Complex transcallosal interactions in visual cortex

Abstract

Reversible inactivation by cooling of the transcallosal projecting neurons in areas 17 and 18 of one hemisphere bring about complex changes in the spontaneous and evoked activity of neurons in the callosal receiving zone of the opposite hemisphere. These changes include increase and decreases in evoked and spotaneous activities. Overall, 90% of neurons in alyers II and III, 50% in layer IV, and 100% in layers V and VI were affected by the block of transcallosal input. The complexity of the changes was greatest in layers II and III, which are the major callosal recipient layers. The results indicate that many excitatory and inhibitory circuits are under the direct control of transcallosal fibers in the normally fuctioning brain.

Selective interhemispheric circuits account for a cardinal bias in spontaneous activity within early visual areas

“…Although transient removal of VIC input can lead to stimulus-dependent de-and increase of spiking (Payne et al, 1991;Schmidt et al, 2010;Wunderle et al, 2013) evoked VSD maps maintained their layout. In agreement, stimulusderived maps in ferrets deteriorated only in vigor but not in layout when deactivating VICs (Schmidt et al, 2010).…”

Influence of Core Auditory Cortical Areas on Acoustically Evoked Activity in Contralateral Primary Auditory Cortex

“…Visual cortex investigations have implicated transcallosal projections in midline fusion (Choudhury et al, 1965;Hubel and Wiesel, 1967;Payne, 1990), midline receptive field extension (Antonini et al, 1979(Antonini et al, , 1983Marzi et al, 1982), binocular activation (Lepore and Guillemot, 1982;Blakemore et al, 1983;Payne et al, 1984), and depth perception (Gardner and Cynader, 1987). While a conspicuous lack of comparable investigations in the auditory system impedes ample scrutiny of functional differences between these two modalities, a study conducted by Payne et al 1991 is distinctly germane to the discussion of the present results. In the study by Payne et al 1991 reversibly deactivation of transcallosally projecting neurons from areas 17 and 18 altered response properties of receiving neurons in the opposite hemisphere.…”

“…Founded upon models of common information processing across sensory systems (Olshausen and Field, 2004), reports of neuronal response strength decreases in primary cortical fields [visual (Payne et al, 1991); somatosensory (Clarey et al, 1996)] during deactivation of contralateral homologous regions, and known interhemispheric connections in the auditory system (Lee and Winer, 2008a), we hypothesized decreases in response strength of contralateral auditory cortex neurons during sup-pression of callosal afferent activity. The hypothesis was tested by examining the impact of individual and combined A1 and AAF reversible deactivation on contralateral A1 neuronal response activity in the cat.…”

The cryoloop: an adaptable reversible cooling deactivation method for behavioral or electrophysiological assessment of neural function

“…Objective measures of cooling induced deactivation are obtained using Brainwave Systems' 'Discovery' software to collect multiple channels of extracellular spike activity (e.g. Lomber et al, 1994Lomber et al, , 1996aMendola and Payne, 1993;Payne et al, 1991Payne et al, , 1996b, and calculation of a cooling block: normal ratio (B:N ratio, Malpeli, 1983). When B:N = 0, neurons are silenced during cooling; when B:NB 1, activity is diminished; and when B:N= 1, there is no change in activity during cooling.…”

“…With these recent advances, broader animal use, and implementation of the technique in a growing number of laboratories it seemed appropriate to provide a thorough description of assembly, implantation procedures, maintenance and use of the cryoloop. The cryoloop method can be applied to assess cortical operations using, with equal success, behavioral or electrophysiological assays of neural operations (Horel, 1984(Horel, , 1992(Horel, , 1996Horel et al 1984Horel et al , 1987Payne et al, 1991Payne et al, , 1996aLomber et al, 1994Lomber et al, , 1996aLomber and Payne, 1996;Girard et al 1997;Hupé et al, 1998).…”