon

In forebrain

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Thalamus: “salience”, sensory relay

Hypothalamus: body regulation (temperature, hunger, thirst, secual behaviour), arousal

Components and functions of limbic system

Basal ganglia

Thalamus

Hypothalamus

Amygdala

Hippocampus

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Motivation, emotion, learning, nmemory

Amygdala functions

salience, perception, learning, memory

Hippocampus functions

spatial navigation and perception

Memory: creating new memories, integrations of new memories with existing ones

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We have 2 of them, not well developed until 3-4 why we have so few memories from that time)

Basal Ganglia

action-selection, skill, motivation, reward

plays role in addiction-→ disorder of dopamine

Frontal lobe roles

planning

STM

strategic thinking

judgement

social cognition

movement

Parietal lobe

processing touch info

complex sensory integration

Temporal lobe

hearing

language

LTM

Occipital lobe

Visual processing

Visual pattern recognition

Structural connectivity

how is the brain “wired” together?

Functional connectivity

the extent to which neural activity in two brain regions is correlated

using resting state fMRI data

Default mode network

responds when a person is not involved in specific tasks

implicated in mind wandering & creativity

Inverse Projection Problem

Determining the object responsible for a particular image on the retina

Objects can be hidden or blurred

How do we go from a 2-dimensional picture to the experience od 3 dimensions

View invariance

If primary visual cortex only gets a 2D map from one angle, how do we know what an object looks like from other angles?

Size constancy

How do we know something is the same size at different distances, since when it’s further away it’s smaller on our retina?

Bottom-up processsing

Basic elements come together until the mind reaches a higher level of understanding

Top-down processing

Prior knowledge or context are used to analyze incoming information to inform perception; faster than bottom-up processing

Helmholtz’s Theory of Unconscious inference

Some of our perceptions are the result of unconscious assumptions we make about the environment

Likelihood principle

we perceive the world in the way that is “most likely” based on our past experiences

Gestalt Principles of Perceptual Organization

Similarity

Proximity

Closure

Common Fate

Symmetry

Good Continuation

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Pre-conscious, bottom-up processing

Closure

humans tend to enclose spaces by completing a contour and ignoring gaps in a picture

Common Fate

If two or more objects are moving in the same direction and at the same speed, they will be perceived as part of the same group

Good Continuation

people tend to connect elements in a way that makes the elements seem continuous or flowing in a particular direction

Bayesian inference

our estimate of the probability of an outcome depends on:

**prior** probability of the outcome

how much the available evidence is consistent with the outcome (**likelihood**)

Dorsal stream concerns…

spatial relation between things

Ventral stream concerns…

what things are

Inferotemporal cortex (IT)

front end of ventral stream

front end is most important as it is extremely specialized

view invariant → angle/positioning has no effect, the object will still activate its respective neuron

Distinctive Features Theory

all complex perceptual stimuli are composed of distinctive and separable attributes called features

Recognition by Components Theory

bottom-up, describes pattern recognition in terms of how people recognize 3D objects; identifying the building blocks (geons) that make up the objects

Template Matching Theory

we store an unlimited number of patterns, literal copies corresponding to every object we have experienced; inefficient and fails to account for our ability to recognize new objects

Prototype Theory

Template is not an exact match but is an average/typical instance of many different views of that object → template is called a prototype slides 2:58 for study)

FFA

fusiform face area, plays a key role in facial recognition

Porsopagnosia

inability to recognize faces → facial recognition is so localized, it’s hard for other parts of the brain to adapt and make up for it

Feedforward process

when signal or information gets passed forward from one area (V1) to the next up until IT

bottom-up

Feedback processes

When signal/info gets passed backward from a higher level (further from V1) to the V1

top-down influences on face and object recongition

V1; Primary Visual Cortex

where information from the eyes reach the cortex and the beginning of both dorsal and ventral visual streams

Prefrontal Cortex; PFC

important for taking context into account in top-down influences on face and object recognition

Inferotemporal cortex

important for recognition of whole objects

Fusiform face area

region of the fusiform gyrus in IT which is important part of the face network

EEG

waves reflect total electrical output of columns of cortical neurons; ERP is averaging of multiple trials & zeroes out outliers

EEG pros and cons

Pros: high temporal resolution, inexpensive, non-invasive

Cons: poor spatial resolution, correlational and not causational

fMRI

detects magnetic signal of brain from blood flow and oxygen; needs appropriate comparison condition to isolate areas specific to findings

fMRI pros and cons

pros: high spatial resolution, non-invasive

cons: expensive, poor temporal resolution, correlational, indirect measure of activity

rTMS

temporary disruption or enhancement of brain activity by repeated magnetic pulses

rTMS pros and cons

pros: can manipulate activity, infer causality, non-invasive

cons: poor spatial resolution, can’t measure deeper structures

Speech segmentation

ability to tell when one word ends and another begins

Transitional probabilities

knowing which sound will likely follow another in a word

Oblique effect

we perceive verticals and horizontals more easily than other orientations

Scene schema

semantic context that helps us perceive contents faster

Top-down context provides perceptual processes with expectation of what is coming

Optic Ataxia

A problem with “visually-guided” behavior stemming from impaired representations in the dorsal pathway

* object identification (ventral stream) intact
* location/spatial relation (dorsal stream) impacted

Apperceptive Agnosia

Failure of perception in which some basic visual functions (acuity, color, motion) are preserved, while others, (shape, angle, size) may be disrupted

cannot orient object to match an example when estimating, but can do it when physically putting the object next to its example

Associative Agnosia

inability to recognize objects despite intact perception of basic visual characteristics; still able to spatially perceive objects

* usually caused by damage to ventral stream

Gist perception

abstract meaning of a scene is automatically extracted

based on little information (colour, orientation, crowing/openness, doesn’t necessarily involve object representations or details

Scene Layout Perception

Similar to gist perception but takes slightly longer

after few seconds, we can perceive spatial layout of objects in a scene

repeated layouts are learned implicitly

Statistical Estimation/Ensemble Perception

when there are many objects, the perceptual system can quickly extract ensemble properties (mean size, orientation, velocity, etc.)

Pattern Detection

perceptual system can detect trends or outliers on a graph

Spatial Perception for Visuomotor Control

there many be more accurate perception for motor planning in the lower visual field

Broadbent’s Filter Model

* filters message before incoming information is anaylsd for meaning
* sensory memory holds all incoming information for a fraction of a section and transfers everything to next stage
* Filter identifies attended message and passes on to next stages
* Detector processes information to determine higher-level characteristics

Treisman’s Attenuation Theory; Intermediate-Selection Theory

Attended message can be separated from unattended message early in the information-processing system

Attenuator analyzes incoming message in terms of physical characteristics, language, and meaning

* unattended message still passed on, but at much weaker strength

Dictionary unit contains words, is destination from attenuator

Feature Integration Theory

Object → preattentive stage → focused attention stage → perception

Feature Integration Theory - Preattentive Stage

Ability to hone in on a relevant event to the exclusion of all else so rapidly that you may be unaware of all the stimuli that have been excluded

Load Theory of Attention: Processing Capacity

how much can you handle in a given moment

McKay - Late Selection

* that meaning of words always processed even if unattended

Perceptual load

difficulty of a task

Top-down attention system

deliberate, conscious, towards our goals

Bottom-up atttention system

involuntary, captures attention, despite our goals

Overt attention

eye moves to fuc on the object ofattention

Covert attention

attend to an area of space but the eye does not move; in peripheral vision

Hemineglect

disorder of attention orienting, usually caused by damage to the parietal lobe; patients cannot voluntarily direct attention to one half of the sensory fields

→ still have precuing advantage in neglected field

Attentional Blink

when people are searching for two items, they fail to notice the second after finding the first

→ reduced by emotion

Change Blindness

failure to notice change in environments

→ controlled attention is required to notice changes

Configural focus

attention is guided towards intersections

Inhibition of Return

after attending to a location, attentional systems are slower to respond to stimuli in that location

Balint’s Syndrome

complex disorder, including attention deficits: optic ataxia, simultagnosia, ocular apraxia

Simultagnosia

Inability to perceive visual field as a whole (poor gestalt), feature search is okay but conjunction search is poor

Ocular apraxia

inability to control voluntary gaze shifting

Executive Attention Network

difficult to define and localize

active during attentional control/shifting

development of EAN appears to overlap with other self-regulation functions like inhibition, planning, task switching, work memory

ADHD

deficit in executive attentions

difficulty sustaining attention and avoiding sustained efforts, easily distracted by peripheral stimuli

bulrting out statements, impulsivity, can’t wait

Stages of Memory

1. Encoding
2. Consolidating
3. Retrieval
4. Reconsolidation

Encoding

Initial perception of the event; attention and pattern recognition

Consolidation

Laying down and strengthening over time

Retrieval

Calling information back up later

Reconsolidation

Adaptive update mechanism allowing new information to be integrated into the initial memory representation

Modal Model of Memory

Sensory Memory

brief retention of the effects of sensory stimulation

persistence of vision - retention of the perception of light

STM vs WM

STM holds moment-to-moment thoughts and perceptions in mind

WM allows manipulation of information in STM and is key for encoding into LTM

Maintenance Rehearsal

Rote rehearsal that maintains items in STM

Elaborative Rehearsal

thinking about meaningful relationships among the items you’re encoding

Retroactive Interference

something in the present makes it difficult to remember something that you learned previously

Proactive Interference

Something from the past that makes it difficult to recall something that you learned recently

Four Subsystems of WM

1. Central executive
2. Verbal STM
3. Visuospatial STM
4. Episodic buffer

Phonological Loop

Verbal STM; dedicated to the temporary storage of spoken and written material

contains:

phonological store (inner ear)

articulatory control process (inner voice)

Phonological Store

Passive

Linked to speech perception

holds spoken words in mind for 102 seconds

Called inner eat bc it’s like internally hearing words

Articulatory Control Process

Active

Linked to speech production

Used to rheards and maintain verbal information from phonological store