Brain Modularity

Brain Modularity
Using the your school Online Library; find two peer-reviewed journal articles on brain modularity, with a focus on visual sensation and perception. In your synopsis, you will include:

• A summary of each of the journal articles
• The main points discussed in each of the journal articles and how they relate to the week’s course and text readings
• Your thoughts and perspectives regarding the concepts covered in each of the journal articles

Submission Details:

• Name your document: SU_PSY3400_W2_Project_LastName_FirstInitial
• Submit your report in a Microsoft Word document to the Submissions Area by the due date assigned.
• Using APA format, cite sources appropriately throughout your assignment, and reference on a separate page.
  Brain Topography, Volume 18, Number 2, Winter 2005 (©2005) 67 DOI: 10.1007/s10548-005-0276-8
  Borowsky et al.68
  Modularity and Intersection 69
  Borowsky et al.70
  Modularity and Intersection 71
  Borowsky et al.72
  Modularity and Intersection 73
  Borowsky et al.74
  Modularity and Intersection 75
  Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

  218
  Perceiving visually presented objects: recognition, awareness, and modularity Anne M Treisman* and Nancy G Kanwisherf
  Object perception may involve seeing, recognition,
  preparation of actions, and emotional responses-functions
  that human brain imaging and neuropsychology suggest are
  localized separately. Perhaps because of this specialization,
  object perception is remarkably rapid and efficient.
  Representations of componential structure and interpolation
  from view-dependent images both play a part in object
  recognition. Unattended objects may be implicitly registered,
  but recent experiments suggest that attention is required to
  bind features, to represent three-dimensional structure, and to
  mediate awareness.
  Addresses *Department of Psychology, Princeton University, Princeton, New Jersey 08544-1010, USA; e-mail: treisman@phoenix.princeton.edu tDepartment of Brain and Cognitive Sciences, El O-243, Massachusetts Institute of Technology, Cambridge, Massachusetts 02138, USA; e-mail: ngk@psyche.mit.edu
  Current Opinion in Neurobiology 1998, 8:218-226
  http://biomednet.com/elecref/0959438800800218
  0 Current Biology Ltd ISSN 0959-4388
  Abbreviations
  ERP event-related potential fMRl functional magnetic resonance imaging IT inferotemporal cortex
  Introduction It is usually assumed that perception is mediated by specific patterns of neural activity that encode a selective
  description of what is seen, distinguishing it from other
  similar sights. When we perceive an object, we may form
  multiple representations, each specialized for a different
  purpose and therefore selecting different properties to
  encode at different levels of detail. There is empirical
  evidence supporting the existence of six different types
  of object representation. First, representation as an ‘object
  token’-a conscious viewpoint-dependent representation
  of the object as currently seen. Second, as a ‘structural de-
  scription’- a non-visually-conscious object-centered rep-
  resentation from which the object’s appearance from other
  angles and distances can be predicted. Third, as an
  ‘object type’-a recognition of the object’s identity (e.g. a
  banana) or membership in one or more stored categories.
  Fourth, a representation based on further knowledge
  associated with the category (such as the fact that the
  banana can be peeled and what it will taste like). Fifth, a
  representation that includes a specification of its emotional
  and motivational significance to the observer. Sixth, an
  ‘action-centered description’, specifying its “affordances”
  [l], that is, the properties we need in order to program
  appropriate motor responses to it, such as its location,
  size and shape relative to our hands. These different
  representations are probably formed in an interactive
  fashion, with prior knowledge facilitating the extraction of
  likely features and structure, and vice versa.
  Evidence suggests that the first four types of encoding
  depend primarily on the ventral (occipitotemporal) path-
  way, the fifth on connections to the amygdala, and the
  sixth on the dorsal (occipitoparietal) pathway; however,
  object tokens have also been equated with action-centered
  descriptions [PI. Dorsal representations appear to be
  distinct from those that mediate conscious perception;
  for example, grasping is unaffected by the Titchener
  size illusion [3]. Emotional responses can also be evoked
  without conscious recognition (e.g. see [4**]). Object
  recognition models differ over whether the type or identity
  of objects is accessed from the view-dependent token or
  from a structural description; in some cases, it may also be
  accessed directly from simpler features.
  The goal of perception is to account for systematic
  patterning of the retinal image, attributing features to their
  real world sources in objects and in the current viewing
  conditions. In order to achieve these representations,
  multiple sources of information are used, such as color,
  luminance, texture, relative size, dynamic cues from mo-
  tion and transformations, and stereo depth; however, the
  most important is typically shape. Many challenges arise in
  solving the inverse problem of retrieving the likely source
  of the retinal image: information about object boundaries
  is often incomplete and noisy; and three-dimensional
  objects are seen from multiple views, producing different
  two-dimensional projections on the retina, and objects in
  normal scenes are often partially occluded. The visual
  system has developed many heuristics for solving these
  problems. Continuity is assumed rather than random varia-
  tion. Regularities in the image are attributed to regularities
  in the real world rather than to accidental coincidences.
  Different types of objects and different levels of specificity
  require diverse discriminations, making it likely that
  specialized modules have evolved, or developed through
  learning, to cope with the particular demands of tasks
  such as face recognition, reading, finding our way through
  places, manipulating tools, and identifying animals, plants,
  minerals and artifacts.
  Research on object perception over the past year has made
  progress on a number of issues. Here, we will discuss
  recent advances in our understanding of the speed of
  object recognition, object types and tokens, and attention
  and awareness in object recognition. In addition, we will

  Perceiving visually presented objects Treisman and Kanwisher 219
  review evidence for cortical specializations for particular
  components of visual recognition.
  The speed of object recognition Evolutionary pressures have given high priority to speed
  of visual recognition, and there is both psychological and
  neuroscientific evidence that objects are discriminated
  within one or two hundred milliseconds. Behavioral
  studies have demonstrated that we can recognize up to
  eight or more objects per second, provided they are
  presented sequentially at fixation, making eye movements
  unnecessary [S]. Although rate measurements cannot tell
  us the absolute amount of time necessary for an individual
  object to be recognized, physiological recordings reveal
  the latency at which the two stimulus classes begin to
  be distinguished. Thorpe et al. [6”] have demonstrated significant differences in event-related brain potential
  (ERP) waveforms for viewing scenes containing animals
  versus scenes not containing animals at 150 ms after stim-
  ulus onset. Several other groups [7,8*,9-111 have found
  face-specific ERPs and magnetoencephalography (MEG)
  waveforms with latencies of 155-190 ms. DiGirolamo and
  Kanwisher (G DiGirolamo, NG Kanwisher, abstract in
  Psychonom Sot 1995, 305) found ERP differences for line drawings of familiar versus unfamiliar three-dimensional
  objects at 170 ms (see also [S]).
  Parallel results were found in the stimulus selectivity
  of early responses of cells in inferotemporal (IT) cortex
  in macaques, initiated at latencies of 80-looms. On
  the basis that IT cells are selective for particular faces
  even in the first 50ms of their response, Wallis and
  Rolls [12] conclude that “visual recognition can occur
  with largely feed-forward processing”. The duration of
  responses by these face-selective cells was reduced from
  250ms to 25 ms by a backward mask appearing 20ms
  after the onset of the face, a stimulus onset asynchrony
  at which human observers can still just recognize the
  face. The data suggest that “a cortical area can perform
  the computation necessary for the recognition of a visual
  stimulus in ZO-30ms”. Thus, a consensus is developing
  that the critical processes involved in object recognition
  are remarkably fast, occurring within lOO-200ms of
  stimulus presentation. However, it may take another
  1OOms for subsequent processes to bring this information
  into awareness.
  Object tokens How then does the visual system solve the problems of
  object perception with such impressive speed and accu-
  racy? A first stage must be a preliminary segregation of the
  sensory data that form separate candidate objects. Even
  at this early level, familiarity can override bottom-up cues
  such as common region and connectedness, supporting
  an interactive cascade process in which “partial results of
  the segmentation process are sent to higher level object
  representations”, which, in turn, guide the segmentation
  process [ 13.1.
  Kahneman, Treisman, and Gibbs [14] have proposed
  that conscious seeing is mediated by episodic ‘object
  files’ within which the object tokens defined earlier
  are constructed. Information about particular instances
  currently being viewed is selected from the sensory
  array, accumulates over time, and is ‘bound’ together in
  structured relations. Evidence for this claim came partly
  from the observation of ‘object-specific’ priming- that
  is, priming that occurs only, or more strongly, when the
  prime and probe are seen as a single object. This occurs
  even when they appear in different locations, if the
  object is seen in real or apparent motion between the
  two. Object-specific priming occurs between pictures and
  names when these are perceptually linked through the
  frames in which they appear (RD Gordon, DE Irwin,
  personal communication), suggesting that object files
  accumulate information not only about sensory features
  but also about more abstract identities. However, priming
  between synonyms or semantic associates is not object
  specific [15], that is, it occurs equally whether they
  are presented in the same perceptual object or in
  different objects. It appears that object files integrate
  object representations with their names, but maintain
  a distinct identity from other semantically associated
  objects. Priming at this level would be between object
  types rather than tokens. Irwin [ 161 has reviewed evidence on transsaccadic integration, suggesting that it is limited to
  about four object files.
  A similar distinction between tokens and types has
  emerged from the study of repetition blindness, a failure
  to see a second token of the same type, which was
  attributed to refractoriness in attaching a new token to
  a recently instantiated type [17]. Recent research has
  further explored this idea. One role of object tokens is
  to maintain spatiotemporal continuity of objects across
  motion and change. Chun and Cavanagh [18”] confirmed
  that repetition blindness is greater when repeated items
  are seen to occur within the same apparent motion
  sequence and hence are integrated as the same perceived
  object. They suggest that perception is biased to minimize
  the number of different tokens formed to account for the
  sensory data. Objects that appear successively are linked
  whenever the spatial and temporal separations make
  this physically plausible. This generally gives veridical
  perception because in the real world, objects seldom
  appear from nowhere or suddenly vanish. Arnell and
  Jolicoeur [ 191 have demonstrated repetition blindness for novel objects for which no pre-existing representations
  existed. According to Kanwisher’s account [ 171, this implies that a single presentation is sufficient to establish
  an object type to which new tokens will be matched.
  The ‘attentional blink’ [ZO] describes a failure to de-
  tect the second of two different targets when it is
  presented soon after the first. Chun (21’1 sees both
  repetition blindness and the attentional blink as failures
  of tokenization, although for different reasons, because

  220 Cognitive neuroscience
  they can be dissociated experimentally. Attentional blinks
  (reduced by target-distractor discriminability) reflect a
  Di I,ollo, JT Enns, personal communication). The account proposed
  is that awareness depends on a match between re-entrant
  information and the current sensory input at early
  visual levels. A mismatch erases the initial tentative
  representation. “It is as though the visual system treats the
  trailing configuration as a transformation or replacement
  of the earlier one.” Conversely, repetition blindness for
  locations (R Epstein, NG Kanwisher, abstract in Psychononz
  Sot 1996, 593) may result when the representation of an
  earlier-presented letter prevents the stable encoding of
  a subsequently presented letter appearing at the same
  location.
  Attention and awareness in object perception Attention seems, then, to be necessary for object tokens
  to mediate awareness. However, there is evidence (see
  [Z-l’]) that objects can be identified without attention
  and awareness. If this is so, do the representations differ
  from those formed with attention? Activation (shown
  by brain-imaging) in specialized regions of cortex for
  processing faces [26] and visual motion [27] is reduced
  when subjects direct attention away from the faces or
  moving objects (respectively), even when eye movements
  are controlled to guarantee identical retinal stimulation
  (see also [28]), consistent with the effects of attention
  on single units in macaque visual cortex. Unattended
  objects are seldom reportable. However, priming studies
  suggest that their shapes can be implicitly registered
  [?.9,30**], although there are clear limits to the number of
  unattended objects that will prime [31]. Representations
  formed without attention may differ from those that
  receive attention: they appear to be viewpoint-dependent
  [32’], two-dimensional, with no interpretation of occlusion
  or amodal completion [30”]. On the other hand, in
  clinical neglect, the ‘invisible’ representations formed in
  a patient’s neglected field include illusory contours and
  filled-in surfaces [33-l, suggesting that neglect arises at
  stages of processing beyond those that are suppressed in
  normal selective attention. With more extreme inattention,
  little explicit information is available beyond simple
  features such as location, color, size, and gross numerosity;
  even these simple features may not be available, produc-
  ing ‘inattentional blindness’ [34’]. Again, however, some
  implicit information is registered: unseen words may prime
  word fragment completion, and there is clear selectivity
  for emotionally important objects such as the person’s own
  name and happy (but not sad) faces.
  Binding of features to objects is often inaccurate unless
  attention is focused on the relevant locations [35].

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